import { createStore, reconcile } from "solid-js/store";
import { createSignal, createEffect, createRoot } from "solid-js";
import { pb } from "@/lib/pocketbase";
import { toast } from "solid-sonner";
import { TASGRID_COLLECTION, TAGS_COLLECTION, SHARE_RULES_COLLECTION, BUCKETS_COLLECTION, NOTES_COLLECTION, URGENCY_HOURS, SIZE_HOURS } from "@/lib/constants";

const LIST_FIELDS = 'id,collectionId,collectionName,created,updated,title,startDate,dueDate,priority,status,completed,tags,user,size,recurrence,sharedWith,deletedAt';

const getStorageKey = () => {
    const userId = pb.authStore.model?.id;
    return userId ? `tasgrid_data_${userId}` : null;
};

export const [now, setNow] = createSignal(Date.now());
// Context: 'mine' = My Bucket (default), { userId: string } = Oversight View for that user, { bucketId: string, name: string } = Bucket View
type TaskContext = 'mine' | { userId: string, name: string } | { bucketId: string, name: string };
export const [activeTaskId, setActiveTaskId] = createSignal<string | null>(null);
export const [activeNoteId, setActiveNoteId] = createSignal<string | null>(null);
export const [currentTaskContext, setCurrentTaskContext] = createSignal<TaskContext>('mine');

export type UrgencyLevel = number;

export interface Task {
    id: string;
    title: string;
    startDate: string;
    dueDate: string;
    priority: number; // 1-10
    status: number; // 0-10
    completed: boolean; // Deprecated, kept for compat/computed from status = 10
    tags: string[];
    ownerId: string | null; // Add ownerId to interface
    content?: string; // HTML content from Tiptap
    deletedAt?: number | null; // Timestamp of soft delete or null if restored
    created: string; // ISO string from PB
    updated: string; // ISO string from PB
    recurrence?: {
        type: 'daily' | 'weekly' | 'monthly';
        days?: number[]; // For weekly (0-6, 0=Sunday)
        dayOfMonth?: number; // For monthly (1-31)
        lastUncompleted?: string; // ISO date of last automatic reset
    };
    size?: number; // 0-10, task complexity/size
    sharedWith?: Array<{ userId: string; access: 'view' | 'edit' }>; // Users this task is shared with
    attachments?: string[]; // Array of filenames from PocketBase
}

export const checkRecurringTasks = () => {
    const tasks = store.tasks;
    const nowObj = new Date();
    const todayStr = nowObj.toLocaleDateString('en-CA'); // YYYY-MM-DD in local time

    tasks.forEach(task => {
        if (task.status !== 10 || !task.recurrence) return;

        // If deleted, we don't recurse?
        if (task.deletedAt) return;

        const { type, days, dayOfMonth, lastUncompleted } = task.recurrence;
        let shouldReset = false;

        // Check if we already reset it today/this cycle
        if (lastUncompleted) {
            const lastDate = new Date(lastUncompleted).toLocaleDateString('en-CA');
            if (lastDate === todayStr) return; // Already reset today
        }

        // Also check 'updated' date. If it was marked completed TODAY, don't reset immediately.
        // We only reset if the completion happened BEFORE the current cycle trigger.
        // E.g. Completed yesterday, today is a new day -> Reset.
        const updatedDate = new Date(task.updated).toLocaleDateString('en-CA');
        if (updatedDate === todayStr) {
            // If manual loop: user completes it, we shouldn't immediately uncomplete it.
            // But what if it's supposed to be uncompleted today?
            // "Tasks that 'uncomplete' at given intervals" implies:
            // If I complete it today, it stays completed until the NEXT interval.
            // So we only reset if it was completed BEFORE today (for daily).
            if (type === 'daily') return;
        }

        if (type === 'daily') {
            // If completed before today, reset.
            if (updatedDate < todayStr) {
                shouldReset = true;
            }
        }
        else if (type === 'weekly') {
            // If today is one of the recurrence days
            const currentDay = nowObj.getDay();
            if (days?.includes(currentDay)) {
                // Reset if it was completed BEFORE today.
                if (updatedDate < todayStr) {
                    shouldReset = true;
                }
            }
        }
        else if (type === 'monthly') {
            const currentDate = nowObj.getDate();
            if (dayOfMonth === currentDate) {
                if (updatedDate < todayStr) {
                    shouldReset = true;
                }
            }
        }

        if (shouldReset) {
            console.log(`Resetting recurring task: ${task.title}`);
            updateTask(task.id, {
                status: 0,
                completed: false,
                recurrence: {
                    ...task.recurrence,
                    lastUncompleted: new Date().toISOString()
                }
            });
        }
    });
};

export interface TaskTemplate {
    id: string;
    name: string;
    title: string;
    priority: number;
    urgency: number;
    tags: string[];
    content: string;
}

export interface TagDefinition {
    id: string;
    name: string;
    value: number;
    color?: string;
    theme?: "light" | "dark";
    isUser?: boolean; // New flag to identify user-based tags
    isBucket?: boolean; // New flag to identify bucket-based tags
}

export interface Note {
    id: string;
    title: string;
    content?: string;
    tags: string[];
    isPrivate: boolean;
    user: string;
    tasks: string[]; // List of related task IDs
    created: string;
    updated: string;
    deletedAt?: number | null; // Timestamp of soft delete or null if restored
}

export interface FilterTag {
    name: string;
    excluded: boolean;
}

export interface Filter {
    query: string;
    tags: FilterTag[];
    priorityMin: number;
    priorityMax: number;
    urgencyMin: number;
    urgencyMax: number;
    editedToday: boolean;
}

// Background sync for Context Switcher (polling fallback for realtime)
let contextSyncInterval: number | undefined;

export const startContextPolling = () => {
    if (contextSyncInterval) {
        clearInterval(contextSyncInterval);
        contextSyncInterval = undefined;
    }

    const ctx = currentTaskContext();
    if (typeof ctx === 'object' && 'userId' in ctx) {
        contextSyncInterval = window.setInterval(async () => {
            if (!pb.authStore.isValid) return;

            try {
                // Fetch only recent updates (last 30s) to minimize payload
                const timeStr = new Date(Date.now() - 30000).toISOString();
                const records = await pb.collection(TASGRID_COLLECTION).getFullList({
                    filter: `user = "${ctx.userId}" && updated >= "${timeStr}"`,
                    sort: '-updated',
                    fields: LIST_FIELDS,
                    requestKey: 'context-poll'
                });

                if (records.length === 0) return;

                setStore("tasks", (currentTasks) => {
                    const taskMap = new Map(currentTasks.map(t => [t.id, t]));
                    let changed = false;

                    records.forEach((r: any) => {
                        if (r.tags?.includes("__template__")) return;

                        const existing = taskMap.get(r.id);
                        if (existing && existing.updated === r.updated) return;

                        const newTask = mapRecordToTask(r);
                        if (existing && existing.content) {
                            newTask.content = existing.content;
                        }
                        taskMap.set(r.id, newTask);
                        changed = true;
                    });

                    if (changed) return Array.from(taskMap.values());
                    return currentTasks;
                });
            } catch (err: any) {
                if (!err.isAbort) {
                    console.warn("Context poll failed:", err);
                }
            }
        }, 5000); // 5 seconds
    }
};

createRoot(() => {
    createEffect(() => {
        // Re-run whenever ctx changes
        currentTaskContext();
        startContextPolling();
    });
});

export interface FilterTemplate {
    id: string;
    name: string;
    filter: Filter;
}


export interface ShareRule {
    id: string;
    ownerId: string;
    targetUserId: string;
    type: 'tag' | 'all';
    tagName?: string;
    share_mode?: 'ADD_USER' | 'SEND_TASK'; // Default to ADD_USER if undefined
}

export interface Bucket {
    id: string;
    name: string;
    color: string;
    description?: string;
}

interface TaskStore {
    tasks: Task[];
    isInitializing: boolean;
    pWeight: number;
    uWeight: number;
    matrixScaleDays: number;
    prefId?: string; // ID of the user record
    tagDefinitions: TagDefinition[];
    templates: TaskTemplate[];
    filter: Filter;
    shareRules: ShareRule[];
    filterTemplates: FilterTemplate[];
    buckets: Bucket[];
    subscribedBuckets: string[]; // IDs of buckets I'm subscribed to
    notes: Note[];
    isNotepadMode: boolean;
    quickloadTasks: string[];
}

// Initial empty state
export const [store, setStore] = createStore<TaskStore>({
    tasks: [],
    isInitializing: false,
    pWeight: 1.0,
    uWeight: 1.0,
    matrixScaleDays: 30,
    tagDefinitions: [],
    templates: [],
    filter: {
        query: "",
        tags: [],
        priorityMin: 1,
        priorityMax: 10,
        urgencyMin: 1,
        urgencyMax: 10,
        editedToday: false
    },
    shareRules: [],
    filterTemplates: [],
    buckets: [],
    subscribedBuckets: [],
    notes: [],
    isNotepadMode: false,
    quickloadTasks: []
});

export const matchesFilter = (task: Task) => {
    const currentUserId = pb.authStore.model?.id;
    const ctx = currentTaskContext();

    // 0. Context Filter
    if (ctx === 'mine') {
        const isOwner = task.ownerId === currentUserId;
        const isExplicitlyShared = task.sharedWith?.some(s => s.userId === currentUserId);

        // Tag-based share rules targeting me
        const isTagRuleShared = store.shareRules.some(r => {
            if (r.targetUserId !== currentUserId) return false;

            // Global Rule / Self-Rule: Match purely on tag, ignore owner check
            // logic: If I have a rule for tag "T" assigned to myself, show ANY task with tag "T"
            if (r.ownerId === r.targetUserId && r.type === 'tag') {
                const tagName = r.tagName || "";

                // EXCLUDE Buckets from the main "Mine" view
                // The user wants to see "Direct Shares" (User Tags), not "Bucket Subscriptions" here.
                const isBucket = store.buckets.some(b => b.name.toLowerCase() === tagName.toLowerCase());
                if (isBucket) return false;

                return task.tags?.some(t => t.toLowerCase() === tagName.toLowerCase());
            }

            // Standard Rule: Match owner AND tag
            return r.ownerId === task.ownerId &&
                r.type === 'tag' &&
                task.tags?.includes(r.tagName || "");
        });

        // Bucket tasks are now tagged with '@' + name.
        if (!isOwner && !isExplicitlyShared && !isTagRuleShared) return false;
    } else if (typeof ctx === 'object' && 'bucketId' in ctx) {
        // Bucket View
        const bucketProxy = store.buckets.find(b => b.id === (ctx as { bucketId: string }).bucketId);
        if (!bucketProxy) return false;

        // Show tasks that have the bucket name (prefixed with @) as a tag
        const bucketTagName = `@${bucketProxy.name}`;
        if (!task.tags?.includes(bucketTagName)) return false;
    } else {
        // Context is Oversight for specific user
        // Show ONLY tasks owned by that user
        // Note: We might want to EXCLUDE bucket tasks from oversight if they are purely bucket tasks, 
        // but typically oversight means "everything that user owns".
        if (task.ownerId !== (ctx as { userId: string }).userId) return false;
    }

    // Hide templates from all regular views
    if (task.tags?.includes("__template__")) return false;

    const f = store.filter;

