'use strict';

/**
 * Migration: Fix double-counted rptOp.coverage on Job documents
 *
 * Background:
 *   The /reportOps endpoint previously computed coverage as:
 *     sum(App.totalSprayed) + sum(App.totalSprLength) × swathWidth × 1e-4
 *   The length-based term was intended to cover SatLoc/non-AgNav apps that have no
 *   totalSprayed area. Once totalSprLength was backfilled for ALL app types (including
 *   AgNav), the addition double-counted AgNav coverage because
 *   totalSprLength × swathWidth ≈ totalSprayed for AgNav data.
 *   Jobs whose pre-app reports were generated and saved while this logic was active
 *   have an inflated rptOp.coverage stored in DB.
 *
 * Fix:
 *   For each affected job, sum App.totalSprayed across all its applications and compare
 *   against the stored rptOp.coverage. If the stored value exceeds the fresh sum by more
 *   than 50%, the job is considered inflated and rptOp.coverage is reset to the fresh sum.
 *
 *   The 50% threshold is chosen because the double-count roughly doubles the coverage
 *   (AgNav: totalSprLength × swathWidth ≈ totalSprayed), so a genuine inflation shows
 *   a delta near 100%. The 50% guard safely excludes small floating-point drift and
 *   legitimate manual overrides while catching all real double-counted values.
 *
 *   Jobs where the stored value is at or below the fresh sum are left untouched —
 *   this preserves any intentional manual reductions entered by the user.
 *
 * Field updated:
 *   Job.rptOp.coverage  — reset to sum(App.totalSprayed) in ha when inflation > 50%
 *
 * Usage:
 *   node scripts/fix_rptop_coverage_double_count.js
 *   node scripts/fix_rptop_coverage_double_count.js --dry-run
 *   node scripts/fix_rptop_coverage_double_count.js --tier-days=30
 *   node scripts/fix_rptop_coverage_double_count.js --from-date=2025-01-01
 *   node scripts/fix_rptop_coverage_double_count.js --env ./environment_prod.env
 *
 * Options:
 *   --env <path>        Environment file (default: ./environment.env)
 *   --dry-run           Report only; make no DB writes
 *   --tier-days=N       Only process jobs created in the last N days
 *   --from-date=YYYY-MM-DD  Only process jobs created on/after this date (UTC)
 *   --batch-size=N      Jobs per bulkWrite flush (default: 50)
 */

// ─── Environment bootstrap (must run before any require that reads process.env) ─
const path = require('path');
const _args = process.argv.slice(2);
let envFile = './environment.env';
for (let i = 0; i < _args.length; i++) {
  if (_args[i] === '--env' && _args[i + 1]) { envFile = _args[i + 1]; i++; }
  else if (_args[i].startsWith('--env='))    { envFile = _args[i].split('=')[1]; }
}
require('dotenv').config({ path: path.resolve(process.cwd(), envFile) });

const debug = require('debug')('agm:fix-rptop-coverage');
const { DBConnection } = require('../helpers/db/connect.js');
const { Job, App } = require('../model/index.js');

// ─── Argument parsing ─────────────────────────────────────────────────────────
const DRY_RUN    = _args.includes('--dry-run');
const BATCH_SIZE = parseInt((_args.find(a => a.startsWith('--batch-size=')) || '').split('=')[1], 10) || 50;
const TIER_DAYS  = parseInt((_args.find(a => a.startsWith('--tier-days='))  || '').split('=')[1], 10) || 0;
const FROM_DATE  = (_args.find(a => a.startsWith('--from-date=')) || '').split('=')[1] || '';

const INFLATION_THRESHOLD = 0.5;  // only fix if stored exceeds fresh sum by > 50%

// ─── Main migration ───────────────────────────────────────────────────────────
async function migrate() {
  debug(`Starting${DRY_RUN ? ' (DRY RUN)' : ''}...`);

  const jobFilter = { 'rptOp.coverage': { $gt: 0 } };
  if (TIER_DAYS)   jobFilter.createdAt = { $gte: new Date(Date.now() - TIER_DAYS * 86400 * 1000) };
  if (FROM_DATE)   jobFilter.createdAt = { $gte: new Date(FROM_DATE + 'T00:00:00Z') };

  debug('Job filter: %o', jobFilter);

  const stats = { examined: 0, updated: 0, skipped: 0, noApps: 0, errors: 0, startedAt: Date.now() };
  let bulk = [];

  async function flushBulk() {
    if (!bulk.length) return;
    if (!DRY_RUN) await Job.bulkWrite(bulk, { ordered: false });
    bulk = [];
  }

  const cursor = Job
    .find(jobFilter)
    .select('_id rptOp')
    .sort({ _id: -1 })
    .lean()
    .cursor();

  for await (const job of cursor) {
    stats.examined++;

    try {
      const [agg] = await App.aggregate([
        { $match: { jobId: job._id, markedDelete: { $ne: true } } },
        { $group: { _id: null, totalSprayed: { $sum: '$totalSprayed' } } },
      ]);

      if (!agg || !agg.totalSprayed) {
        stats.noApps++;
        continue;
      }

      const stored = job.rptOp.coverage;
      const fresh  = agg.totalSprayed;
      const delta  = stored - fresh;

      // Only fix inflated values: stored must exceed fresh sum by > 50%
      if (delta / fresh <= INFLATION_THRESHOLD) {
        stats.skipped++;
        continue;
      }

      debug(`Job ${job._id}: stored=${stored.toFixed(4)} ha  fresh=${fresh.toFixed(4)} ha  over by ${delta.toFixed(4)} ha (${(delta / fresh * 100).toFixed(1)}%)`);

      bulk.push({
        updateOne: {
          filter: { _id: job._id },
          update: { $set: { 'rptOp.coverage': fresh } },
        },
      });
      stats.updated++;

      if (bulk.length >= BATCH_SIZE) await flushBulk();

    } catch (err) {
      debug(`Error on job ${job._id}: ${err.message}`);
      stats.errors++;
    }

    if (stats.examined % 100 === 0) {
      const elapsed = ((Date.now() - stats.startedAt) / 1000).toFixed(1);
      debug(`Progress: examined=${stats.examined} updated=${stats.updated} skipped=${stats.skipped} errors=${stats.errors} elapsed=${elapsed}s`);
    }
  }

  await flushBulk();

  const elapsed = ((Date.now() - stats.startedAt) / 1000).toFixed(1);
  debug('─'.repeat(60));
  debug('Migration complete.');
  debug(`  Examined : ${stats.examined}`);
  debug(`  Updated  : ${stats.updated}${DRY_RUN ? '  (dry-run — no writes)' : ''}`);
  debug(`  Skipped  : ${stats.skipped}  (stored coverage already correct)`);
  debug(`  No apps  : ${stats.noApps}  (job has no App records)`);
  debug(`  Errors   : ${stats.errors}`);
  debug(`  Duration : ${elapsed}s`);
  debug('─'.repeat(60));
}

// ─── Entry point ──────────────────────────────────────────────────────────────
const workerDB = new DBConnection('fix-rptop-coverage');
workerDB.initialize({
  setupExitHandlers: false,
  onReady: async () => {
    try {
      await migrate();
      process.exit(0);
    } catch (err) {
      debug('Migration failed:', err);
      process.exit(1);
    }
  }
});