#!/usr/bin/env node

import express from 'express';
import cors from 'cors';
import path from 'path';
import { fileURLToPath } from 'url';
import fs from 'fs';
import zlib from 'zlib';
import chokidar from 'chokidar';
import { meiliClient, vaultIndexName, ensureIndexSettings } from './meilisearch.client.mjs';
import { fullReindex, upsertFile, deleteFile } from './meilisearch-indexer.mjs';
import { mapObsidianQueryToMeili, buildSearchParams } from './search.mapping.mjs';
import { PORT as CFG_PORT, VAULT_PATH as CFG_VAULT_PATH, debugPrintConfig } from './config.mjs';
import { z } from 'zod';
import { 
  parseExcalidrawAny, 
  toObsidianExcalidrawMd, 
  extractFrontMatter, 
  isValidExcalidrawScene 
} from './excalidraw-obsidian.mjs';
import { rewriteTagsFrontmatter, extractTagsFromFrontmatter } from './markdown-frontmatter.mjs';
import { enrichFrontmatterOnOpen } from './ensureFrontmatter.mjs';
import { loadVaultMetadataOnly } from './vault-metadata-loader.mjs';
import { MetadataCache as MetadataCacheOld, PerformanceLogger } from './performance-config.mjs';
import { MetadataCache } from './perf/metadata-cache.js';
import { PerformanceMonitor } from './perf/performance-monitor.js';
import { retryWithBackoff, CircuitBreaker } from './utils/retry.js';
import {
  setupMetadataEndpoint,
  setupPaginatedMetadataEndpoint,
  setupPerformanceEndpoint,
  setupDeferredIndexing,
  setupCreateNoteEndpoint,
  setupUpdateNoteEndpoint,
  setupDeleteNoteEndpoint,
  setupRenameFolderEndpoint,
  setupDeleteFolderEndpoint,
  setupCreateFolderEndpoint,
  setupRenameFileEndpoint,
  setupMoveNoteEndpoint
} from './index-phase3-patch.mjs';
import geminiRoutes from './integrations/gemini/gemini.routes.mjs';
import unsplashRoutes from './integrations/unsplash.routes.mjs';

const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);

const app = express();
const PORT = CFG_PORT;

const rootDir = path.resolve(__dirname, '..');
const distDir = path.join(rootDir, 'dist');
// Centralized vault directory
const vaultDir = path.isAbsolute(CFG_VAULT_PATH) ? CFG_VAULT_PATH : path.join(rootDir, CFG_VAULT_PATH);

const settingsPath = path.join(vaultDir, '.obsidian', 'obsiviewer.json');
let enableBackups = true;

try {
  const settings = JSON.parse(fs.readFileSync(settingsPath, 'utf8'));
  enableBackups = settings.enableBackups;
} catch (error) {
  // No settings file or invalid JSON, use default
}

const vaultEventClients = new Set();

// Phase 3: Advanced caching and monitoring
const metadataCache = new MetadataCache({ ttlMs: 5 * 60 * 1000, maxItems: 10_000 });

// ---------- Settings storage helpers ----------
function ensureSettingsStorage() {
  const obsidianDir = path.join(vaultDir, '.obsidian');
  if (!fs.existsSync(obsidianDir)) {
    fs.mkdirSync(obsidianDir, { recursive: true });
  }
  if (!fs.existsSync(settingsPath)) {
    const initial = { enableBackups: true };
    try { fs.writeFileSync(settingsPath, JSON.stringify(initial, null, 2), 'utf-8'); } catch {}
  }
}

function readSettings() {
  ensureSettingsStorage();
  try {
    const raw = fs.readFileSync(settingsPath, 'utf-8');
    const parsed = JSON.parse(raw);
    return { enableBackups: parsed.enableBackups !== false };
  } catch {
    return { enableBackups: true };
  }
}

function writeSettings(next) {
  ensureSettingsStorage();
  try {
    fs.writeFileSync(settingsPath, JSON.stringify(next, null, 2), 'utf-8');
  } catch {}
}

function deleteAllBakFiles(root) {
  let count = 0;
  const stack = [root];
  while (stack.length) {
    const dir = stack.pop();
    let entries = [];
    try { entries = fs.readdirSync(dir, { withFileTypes: true }); } catch { continue; }
    for (const de of entries) {
      const full = path.join(dir, de.name);
      if (de.isDirectory()) { stack.push(full); continue; }
      if (!de.isFile()) continue;
      if (de.name.toLowerCase().endsWith('.bak')) {
        try { fs.unlinkSync(full); count++; } catch {}
      }
    }
  }
  return count;
}

// Initialize settings on startup
ensureSettingsStorage();
enableBackups = readSettings().enableBackups;

// List all folders under the vault (relative paths, forward slashes)
app.get('/api/folders/list', (req, res) => {
  try {
    const out = [];
    const walk = (dir, relBase = '') => {
      const entries = fs.readdirSync(dir, { withFileTypes: true });
      for (const de of entries) {
        if (!de.isDirectory()) continue;
        const name = de.name;
        // Skip hidden backup folders but keep .trash
        const rel = relBase ? `${relBase}/${name}` : name;
        const abs = path.join(dir, name);
        out.push(rel.replace(/\\/g, '/'));
        walk(abs, rel);
      }
    };
    walk(vaultDir, '');
    return res.json(out);
  } catch (error) {
    console.error('GET /api/folders/list error:', error);
    return res.status(500).json({ error: 'Unable to list folders' });
  }
});

