/**
 * Directus → MongoDB migration script
 *
 * Run from the backend directory:
 *   npx tsx scripts/migrate-directus.ts
 *
 * What it does:
 *   - Fetches all records from db.lad1908.org (updates, events, minutes, deaffocus)
 *   - Downloads publicly-accessible PDFs into uploads/documents/
 *   - Downloads publicly-accessible images into uploads/images/
 *   - Inserts records into MongoDB (skips existing directusId to allow re-runs)
 *   - Writes scripts/migration-report.json with a full manifest
 */

import 'dotenv/config';
import mongoose from 'mongoose';
import fs from 'fs-extra';
import path from 'path';
import https from 'https';
import http from 'http';
import { fileURLToPath } from 'url';

import Update from '../src/models/Update.js';
import Article from '../src/models/Article.js';
import Event from '../src/models/Event.js';
import Document from '../src/models/Document.js';

const __dirname = path.dirname(fileURLToPath(import.meta.url));
const BACKEND_ROOT = path.resolve(__dirname, '..');
const DIRECTUS = 'https://db.lad1908.org';

// ── helpers ──────────────────────────────────────────────────────────────────

async function connectDB() {
  const user = process.env.MONGO_USER;
  const pass = process.env.MONGO_PASSWORD;
  const host = process.env.MONGO_HOST || 'localhost';
  const port = process.env.MONGO_PORT || '27017';
  const db   = process.env.MONGO_DB   || 'lad_db';
  const uri  = user && pass
    ? `mongodb://${user}:${pass}@${host}:${port}/${db}?authSource=${db}`
    : `mongodb://${host}:${port}/${db}`;
  await mongoose.connect(uri);
  console.log('✓ MongoDB connected');
}

async function fetchAll(collection: string): Promise<any[]> {
  const results: any[] = [];
  const limit = 100;
  let offset = 0;
  while (true) {
    const url = `${DIRECTUS}/items/${collection}?limit=${limit}&offset=${offset}`;
    const res = await fetch(url);
    if (!res.ok) throw new Error(`Directus ${collection} fetch failed: ${res.status}`);
    const json: any = await res.json();
    const batch: any[] = json.data ?? [];
    results.push(...batch);
    if (batch.length < limit) break;
    offset += limit;
  }
  return results;
}

function downloadFile(url: string, dest: string): Promise<{ ok: boolean; size: number }> {
  return new Promise((resolve) => {
    const proto = url.startsWith('https') ? https : http;
    const req = proto.get(url, (res) => {
      if (res.statusCode === 301 || res.statusCode === 302) {
        return downloadFile(res.headers.location!, dest).then(resolve);
      }
      if (res.statusCode !== 200) {
        res.resume();
        return resolve({ ok: false, size: 0 });
      }
      const stream = fs.createWriteStream(dest);
      let size = 0;
      res.on('data', (chunk: Buffer) => { size += chunk.length; });
      res.pipe(stream);
      stream.on('finish', () => resolve({ ok: true, size }));
      stream.on('error', () => resolve({ ok: false, size: 0 }));
    });
    req.on('error', () => resolve({ ok: false, size: 0 }));
  });
}

function safeFilename(prefix: string, id: number, date: string, ext: string): string {
  return `${prefix}-${date.replace(/[^0-9-]/g, '')}-${id}${ext}`;
}

function mapMinutesType(type: string | null): string {
  switch (type) {
    case 'Board Meeting':      return 'board_meeting_minutes';
    case 'Committee Meeting':  return 'committee_meeting_minutes';
    case 'Quarterly Meeting':  return 'quarterly_meeting_minutes';
    case 'Conference Minutes': return 'conference_minutes';
    case 'Financial Report':   return 'financial_report';
    case 'Special Meeting':    return 'special_meeting_minutes';
    default:                   return 'meeting_minutes';
  }
}

// ── main ─────────────────────────────────────────────────────────────────────

interface Report {
  startedAt: string;
  finishedAt?: string;
  inserted: Record<string, number>;
  skipped: Record<string, number>;
  downloadedFiles: number;
  failedDownloads: { collection: string; directusId: number; assetId: string; reason: string }[];
  membersOnlyPDFs: { directusId: number; date: string; type: string; assetId: string }[];
  errors: { collection: string; directusId: number; message: string }[];
}

async function main() {
  await connectDB();

  await fs.ensureDir(path.join(BACKEND_ROOT, 'uploads/documents'));
  await fs.ensureDir(path.join(BACKEND_ROOT, 'uploads/images'));

  const report: Report = {
    startedAt: new Date().toISOString(),
    inserted: { updates: 0, events: 0, minutes: 0, articles: 0 },
    skipped:  { updates: 0, events: 0, minutes: 0, articles: 0 },
    downloadedFiles: 0,
    failedDownloads: [],
    membersOnlyPDFs: [],
    errors: []
  };