    // Query search (title or content)
    if (f.query) {
        const q = f.query.toLowerCase();
        const inTitle = task.title.toLowerCase().includes(q);
        const inContent = task.content?.toLowerCase().includes(q);
        if (!inTitle && !inContent) return false;
    }

    // Tags
    if (f.tags.length > 0) {
        const includedTags = f.tags.filter(t => !t.excluded).map(t => t.name);
        const excludedTags = f.tags.filter(t => t.excluded).map(t => t.name);

        // 1. Task must NOT have any of the excluded tags
        if (excludedTags.length > 0) {
            const hasExcluded = excludedTags.some(tag => task.tags?.includes(tag));
            if (hasExcluded) return false;
        }

        // 2. Task must have at least one of the included tags (if any are specified)
        if (includedTags.length > 0) {
            const hasIncluded = includedTags.some(tag => task.tags?.includes(tag));
            if (!hasIncluded) return false;
        }
    }

    // Priority
    if (task.priority < f.priorityMin || task.priority > f.priorityMax) return false;

    // Urgency (calculated)
    const urgency = calculateUrgencyFromDate(task.dueDate);
    if (urgency < f.urgencyMin || urgency > f.urgencyMax) return false;

    // Edited Today
    if (f.editedToday) {
        const today = new Date().toLocaleDateString('en-CA');
        const updated = new Date(task.updated).toLocaleDateString('en-CA');
        if (today !== updated) return false;
    }

    return true;
};

// Auto-persist changes to localStorage (wrapped in root to avoid console warning)
createRoot(() => {
    createEffect(() => {
        const key = getStorageKey();
        if (key) {
            localStorage.setItem(key, JSON.stringify(store));
        }
    });

    let debouncedSync: number | undefined;
    createEffect(() => {
        if (store.isInitializing || !pb.authStore.model?.id) return;

        // Calculate Top 20 Tasks
        const incompleteTasks = store.tasks.filter(t =>
            !t.completed &&
            t.ownerId === pb.authStore.model?.id &&
            !t.tags?.includes("__template__") &&
            !t.deletedAt
        );

        const scoredTasks = incompleteTasks.map(t => ({ id: t.id, score: getCombinedScore(t) }));
        scoredTasks.sort((a, b) => b.score - a.score);

        const top20Ids = scoredTasks.slice(0, 20).map(t => t.id);

        // Compare with current
        const currentIds = store.quickloadTasks || [];
        const isDifferent = top20Ids.length !== currentIds.length || top20Ids.some((id, i) => id !== currentIds[i]);

        if (isDifferent) {
            setStore("quickloadTasks", top20Ids);

            // Debounce save by 10s
            if (debouncedSync) window.clearTimeout(debouncedSync);
            debouncedSync = window.setTimeout(() => {
                syncPreferences();
            }, 10000);
        }
    });
});

// -- Calibration --
export const calculateUrgencyScore = (dueDateStr: string): number => {
    const due = new Date(dueDateStr).getTime();
    const diffHours = (due - now()) / (1000 * 60 * 60);

    if (diffHours <= URGENCY_HOURS[10]) return 10;
    if (diffHours >= URGENCY_HOURS[1]) return 1;

    // Linear interpolation between breakpoints
    const levels = Object.keys(URGENCY_HOURS).map(Number).sort((a, b) => b - a); // 10, 9, 8...
    for (let i = 0; i < levels.length - 1; i++) {
        const highLevel = levels[i];
        const lowLevel = levels[i + 1];
        const highHours = URGENCY_HOURS[highLevel];
        const lowHours = URGENCY_HOURS[lowLevel];

        if (diffHours >= highHours && diffHours <= lowHours) {
            // Level decreases as hours increase
            const range = lowHours - highHours;
            const progress = (diffHours - highHours) / range;
            return highLevel - progress * (highLevel - lowLevel);
        }
    }

    return 1;
};

export const calculateDateFromUrgency = (level: number): string => {
    const roundedLevel = Math.max(1, Math.min(10, Math.round(level)));
    const hours = URGENCY_HOURS[roundedLevel] || 24;
    return new Date(now() + hours * 60 * 60 * 1000).toISOString();
};

export const calculateUrgencyFromDate = (dateStr: string): number => {
    return Math.round(calculateUrgencyScore(dateStr));
};

export const getCombinedScore = (task: Task): number => {
    // 1. Calculate an effective due date by subtracting size hours
    const size = task.size ?? 3; // Default size 3
    const sizeHours = SIZE_HOURS[size] ?? 12;
    const dueTime = new Date(task.dueDate).getTime();
    if (isNaN(dueTime)) return 0;

    // effective due date = due date - size task time
    const effectiveDueTime = dueTime - (sizeHours * 60 * 60 * 1000);
    const effectiveDueDateStr = new Date(effectiveDueTime).toISOString();

    const urgencyScore = calculateUrgencyScore(effectiveDueDateStr);
    let baseScore = (task.priority * store.pWeight) + (urgencyScore * store.uWeight);

    // Tag adjustments
    if (task.tags && task.tags.length > 0) {
        task.tags.forEach(tagName => {
            const def = store.tagDefinitions.find(d => d.name === tagName);
            if (def) {
                // Formula: (Value - 5) * 0.1
                // 5 -> 0, 10 -> 0.5, 0 -> -0.5
                baseScore += (def.value - 5) * 0.1;
            }
        });
    }

    // Size adjustment: linear scale from +1.9 (for size 0) to 0 (for size 10)
    const sizeScore = (10 - size) * 0.19;
    baseScore += sizeScore;

    // Status adjustment: 0-9 -> 0.0-2.0 weight
    if (task.status < 10) {
        // Map 0-9 to 0-2 range
        const statusWeight = (task.status / 9) * 2.0;
        baseScore += statusWeight;
    }

    return baseScore;
};

// -- Persistence & Sync --

let heartbeatInterval: number | undefined;

const mapRecordToTask = (r: any): Task => {
    // Check if it's a template? The caller handles filtering templates usually, 
    // but here we just map fields.
    const tags = r.tags || [];
    return {
        id: r.id,
        title: r.title,
        startDate: r.startDate,
        dueDate: r.dueDate,
        priority: r.priority,
        status: r.status ?? (r.completed ? 10 : 0),
        completed: r.status === 10 || r.completed,
        tags: tags,
        ownerId: r.user || null,
        content: r.content,
        deletedAt: r.deletedAt ? new Date(r.deletedAt).getTime() : undefined,
        created: r.created,
        updated: r.updated,
        recurrence: r.recurrence,
        size: (r.size === null || r.size === undefined) ? undefined : r.size,
        sharedWith: r.sharedWith,
        attachments: r.attachments || []
    };
};

export const uploadTaskAttachment = async (taskId: string, file: File): Promise<string> => {
    try {
        const formData = new FormData();
        formData.append('attachments', file);

        const record = await pb.collection(TASGRID_COLLECTION).update(taskId, formData);

        // Return the URL for the newly uploaded file. PocketBase appends new files to the array.
        // We need to find the specific filename that was just uploaded to get its URL.
        // Since we don't know the exact generated filename, we can return the URL of the last file in the array.
        if (record.attachments && record.attachments.length > 0) {
            const latestFilename = record.attachments[record.attachments.length - 1];
            return pb.files.getURL(record, latestFilename);
        }

        throw new Error("File uploaded but no attachment returned");
    } catch (err: any) {
        console.error("Error uploading attachment:", err);
        toast.error("Failed to upload image.");
        throw err;
    }
};

export const uploadNoteAttachment = async (noteId: string, file: File): Promise<string> => {
    try {
        const formData = new FormData();
        formData.append('attachments', file);

        const record = await pb.collection(NOTES_COLLECTION).update(noteId, formData);

        if (record.attachments && record.attachments.length > 0) {
            const latestFilename = record.attachments[record.attachments.length - 1];
            return pb.files.getURL(record, latestFilename);
        }

        throw new Error("File uploaded but no attachment returned");
    } catch (err: any) {
        console.error("Error uploading note attachment:", err);
        toast.error("Failed to upload image to note.");
        throw err;
    }
};

export const cleanupNoteAttachments = async (noteId: string) => {
    if (!pb.authStore.isValid) return;

    try {
        const note = store.notes.find(n => n.id === noteId);
        if (!note) return;

        const record = await pb.collection(NOTES_COLLECTION).getOne(noteId);
        if (!record.attachments || record.attachments.length === 0) return;

        const content = note.content || "";
        const filesToDelete: string[] = [];
        for (const filename of record.attachments) {
            if (!content.includes(filename)) {
                filesToDelete.push(filename);
            }
        }

        if (filesToDelete.length > 0) {
            await pb.collection(NOTES_COLLECTION).update(noteId, {
                "attachments-": filesToDelete
            });
            console.log(`[CLEANUP] Deleted ${filesToDelete.length} orphaned attachment(s) for note ${noteId}`);
        }
    } catch (err) {
        console.error("[CLEANUP] Failed to clean up orphaned note attachments:", err);
    }
};

export const cleanupTaskAttachments = async (taskId: string) => {
    if (!pb.authStore.isValid) return;

    try {
        const task = store.tasks.find(t => t.id === taskId);
        if (!task) return;

        const record = await pb.collection(TASGRID_COLLECTION).getOne(taskId);
        if (!record.attachments || record.attachments.length === 0) return;

        const content = task.content || "";
        const filesToDelete: string[] = [];
        for (const filename of record.attachments) {
            if (!content.includes(filename)) {
                filesToDelete.push(filename);
            }
        }

        if (filesToDelete.length > 0) {
            await pb.collection(TASGRID_COLLECTION).update(taskId, {
                "attachments-": filesToDelete
            });
            console.log(`[CLEANUP] Deleted ${filesToDelete.length} orphaned attachment(s) for task ${taskId}`);
        }
    } catch (err) {
        console.error("[CLEANUP] Failed to clean up orphaned task attachments:", err);
    }
};

const mapRecordToShareRule = (r: any): ShareRule => {
    return {
        id: r.id,
        ownerId: r.ownerId,
        targetUserId: r.targetUserId,
        type: r.type as 'tag' | 'all',
        tagName: r.tagName,
        share_mode: r.share_mode || 'ADD_USER'
    };
};

const mapRecordToNote = (r: any): Note => {
    return {
        id: r.id,
        title: r.title,
        content: r.content,
        tags: r.tags || [],
        isPrivate: r.isPrivate || false,
        user: r.user,
        tasks: r.tasks || [],
        created: r.created,
        updated: r.updated,
        deletedAt: r.deletedAt ? new Date(r.deletedAt).getTime() : undefined
    };
};

// Helper to check if a task should be visible based on ownership, shares, or rules
const shouldTaskBeVisible = (task: any, currentUserId: string): boolean => {
    // Own task
    if (task.user === currentUserId) return true;

    // Individually shared
    const sharedWith = task.sharedWith || [];
    if (sharedWith.some((s: any) => s.userId === currentUserId)) return true;

    // ShareRule match
    const matchingRule = store.shareRules.find(rule => {
        if (rule.targetUserId !== currentUserId) return false;