// Duplicate a folder recursively
app.post('/api/folders/duplicate', express.json(), (req, res) => {
  try {
    const { sourcePath, destinationPath } = req.body || {};
    if (!sourcePath || !destinationPath) {
      return res.status(400).json({ error: 'Missing sourcePath or destinationPath' });
    }
    const srcRel = String(sourcePath).replace(/\\/g, '/').replace(/^\/+|\/+$/g, '');
    const dstRel = String(destinationPath).replace(/\\/g, '/').replace(/^\/+|\/+$/g, '');
    const srcAbs = path.join(vaultDir, srcRel);
    const dstAbs = path.join(vaultDir, dstRel);
    if (!fs.existsSync(srcAbs) || !fs.statSync(srcAbs).isDirectory()) {
      return res.status(404).json({ error: 'Source folder not found' });
    }
    if (fs.existsSync(dstAbs)) {
      return res.status(409).json({ error: 'Destination already exists' });
    }
    const copyRecursive = (from, to) => {
      fs.mkdirSync(to, { recursive: true });
      for (const entry of fs.readdirSync(from, { withFileTypes: true })) {
        const s = path.join(from, entry.name);
        const d = path.join(to, entry.name);
        if (entry.isDirectory()) copyRecursive(s, d);
        else fs.copyFileSync(s, d);
      }
    };
    copyRecursive(srcAbs, dstAbs);

    if (metadataCache) metadataCache.clear();
    if (broadcastVaultEvent) {
      broadcastVaultEvent({ event: 'folder-duplicate', sourcePath: srcRel, path: dstRel, timestamp: Date.now() });
    }
    return res.json({ success: true, sourcePath: srcRel, path: dstRel });
  } catch (error) {
    console.error('POST /api/folders/duplicate error:', error);
    return res.status(500).json({ error: 'Internal server error' });
  }
});

// Delete all pages (markdown/excalidraw) inside a folder recursively, keep folder structure
app.delete('/api/folders/pages', express.json(), (req, res) => {
  try {
    const q = typeof req.query.path === 'string' ? req.query.path : '';
    if (!q) return res.status(400).json({ error: 'Missing path' });
    const rel = q.replace(/\\/g, '/').replace(/^\/+|\/+$/g, '');
    const abs = path.join(vaultDir, rel);
    if (!fs.existsSync(abs) || !fs.statSync(abs).isDirectory()) {
      return res.status(404).json({ error: 'Folder not found' });
    }
    const deleted = [];
    const walk = (dir) => {
      for (const entry of fs.readdirSync(dir, { withFileTypes: true })) {
        const p = path.join(dir, entry.name);
        if (entry.isDirectory()) walk(p);
        else {
          const low = entry.name.toLowerCase();
          if (low.endsWith('.md') || low.endsWith('.excalidraw') || low.endsWith('.excalidraw.md')) {
            try { fs.unlinkSync(p); deleted.push(path.relative(vaultDir, p).replace(/\\/g, '/')); } catch {}
          }
        }
      }
    };
    walk(abs);
    if (metadataCache) metadataCache.clear();
    if (broadcastVaultEvent) {
      broadcastVaultEvent({ event: 'folder-delete-pages', path: rel, count: deleted.length, timestamp: Date.now() });
    }
    return res.json({ success: true, path: rel, deletedCount: deleted.length });
  } catch (error) {
    console.error('DELETE /api/folders/pages error:', error);
    return res.status(500).json({ error: 'Internal server error' });
  }
});
const performanceMonitor = new PerformanceMonitor();
const meilisearchCircuitBreaker = new CircuitBreaker({ failureThreshold: 5, resetTimeoutMs: 30_000 });

const registerVaultEventClient = (res) => {
  const heartbeat = setInterval(() => {
    try {
      res.write(':keepalive\n\n');
    } catch (error) {
      // Client disconnected, clean up
      console.log('[SSE] Client heartbeat failed, cleaning up');
      unregisterVaultEventClient({ res, heartbeat });
    }
  }, 20000); // Send heartbeat every 20 seconds

  const client = { res, heartbeat };
  vaultEventClients.add(client);
  return client;
};

const unregisterVaultEventClient = (client) => {
  clearInterval(client.heartbeat);
  vaultEventClients.delete(client);
};

const broadcastVaultEvent = (payload) => {
  if (!vaultEventClients.size) {
    return;
  }

  const data = `data: ${JSON.stringify(payload)}\n\n`;
  for (const client of [...vaultEventClients]) {
    try {
      client.res.write(data);
    } catch (error) {
      console.error('Failed to notify vault event client:', error);
      unregisterVaultEventClient(client);
    }
  }
};

const isMarkdownFile = (entry) => entry.isFile() && entry.name.toLowerCase().endsWith('.md');

const normalizeString = (value) => {
  return value
    .normalize('NFKD')
    .replace(/[\u0300-\u036f]/g, '')
    .trim();
};

const slugifySegment = (segment) => {
  const normalized = normalizeString(segment);
  const slug = normalized
    .toLowerCase()
    .replace(/[^a-z0-9]+/g, '-')
    .replace(/^-+|-+$/g, '');
  return slug || normalized.toLowerCase() || segment.toLowerCase();
};

const slugifyPath = (relativePath) => {
  return relativePath
    .split('/')
    .map((segment) => slugifySegment(segment))
    .filter(Boolean)
    .join('/');
};

const extractTitle = (content, fallback) => {
  const headingMatch = content.match(/^\s*#\s+(.+)$/m);
  if (headingMatch) {
    return headingMatch[1].trim();
  }
  return fallback;
};

