// excelsync.js
import { FIELD_CONFIG } from "./fieldConfig.js";
import fs from "fs";
import axios from "axios";
import qs from "qs";
import dotenv from "dotenv";
import PocketBase from "pocketbase";

dotenv.config();

// -----------------------------
// EXCEL PARSER
// -----------------------------
const HEADER_ROW_INDEX = 2;       // 0-index → Row 3 actual
const DATA_START_ROW_INDEX = 3;   // 0-index → Row 4 actual

// -----------------------------
// CONFIG
// -----------------------------
const CONFIG = JSON.parse(fs.readFileSync("config.json", "utf8"));
const tenantId = CONFIG.tenantId;
const clientId = CONFIG.clientId;
const pbUrl = CONFIG.pbUrl;
const pbCollection = CONFIG.pbCollection || "Job_Info_TestEnv";
const pbEmail = CONFIG.pbEmail;
const clientSecret = process.env.CLIENT_SECRET;
const pbPassword = process.env.PB_PASSWORD;

// -----------------------------
// LOGGING
// -----------------------------
function log(message) {
  console.log(message);
  fs.appendFileSync("excelsync.log", message + "\n");
}

// -----------------------------
// GRAPH TOKEN
// -----------------------------
async function getGraphToken() {
  log("🔵 Requesting Graph token...");
  const tokenUrl = `https://login.microsoftonline.com/${tenantId}/oauth2/v2.0/token`;
  const body = qs.stringify({
    client_id: clientId,
    client_secret: clientSecret,
    scope: "https://graph.microsoft.com/.default",
    grant_type: "client_credentials",
  });
  const res = await axios.post(tokenUrl, body, {
    headers: { "Content-Type": "application/x-www-form-urlencoded" },
  });
  log("✅ Graph token acquired");
  return res.data.access_token;
}

// -----------------------------
// POCKETBASE LOGIN
// -----------------------------
async function getPocketBaseClient() {
  log("🔵 Logging into PocketBase...");
  const pb = new PocketBase(pbUrl);
  // ⚠️ CHANGE "users" if your auth collection is different
  await pb.collection("users").authWithPassword(pbEmail, pbPassword);
  log("✅ PocketBase token acquired");
  return pb;
}
// -----------------------------
// CLEAN + COERCE
// -----------------------------
function cleanString(value) {
  if (value == null) return "";
  return String(value).replace(/\u00A0/g, " ").trim();
}

function coerceValue(fieldConfig, rawValue) {
  switch (fieldConfig.type) {
    case "string": return cleanString(rawValue);
    case "bool": return ["true","1","yes","y"].includes(cleanString(rawValue).toLowerCase());
    case "date":
      if (typeof rawValue === "number") {
        const origin = new Date(Date.UTC(1899, 11, 30));
        return new Date(origin.getTime() + rawValue * 86400000).toISOString();
      }
      const d = new Date(cleanString(rawValue));
      return isNaN(d.getTime()) ? null : d.toISOString();
    case "number": return Number(cleanString(rawValue));
    case "json": try { return JSON.parse(cleanString(rawValue)); } catch { return null; }
    case "relation": return cleanString(rawValue);
    default: return cleanString(rawValue);
  }
}

// -----------------------------
// PAYLOAD BUILDER
// -----------------------------
export function buildPayload(headers, row) {
  const payload = {};
  headers.forEach((excelHeader, i) => {
    const fieldConfig = Object.values(FIELD_CONFIG).find(f => f.excelHeader === excelHeader);
    if (!fieldConfig) return;
    payload[fieldConfig.pbField] = coerceValue(fieldConfig, row[i]);
  });
  return payload;
}

// -----------------------------
// DIFFERENCE LOGGER + UPDATE CHECK
// -----------------------------
function logDifferences(pbRecord, headers, row) {
  const diffs = [];
  headers.forEach((excelHeader, i) => {
    const fieldConfig = Object.values(FIELD_CONFIG).find(f => f.excelHeader === excelHeader);
    if (!fieldConfig) return;
    const newValue = coerceValue(fieldConfig, row[i]);
    const currentValue = coerceValue(fieldConfig, pbRecord[fieldConfig.pbField]);
    if (newValue !== currentValue) {
      diffs.push({ field: fieldConfig.pbField, excelHeader, current: currentValue, incoming: newValue });
    }
  });
  if (diffs.length > 0) {
    log(`Differences detected for record: ${pbRecord.id}`);
    diffs.forEach(d => {
      log(`Field: ${d.field} (Excel: ${d.excelHeader})\n  Current: ${JSON.stringify(d.current)}\n  Incoming: ${JSON.stringify(d.incoming)}\n`);
    });
  }
}