        // Global Rule Logic: If owner == target, it's a "Global Subscription" to that tag.
        // We ignore the rule.ownerId check (which would match the task.user)
        // and instead match purely on the tag.
        if (rule.ownerId === rule.targetUserId && rule.type === 'tag') {
            const tags: string[] = task.tags || [];
            return tags.some(t => t.toLowerCase() === (rule.tagName || "").toLowerCase());
        }

        // Standard Rule Logic: Match specific owner
        if (task.user !== rule.ownerId) return false;
        if (rule.type === 'all') return true;
        if (rule.type === 'tag') {
            const tags = task.tags || [];
            return tags.includes(rule.tagName);
        }
        return false;
    });

    // Bucket check
    if (isTaskInSubscribedBucket(task)) return true;

    return !!matchingRule;
};

// Check if task is visible because it belongs to a subscribed bucket
const isTaskInSubscribedBucket = (task: any): boolean => {
    const taskTags = task.tags || [];
    if (taskTags.length === 0) return false;

    // Check if any of the task's tags match a bucket we are subscribed to
    return store.subscribedBuckets.some(subId => {
        const bucket = store.buckets.find(b => b.id === subId);
        return bucket && taskTags.includes(`@${bucket.name}`);
    });
};

export const subscribeToRealtime = async () => {
    // Unsubscribe first to avoid duplicates
    await pb.collection(TASGRID_COLLECTION).unsubscribe('*');

    pb.collection(TASGRID_COLLECTION).subscribe('*', (e) => {
        console.log("Realtime event:", e.action, e.record.id);

        if (e.action === 'create') {
            // Check if it's a template
            const isTemplate = e.record.tags?.includes("__template__");
            if (isTemplate) {
                // Check if template already exists (from optimistic update)
                const templateExists = store.templates?.some(t => t.id === e.record.id);
                if (templateExists) return;

                let meta: any = {};
                try { meta = JSON.parse(e.record.content || "{}"); } catch (e) { }
                const newTemplate: TaskTemplate = {
                    id: e.record.id,
                    name: e.record.title,
                    title: meta.title || "",
                    priority: e.record.priority,
                    urgency: meta.urgency || 5,
                    tags: meta.tags || [],
                    content: meta.content || ""
                };
                setStore("templates", t => [...(t || []), newTemplate]);
                return;
            }

            // Regular Task - check if already exists and if it should be visible
            const exists = store.tasks.find(t => t.id === e.record.id);
            if (!exists) {
                const currentUserId = pb.authStore.model?.id;
                const isOwnTask = e.record.user === currentUserId;

                // Only add if it's own task or should be visible via sharing
                if (isOwnTask || (currentUserId && shouldTaskBeVisible(e.record, currentUserId))) {
                    const newTask = mapRecordToTask(e.record);
                    setStore("tasks", t => [newTask, ...t]);
                }
            }
        }

        if (e.action === 'update') {
            // Is it a template?
            const isTemplate = e.record.tags?.includes("__template__");
            if (isTemplate) {
                // Update template store
                let meta: any = {};
                try { meta = JSON.parse(e.record.content || "{}"); } catch (e) { }
                setStore("templates", t => t.id === e.record.id, {
                    name: e.record.title,
                    title: meta.title || "",
                    priority: e.record.priority,
                    urgency: meta.urgency || 5,
                    tags: meta.tags || [],
                    content: meta.content || ""
                });
                return;
            }

            const currentUserId = pb.authStore.model?.id;
            const existingTask = store.tasks.find(t => t.id === e.record.id);
            const isOwnTask = e.record.user === currentUserId;
            const incomingUpdated = new Date(e.record.updated).getTime();

            if (existingTask) {
                const localUpdated = new Date(existingTask.updated).getTime();

                // Only apply update if incoming is newer (or we don't have a timestamp)
                if (!existingTask.updated || incomingUpdated >= localUpdated) {
                    // For shared tasks, re-evaluate visibility (e.g., tags may have changed)
                    if (!isOwnTask && currentUserId) {
                        if (!shouldTaskBeVisible(e.record, currentUserId)) {
                            // No longer visible, remove it
                            setStore("tasks", t => t.filter(x => x.id !== e.record.id));
                            return;
                        }
                    }

                    const updatedTask = mapRecordToTask(e.record);
                    setStore("tasks", t => t.id === e.record.id, updatedTask);
                } else {
                    console.log("Skipping stale realtime update for task:", e.record.id);
                }
            } else {
                // Task doesn't exist locally - check if it should be visible now
                if (currentUserId && shouldTaskBeVisible(e.record, currentUserId)) {
                    const newTask = mapRecordToTask(e.record);
                    setStore("tasks", t => [newTask, ...t]);
                }
            }
        }

        if (e.action === 'delete') {
            // Try deleting from both just in case
            setStore("tasks", t => t.filter(x => x.id !== e.record.id));
            setStore("templates", t => (t || []).filter(x => x.id !== e.record.id));
        }
    });

    // Subscribe to Notes
    await pb.collection(NOTES_COLLECTION).unsubscribe('*');
    pb.collection(NOTES_COLLECTION).subscribe('*', (e) => {
        const currentUserId = pb.authStore.model?.id;

        // Only process if public or owned by current user
        const isVisible = !e.record.isPrivate || e.record.user === currentUserId;

        if (e.action === 'create' || e.action === 'update') {
            if (isVisible) {
                const updatedNote = mapRecordToNote(e.record);
                setStore("notes", prev => {
                    const exists = prev.find(n => n.id === updatedNote.id);
                    if (exists) return prev.map(n => n.id === updatedNote.id ? updatedNote : n);
                    return [updatedNote, ...prev];
                });
            } else {
                // If it became private and we're not the owner, remove it
                setStore("notes", prev => prev.filter(n => n.id !== e.record.id));
            }
        }

        if (e.action === 'delete') {
            setStore("notes", prev => prev.filter(n => n.id !== e.record.id));
        }
    });

    // Subscribe to Buckets
    // We need to know if buckets are added/removed/renamed
    await pb.collection(BUCKETS_COLLECTION).unsubscribe('*');
    pb.collection(BUCKETS_COLLECTION).subscribe('*', async (e) => {
        if (e.action === 'create' || e.action === 'update') {
            const bucket = {
                id: e.record.id,
                name: e.record.name,
                color: e.record.color,
                description: e.record.description
            };

            setStore("buckets", (prev) => {
                const exists = prev.find(b => b.id === bucket.id);
                if (exists) return prev.map(b => b.id === bucket.id ? bucket : b);
                return [...prev, bucket];
            });
        }

        if (e.action === 'delete') {
            setStore("buckets", (prev) => prev.filter(b => b.id !== e.record.id));
            // Also remove from subscribed if present?
            // The user record might still have it, but we can filter display.
        }
    });

    // Subscribe to Share Rules
    await pb.collection(SHARE_RULES_COLLECTION).unsubscribe('*');
    pb.collection(SHARE_RULES_COLLECTION).subscribe('*', async (e) => {
        const currentUserId = pb.authStore.model?.id;

        if (e.action === 'create') {
            const newRule = mapRecordToShareRule(e.record);

            // Add to shareRules store
            setStore("shareRules", (rules) => {
                if (rules.some(r => r.id === newRule.id)) return rules;
                return [...rules, newRule];
            });

            // If I'm the target, fetch matching tasks from the owner
            if (newRule.targetUserId === currentUserId) {
                try {
                    let filter = `user = "${newRule.ownerId}"`;
                    if (newRule.type === 'tag' && newRule.tagName) {
                        filter += ` && tags ~ "${newRule.tagName}"`;
                    }

                    const records = await pb.collection(TASGRID_COLLECTION).getFullList({
                        filter,
                        sort: '-created',
                        requestKey: null
                    });

                    records.forEach((r: any) => {
                        if (!r.tags?.includes("__template__") && !store.tasks.find(t => t.id === r.id)) {
                            const newTask = mapRecordToTask(r);
                            setStore("tasks", t => [newTask, ...t]);
                        }
                    });
                } catch (err) {
                    console.warn("Failed to fetch tasks for new share rule:", err);
                }
            }
        }

        if (e.action === 'delete') {
            const deletedRuleId = e.record.id;
            const deletedRule = store.shareRules.find(r => r.id === deletedRuleId);

            // Remove from shareRules store
            setStore("shareRules", (rules) => rules.filter(r => r.id !== deletedRuleId));

            // If I was the target, remove tasks that are no longer visible
            if (deletedRule && deletedRule.targetUserId === currentUserId) {
                setStore("tasks", tasks =>
                    tasks.filter(task => shouldTaskBeVisible(task, currentUserId!))
                );
            }
        }

        if (e.action === 'update') {
            const updatedRule = mapRecordToShareRule(e.record);
            setStore("shareRules", (rules) => rules.map(r => r.id === updatedRule.id ? updatedRule : r));
        }
    });
};

const runLegacyTagMigration = async () => {
    const currentUserId = pb.authStore.model?.id;
    if (!currentUserId) return;

    try {
        const userRec = await pb.collection('users').getOne(currentUserId, { requestKey: null });
        const prefs = userRec.Taskgrid_pref || {};

        if (prefs.migratedLegacyTagsV1) {
            return; // Already migrated
        }

        console.log("[MIGRATION] Starting legacy tag migration...");

        // Fetch users and buckets
        const [allUsers, allBuckets] = await Promise.all([
            pb.collection('users').getFullList({
                filter: 'verified = true',
                fields: 'name,email',
                requestKey: null
            }),
            pb.collection(BUCKETS_COLLECTION).getFullList({
                fields: 'name',
                requestKey: null
            })
        ]);

        const validNames = new Set([
            ...allBuckets.map(b => b.name.toLowerCase()),
            ...allUsers.map(u => (u.name || u.email)?.toLowerCase()).filter(Boolean)
        ]);

        // Fetch all Tasks for this user
        const tasks = await pb.collection(TASGRID_COLLECTION).getFullList({
            filter: `user = "${currentUserId}"`,
            requestKey: null
        });

        let tasksUpdated = 0;
        for (const t of tasks) {
            if (!t.tags || t.tags.length === 0) continue;
            let changed = false;
            const newTags = t.tags.map((tag: string) => {
                if (!tag.startsWith("@") && validNames.has(tag.toLowerCase())) {
                    changed = true;
                    return `@${tag}`;
                }
                return tag;
            });

            if (changed) {
                await pb.collection(TASGRID_COLLECTION).update(t.id, { tags: newTags }, { requestKey: null });
                tasksUpdated++;
            }
        }

        // Fetch all Notes for this user
        const notes = await pb.collection(NOTES_COLLECTION).getFullList({
            filter: `user = "${currentUserId}"`,
            requestKey: null
        });

        let notesUpdated = 0;
        for (const n of notes) {
            if (!n.tags || n.tags.length === 0) continue;
            let changed = false;
            const newTags = n.tags.map((tag: string) => {
                if (!tag.startsWith("@") && validNames.has(tag.toLowerCase())) {
                    changed = true;
                    return `@${tag}`;
                }
                return tag;
            });

            if (changed) {
                await pb.collection(NOTES_COLLECTION).update(n.id, { tags: newTags }, { requestKey: null });
                notesUpdated++;
            }
        }

        prefs.migratedLegacyTagsV1 = true;
        await pb.collection('users').update(currentUserId, { Taskgrid_pref: prefs }, { requestKey: null });

        if (pb.authStore.model) {
            pb.authStore.model.Taskgrid_pref = prefs;
        }

        console.log(`[MIGRATION] Completed. Updated ${tasksUpdated} tasks and ${notesUpdated} notes.`);

