/**
 * One-shot: backfill `interests.source` for legacy NocoDB-imported rows.
 *
 * Why this exists: the legacy NocoDB Interests table left the `Source`
 * column null for ~95 % of rows. The migration mapped null → null, so the
 * Lead Source Attribution chart shows them as "Unspecified". Per the
 * operator's best knowledge, almost all of those legacy rows came in
 * through the website (web form / portal) — the few that didn't are the
 * ones that already carry an explicit `Source` value (Form / portal /
 * External). Defaulting null → 'website' is therefore the closest
 * truth we can reconstruct without per-row sales notes review.
 *
 * Idempotent: only updates rows where `source IS NULL` AND the row has a
 * `migration_source_links` entry tying it back to the legacy NocoDB import,
 * so net-new manually-created interests with null source aren't touched.
 *
 * Usage:
 *   pnpm tsx scripts/backfill-legacy-lead-source.ts --port-slug port-nimara [--dry-run]
 */
import 'dotenv/config';
import { eq, and, isNull, inArray } from 'drizzle-orm';

import { db } from '@/lib/db';
import { ports } from '@/lib/db/schema/ports';
import { interests } from '@/lib/db/schema/interests';
import { migrationSourceLinks } from '@/lib/db/schema/migration';

interface CliArgs {
  portSlug: string | null;
  dryRun: boolean;
}

function parseArgs(argv: string[]): CliArgs {
  const args: CliArgs = { portSlug: null, dryRun: false };
  for (let i = 0; i < argv.length; i += 1) {
    const a = argv[i]!;
    if (a === '--port-slug') args.portSlug = argv[++i] ?? null;
    else if (a === '--dry-run') args.dryRun = true;
    else if (a === '-h' || a === '--help') {
      console.log(
        'Usage: pnpm tsx scripts/backfill-legacy-lead-source.ts --port-slug <slug> [--dry-run]',
      );
      process.exit(0);
    }
  }
  if (!args.portSlug) {
    console.error('Missing required --port-slug');
    process.exit(1);
  }
  return args;
}

async function main() {
  const args = parseArgs(process.argv.slice(2));

  const [port] = await db
    .select({ id: ports.id, name: ports.name })
    .from(ports)
    .where(eq(ports.slug, args.portSlug!))
    .limit(1);
  if (!port) {
    console.error(`No port found with slug "${args.portSlug}"`);
    process.exit(1);
  }
  console.log(`[backfill] target: ${port.name} (${port.id})`);

  // Pull every interest id this port owns that has a NULL source.
  const candidateInterests = await db
    .select({ id: interests.id })
    .from(interests)
    .where(and(eq(interests.portId, port.id), isNull(interests.source)));

  console.log(`[backfill] interests with NULL source in this port: ${candidateInterests.length}`);

  if (candidateInterests.length === 0) {
    console.log('Nothing to backfill.');
    return;
  }

  // Filter to ONLY those that came in via the legacy migration — preserves
  // null on net-new rows where the operator hasn't picked a source yet.
  const candidateIds = candidateInterests.map((r) => r.id);
  const legacyLinks = await db
    .select({ targetEntityId: migrationSourceLinks.targetEntityId })
    .from(migrationSourceLinks)
    .where(
      and(
        eq(migrationSourceLinks.sourceSystem, 'nocodb_interests'),
        eq(migrationSourceLinks.targetEntityType, 'interest'),
        inArray(migrationSourceLinks.targetEntityId, candidateIds),
      ),
    );

  const legacyIds = new Set(legacyLinks.map((l) => l.targetEntityId));
  const toUpdate = candidateIds.filter((id) => legacyIds.has(id));

  console.log(
    `[backfill] of those, ${toUpdate.length} are legacy migration rows (will set source='website')`,
  );
  console.log(
    `[backfill] ${candidateInterests.length - toUpdate.length} are net-new rows (left untouched)`,
  );

  if (args.dryRun) {
    console.log('[backfill] --dry-run set; no writes.');
    return;
  }

  if (toUpdate.length === 0) {
    console.log('Nothing to write.');
    return;
  }

  // Update in chunks of 500 to keep query size sane.
  const CHUNK = 500;
  let updated = 0;
  for (let i = 0; i < toUpdate.length; i += CHUNK) {
    const chunk = toUpdate.slice(i, i + CHUNK);
    // Belt-and-suspenders: re-assert `source IS NULL` in the WHERE so
    // a concurrent process that set source on one of these rows
    // between SELECT and UPDATE doesn't get its value clobbered.
    const result = await db
      .update(interests)
      .set({ source: 'website' })
      .where(and(inArray(interests.id, chunk), isNull(interests.source)))
      .returning({ id: interests.id });
    updated += result.length;
  }
  console.log(`[backfill] updated ${updated} rows.`);
}

main().catch((err) => {
  console.error('FATAL', err);
  process.exit(1);
});