const extractTags = (content) => {
  const tagRegex = /(^|\s)#([A-Za-z0-9_\/-]+)/g;
  const tags = new Set();
  let match;
  while ((match = tagRegex.exec(content)) !== null) {
    tags.add(match[2]);
  }
  return Array.from(tags);
};

const loadVaultNotes = async (vaultPath) => {
  const notes = [];

  const walk = async (currentDir) => {
    if (!fs.existsSync(currentDir)) {
      return;
    }

    const entries = fs.readdirSync(currentDir, { withFileTypes: true });
    for (const entry of entries) {
      const entryPath = path.join(currentDir, entry.name);

      if (entry.isDirectory()) {
        await walk(entryPath);
        continue;
      }

      if (!isMarkdownFile(entry)) {
        continue;
      }

      try {
        // Skip enrichment during initial load for performance (Phase 1)
        // Enrichment will happen on-demand when file is opened via /api/files
        const content = fs.readFileSync(entryPath, 'utf-8');
        
        const stats = fs.statSync(entryPath);
        const relativePathWithExt = path.relative(vaultPath, entryPath).replace(/\\/g, '/');
        const relativePath = relativePathWithExt.replace(/\.md$/i, '');
        const id = slugifyPath(relativePath);
        const fileNameWithExt = entry.name;

        const fallbackTitle = path.basename(relativePath);
        const title = extractTitle(content, fallbackTitle);
        const finalId = id || slugifySegment(fallbackTitle) || fallbackTitle;
        const createdDate = stats.birthtimeMs ? new Date(stats.birthtimeMs) : new Date(stats.ctimeMs);
        const updatedDate = new Date(stats.mtimeMs);

        notes.push({
          id: finalId,
          title,
          content,
          tags: extractTags(content),
          mtime: stats.mtimeMs,
          fileName: fileNameWithExt,
          filePath: relativePathWithExt,
          originalPath: relativePath,
          createdAt: createdDate.toISOString(),
          updatedAt: updatedDate.toISOString()
        });
      } catch (err) {
        console.error(`Failed to read/enrich note at ${entryPath}:`, err);
      }
    }
  };

  await walk(vaultPath);
  return notes;
};

// Scan vault for .excalidraw.md files and return FileMetadata-like entries
const scanVaultDrawings = (vaultPath) => {
  const items = [];
  const walk = (currentDir) => {
    let entries = [];
    try {
      entries = fs.readdirSync(currentDir, { withFileTypes: true });
    } catch {
      return;
    }
    for (const entry of entries) {
      const entryPath = path.join(currentDir, entry.name);
      if (entry.isDirectory()) {
        walk(entryPath);
        continue;
      }
      if (!entry.isFile()) continue;
      const lower = entry.name.toLowerCase();
      if (!lower.endsWith('.excalidraw.md')) continue;
      try {
        const stats = fs.statSync(entryPath);
        const relPath = path.relative(vaultPath, entryPath).replace(/\\/g, '/');
        const id = slugifyPath(relPath.replace(/\.excalidraw(?:\.md)?$/i, ''));
        const title = path.basename(relPath).replace(/\.excalidraw(?:\.md)?$/i, '');
        items.push({
          id,
          title,
          path: relPath,
          createdAt: new Date(stats.birthtimeMs ? stats.birthtimeMs : stats.ctimeMs).toISOString(),
          updatedAt: new Date(stats.mtimeMs).toISOString(),
        });
      } catch {}
    }
  };
  walk(vaultPath);
  return items;
};

const buildFileMetadata = (notes) =>
  notes.map((note) => ({
    id: note.id,
    title: note.title,
    path: note.filePath,
    createdAt: note.createdAt,
    updatedAt: note.updatedAt,
  }));

// Scan vault for NON-markdown files to include in metadata (images/pdf/video/code/others)
const scanVaultNonNotes = (vaultPath) => {
  const items = [];
  const includeExt = new Set([
    // images
    '.png','.jpg','.jpeg','.gif','.svg','.webp','.bmp','.ico',
    // pdf
    '.pdf',
    // video
    '.mp4','.mov','.avi','.mkv','.webm',
    // code/text configs
    '.json','.js','.ts','.jsx','.tsx','.html','.css','.yml','.yaml','.toml','.ini','.cfg','.conf','.sh','.bash','.ps1','.bat','.csv','.txt','.py'
  ]);

  const walk = (dir) => {
    let entries = [];
    try {
      entries = fs.readdirSync(dir, { withFileTypes: true });
    } catch {
      return;
    }
    for (const entry of entries) {
      const entryPath = path.join(dir, entry.name);
      if (entry.isDirectory()) {
        walk(entryPath);
        continue;
      }
      if (!entry.isFile()) continue;

      const lower = entry.name.toLowerCase();
      if (lower.endsWith('.md') || lower.endsWith('.excalidraw.md')) continue; // handled elsewhere

      const ext = path.extname(lower);
      if (!includeExt.has(ext)) continue;

      try {
        const stats = fs.statSync(entryPath);
        const relPath = path.relative(vaultPath, entryPath).replace(/\\/g, '/');
        const id = slugifyPath(relPath.replace(/\.[^.]+$/i, ''));
        const title = path.basename(relPath);
        items.push({
          id,
          title,
          path: relPath,
          createdAt: new Date(stats.birthtimeMs ? stats.birthtimeMs : stats.ctimeMs).toISOString(),
          updatedAt: new Date(stats.mtimeMs).toISOString(),
        });
      } catch {}
    }
  };

  walk(vaultPath);
  return items;
};

const normalizeDateInput = (value) => {
  if (!value) {
    return null;
  }
  const date = new Date(value);
  return Number.isNaN(date.getTime()) ? null : date;
};