        // Update local state directly so it reflects immediately
        setStore("tasks", (tasks) => tasks.map(t => {
            let localChanged = false;
            const nt = t.tags?.map(tag => {
                if (!tag.startsWith("@") && validNames.has(tag.toLowerCase())) {
                    localChanged = true;
                    return `@${tag}`;
                }
                return tag;
            });
            if (localChanged) return { ...t, tags: nt };
            return t;
        }));

        setStore("notes", (items) => items.map(n => {
            let localChanged = false;
            const nt = n.tags?.map(tag => {
                if (!tag.startsWith("@") && validNames.has(tag.toLowerCase())) {
                    localChanged = true;
                    return `@${tag}`;
                }
                return tag;
            });
            if (localChanged) return { ...n, tags: nt };
            return n;
        }));

    } catch (err) {
        console.error("[MIGRATION] Failed:", err);
    }
};

export const initStore = async () => {
    if (!pb.authStore.isValid || store.isInitializing) return;
    setStore("isInitializing", true);

    const currentUserId = pb.authStore.model?.id;

    // STAGE 1: Instant Focus from Local Auth Model (Top 20 + Fallback)
    // Goal: < 100ms First Paint. Doesn't wait for any other network requests.
    if (currentUserId) {
        try {
            const prefs = pb.authStore.model?.Taskgrid_pref || {};
            const cachedQuickload = prefs.quickloadTasks || [];

            let focusRecords;
            if (cachedQuickload.length > 0) {
                const idFilter = cachedQuickload.map((id: string) => `id = "${id}"`).join(' || ');
                const res = await pb.collection(TASGRID_COLLECTION).getFullList({
                    filter: `(${idFilter}) && deletedAt = ""`,
                    requestKey: null
                });

                // Sort manually to match quickload order
                res.sort((a, b) => cachedQuickload.indexOf(a.id) - cachedQuickload.indexOf(b.id));
                focusRecords = { items: res };
            } else {
                focusRecords = await pb.collection(TASGRID_COLLECTION).getList(1, 30, {
                    filter: `user = "${currentUserId}" && completed = false && deletedAt = ""`,
                    sort: '-priority,dueDate',
                    requestKey: null
                });
            }

            // Filter out templates client-side to ensure tasks with empty/null tags aren't excluded by DB
            const focusTasks = focusRecords.items
                .map(mapRecordToTask)
                .filter(t => !t.tags?.includes("__template__"));

            setStore("tasks", focusTasks);
        } catch (focusErr) {
            console.warn("Stage 1 load failed:", focusErr);
        }
    }

    // 0. Synchronous hydration from localStorage for "instant" first paint
    const key = getStorageKey();
    if (key) {
        const saved = localStorage.getItem(key);
        if (saved) {
            try {
                setStore(JSON.parse(saved));
            } catch (e) {
                console.error("Failed to parse cached data", e);
            }
        }
    }

    // Heartbeat - Ensure only one interval is running
    if (heartbeatInterval) clearInterval(heartbeatInterval);
    heartbeatInterval = setInterval(() => {
        setNow(Date.now());
        checkRecurringTasks(); // Check for recurrence triggers (minutely, etc.)
    }, 60000);

    try {
        // 1. Fetch Preferences from User Profile (Weights, Scale, Tags)
        try {
            const userId = pb.authStore.model?.id;
            if (userId) {
                const user = await pb.collection('users').getOne(userId, { requestKey: null });
                const prefs = user.Taskgrid_pref || {};

                setStore({
                    pWeight: prefs.pWeight || 1.0,
                    uWeight: prefs.uWeight || 1.0,
                    matrixScaleDays: prefs.matrixScaleDays || 30,
                    prefId: userId,
                    subscribedBuckets: user.subscribedBuckets || [],
                    quickloadTasks: prefs.quickloadTasks || []
                });
            }
        } catch (prefErr) {
            console.warn("Failed to load preferences:", prefErr);
        }

        // 1.2 Fetch Buckets
        try {
            const buckets = await pb.collection(BUCKETS_COLLECTION).getFullList({ sort: 'name', requestKey: null });
            setStore("buckets", buckets.map((b: any) => ({
                id: b.id,
                name: b.name,
                color: b.color,
                description: b.description
            })));
        } catch (bucketErr) {
            console.warn("Failed to load buckets (collection might not exist yet):", bucketErr);
        }

        // 1.3 Fetch Notes
        try {
            const currentUserId = pb.authStore.model?.id;
            const notesRecords = await pb.collection(NOTES_COLLECTION).getFullList({
                filter: `isPrivate = false || user = "${currentUserId}"`,
                sort: '-created',
                requestKey: null
            });
            setStore("notes", notesRecords.map(mapRecordToNote));
        } catch (notesErr) {
            console.warn("Failed to load notes (collection might not exist yet):", notesErr);
        }

        // 1.5. Fetch Tag Definitions
        try {
            const tagRecords = await pb.collection(TAGS_COLLECTION).getFullList({
                filter: `user = "${pb.authStore.model?.id}"`,
                requestKey: null
            });
            const loadedTags: TagDefinition[] = tagRecords.map(r => ({
                id: r.id,
                name: r.name,
                value: r.value,
                color: r.color,
                theme: r.theme,
                isUser: r.isUser || false,
                isBucket: r.isBucket || false
            }));
            setStore("tagDefinitions", reconcile(loadedTags));
        } catch (tagErr) {
            console.warn("Failed to load tags:", tagErr);
        }

        // 1.8 Fetch Share Rules (CRITICAL for filter construction)
        // We need these loaded BEFORE we construct the focus filter
        await loadShareRules();

        const currentUserId = pb.authStore.model?.id;
        if (!currentUserId) return;

        // --- PHASE 2: Multi-Stage Loading ---

        // --- WINDOWED SYNC STRATEGY ---


        // STAGE 2 & 3: Background Sync
        const backgroundSync = async () => {

            const bucketNames = store.subscribedBuckets
                .map(id => store.buckets.find(b => b.id === id)?.name)
                .filter(Boolean);

            // Sync System Tags & Share Rules FIRST to ensure Self-Rules exist for query construction
            await syncSystemTagsAndRules();

            // Add rules from shareRules store (which was just synced)
            const incomingRules = store.shareRules.filter(r => r.targetUserId === currentUserId);

            // 2a. Fetch ALL Incomplete Tasks (Metadata Only) to ensure availability
            // We must replicate the complex sharing logic here
            const incompletePromises = [
                // Own Incomplete
                pb.collection(TASGRID_COLLECTION).getFullList({
                    filter: `user = "${currentUserId}" && completed = false`,
                    sort: '-created',
                    fields: LIST_FIELDS,
                    requestKey: null
                }),
                // Shared With Individual Incomplete
                pb.collection(TASGRID_COLLECTION).getFullList({
                    filter: `sharedWith ~ "${currentUserId}" && completed = false`,
                    sort: '-created',
                    fields: LIST_FIELDS,
                    requestKey: null
                }).catch(() => []),
                // Bucket Incomplete
                (bucketNames.length > 0) ? pb.collection(TASGRID_COLLECTION).getFullList({
                    filter: `(${bucketNames.map(name => `tags ~ "${name}"`).join(' || ')}) && completed = false`,
                    sort: '-created',
                    fields: LIST_FIELDS,
                    requestKey: null
                }).catch(() => []) : Promise.resolve([])
            ];

            // Share Rules Incomplete
            if (incomingRules.length > 0) {
                // Separate "Global Rules" (Self-Rules) from "Specific User Rules"
                const globalTagRules: string[] = [];
                const specificUserRules = new Map<string, { type: 'all' | 'tag', tagName?: string }[]>();

                incomingRules.forEach((rule: any) => {
                    if (rule.ownerId === rule.targetUserId && rule.type === 'tag' && rule.tagName) {
                        globalTagRules.push(rule.tagName);
                    } else {
                        const existing = specificUserRules.get(rule.ownerId) || [];
                        existing.push({ type: rule.type, tagName: rule.tagName });
                        specificUserRules.set(rule.ownerId, existing);
                    }
                });

                // 1. Fetch Global Rule Tasks (from ANY user)
                // 1. Fetch Global Rule Tasks (from ANY user)
                if (globalTagRules.length > 0) {
                    // We want tasks that have ANY of these tags, AND are not completed
                    // filter: (tags ~ "A" || tags ~ "B") && completed = false
                    const tagFilter = globalTagRules.map(t => `tags ~ "${t}"`).join(' || ');
                    incompletePromises.push(pb.collection(TASGRID_COLLECTION).getFullList({
                        filter: `(${tagFilter}) && completed = false`,
                        sort: '-created',
                        fields: LIST_FIELDS,
                        requestKey: null
                    }).catch(() => []));
                }

                // 2. Fetch Specific User Rule Tasks (from specific owner)
                Array.from(specificUserRules.entries()).forEach(([ownerId, rules]) => {
                    const hasAllRule = rules.some(r => r.type === 'all');
                    const tagRules = rules.filter(r => r.type === 'tag').map(r => r.tagName).filter(Boolean);

                    let filter = `user = "${ownerId}" && completed = false`;

                    if (hasAllRule) {
                        // Get everything from this user
                    } else if (tagRules.length > 0) {
                        // Get specific tags from this user
                        filter += ` && (${tagRules.map(t => `tags ~ "${t}"`).join(' || ')})`;
                    } else {
                        return; // No valid rules for this user
                    }

                    incompletePromises.push(pb.collection(TASGRID_COLLECTION).getFullList({
                        filter,
                        sort: '-created',
                        fields: LIST_FIELDS,
                        requestKey: null
                    }).catch(() => []));
                });
            }

            const stage2Results = await Promise.all(incompletePromises);
            const allIncomplete = stage2Results.flat();

            setStore("tasks", (currentTasks) => {
                const taskMap = new Map(currentTasks.map(t => [t.id, t]));
                allIncomplete.forEach((r: any) => {
                    if (r.tags?.includes("__template__")) return;

                    const existing = taskMap.get(r.id);

                    // Prevent DOM rebuilding/flickering for tasks that haven't changed
                    if (existing && existing.updated === r.updated) {
                        return; // Keeps the exact same reference in the map
                    }

                    // If existing has content, keep it. Otherwise use new record (which likely has no content yet)
                    const newTask = mapRecordToTask(r);
                    if (existing && existing.content) {
                        newTask.content = existing.content;
                    }
                    taskMap.set(r.id, newTask);
                });
                return Array.from(taskMap.values());
            });

            // 2b. Content Backfill for Incomplete Tasks
            // Fetch content for tasks that don't have it yet, in chunks
            const tasksNeedingContent = store.tasks.filter(t => !t.completed && t.content === undefined).map(t => t.id);
            if (tasksNeedingContent.length > 0) {
                // Fetch in chunks of 20 to avoid URL length limits
                const chunkSize = 20;
                for (let i = 0; i < tasksNeedingContent.length; i += chunkSize) {
                    const ids = tasksNeedingContent.slice(i, i + chunkSize);
                    // We fetch just ID and Content
                    try {
                        const contentRecords = await pb.collection(TASGRID_COLLECTION).getFullList({
                            filter: ids.map(id => `id="${id}"`).join(' || '),
                            fields: 'id,content',
                            requestKey: null
                        });