  // ── UPDATES ────────────────────────────────────────────────────────────────
  console.log('\n── Fetching updates…');
  const directusUpdates = await fetchAll('updates');
  console.log(`   Found ${directusUpdates.length} records`);

  for (const r of directusUpdates) {
    if (!r.id) continue;
    const exists = await Update.findOne({ directusId: r.id });
    if (exists) { report.skipped.updates++; continue; }

    let photoUrl: string | undefined;
    if (r.main_photo) {
      const assetUrl = `${DIRECTUS}/assets/${r.main_photo}`;
      const fname    = safeFilename('update', r.id, r.date ?? 'undated', '.jpg');
      const dest     = path.join(BACKEND_ROOT, 'uploads/images', fname);
      const dl       = await downloadFile(assetUrl, dest);
      if (dl.ok) {
        photoUrl = `uploads/images/${fname}`;
        report.downloadedFiles++;
      } else {
        photoUrl = assetUrl; // fall back to Directus URL; replace when images are provided
        report.failedDownloads.push({ collection: 'updates', directusId: r.id, assetId: r.main_photo, reason: '403 or unreachable' });
      }
    }

    try {
      await new Update({
        directusId:   r.id,
        title:        r.title ?? '(untitled)',
        date:         r.date ? new Date(r.date) : new Date(r.created_on),
        body:         r.info ?? '',
        status:       r.status === 'published' ? 'published' : 'draft',
        photoUrl,
        photoCaption: r.main_photo_caption ?? undefined,
        videoUrl:     r.video ?? undefined,
        gallery:      Array.isArray(r.gallery) ? r.gallery : []
      }).save();
      report.inserted.updates++;
    } catch (e: any) {
      report.errors.push({ collection: 'updates', directusId: r.id, message: e.message });
    }
  }
  console.log(`   Inserted ${report.inserted.updates}, skipped ${report.skipped.updates}`);

  // ── EVENTS ─────────────────────────────────────────────────────────────────
  console.log('\n── Fetching events…');
  const directusEvents = await fetchAll('events');
  console.log(`   Found ${directusEvents.length} records`);

  for (const r of directusEvents) {
    if (!r.id) continue;
    const exists = await Event.findOne({ directusId: r.id });
    if (exists) { report.skipped.events++; continue; }

    let photoUrl: string | undefined;
    if (r.main_photo) {
      const assetUrl = `${DIRECTUS}/assets/${r.main_photo}`;
      const fname    = safeFilename('event', r.id, r.date ?? 'undated', '.jpg');
      const dest     = path.join(BACKEND_ROOT, 'uploads/images', fname);
      const dl       = await downloadFile(assetUrl, dest);
      if (dl.ok) {
        photoUrl = `uploads/images/${fname}`;
        report.downloadedFiles++;
      } else {
        photoUrl = assetUrl;
        report.failedDownloads.push({ collection: 'events', directusId: r.id, assetId: r.main_photo, reason: '403 or unreachable' });
      }
    }

    try {
      await new Event({
        directusId:          r.id,
        title:               r.title ?? '(untitled)',
        description:         r.info?.trim() || 'No description provided',
        date:                r.date ? new Date(r.date) : new Date(r.created_on),
        time:                'TBD',
        location:            'TBD',
        category:            'general',
        status:              r.status === 'published' ? 'published' : 'draft',
        registrationRequired: false,
        registeredCount:     0,
        photoUrl,
        photoCaption:        r.main_photo_caption ?? undefined
      }).save();
      report.inserted.events++;
    } catch (e: any) {
      report.errors.push({ collection: 'events', directusId: r.id, message: e.message });
    }
  }
  console.log(`   Inserted ${report.inserted.events}, skipped ${report.skipped.events}`);