const isDateWithinRange = (target, start, end) => {
  const targetTime = target.getTime();
  return targetTime >= start.getTime() && targetTime <= end.getTime();
};

const vaultWatcher = chokidar.watch(vaultDir, {
  persistent: true,
  ignoreInitial: true,
  awaitWriteFinish: {
    stabilityThreshold: 250,
    pollInterval: 100,
  },
});

const watchedVaultEvents = ['add', 'change', 'unlink', 'addDir', 'unlinkDir'];

watchedVaultEvents.forEach((eventName) => {
  vaultWatcher.on(eventName, (changedPath) => {
    const relativePath = path.relative(vaultDir, changedPath).replace(/\\/g, '/');
    broadcastVaultEvent({
      event: eventName,
      path: relativePath,
      timestamp: Date.now(),
    });
  });
});

// Integrate Meilisearch with Chokidar for incremental updates
vaultWatcher.on('add', async (filePath) => {
  if (filePath.toLowerCase().endsWith('.md')) {
    // Clear metadata cache (Phase 1)
    metadataCache.clear();
    
    // Enrichir le frontmatter pour les nouveaux fichiers
    try {
      const enrichResult = await enrichFrontmatterOnOpen(filePath);
      if (enrichResult.modified) {
        console.log('[Watcher] Enriched frontmatter for new file:', path.basename(filePath));
      }
    } catch (enrichError) {
      console.warn('[Watcher] Failed to enrich frontmatter for new file:', enrichError);
    }
    
    // Puis indexer dans Meilisearch
    upsertFile(filePath).catch(err => console.error('[Meili] Upsert on add failed:', err));
  }
});

vaultWatcher.on('change', (filePath) => {
  if (filePath.toLowerCase().endsWith('.md')) {
    // Clear metadata cache (Phase 1)
    metadataCache.clear();
    
    upsertFile(filePath).catch(err => console.error('[Meili] Upsert on change failed:', err));
  }
});

vaultWatcher.on('unlink', (filePath) => {
  if (filePath.toLowerCase().endsWith('.md')) {
    // Clear metadata cache (Phase 1)
    metadataCache.clear();
    
    const relativePath = path.relative(vaultDir, filePath).replace(/\\/g, '/');
    deleteFile(relativePath).catch(err => console.error('[Meili] Delete failed:', err));
  }
});

vaultWatcher.on('ready', () => {
  broadcastVaultEvent({
    event: 'ready',
    timestamp: Date.now(),
  });
});

vaultWatcher.on('error', (error) => {
  console.error('Vault watcher error:', error);
  broadcastVaultEvent({
    event: 'error',
    message: typeof error?.message === 'string' ? error.message : 'Unknown watcher error',
    timestamp: Date.now(),
  });
});

// Vérifier si le répertoire dist existe
if (!fs.existsSync(distDir)) {
  console.warn(`Warning: build directory not found at ${distDir}. Did you run \`npm run build\`?`);
}

// Servir les fichiers statiques de l'application Angular
app.use(express.static(distDir));

// CORS configuration for development
app.use(cors({
  origin: "http://localhost:3000",
  credentials: true
}));

// Exposer les fichiers de la voûte pour un accès direct, y compris les dotfiles (ex: .test, .obsidian)
// Utiliser fallthrough:false pour renvoyer un 404 au lieu de tomber sur le fallback Angular index.html
app.use('/vault', express.static(vaultDir, {
  dotfiles: 'allow',
  fallthrough: false,
  index: false,
  etag: true
}));

// ---------- Settings API ----------
app.get('/api/settings', (req, res) => {
  try {
    const current = readSettings();
    return res.json(current);
  } catch (error) {
    console.error('GET /api/settings error:', error);
    return res.status(500).json({ error: 'Unable to read settings' });
  }
});

app.put('/api/settings', express.json(), (req, res) => {
  try {
    const body = req.body || {};
    const nextEnable = body.enableBackups !== false;
    const prev = readSettings();
    const next = { enableBackups: nextEnable };
    writeSettings(next);
    enableBackups = nextEnable;

    let deleted = 0;
    if (prev.enableBackups && !nextEnable) {
      // On disabling backups, remove all existing .bak files
      deleted = deleteAllBakFiles(vaultDir);
    }

    return res.json({ success: true, enableBackups, deletedBakFiles: deleted });
  } catch (error) {
    console.error('PUT /api/settings error:', error);
    return res.status(500).json({ error: 'Unable to save settings' });
  }
});

// Résolution des attachements: recherche le fichier en remontant les dossiers depuis la note, puis dans la voûte
app.get('/api/attachments/resolve', (req, res) => {
  try {
    const rawName = typeof req.query.name === 'string' ? req.query.name.trim() : '';
    if (!rawName) {
      return res.status(400).type('text/plain').send('Missing required query parameter: name');
    }

    const sanitize = (value) => value.replace(/\\/g, '/').replace(/^[/]+|[/]+$/g, '');
    const name = sanitize(rawName);
    const noteRelPath = typeof req.query.note === 'string' ? sanitize(req.query.note) : '';
    const baseRaw = typeof req.query.base === 'string' ? req.query.base : '';
    const baseRel = sanitize(baseRaw);

    const candidateDirs = new Set();

    const addCandidate = (dir, extra) => {
      const dirSegments = sanitize(dir);
      const extraSegments = sanitize(extra);
      if (dirSegments && extraSegments) {
        candidateDirs.add(`${dirSegments}/${extraSegments}`);
      } else if (dirSegments) {
        candidateDirs.add(dirSegments);
      } else if (extraSegments) {
        candidateDirs.add(extraSegments);
      } else {
        candidateDirs.add('');
      }
    };