                        setStore("tasks", (tasks) => tasks.map(t => {
                            const match = contentRecords.find((r: any) => r.id === t.id);
                            if (match) return { ...t, content: match.content };
                            return t;
                        }));
                    } catch (e) { console.warn("Backfill chunk failed", e); }
                }
            }

            // STAGE 3: Recent History (Cap 150)
            const currentCount = store.tasks.length;
            const remainingSlots = 150 - currentCount;

            if (remainingSlots > 0) {
                try {
                    const recentCompleted = await pb.collection(TASGRID_COLLECTION).getList(1, remainingSlots, {
                        filter: `user = "${currentUserId}" && completed = true`,
                        sort: '-updated',
                        fields: LIST_FIELDS,
                        requestKey: null
                    });

                    setStore("tasks", (prev) => {
                        const newTasks = [...prev];
                        recentCompleted.items.forEach((r: any) => {
                            if (!newTasks.some(t => t.id === r.id)) {
                                newTasks.push(mapRecordToTask(r));
                            }
                        });
                        return newTasks;
                    });
                } catch (e) {
                    console.warn("Stage 3 load failed", e);
                }
            }

            checkRecurringTasks();

            // Reconstructive migration
            const foundTagNames = new Set<string>();
            store.tasks.forEach(t => t.tags?.forEach(tag => foundTagNames.add(tag)));
            for (const tagName of foundTagNames) {
                if (tagName === "__template__") continue;
                if (!store.tagDefinitions.find(d => d.name === tagName)) {
                    await upsertTagDefinition(tagName, 5, undefined, document.documentElement.classList.contains("dark") ? "dark" : "light");
                }
            }

            // Sync System Tags & Share Rules (Moved to top of backgroundSync to ensure rules exist before use)
            // await syncSystemTagsAndRules();
        };

        // Fire off background sync
        await backgroundSync();

        // Run one-time migration for legacy tags
        await runLegacyTagMigration();

        // Separate Templates load (less critical)
        try {
            const templates = await pb.collection(TASGRID_COLLECTION).getFullList({
                filter: `user = "${currentUserId}" && tags ~ "__template__"`,
                requestKey: null
            });
            const loadedTemplates = templates.map(r => {
                let meta: any = {};
                try { meta = JSON.parse(r.content || "{}"); } catch (e) { }
                return {
                    id: r.id,
                    name: r.title,
                    title: meta.title || "",
                    priority: r.priority,
                    urgency: meta.urgency || 5,
                    tags: meta.tags || [],
                    content: meta.content || ""
                };
            });
            setStore("templates", loadedTemplates);
        } catch (err) { }

        // Start real-time subscription
        await subscribeToRealtime();

        // 2.8 Fetch Filter Templates
        await loadFilterTemplates();
    } catch (err) {
        if (store.tasks.length === 0) {
            console.error("Failed to load data:", err);
            toast.error("Failed to sync with server.");
        }
    } finally {
        setStore("isInitializing", false);
    }
};

// -- Actions --

export const toggleBucketSubscription = async (bucketId: string) => {
    const currentSubscribed = store.subscribedBuckets;
    const isSubscribed = currentSubscribed.includes(bucketId);

    let newSubscribed = [];
    if (isSubscribed) {
        newSubscribed = currentSubscribed.filter(id => id !== bucketId);
    } else {
        newSubscribed = [...currentSubscribed, bucketId];
    }

    setStore("subscribedBuckets", newSubscribed);

    // Persist to user profile
    const userId = pb.authStore.model?.id;
    if (userId) {
        try {
            await pb.collection('users').update(userId, {
                subscribedBuckets: newSubscribed
            });

            // If we just subscribed, we should fetch the tasks for this bucket immediately
            if (!isSubscribed) {
                const bucketName = store.buckets.find(b => b.id === bucketId)?.name;
                if (bucketName) {
                    const records = await pb.collection(TASGRID_COLLECTION).getFullList({
                        filter: `tags ~ "${bucketName}"`,
                        sort: '-created',
                        fields: LIST_FIELDS
                    });

                    const newTasks: Task[] = [];
                    records.forEach((r: any) => {
                        const exists = store.tasks.find(t => t.id === r.id);
                        if (!exists && !r.tags?.includes("__template__")) {
                            newTasks.push(mapRecordToTask(r));
                        }
                    });

                    if (newTasks.length > 0) {
                        setStore("tasks", t => [...newTasks, ...t]);
                    }
                }
            }
        } catch (err) {
            console.error("Failed to update subscriptions:", err);
            // Revert on error
            setStore("subscribedBuckets", currentSubscribed);
        }
    }
};

export const createBucket = async (name: string, color: string, description?: string) => {
    try {
        await pb.collection(BUCKETS_COLLECTION).create({
            name,
            color,
            description
        });
        await syncSystemTagsAndRules();
        toast.success("Bucket created");
    } catch (err) {
        console.error("Failed to create bucket:", err);
        toast.error("Failed to create bucket");
    }
};

export const updateBucket = async (id: string, data: { name?: string, color?: string, description?: string }) => {
    try {
        await pb.collection(BUCKETS_COLLECTION).update(id, data);
        if (data.name) {
            await syncSystemTagsAndRules();
        }
        toast.success("Bucket updated");
    } catch (err) {
        console.error("Failed to update bucket:", err);
        toast.error("Failed to update bucket");
    }
};

export const deleteBucket = async (id: string) => {
    try {
        await pb.collection(BUCKETS_COLLECTION).delete(id);
        toast.success("Bucket deleted");
    } catch (err) {
        console.error("Failed to delete bucket:", err);
        toast.error("Failed to delete bucket");
    }
};

export const addTask = async (title: string, options?: { dueDate?: Date | string, priority?: number, tags?: string[], content?: string, size?: number }) => {
    if (!pb.authStore.isValid) return;

    // Default to ~24h from now if no date provided
    let dueDate = new Date(Date.now() + 24 * 60 * 60 * 1000).toISOString();
    if (options?.dueDate) {
        dueDate = options.dueDate instanceof Date ? options.dueDate.toISOString() : options.dueDate;
    }

    const startDate = new Date().toISOString();
    const priority = options?.priority ?? 5;
    const tags = options?.tags ?? ["work"];
    const content = options?.content ?? "";
    const size = options?.size ?? 3;

    const tempId = "temp-" + Date.now();
    const initialTask: Task = {
        id: tempId,
        title,
        startDate,
        dueDate,
        priority,
        status: 0,
        completed: false,
        tags,
        ownerId: pb.authStore.model?.id || "",
        content,
        size,
        created: new Date().toISOString(),
        updated: new Date().toISOString()
    };

    // Apply Handoff Logic (e.g. transfer ownership if tagging for another user)
    // We treat the entire new task as "updates" to check against itself
    const handoffUpdates = checkForHandoffs(initialTask, initialTask);
    const newTask = { ...initialTask, ...handoffUpdates };

    // Optimistic UI update
    setStore("tasks", (t) => [newTask, ...t]);

    try {
        const record = await pb.collection(TASGRID_COLLECTION).create({
            user: newTask.ownerId, // Use the (potentially updated) ownerId
            title,
            startDate,
            dueDate,
            priority,
            status: 0,
            completed: false,
            tags,
            content,
            size,
            // If checking for handoffs added specific sharedWith, we might need to handle that,
            // but currently checkForHandoffs modifies ownerId/sharedWith. 
            // PB API expects 'sharedWith' if we want to set it, but our types might be complex?
            // Wait, checkForHandoffs returns Partial<Task>. 
            // If it sets ownerId to someone else, we rely on 'user' field in create.
            // If it sets sharedWith (e.g. for bucket rule clearing), we need to send that too?
            // Standard create doesn't support 'sharedWith' directly in this code block usually?
            // Let's check mapRecordToTask. sharedWith comes from record expansion usually.
            // But if we are creating, we might need to set standard relation fields if they exist.
            // However, the original code didn't set sharedWith.
            // The handoff logic usually just changes OWNER.
            // If it changes owner, 'user' field covers it.
        });

        // Replace temp task with real record (merging server fields like id, created, updated)
        setStore("tasks", (t) => {
            // Check if REAL ID exists already (from subscription race)
            const realExists = t.some(x => x.id === record.id);
            if (realExists) {
                // If real exists, just remove temp.
                return t.filter(x => x.id !== tempId);
            }
            // Otherwise, replace temp with real
            return t.map(task => task.id === tempId ? {
                ...task,
                id: record.id,
                created: record.created,
                updated: record.updated,
                ownerId: record.user // Add missing ownerId from record
            } : task);
        });
    } catch (err) {
        console.error("create failed", err);
        toast.error("Failed to save task.");
        // Rollback?
        setStore("tasks", (t) => t.filter(task => task.id !== tempId));
    }
};

export const copyTask = async (id: string) => {
    const original = store.tasks.find(t => t.id === id);
    if (!original) return;

    // Create a new task based on the original
    await addTask(`${original.title} (Copy)`, {
        priority: original.priority,
        dueDate: original.dueDate,
        tags: [...(original.tags || [])],
        content: original.content,
        size: original.size
    });

    toast.success("Task duplicated");
};

const checkForHandoffs = (task: Task, updates: Partial<Task>): Partial<Task> => {
    // Only check if tags are being modified
    if (!updates.tags) return updates;

    const currentUserId = pb.authStore.model?.id;
    if (!currentUserId || task.ownerId !== currentUserId) return updates;

    // Check for any tag that triggers a SEND_TASK rule
    for (const tag of updates.tags) {
        // Handle @ prefix in rule matching
        const rule = store.shareRules.find(r =>
            r.ownerId === pb.authStore.model?.id &&
            r.type === 'tag' &&
            r.tagName === tag &&
            r.share_mode === 'SEND_TASK'
        );

        if (rule) {
            console.log(`Handoff triggered by tag "${tag}" -> Transferring to ${rule.targetUserId}`);

            // Check if it's a bucket tag
            const isBucketRule = rule.targetUserId === currentUserId && store.tagDefinitions.find(t => t.name === tag)?.isBucket;

            if (isBucketRule) {
                return {
                    ...updates,
                    ownerId: null, // Unassign from current user (null is better for PB relations)
                    // Remove current user from sharedWith to ensure it disappears from their view
                    sharedWith: (task.sharedWith || []).filter(s => s.userId !== currentUserId)
                };
            }

            return {
                ...updates,
                ownerId: rule.targetUserId,
                // Also clear sharedWith for the specific target user if they were already shared
                sharedWith: (task.sharedWith || []).filter(s => s.userId !== rule.targetUserId)
            };
        }
    }

    return updates;
};

export const updateTask = async (id: string, updates: Partial<Task>) => {
    if (!pb.authStore.isValid) return;

    // 0. Check for Hand-off Logic (Tag-based ownership transfer)
    const currentTask = store.tasks.find(t => t.id === id);
    let finalUpdates = { ...updates };