export function needsUpdate(pbRecord, headers, row) {
  let hasDiff = false;
  headers.forEach((excelHeader, i) => {
    const fieldConfig = Object.values(FIELD_CONFIG).find(f => f.excelHeader === excelHeader);
    if (!fieldConfig) return;
    const newValue = coerceValue(fieldConfig, row[i]);
    const currentValue = coerceValue(fieldConfig, pbRecord[fieldConfig.pbField]);
    if (newValue !== currentValue) hasDiff = true;
  });
  if (hasDiff) logDifferences(pbRecord, headers, row);
  return hasDiff;
}
// -----------------------------
// GRAPH HELPERS
// -----------------------------
async function getUsedRangeInfo(graphToken, driveId, itemId, worksheetName) {
  log(`🔵 Requesting usedRange for ${worksheetName}`);
  const url = `https://graph.microsoft.com/v1.0/drives/${driveId}/items/${itemId}/workbook/worksheets('${worksheetName}')/usedRange`;
  const res = await axios.get(url, { headers: { Authorization: `Bearer ${graphToken}` } });
  log(`✅ Used range address: ${res.data.address}`);
  return res.data.address;
}

function extractLastColumn(address) {
  const match = address.match(/:([A-Z]+)\d+$/);
  if (!match) {
    log("⚠️ Falling back to column Z, check sheet width");
    return "Z";
  }
  return match[1];
}

async function fetchExcelRange(graphToken, driveId, itemId, worksheetName, range) {
  log(`🔵 Fetching range ${range} from worksheet ${worksheetName}`);
  const url = `https://graph.microsoft.com/v1.0/drives/${driveId}/items/${itemId}/workbook/worksheets('${worksheetName}')/range(address='${range}')`;
  const res = await axios.get(url, { headers: { Authorization: `Bearer ${graphToken}` } });
  log(`✅ Range ${range} returned ${res.data.values?.length || 0} rows`);
  return res.data.values || [];
}

async function fetchAllRows(graphToken, driveId, itemId, worksheetName, blockSize = 500) {
  const address = await getUsedRangeInfo(graphToken, driveId, itemId, worksheetName);
  const lastCol = extractLastColumn(address);

  let allRows = [];
  let startRow = 1;

  while (true) {
    const endRow = startRow + blockSize - 1;
    const range = `A${startRow}:${lastCol}${endRow}`;
    const rows = await fetchExcelRange(graphToken, driveId, itemId, worksheetName, range);

    if (!rows.length) break;
    allRows = allRows.concat(rows);

    if (rows.length < blockSize) break;
    startRow = endRow + 1;
  }

  return allRows;
}

// -----------------------------
// MAIN
// -----------------------------
(async () => {
  try {
    log("🔵 Checking token acquisition and excel readiness");

    const graphToken = await getGraphToken();
    const pb = await getPocketBaseClient();

    const driveId = "b!9YOqqr2xM0G2DFBwMEJYY4UzQgocFddEtpLYWuS9_AtkCKl2q8yjQJteQ7Ti4QSx";
    const itemId = "01SPNXLDSQTMG4F6BDANCLJU2FZKEDQLVU";
    const worksheetName = "Job Sheet";

    const rows = await fetchAllRows(graphToken, driveId, itemId, worksheetName);
    log(`✅ Total rows fetched: ${rows.length}`);

    if (!rows.length) {
      log("⚠️ No rows returned from Graph. Check driveId, itemId, and worksheetName.");
      return;
    }

    const headers = rows[HEADER_ROW_INDEX];
    const dataRows = rows.slice(DATA_START_ROW_INDEX);

    if (!headers || !Array.isArray(headers)) {
      log("❌ Header row not found at expected index. Verify HEADER_ROW_INDEX alignment.");
      return;
    }

    log(`✅ Headers detected: ${JSON.stringify(headers)}`);
    log(`✅ Data rows to process: ${dataRows.length}`);

    for (const row of dataRows) {
      if (!row || row.length === 0) continue; // skip empty rows

      const payload = buildPayload(headers, row);

      // Ensure primary key exists before querying PocketBase
      const jobNumber = payload.Job_Number;
      if (!jobNumber || String(jobNumber).trim() === "") {
        log("⚠️ Skipping row with missing Job_Number.");
        continue;
      }

      let existing = null;
      try {
        existing = await pb.collection(pbCollection).getFirstListItem(`Job_Number="${jobNumber}"`);
      } catch {
        existing = null;
      }

      if (!existing) {
        log(`➕ Creating new record: ${jobNumber}`);
        await pb.collection(pbCollection).create(payload);
      } else {
        if (needsUpdate(existing, headers, row)) {
          log(`✏️ Updating record: ${existing.id} (${jobNumber})`);
          await pb.collection(pbCollection).update(existing.id, payload);
        } else {
          log(`✅ No changes for record: ${existing.id} (${jobNumber})`);
        }
      }
    }

    log("✅ Sync complete, PocketBase updated!");
  } catch (err) {
    log("❌ Error, not ready for updating. " + (err?.message || err));
    process.exit(1);
  }
})();