    // Dossiers parents de la note
    if (noteRelPath) {
      const segments = noteRelPath.split('/');
      segments.pop(); // retirer le nom de fichier
      while (segments.length >= 0) {
        const currentDir = segments.join('/');
        addCandidate(currentDir, baseRel);
        addCandidate(currentDir, '');
        if (!segments.length) break;
        segments.pop();
      }
    }

    // Si base est défini, tenter aussi directement depuis la racine
    if (baseRel) {
      addCandidate('', baseRel);
    }

    // Toujours ajouter la racine seule en dernier recours
    addCandidate('', '');

    for (const dir of candidateDirs) {
      const absoluteDir = dir ? path.join(vaultDir, dir) : vaultDir;
      const candidatePath = path.join(absoluteDir, name);
      try {
        if (fs.existsSync(candidatePath) && fs.statSync(candidatePath).isFile()) {
          return res.sendFile(candidatePath);
        }
      } catch {
        // Ignorer et poursuivre
      }
    }

    // Recherche exhaustive en dernier recours (coût plus élevé)
    const stack = [vaultDir];
    const nameLower = name.toLowerCase();
    while (stack.length) {
      const currentDir = stack.pop();
      let entries = [];
      try {
        entries = fs.readdirSync(currentDir, { withFileTypes: true });
      } catch {
        continue;
      }

      for (const entry of entries) {
        const fullPath = path.join(currentDir, entry.name);
        if (entry.isDirectory()) {
          stack.push(fullPath);
        } else if (entry.isFile() && entry.name.toLowerCase() === nameLower) {
          return res.sendFile(fullPath);
        }
      }
    }

    return res.status(404).type('text/plain').send(`‼️Attachement ${rawName} introuvable`);
  } catch (error) {
    console.error('Attachment resolve error:', error);
    return res.status(500).type('text/plain').send('Attachment resolver internal error');
  }
});

// API endpoint pour la santé
app.get('/api/health', (req, res) => {
  res.json({ status: 'ok', timestamp: new Date().toISOString() });
});

app.get('/api/url-preview', async (req, res) => {
  try {
    const raw = String(req.query.url || '').trim();
    if (!raw) {
      return res.status(400).json({ error: 'missing_url' });
    }
    let targetUrl;
    try {
      let normalized = raw;
      // If the user did not specify a protocol, default to https:// (or http:// for localhost)
      if (!/^[a-zA-Z][a-zA-Z0-9+\-.]*:/.test(normalized)) {
        if (normalized.startsWith('localhost') || normalized.startsWith('127.0.0.1')) {
          normalized = 'http://' + normalized;
        } else {
          normalized = 'https://' + normalized;
        }
      }
      targetUrl = new URL(normalized);
      if (targetUrl.protocol !== 'http:' && targetUrl.protocol !== 'https:') {
        return res.status(400).json({ error: 'unsupported_protocol' });
      }
    } catch {
      return res.status(400).json({ error: 'invalid_url' });
    }

    const controller = new AbortController();
    const timeout = setTimeout(() => controller.abort(), 8000);
    let html = '';
    try {
      const resp = await fetch(targetUrl.toString(), {
        signal: controller.signal,
        headers: {
          'User-Agent': 'ObsiViewer/1.0 (+https://github.com/)',
          'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8'
        }
      });
      clearTimeout(timeout);
      if (!resp.ok) {
        return res.status(502).json({ error: 'upstream_error', status: resp.status });
      }
      html = await resp.text();
    } catch (e) {
      clearTimeout(timeout);
      console.error('url-preview fetch error', e);
      return res.status(500).json({ error: 'fetch_failed' });
    }

    const result = {
      url: targetUrl.toString(),
      title: null,
      description: null,
      siteName: null,
      imageUrl: null,
      faviconUrl: null,
    };

    const ogTitle = html.match(/<meta[^>]+property=["']og:title["'][^>]*content=["']([^"']+)["'][^>]*>/i);
    const titleTag = html.match(/<title[^>]*>([^<]+)<\/title>/i);
    if (ogTitle && ogTitle[1]) {
      result.title = ogTitle[1].trim();
    } else if (titleTag && titleTag[1]) {
      result.title = titleTag[1].trim();
    }

    const ogDesc = html.match(/<meta[^>]+property=["']og:description["'][^>]*content=["']([^"']+)["'][^>]*>/i);
    const metaDesc = html.match(/<meta[^>]+name=["']description["'][^>]*content=["']([^"']+)["'][^>]*>/i);
    if (ogDesc && ogDesc[1]) {
      result.description = ogDesc[1].trim();
    } else if (metaDesc && metaDesc[1]) {
      result.description = metaDesc[1].trim();
    }

    const ogSite = html.match(/<meta[^>]+property=["']og:site_name["'][^>]*content=["']([^"']+)["'][^>]*>/i);
    if (ogSite && ogSite[1]) {
      result.siteName = ogSite[1].trim();
    }

    const absolutizeImageUrl = (rawUrl) => {
      if (!rawUrl) return null;
      let img = String(rawUrl).trim();
      if (!img) return null;
      if (img.startsWith('//')) {
        img = targetUrl.protocol + img;
      } else if (img.startsWith('/')) {
        img = targetUrl.origin + img;
      } else if (!/^[a-zA-Z][a-zA-Z0-9+\-.]*:/.test(img)) {
        // Relative URL like "images/cover.png"
        img = targetUrl.origin.replace(/\/+$/, '') + '/' + img.replace(/^\/+/, '');
      }
      return img;
    };