    // Sync status and completed
    if (finalUpdates.status !== undefined) {
        finalUpdates.completed = finalUpdates.status === 10;
    } else if (finalUpdates.completed !== undefined) {
        // If only completed is passed, sync status
        // But if both pass, status takes precedence (above)
        // Wait, if I change completed to false, status should be 0? Or previous status? 
        // Let's assume toggleTask handles that. updateTask is lower level.
        // But for safety:
        if (finalUpdates.completed) {
            finalUpdates.status = 10;
        } else if (currentTask && currentTask.status === 10) {
            // Uncompleting a completed task -> reset to 0
            finalUpdates.status = 0;
        }
        // If uncompleting a non-completed task (weird), keep status?
    }

    if (currentTask) {
        finalUpdates = checkForHandoffs(currentTask, finalUpdates);
    }

    // Optimistic update with timestamp to prevent stale realtime events
    const optimisticUpdates = {
        ...finalUpdates,
        updated: new Date().toISOString()
    };
    setStore("tasks", (t) => t.id === id, optimisticUpdates);

    try {
        // Map Task fields to PB fields if needed (dates are ISO strings, so should matches)
        // Check for specific fields being updated
        const pbUpdates: any = { ...finalUpdates };

        if (finalUpdates.ownerId !== undefined) {
            pbUpdates.user = finalUpdates.ownerId || null; // Map ownerId to 'user' field in PB
            delete pbUpdates.ownerId;
        }

        if ("deletedAt" in finalUpdates) {
            // PB expects a date string or null for date fields.
            // Using finalUpdates.deletedAt check to distinguish between soft-delete (timestamp) and restore (null/falsy)
            if (finalUpdates.deletedAt) {
                pbUpdates.deletedAt = new Date(finalUpdates.deletedAt).toISOString();
            } else {
                pbUpdates.deletedAt = null; // restore task
            }
        }

        // Disable auto-cancellation for updates to prevent aborted errors during rapid typing
        await pb.collection(TASGRID_COLLECTION).update(id, pbUpdates, { requestKey: null });
    } catch (err) {
        console.error("update failed", err);
        toast.error("Failed to update task.");
    }
};

// Wrapper for updateTask to fit setStore style usage in components if needed,
// but for now we'll just intercept the setStore calls or provide specific actions.
// The components currently use `setStore("tasks", ...)` directly in some places.
// We need to verify if we should refactor those components to use actions or use a store effect.
// Ideally, we use a createEffect to watch the store, but that can trigger on every load.
// Better to export specific actions.

// -- Legacy Adapters -- 
// Many components use setStore directly. To support them without full refactor, 
// we can watch specific fields or just migrate them to use actions.
// Given strict instructions, let's look at what we've seen.
// TaskDetail uses `removeTask`. 
// QuickEntry uses `addTask`.
// TaskDetail uses `setStore` for title/priority updates. THIS IS A PROBLEM for sync.
// We should provide a way to sync these changes.

// Let's adding a store effect to sync changes? 
// It's risky. Let's provide an explicit hook or functions and fix the components.
// OR, we overwrite the `setStore` export? No, that's internal.
// Let's updated `setStore` usage in this file to be purely local, 
// and add a `syncTask` helper that components should call?
// Or better: Replace the `setStore` export with a wrapped version? Hard with type inference.
//
// Best approach for now:
// Keep `setStore` for local UI state.
// Add a `createEffect` that watches `store.tasks`? 
// No, deep watching is expensive.
//
// Let's sticking to: Components SHOULD call actions.
// But TaskDetail calls `setStore`.
// I will start by modifying `setStore` usages in TaskDetail/etc in a subsequent step if needed.
// FOR NOW: I will export a `updateTaskField` helper and update components to use it.
// Actually, `TaskDetail` was edited to use `setStore` in Step 1520.
// line 33: setStore("tasks", (t) => t.id === props.task.id, "content", html);
// line 38, 44, 52, 60... all use setStore.
// I MUST refactor TaskDetail to use an action.

export const updateTaskField = (id: string, field: keyof Task, value: any) => {
    setStore("tasks", (t) => t.id === id, field, value);
    // Debounce this?
    // For now, fire and forget update
    updateTask(id, { [field]: value });
};

// -- Matrix Scale --

export const setMatrixScaleDays = async (days: number) => {
    setStore("matrixScaleDays", days);
    await syncPreferences();
};

export const toggleTask = (id: string) => {
    const task = store.tasks.find(t => t.id === id);
    if (task) {
        const newCompleted = !task.completed;
        updateTask(id, {
            completed: newCompleted,
            status: newCompleted ? 10 : 0
        });
    }
};

export const removeTask = (id: string) => {
    // Soft delete
    const nowTs = Date.now();
    updateTask(id, { deletedAt: nowTs });
};

export const restoreTask = (id: string) => {
    // updateTask handles both optimistic update and PB sync
    // Pass null for deletedAt to explicitly clear it in PB
    updateTask(id, { deletedAt: null });
};

export const deleteTaskPermanently = async (id: string) => {
    if (!pb.authStore.isValid) return;

    // Optimistic
    setStore("tasks", (t) => t.filter((t) => t.id !== id));

    try {
        await pb.collection(TASGRID_COLLECTION).delete(id);
    } catch (err) {
        console.error("delete failed", err);
        toast.error("Failed to delete task.");
        // Reload tasks?
    }
};

export const upsertTagDefinition = async (name: string, value: number, color?: string, theme?: "light" | "dark") => {
    if (!pb.authStore.isValid) return;

    const existing = store.tagDefinitions.find(d => d.name === name);
    const finalTheme = theme || (document.documentElement.classList.contains("dark") ? "dark" : "light");

    try {
        if (existing) {
            const updateData: any = { value };
            if (color !== undefined) updateData.color = color;
            if (theme !== undefined) updateData.theme = theme;

            await pb.collection(TAGS_COLLECTION).update(existing.id, updateData, { requestKey: null });

            setStore("tagDefinitions", (d) => d.id === existing.id, {
                value,
                color: color !== undefined ? color : existing.color,
                theme: theme !== undefined ? theme : existing.theme
            });
        } else {

            // Check for case-insensitive duplicate
            const nameLower = name.toLowerCase();
            const duplicate = store.tagDefinitions.find(d => d.name.toLowerCase() === nameLower);

            if (duplicate) {
                if (duplicate.name !== name) {
                    // Case difference only -> Update to new casing? 
                    // Or just warn? "Tag already exists with different casing".
                    // For now, we'll just return the existing one to be safe, or update it if needed.
                    // A strict interpretation of "There should never be two tags with the same name"
                    // usually implies normalization.
                    // But if the user typed "Work" and "work" exists, maybe they mean "work".
                    toast.error(`Tag "${duplicate.name}" already exists.`);
                    return;
                }
                // Exact match logic handled by 'existing' check above usually, but 'existing' uses strict equality?
                // The existing check at top of function is strict: `existing = store.tagDefinitions.find(d => d.name === name);`
                // So this block handles case-insensitive duplicates that weren't caught by strict check.
                // We should update the existing one if we want to change casing, or just reject.
                // Rejection is safer for unique constraint.
                toast.error(`Tag "${duplicate.name}" already exists.`);
                return;
            }

            const record = await pb.collection(TAGS_COLLECTION).create({
                user: pb.authStore.model?.id,
                name,
                value,
                color: color || "#6366f1", // Default indigo
                theme: finalTheme
            }, { requestKey: null });

            const newDef: TagDefinition = {
                id: record.id,
                name: record.name,
                value: record.value,
                color: record.color,
                theme: record.theme as "light" | "dark",
                isBucket: record.isBucket || false
            };
            setStore("tagDefinitions", (prev) => [...prev, newDef]);
        }
    } catch (err) {
        console.error("Failed to upsert tag:", err);
        toast.error("Failed to save tag definition.");
    }
};

export const removeTagDefinition = async (name: string) => {
    if (!pb.authStore.isValid) return;
    const def = store.tagDefinitions.find(d => d.name === name);
    if (!def) return;

    try {
        await pb.collection(TAGS_COLLECTION).delete(def.id);
        setStore("tagDefinitions", (prev) => prev.filter(d => d.id !== def.id));

        const tasksWithTag = store.tasks.filter(t => t.tags?.includes(name));
        for (const task of tasksWithTag) {
            const nextTags = (task.tags || []).filter(t => t !== name);
            updateTask(task.id, { tags: nextTags });
        }

        toast.success(`Tag "${name}" deleted`);
    } catch (err) {
        console.error("Failed to delete tag:", err);
        toast.error("Failed to delete tag.");
    }
};

export const updateNote = async (id: string, updates: Partial<Note>) => {
    if (!pb.authStore.isValid) return;

    // Optimistic update
    const optimisticUpdates = {
        ...updates,
        updated: new Date().toISOString()
    };
    setStore("notes", (n) => n.id === id, optimisticUpdates);

    try {
        const pbUpdates: any = { ...updates };

        if ("deletedAt" in updates) {
            if (updates.deletedAt) {
                pbUpdates.deletedAt = new Date(updates.deletedAt).toISOString();
            } else {
                pbUpdates.deletedAt = null;
            }
        }

        await pb.collection(NOTES_COLLECTION).update(id, pbUpdates, { requestKey: null });
    } catch (err) {
        console.error("Note update failed", err);
        toast.error("Failed to update note.");
    }
};

export const removeNote = (id: string) => {
    const nowTs = Date.now();
    updateNote(id, { deletedAt: nowTs });
};

export const restoreNote = (id: string) => {
    updateNote(id, { deletedAt: null });
};

export const deleteNotePermanently = async (id: string) => {
    if (!pb.authStore.isValid) return;

    // Optimistic
    setStore("notes", (n) => n.filter((n) => n.id !== id));

    try {
        await pb.collection(NOTES_COLLECTION).delete(id);
    } catch (err) {
        console.error("Note delete failed", err);
        toast.error("Failed to delete note.");
    }
};



export const syncSystemTagsAndRules = async () => {
    if (!pb.authStore.isValid) return;
    const currentUserId = pb.authStore.model?.id;

    try {
        // 1. Fetch data
        const [users, pbRules, tagDefinitions] = await Promise.all([
            pb.collection('users').getFullList({
                filter: 'verified = true',
                fields: 'id,name,email,verified',
                requestKey: null
            }),
            pb.collection(SHARE_RULES_COLLECTION).getFullList({
                filter: `ownerId = "${currentUserId}"`,
                requestKey: null
            }),
            pb.collection(TAGS_COLLECTION).getFullList({
                filter: `user = "${currentUserId}"`,
                requestKey: null
            })
        ]);

        const normalizedRules = pbRules.map(r => ({
            id: r.id,
            ownerId: r.ownerId,
            targetUserId: r.targetUserId,
            type: r.type,
            tagName: r.tagName
        }));

