import { createSignal, createEffect, onCleanup, untrack } from "solid-js";
import type { Task } from "@/store";

export function useDelayedSort(
    sourceTasks: () => Task[],
    sortFn: (a: Task, b: Task) => number,
    delayMs = 300
) {
    const initialTasks = untrack(() => [...sourceTasks()].sort(sortFn));
    const [displayedTasks, setDisplayedTasks] = createSignal<Task[]>(initialTasks);
    const [shakingTaskIds, setShakingTaskIds] = createSignal<string[]>([]);

    let timer: number | undefined;

    createEffect(() => {
        const sorted = [...sourceTasks()].sort(sortFn);
        const currentDisplayed = untrack(() => displayedTasks());

        // Initial load (though now handled by initial state, kept for safety if it resets)
        if (currentDisplayed.length === 0 && sorted.length > 0) {
            setDisplayedTasks(sorted);
            return;
        }

        // Check if anything fundamentally changed order
        const newIds = sorted.map(t => t.id).join(',');
        const oldIds = currentDisplayed.map(t => t.id).join(',');

        if (newIds !== oldIds) {
            // Find which IDs have moved or changed their presence
            // To be safe, let's just shake all currently visible ones, or maybe just the ones moving.
            // A simple "shake everything" works perfectly for a brief warning: "Items are shifting!"
            // The user wanted "tasks an animation when they rearange where they shake"
            const changedSet = new Set<string>();
            sorted.forEach((t: Task, i: number) => {
                if (currentDisplayed[i]?.id !== t.id) {
                    changedSet.add(t.id);
                    if (currentDisplayed[i]) changedSet.add(currentDisplayed[i].id);
                }
            });

            if (changedSet.size > 0) {
                setShakingTaskIds(Array.from(changedSet));

                if (timer) clearTimeout(timer);
                timer = window.setTimeout(() => {
                    setShakingTaskIds([]);
                    setDisplayedTasks(sorted);
                }, delayMs);
            } else {
                setDisplayedTasks(sorted);
            }
        } else {
            // Identical order, just data updates (e.g. title changes)
            // We want these to pass through instantly without rearranging
            setDisplayedTasks(sorted);
        }
    });

    onCleanup(() => {
        if (timer) clearTimeout(timer);
    });

    return { displayedTasks, shakingTaskIds };
}