    // Try multiple sources for preview image
    const ogImage =
      html.match(/<meta[^>]+property=["']og:image["'][^>]*content=["']([^"']+)["'][^>]*>/i) ||
      html.match(/<meta[^>]+content=["']([^"']+)["'][^>]*property=["']og:image["'][^>]*>/i);

    const ogImageSecure =
      html.match(/<meta[^>]+property=["']og:image:secure_url["'][^>]*content=["']([^"']+)["'][^>]*>/i) ||
      html.match(/<meta[^>]+content=["']([^"']+)["'][^>]*property=["']og:image:secure_url["'][^>]*>/i);

    const twitterImage =
      html.match(/<meta[^>]+name=["']twitter:image["'][^>]*content=["']([^"']+)["'][^>]*>/i) ||
      html.match(/<meta[^>]+content=["']([^"']+)["'][^>]*name=["']twitter:image["'][^>]*>/i);

    const linkImage = html.match(/<link[^>]+rel=["']image_src["'][^>]*href=["']([^"']+)["'][^>]*>/i);

    const imageCandidate =
      (ogImage && ogImage[1]) ||
      (ogImageSecure && ogImageSecure[1]) ||
      (twitterImage && twitterImage[1]) ||
      (linkImage && linkImage[1]);

    const resolvedImage = absolutizeImageUrl(imageCandidate);
    if (resolvedImage) {
      result.imageUrl = resolvedImage;
    }

    const faviconMatch = html.match(/<link[^>]+rel=["'](?:shortcut icon|icon)["'][^>]*href=["']([^"']+)["'][^>]*>/i);
    if (faviconMatch && faviconMatch[1]) {
      let fav = faviconMatch[1].trim();
      if (fav.startsWith('//')) {
        fav = targetUrl.protocol + fav;
      } else if (fav.startsWith('/')) {
        fav = targetUrl.origin + fav;
      }
      result.faviconUrl = fav;
    }

    // Fallback: if no explicit preview image, reuse favicon as tile image
    if (!result.imageUrl && result.faviconUrl) {
      result.imageUrl = result.faviconUrl;
    }

    return res.json(result);
  } catch (error) {
    console.error('url-preview internal error', error);
    return res.status(500).json({ error: 'internal_error' });
  }
});

// Gemini Integration endpoints
app.use('/api/integrations/gemini', geminiRoutes);
app.use('/api/integrations/unsplash', unsplashRoutes);

app.get('/api/vault/events', (req, res) => {
  res.set({
    'Content-Type': 'text/event-stream',
    'Cache-Control': 'no-cache',
    Connection: 'keep-alive',
    'X-Accel-Buffering': 'no',
  });

  res.flushHeaders?.();
  res.write(
    `data: ${JSON.stringify({
      event: 'connected',
      timestamp: Date.now(),
    })}\n\n`,
  );

  const client = registerVaultEventClient(res);

  req.on('close', () => {
    unregisterVaultEventClient(client);
  });
});

// API endpoint pour les données de la voûte (contenu réel)
app.get('/api/vault', async (req, res) => {
  try {
    const notes = await loadVaultNotes(vaultDir);
    res.json({ notes });
  } catch (error) {
    console.error('Failed to load vault notes:', error);
    res.status(500).json({ error: 'Unable to load vault notes.' });
  }
});

// Fast file list from Meilisearch (id, title, path, createdAt, updatedAt)
app.get('/api/files/list', async (req, res) => {
  try {
    const client = meiliClient();
    const indexUid = vaultIndexName(vaultDir);
    const index = await ensureIndexSettings(client, indexUid);
    const result = await index.search('', {
      limit: 10000,
      attributesToRetrieve: ['id', 'title', 'path', 'createdAt', 'updatedAt']
    });

    const items = Array.isArray(result.hits) ? result.hits.map(hit => ({
      id: hit.id,
      title: hit.title,
      path: hit.path,
      createdAt: typeof hit.createdAt === 'number' ? new Date(hit.createdAt).toISOString() : hit.createdAt,
      updatedAt: typeof hit.updatedAt === 'number' ? new Date(hit.updatedAt).toISOString() : hit.updatedAt,
    })) : [];

    res.json(items);
  } catch (error) {
    console.error('Failed to list files via Meilisearch, falling back to FS:', error);
    try {
      const notes = await loadVaultNotes(vaultDir);
      res.json(buildFileMetadata(notes));
    } catch (err2) {
      console.error('FS fallback failed:', err2);
      res.status(500).json({ error: 'Unable to list files.' });
    }
  }
});

// Phase 3: Fast metadata endpoint with cache read-through and monitoring
setupMetadataEndpoint(app, metadataCache, performanceMonitor, vaultDir, meilisearchCircuitBreaker, retryWithBackoff, {
  meiliClient,
  vaultIndexName,
  ensureIndexSettings,
  loadVaultMetadataOnly
});