        // Fetch task content on demand
        // We'll call this when a task is opened

        // --- Sync Bucket Tags ---
        for (const bucket of store.buckets) {
            const bucketTagName = `@${bucket.name}`;
            const tagExistsExact = tagDefinitions.find(t => t.name.toLowerCase() === bucketTagName.toLowerCase());
            if (!tagExistsExact) {
                try {
                    const record = await pb.collection(TAGS_COLLECTION).create({
                        user: currentUserId,
                        name: bucketTagName,
                        value: 5,
                        color: bucket.color || "#64748b",
                        theme: "dark",
                        isBucket: true
                    }, { requestKey: null });
                    setStore("tagDefinitions", prev => [...prev, {
                        id: record.id,
                        name: record.name,
                        value: record.value,
                        color: record.color,
                        theme: record.theme,
                        isBucket: true
                    }]);
                } catch (e) {
                    console.error(`Failed to create bucket tag ${bucketTagName}`, e);
                }
            } else if (!tagExistsExact.isBucket) {
                try {
                    await pb.collection(TAGS_COLLECTION).update(tagExistsExact.id, { isBucket: true }, { requestKey: null });
                    setStore("tagDefinitions", d => d.id === tagExistsExact.id, { isBucket: true });
                } catch (e) {
                    console.error(`Failed to flag tag ${bucketTagName} as bucket`, e);
                }
            }
            // --- Sync Bucket System Rule ---
            const bucketRuleExact = normalizedRules.find(r =>
                r.ownerId === currentUserId &&
                r.targetUserId === currentUserId &&
                r.type === 'tag' &&
                r.tagName === bucketTagName
            );
            const bucketRuleLegacy = normalizedRules.find(r =>
                r.ownerId === currentUserId &&
                r.targetUserId === currentUserId &&
                r.type === 'tag' &&
                r.tagName === bucket.name
            );

            if (bucketRuleLegacy && !bucketRuleExact) {
                // Rename legacy rule
                try {
                    await pb.collection(SHARE_RULES_COLLECTION).update(bucketRuleLegacy.id, { tagName: bucketTagName }, { requestKey: null });
                    setStore("shareRules", r => r.id === bucketRuleLegacy.id, { tagName: bucketTagName });
                    console.log(`Renamed legacy bucket rule: ${bucket.name} -> ${bucketTagName}`);
                } catch (e) {
                    console.error(`Failed to rename legacy bucket rule ${bucket.name}`, e);
                }
            } else if (!bucketRuleExact) {
                try {
                    await pb.collection(SHARE_RULES_COLLECTION).create({
                        ownerId: currentUserId,
                        targetUserId: currentUserId,
                        type: 'tag',
                        tagName: bucketTagName,
                        share_mode: 'SEND_TASK'
                    }, { requestKey: null });
                } catch (e) {
                    console.error(`Failed to ensure system rule for bucket ${bucketTagName}`, e);
                }
            }
        }

        // --- Sync User Tags ---
        for (const user of users) {
            const originalName = user.name || user.email;
            if (!originalName) continue;
            const userName = `@${originalName}`;

            const tagExistsExact = tagDefinitions.find(t => t.name.toLowerCase() === userName.toLowerCase());
            if (!tagExistsExact) {
                try {
                    const record = await pb.collection(TAGS_COLLECTION).create({
                        user: currentUserId,
                        name: userName,
                        value: 5,
                        color: "#64748b",
                        theme: "dark",
                        isUser: true
                    }, { requestKey: null });
                    setStore("tagDefinitions", prev => [...prev, {
                        id: record.id,
                        name: record.name,
                        value: record.value,
                        color: record.color,
                        theme: record.theme,
                        isUser: true
                    }]);
                } catch (e) {
                    // console.error(`Failed to create user tag ${userName}`, e);
                }
            } else if (!tagExistsExact.isUser) {
                try {
                    await pb.collection(TAGS_COLLECTION).update(tagExistsExact.id, { isUser: true }, { requestKey: null });
                    setStore("tagDefinitions", d => d.id === tagExistsExact.id, { isUser: true });
                } catch (e) {
                    console.error(`Failed to flag tag ${userName} as user`, e);
                }
            }

            // --- Ensure Self-Rule for Current User (Global Subscription) ---
            if (user.id === currentUserId) {
                const selfRuleExact = normalizedRules.find(r =>
                    r.ownerId === currentUserId &&
                    r.targetUserId === currentUserId &&
                    r.type === 'tag' &&
                    r.tagName === userName
                );
                const selfRuleLegacy = normalizedRules.find(r =>
                    r.ownerId === currentUserId &&
                    r.targetUserId === currentUserId &&
                    r.type === 'tag' &&
                    r.tagName === originalName
                );

                if (selfRuleLegacy && !selfRuleExact) {
                    // Rename legacy self-rule
                    try {
                        await pb.collection(SHARE_RULES_COLLECTION).update(selfRuleLegacy.id, { tagName: userName }, { requestKey: null });
                        setStore("shareRules", r => r.id === selfRuleLegacy.id, { tagName: userName });
                        console.log(`Renamed legacy self-rule: ${originalName} -> ${userName}`);
                    } catch (e) {
                        console.error(`Failed to rename legacy self-rule ${originalName}`, e);
                    }
                } else if (!selfRuleExact) {
                    try {
                        const record = await pb.collection(SHARE_RULES_COLLECTION).create({
                            ownerId: currentUserId,
                            targetUserId: currentUserId,
                            type: 'tag',
                            tagName: userName,
                            share_mode: 'ADD_USER'
                        }, { requestKey: null });

                        const newRule: ShareRule = {
                            id: record.id,
                            ownerId: currentUserId,
                            targetUserId: currentUserId,
                            type: 'tag',
                            tagName: userName,
                            share_mode: 'ADD_USER'
                        };
                        setStore("shareRules", prev => [...prev, newRule]);

                        console.log(`Created self-rule for global sharing: ${userName}`);
                    } catch (e) {
                        console.error(`Failed to create self-rule for ${userName}`, e);
                    }
                }
            }
        }

    } catch (err) {
        console.error("Failed to sync system tags/rules:", err);
    }
};

export const renameTagDefinition = async (oldName: string, newName: string) => {
    if (!newName || !newName.trim() || newName === oldName) return;
    if (!pb.authStore.isValid) return;

    const def = store.tagDefinitions.find(d => d.name === oldName);
    if (!def) return;

    const finalName = newName.trim();
    const finalNameLower = finalName.toLowerCase();

    // Check availability (case-insensitive)
    const duplicate = store.tagDefinitions.find(d => d.name.toLowerCase() === finalNameLower && d.id !== def.id);
    if (duplicate) {
        toast.error(`Tag "${duplicate.name}" already exists.`);
        return;
    }

    try {
        await pb.collection(TAGS_COLLECTION).update(def.id, { name: finalName }, { requestKey: null });
        setStore("tagDefinitions", (d) => d.id === def.id, { name: finalName });

        const tasksWithTag = store.tasks.filter(t => t.tags?.includes(oldName));
        for (const task of tasksWithTag) {
            const newTags = task.tags.map(t => t === oldName ? finalName : t);
            const uniqueTags = [...new Set(newTags)];
            updateTask(task.id, { tags: uniqueTags });
        }

        // Sync Share Rules
        const rulesWithTag = store.shareRules.filter(r => r.tagName === oldName);
        for (const rule of rulesWithTag) {
            try {
                await pb.collection(SHARE_RULES_COLLECTION).update(rule.id, { tagName: finalName }, { requestKey: null });
                setStore("shareRules", (r) => r.id === rule.id, { tagName: finalName });
                console.log(`Synced ShareRule ${rule.id}: ${oldName} -> ${finalName}`);
            } catch (ruleErr) {
                console.error(`Failed to sync ShareRule ${rule.id} during tag rename:`, ruleErr);
            }
        }
    } catch (err) {
        console.error("Failed to rename tag:", err);
        toast.error("Failed to rename tag.");
    }
};

// --- HISTORY ACTIONS ---

export const loadAllHistory = async () => {
    if (!pb.authStore.isValid) return;
    const userId = pb.authStore.model?.id;
    if (!userId) return;

    try {
        toast.promise(
            (async () => {
                // Fetch ALL tasks for user (including completed)
                // We use a simplified query for the user's own history + shared items
                // Note: This matches the components of the background sync but without the 'completed=false' restriction
                const bucketNames = store.subscribedBuckets
                    .map(id => store.buckets.find(b => b.id === id)?.name)
                    .filter(Boolean);

                const promises = [
                    pb.collection(TASGRID_COLLECTION).getFullList({ filter: `user = "${userId}"`, sort: '-created', fields: LIST_FIELDS, requestKey: null }),
                    pb.collection(TASGRID_COLLECTION).getFullList({ filter: `sharedWith ~ "${userId}"`, sort: '-created', fields: LIST_FIELDS, requestKey: null }).catch(() => [])
                ];

                if (bucketNames.length > 0) {
                    promises.push(pb.collection(TASGRID_COLLECTION).getFullList({
                        filter: bucketNames.map(name => `tags ~ "${name}"`).join(' || '),
                        sort: '-created',
                        fields: LIST_FIELDS,
                        requestKey: null
                    }).catch(() => []));
                }



                // Add Share Rules
                const incomingRules = store.shareRules.filter(r => r.targetUserId === userId);
                console.log("[DEBUG] loadAllHistory - Incoming Rules for User:", userId, incomingRules);

                if (incomingRules.length > 0) {
                    const rulesToFetch: string[] = [];

                    incomingRules.forEach((rule: any) => {
                        // Global Rule (Self-Targeted)
                        if (rule.ownerId === rule.targetUserId && rule.type === 'tag' && rule.tagName) {
                            console.log("[DEBUG] Found Self-Rule:", rule.tagName);
                            rulesToFetch.push(`tags ~ "${rule.tagName}"`);
                        } else {
                            // Standard Rule
                            let f = `user = "${rule.ownerId}"`;
                            if (rule.type === 'tag' && rule.tagName) f += ` && tags ~ "${rule.tagName}"`;
                            rulesToFetch.push(f);
                        }
                    });

                    // Optimization: Group Global Rules?
                    // For now, simpler to just push them all.
                    // But if we have many global rules (e.g. buckets), we might want to group them.
                    // The Global Rules usually behave like buckets.
                    // Let's just push them as individual queries for safety.

                    rulesToFetch.forEach(filter => {
                        console.log("[DEBUG] Fetching with filter:", filter);
                        promises.push(pb.collection(TASGRID_COLLECTION).getFullList({ filter, sort: '-created', fields: LIST_FIELDS, requestKey: null }).then(res => {
                            console.log(`[DEBUG] Filter "${filter}" returned ${res.length} items`);
                            return res;
                        }).catch(err => {
                            console.error(`[DEBUG] Filter "${filter}" FAILED:`, err);
                            return [];
                        }));
                    });
                }

                const results = await Promise.all(promises);
                const allRecords = results.flat();

                setStore("tasks", (currentTasks) => {
                    const taskMap = new Map(currentTasks.map(t => [t.id, t]));
                    let addedCount = 0;
                    allRecords.forEach((r: any) => {
                        if (r.tags?.includes("__template__")) return;
                        if (!taskMap.has(r.id)) {
                            taskMap.set(r.id, mapRecordToTask(r));
                            addedCount++;
                        }
                    });
                    return Array.from(taskMap.values());
                });

                return `Loaded history.`;
            })(),
            {
                loading: 'Loading full history...',
                success: (msg) => msg,
                error: 'Failed to load history'
            }
        );
    } catch (err) {
        console.error("Failed to load history:", err);
    }
};

export const loadTaskContent = async (id: string) => {
    if (!pb.authStore.isValid) return;
    try {
        const record = await pb.collection(TASGRID_COLLECTION).getOne(id, { requestKey: null });
        // Only update if content is still undefined (i.e. not edited locally while loading)
        setStore("tasks", t => t.id === id && t.content === undefined, { content: record.content });
    } catch (err) {
        console.error("Failed to load task content:", err);
    }
};