  // ── MINUTES ────────────────────────────────────────────────────────────────
  console.log('\n── Fetching minutes…');
  const directusMinutes = await fetchAll('minutes');
  console.log(`   Found ${directusMinutes.length} records`);

  for (const r of directusMinutes) {
    if (!r.id) continue;
    const exists = await Document.findOne({ directusId: r.id });
    if (exists) { report.skipped.minutes++; continue; }

    if (r.members_only) {
      report.membersOnlyPDFs.push({
        directusId: r.id,
        date:       r.date ?? '',
        type:       r.type ?? '',
        assetId:    r.attachment ?? ''
      });
      report.skipped.minutes++;
      continue;
    }

    if (!r.attachment) {
      report.errors.push({ collection: 'minutes', directusId: r.id, message: 'No attachment UUID' });
      continue;
    }

    const assetUrl = `${DIRECTUS}/assets/${r.attachment}`;
    const dateStr  = (r.date ?? 'undated').substring(0, 10);
    const fname    = safeFilename('minutes', r.id, dateStr, '.pdf');
    const dest     = path.join(BACKEND_ROOT, 'uploads/documents', fname);
    const dl       = await downloadFile(assetUrl, dest);

    if (!dl.ok) {
      report.failedDownloads.push({ collection: 'minutes', directusId: r.id, assetId: r.attachment, reason: '403 or unreachable' });
      continue;
    }
    report.downloadedFiles++;

    const title = `${r.type ?? 'Meeting'} — ${dateStr}`;

    try {
      await new Document({
        directusId:           r.id,
        directusAssetId:      r.attachment,
        title,
        description:          title,
        filePath:             `uploads/documents/${fname}`,
        originalFilename:     fname,
        fileType:             'pdf',
        fileSize:             dl.size,
        documentType:         mapMinutesType(r.type),
        isPublic:             true,
        meetingDate:          r.date ? new Date(r.date) : undefined,
        uploadDate:           new Date(r.created_on),
        lastModified:         new Date(r.created_on),
        accessibilityChecked: false,
        hasTextVersion:       false
      }).save();
      report.inserted.minutes++;
    } catch (e: any) {
      report.errors.push({ collection: 'minutes', directusId: r.id, message: e.message });
    }
  }
  console.log(`   Inserted ${report.inserted.minutes}, skipped ${report.skipped.minutes} (${report.membersOnlyPDFs.length} members-only)`);

  // ── DEAF FOCUS ARTICLES ────────────────────────────────────────────────────
  console.log('\n── Fetching Deaf Focus articles…');
  const directusArticles = await fetchAll('deaffocus');
  console.log(`   Found ${directusArticles.length} records`);

  for (const r of directusArticles) {
    if (!r.id) continue;
    const exists = await Article.findOne({ directusId: r.id });
    if (exists) { report.skipped.articles++; continue; }

    try {
      await new Article({
        directusId: r.id,
        title:      r.title ?? '(untitled)',
        body:       r.body ?? '',
        order:      r.order ?? 0,
        status:     'published'
      }).save();
      report.inserted.articles++;
    } catch (e: any) {
      report.errors.push({ collection: 'articles', directusId: r.id, message: e.message });
    }
  }
  console.log(`   Inserted ${report.inserted.articles}, skipped ${report.skipped.articles}`);

  // ── REPORT ─────────────────────────────────────────────────────────────────
  report.finishedAt = new Date().toISOString();
  const reportPath  = path.join(__dirname, 'migration-report.json');
  await fs.writeJSON(reportPath, report, { spaces: 2 });

  console.log('\n══════════════════════════════════════════');
  console.log('Migration complete');
  console.log(`  Updates inserted:    ${report.inserted.updates}`);
  console.log(`  Events inserted:     ${report.inserted.events}`);
  console.log(`  Minutes inserted:    ${report.inserted.minutes}`);
  console.log(`  Articles inserted:   ${report.inserted.articles}`);
  console.log(`  Files downloaded:    ${report.downloadedFiles}`);
  console.log(`  Members-only PDFs:   ${report.membersOnlyPDFs.length} (manual upload needed)`);
  console.log(`  Failed downloads:    ${report.failedDownloads.length}`);
  console.log(`  Errors:              ${report.errors.length}`);
  console.log(`  Full report:         scripts/migration-report.json`);
  console.log('══════════════════════════════════════════\n');

  if (report.membersOnlyPDFs.length > 0) {
    console.log('Members-only PDFs that need manual upload via the admin panel:');
    for (const m of report.membersOnlyPDFs) {
      console.log(`  [${m.directusId}] ${m.date} — ${m.type} (asset: ${m.assetId})`);
    }
  }

  await mongoose.disconnect();
}

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