// Phase 3: Paginated metadata endpoint with cache read-through and monitoring
setupPaginatedMetadataEndpoint(app, metadataCache, performanceMonitor, vaultDir, meilisearchCircuitBreaker, retryWithBackoff, {
  meiliClient,
  vaultIndexName,
  ensureIndexSettings,
  loadVaultMetadataOnly
});

app.get('/api/files/metadata', async (req, res) => {
  try {
    // If explicitly requested, bypass Meilisearch and read from filesystem for authoritative state
    const forceFs = String(req.query.source || '').toLowerCase() === 'fs';

    if (!forceFs) {
      // Prefer Meilisearch for fast metadata
      const client = meiliClient();
      const indexUid = vaultIndexName(vaultDir);
      const index = await ensureIndexSettings(client, indexUid);
      const result = await index.search('', {
        limit: 10000,
        attributesToRetrieve: ['id', 'title', 'path', 'createdAt', 'updatedAt']
      });

      const items = Array.isArray(result.hits) ? result.hits.map(hit => ({
        id: hit.id,
        title: hit.title,
        path: hit.path,
        createdAt: typeof hit.createdAt === 'number' ? new Date(hit.createdAt).toISOString() : hit.createdAt,
        updatedAt: typeof hit.updatedAt === 'number' ? new Date(hit.updatedAt).toISOString() : hit.updatedAt,
      })) : [];

      // Merge .excalidraw files discovered via FS
      const drawings = scanVaultDrawings(vaultDir);
      const nonNotes = scanVaultNonNotes(vaultDir);
      const byPath = new Map(items.map(it => [String(it.path).toLowerCase(), it]));
      for (const d of drawings) {
        const key = String(d.path).toLowerCase();
        if (!byPath.has(key)) {
          byPath.set(key, d);
        }
      }
      for (const f of nonNotes) {
        const key = String(f.path).toLowerCase();
        if (!byPath.has(key)) byPath.set(key, f);
      }

      return res.json(Array.from(byPath.values()));
    }

    // Filesystem authoritative listing
    const notes = await loadVaultNotes(vaultDir);
    const base = buildFileMetadata(notes);
    const drawings = scanVaultDrawings(vaultDir);
    const nonNotes = scanVaultNonNotes(vaultDir);
    const byPath = new Map(base.map(it => [String(it.path).toLowerCase(), it]));
    for (const d of drawings) {
      const key = String(d.path).toLowerCase();
      if (!byPath.has(key)) byPath.set(key, d);
    }
    for (const f of nonNotes) {
      const key = String(f.path).toLowerCase();
      if (!byPath.has(key)) byPath.set(key, f);
    }
    return res.json(Array.from(byPath.values()));
  } catch (error) {
    console.error('Failed to load file metadata:', error);
    return res.status(500).json({ error: 'Unable to load file metadata.' });
  }
});

app.get('/api/files/by-date', async (req, res) => {
  const { date } = req.query;
  const targetDate = normalizeDateInput(date);

  if (!targetDate) {
    return res.status(400).json({ error: 'Invalid or missing date query parameter.' });
  }

  try {
    const notes = await loadVaultNotes(vaultDir);
    const startOfDay = new Date(targetDate);
    startOfDay.setHours(0, 0, 0, 0);
    const endOfDay = new Date(targetDate);
    endOfDay.setHours(23, 59, 59, 999);

    const filtered = notes.filter((note) => {
      const createdAt = normalizeDateInput(note.createdAt);
      const updatedAt = normalizeDateInput(note.updatedAt);
      const matchesCreated = createdAt && isDateWithinRange(createdAt, startOfDay, endOfDay);
      const matchesUpdated = updatedAt && isDateWithinRange(updatedAt, startOfDay, endOfDay);
      return matchesCreated || matchesUpdated;
    });

    res.json(buildFileMetadata(filtered));
  } catch (error) {
    console.error('Failed to search files by date:', error);
    res.status(500).json({ error: 'Unable to search files by date.' });
  }
});

app.get('/api/files/by-date-range', async (req, res) => {
  const { start, end } = req.query;
  const startDate = normalizeDateInput(start);
  const endDate = normalizeDateInput(end ?? start);

  if (!startDate || !endDate || startDate > endDate) {
    return res.status(400).json({ error: 'Invalid start or end date parameters.' });
  }

  const normalizedStart = new Date(startDate);
  normalizedStart.setHours(0, 0, 0, 0);
  const normalizedEnd = new Date(endDate);
  normalizedEnd.setHours(23, 59, 59, 999);

  try {
    const notes = await loadVaultNotes(vaultDir);
    const filtered = notes.filter((note) => {
      const createdAt = normalizeDateInput(note.createdAt);
      const updatedAt = normalizeDateInput(note.updatedAt);
      const matchesCreated = createdAt && isDateWithinRange(createdAt, normalizedStart, normalizedEnd);
      const matchesUpdated = updatedAt && isDateWithinRange(updatedAt, normalizedStart, normalizedEnd);
      return matchesCreated || matchesUpdated;
    });

    res.json(buildFileMetadata(filtered));
  } catch (error) {
    console.error('Failed to search files by date range:', error);
    res.status(500).json({ error: 'Unable to search files by date range.' });
  }
});

// Bookmarks API - reads/writes <vault>/.obsidian/bookmarks.json
app.use(express.json());

app.post('/api/log', (req, res) => {
  try {
    const payload = req.body;

    if (!payload) {
      return res.status(400).json({ error: 'Missing log payload' });
    }

    const records = Array.isArray(payload) ? payload : [payload];