// -- Templates --

export const syncPreferences = async () => {
    const userId = pb.authStore.model?.id;
    if (!userId) return;

    try {
        const prefs = {
            pWeight: store.pWeight,
            uWeight: store.uWeight,
            matrixScaleDays: store.matrixScaleDays,
            tagDefinitions: store.tagDefinitions,
            quickloadTasks: store.quickloadTasks
        };

        await pb.collection('users').update(userId, {
            Taskgrid_pref: prefs
        }, { requestKey: null });
    } catch (e: any) {
        if (e.isAbort) return;
        console.error("Failed to sync preferences", e);
        // We could toast here, but many of these are background syncs
    }
};

export const addTemplate = async (template: Omit<TaskTemplate, "id">) => {
    if (!pb.authStore.isValid) return;

    const meta = {
        title: template.title,
        urgency: template.urgency,
        tags: template.tags,
        content: template.content
    };

    try {
        const record = await pb.collection(TASGRID_COLLECTION).create({
            user: pb.authStore.model?.id,
            title: template.name,
            priority: template.priority,
            tags: ["__template__"],
            content: JSON.stringify(meta),
            completed: false,
            startDate: new Date().toISOString(),
            dueDate: new Date().toISOString()
        }, { requestKey: null });

        const newTemplate = { ...template, id: record.id };
        // Check if already added by realtime subscription
        setStore("templates", (prev) => {
            if (prev?.some(t => t.id === record.id)) return prev;
            return [...(prev || []), newTemplate];
        });
        return newTemplate;
    } catch (err) {
        console.error("Failed to add template:", err);
        toast.error("Failed to save template.");
    }
};

export const updateTemplate = async (id: string, updates: Partial<TaskTemplate>) => {
    if (!pb.authStore.isValid) return;

    // Optimistic
    setStore("templates", (t) => t!.id === id, updates);

    const template = store.templates?.find(t => t.id === id);
    if (!template) return;

    const meta = {
        title: template.title,
        urgency: template.urgency,
        tags: template.tags,
        content: template.content
    };

    try {
        await pb.collection(TASGRID_COLLECTION).update(id, {
            title: template.name,
            priority: template.priority,
            content: JSON.stringify(meta)
        }, { requestKey: null });
    } catch (err) {
        console.error("Failed to update template:", err);
        toast.error("Failed to update template.");
    }
};

export const removeTemplate = async (id: string) => {
    if (!pb.authStore.isValid) return;

    setStore("templates", (t) => (t || []).filter(tmpl => tmpl.id !== id));

    try {
        await pb.collection(TASGRID_COLLECTION).delete(id);
    } catch (err) {
        console.error("Failed to delete template:", err);
        toast.error("Failed to delete template.");
    }
};

export const saveTaskAsTemplate = async (taskId: string, name: string) => {
    const task = store.tasks.find(t => t.id === taskId);
    if (!task) return;

    const template: Omit<TaskTemplate, "id"> = {
        name,
        title: task.title,
        priority: task.priority,
        urgency: calculateUrgencyFromDate(task.dueDate),
        tags: [...(task.tags || [])],
        content: task.content || ""
    };

    return await addTemplate(template);
};

export const setFilter = (update: Partial<Filter>) => {
    setStore("filter", (f) => ({ ...f, ...update }));
};

// -- Sharing Functions --

export const shareTask = async (taskId: string, userId: string, access: 'view' | 'edit' = 'view') => {
    if (!pb.authStore.isValid) return;

    const task = store.tasks.find(t => t.id === taskId);
    if (!task) return;

    const existingShares = task.sharedWith || [];
    if (existingShares.some(s => s.userId === userId)) {
        toast.info(`Task is already shared with this user`);
        return;
    }

    const newShares = [...existingShares, { userId, access }];

    // Update task with new sharedWith
    await updateTask(taskId, { sharedWith: newShares });
    toast.success(`Task shared successfully`);
};

export const revokeShare = async (taskId: string, userId: string) => {
    if (!pb.authStore.isValid) return;

    const task = store.tasks.find(t => t.id === taskId);
    if (!task) return;

    const existingShares = task.sharedWith || [];
    const newShares = existingShares.filter(s => s.userId !== userId);

    await updateTask(taskId, { sharedWith: newShares });
    toast.success(`Share revoked`);
};

export const splitTask = async (taskId: string, userId: string) => {
    if (!pb.authStore.isValid) return;

    const task = store.tasks.find(t => t.id === taskId);
    if (!task) return;

    try {
        // Create a duplicate task owned by the target user
        const duplicateData = {
            user: userId,
            title: task.title,
            content: task.content,
            priority: task.priority,
            size: task.size,
            tags: task.tags,
            startDate: task.startDate,
            dueDate: task.dueDate,
            status: task.status,
            completed: task.completed,
            deletedAt: null,
            sharedWith: [], // Start fresh with no shares
            recurrence: task.recurrence
        };

        await pb.collection(TASGRID_COLLECTION).create(duplicateData, { requestKey: null });

        // Remove the user from the original task's sharedWith
        const existingShares = task.sharedWith || [];
        const newShares = existingShares.filter(s => s.userId !== userId);
        await updateTask(taskId, { sharedWith: newShares });

        toast.success(`Task split - user now has their own copy`);
    } catch (err: any) {
        console.error("Failed to split task:", err);
        console.error("Error details:", err.response?.data || err.data || err.message);
        toast.error("Failed to split task: " + (err.response?.data?.message || err.message || "Unknown error"));
    }
};

// -- Share Rules (for tag-based and all-tasks sharing) --



export const loadShareRules = async () => {
    if (!pb.authStore.isValid) return;

    try {
        const currentUserId = pb.authStore.model?.id;
        const records = await pb.collection(SHARE_RULES_COLLECTION).getFullList({
            filter: `ownerId = "${currentUserId}" || targetUserId = "${currentUserId}"`,
            requestKey: null
        });

        const rules: ShareRule[] = records.map(r => ({
            id: r.id,
            ownerId: r.ownerId,
            targetUserId: r.targetUserId,
            type: r.type as 'tag' | 'all',
            tagName: r.tagName,
            share_mode: r.share_mode || 'ADD_USER'
        }));

        setStore("shareRules", reconcile(rules));
    } catch (err) {
        console.error("Failed to load share rules:", err);
    }
};

export const addShareRule = async (type: 'tag' | 'all', targetUserId: string, tagName?: string, share_mode: 'ADD_USER' | 'SEND_TASK' = 'ADD_USER') => {
    if (!pb.authStore.isValid) return;

    // Check for duplicates
    // We check against the local store to avoid network round-trip delay issues
    const currentUserId = pb.authStore.model?.id;
    const exists = store.shareRules.some(r =>
        r.ownerId === currentUserId &&
        r.targetUserId === targetUserId &&
        r.type === type &&
        (type === 'all' || r.tagName === tagName)
        // We don't strictly check share_mode because having two rules for same tag/person with different modes is confusing.
        // Usually we update the existing one if mode changes.
    );

    if (exists) {
        // toast.info("Share rule already exists.");
        return; // Silent return or update?
    }

    try {
        await pb.collection(SHARE_RULES_COLLECTION).create({
            ownerId: pb.authStore.model?.id,
            targetUserId,
            type,
            tagName: type === 'tag' ? tagName : null,
            share_mode: share_mode || 'ADD_USER'
        }, { requestKey: null });
        // Realtime subscription will handle adding to store
        toast.success(`Share rule created`);
    } catch (err) {
        console.error("Failed to create share rule:", err);
        toast.error("Failed to create share rule. Make sure the collection exists in PocketBase.");
    }
};

export const updateShareRule = async (ruleId: string, updates: Partial<ShareRule>) => {
    if (!pb.authStore.isValid) return;

    try {
        await pb.collection(SHARE_RULES_COLLECTION).update(ruleId, updates, { requestKey: null });
        setStore("shareRules", (rules) =>
            rules.map(r => r.id === ruleId ? { ...r, ...updates } : r)
        );
        toast.success("Share rule updated");
    } catch (err) {
        console.error("Failed to update share rule:", err);
        toast.error("Failed to update share rule.");
    }
};

export const removeShareRule = async (ruleId: string) => {
    if (!pb.authStore.isValid) return;

    try {
        await pb.collection(SHARE_RULES_COLLECTION).delete(ruleId);
        setStore("shareRules", (rules) => rules.filter(r => r.id !== ruleId));
        toast.success("Share rule removed");
    } catch (err) {
        console.error("Failed to delete share rule:", err);
        toast.error("Failed to delete share rule.");
    }
};

// -- Filter Templates --
const FILTER_TEMPLATES_COLLECTION = 'TasGrid_FilterTemplates';

export const loadFilterTemplates = async () => {
    if (!pb.authStore.isValid) return;
    try {
        const records = await pb.collection(FILTER_TEMPLATES_COLLECTION).getFullList({
            filter: `user = "${pb.authStore.model?.id}"`,
            requestKey: null
        });
        const templates: FilterTemplate[] = records.map(r => ({
            id: r.id,
            name: r.name,
            filter: r.filter as Filter
        }));
        setStore("filterTemplates", templates);
    } catch (err) {
        console.error("Failed to load filter templates:", err);
    }
};

export const saveFilterTemplate = async (name: string) => {
    if (!pb.authStore.isValid) return;
    try {
        const record = await pb.collection(FILTER_TEMPLATES_COLLECTION).create({
            user: pb.authStore.model?.id,
            name,
            filter: store.filter
        }, { requestKey: null });

        const newTemplate: FilterTemplate = {
            id: record.id,
            name: record.name,
            filter: record.filter as Filter
        };

        setStore("filterTemplates", prev => [...prev, newTemplate]);
        toast.success(`Filter template "${name}" saved`);
    } catch (err) {
        console.error("Failed to save filter template:", err);
        toast.error("Failed to save filter template.");
    }
};

export const applyFilterTemplate = (id: string) => {
    const template = store.filterTemplates.find(t => t.id === id);
    if (template) {
        setFilter(template.filter);
        toast.success(`Applied filter: ${template.name}`);
    }
};

export const removeFilterTemplate = async (id: string) => {
    if (!pb.authStore.isValid) return;
    try {
        await pb.collection(FILTER_TEMPLATES_COLLECTION).delete(id);
        setStore("filterTemplates", prev => prev.filter(t => t.id !== id));
        toast.success("Filter template deleted");
    } catch (err) {
        console.error("Failed to delete filter template:", err);
        toast.error("Failed to delete filter template.");
    }
};

export const clearFilter = () => {
    setStore("filter", {
        query: "",
        tags: [],
        priorityMin: 1,
        priorityMax: 10,
        urgencyMin: 1,
        urgencyMax: 10,
        editedToday: false
    });
};

// Legacy cleanup - We don't need local storage persistence setup anymore
export const setupPersistence = () => {
    // Moved logic to initStore which is called on auth.
    // Keeping function signature to avoid breaking index.js calls immediately, 
    // but it will be empty or a no-op if called before auth.
    // Actually, index.tsx calls this. We can leave it empty or have it check auth.
    initStore();
};