    // Validate and process records
    const validRecords = records.filter((record) => {
      if (!record || typeof record !== 'object') {
        console.warn('[FrontendLog] Ignored invalid record', record);
        return false;
      }
      return true;
    });

    if (validRecords.length === 0) {
      return res.status(400).json({ error: 'No valid log records provided' });
    }

    validRecords.forEach((record) => {
      const {
        event = 'UNKNOWN_EVENT',
        level = 'info',
        sessionId,
        userAgent,
        context = {},
        data,
      } = record;

      const summary = {
        sessionId,
        route: context?.route ?? 'n/a',
        theme: context?.theme ?? 'n/a',
        version: context?.version ?? 'n/a',
      };

      if (data !== undefined) {
        summary.data = data;
      }

      console.log(`[FrontendLog:${level}]`, event, summary, userAgent ?? '');
    });

    return res.status(202).json({ ok: true, processed: validRecords.length });
  } catch (error) {
    console.error('Failed to process frontend logs:', error);
    return res.status(500).json({
      error: 'Failed to process logs',
      message: error.message || 'Internal server error'
    });
  }
});

app.post('/api/logs', (req, res) => {
  try {
    const { source = 'frontend', level = 'info', message = '', data = null, timestamp = Date.now() } = req.body || {};

    // Validate inputs
    if (!message || typeof message !== 'string') {
      return res.status(400).json({ error: 'Invalid or missing message' });
    }

    if (!['error', 'warn', 'info', 'debug'].includes(level)) {
      return res.status(400).json({ error: 'Invalid log level' });
    }

    const prefix = `[ClientLog:${source}]`;
    const payload = data !== undefined ? { data } : undefined;

    switch (level) {
      case 'error':
        console.error(prefix, message, payload ?? '', new Date(timestamp).toISOString());
        break;
      case 'warn':
        console.warn(prefix, message, payload ?? '', new Date(timestamp).toISOString());
        break;
      case 'debug':
        console.debug(prefix, message, payload ?? '', new Date(timestamp).toISOString());
        break;
      default:
        console.log(prefix, message, payload ?? '', new Date(timestamp).toISOString());
        break;
    }

    res.status(202).json({ status: 'queued' });
  } catch (error) {
    console.error('Failed to process client logs:', error);
    res.status(500).json({
      error: 'Failed to process logs',
      message: error.message || 'Internal server error'
    });
  }
});

// --- Files API (supports .excalidraw.md (Markdown-wrapped JSON), .excalidraw, .json and binary sidecars) ---
// Helpers
const sanitizeRelPath = (rel) => String(rel || '').replace(/\\/g, '/').replace(/^\/+/, '');
const resolveVaultPath = (rel) => {
  const clean = sanitizeRelPath(rel);
  const abs = path.resolve(vaultDir, clean);
  if (!abs.startsWith(path.resolve(vaultDir))) {
    throw Object.assign(new Error('Invalid path'), { status: 400 });
  }
  return abs;
};

const excalidrawSceneSchema = z.object({
  elements: z.array(z.any()),
  appState: z.record(z.any()).optional(),
  files: z.record(z.any()).optional(),
}).passthrough();

// Helper to determine content type
function guessContentType(filePath) {
  const lower = filePath.toLowerCase();
  if (lower.endsWith('.md')) return 'text/markdown; charset=utf-8';
  if (lower.endsWith('.json')) return 'application/json; charset=utf-8';
  return 'application/octet-stream';
}

// GET file content (supports .excalidraw.md, .excalidraw, .json, .md)
app.get('/api/files', async (req, res) => {
  try {
    const pathParam = req.query.path;
    if (!pathParam || typeof pathParam !== 'string') {
      return res.status(400).json({ error: 'Missing path query parameter' });
    }
    
    const rel = decodeURIComponent(pathParam);
    const abs = resolveVaultPath(rel);
    
    if (!fs.existsSync(abs) || !fs.statSync(abs).isFile()) {
      return res.status(404).json({ error: 'File not found' });
    }
    
    const base = path.basename(abs).toLowerCase();
    const ext = path.extname(abs).toLowerCase();
    const isExcalidrawMd = base.endsWith('.excalidraw.md');
    const isExcalidraw = ext === '.excalidraw' || ext === '.json' || isExcalidrawMd;
    
    if (!isExcalidraw && ext !== '.md') {
      return res.status(415).json({ error: 'Unsupported file type' });
    }
    
    // For regular markdown files, enrich front-matter before reading
    if (!isExcalidraw && ext === '.md') {
      try {
        const enrichResult = await enrichFrontmatterOnOpen(abs);
        
        // If modified, trigger Meilisearch reindex
        if (enrichResult.modified) {
          upsertFile(abs).catch(err => 
            console.warn('[GET /api/files] Failed to reindex after enrichment:', err)
          );
        }
        
        const rev = calculateSimpleHash(enrichResult.content);
        res.setHeader('ETag', rev);
        res.setHeader('Content-Type', guessContentType(abs));
        return res.send(enrichResult.content);
      } catch (enrichError) {
        console.error('[GET /api/files] Front-matter enrichment failed:', enrichError);
        // Fallback to reading without enrichment
      }
    }
    
    const content = fs.readFileSync(abs, 'utf-8');
    
    // For Excalidraw files, parse and return JSON
    if (isExcalidraw) {
      const data = parseExcalidrawAny(content);
      
      if (!data || !isValidExcalidrawScene(data)) {
        return res.status(400).json({ error: 'Invalid Excalidraw format' });
      }
      
      // Normalize scene structure
      const normalized = {
        elements: Array.isArray(data.elements) ? data.elements : [],
        appState: (data && typeof data.appState === 'object') ? data.appState : {},
        files: (data && typeof data.files === 'object') ? data.files : {}
      };
      
      const rev = calculateSimpleHash(content);
      res.setHeader('ETag', rev);
      res.setHeader('Content-Type', 'application/json; charset=utf-8');
      return res.send(JSON.stringify(normalized));
    }
    
    // For regular markdown, return as-is (fallback)
    const rev = calculateSimpleHash(content);
    res.setHeader('ETag', rev);
    res.setHeader('Content-Type', guessContentType(abs));
    return res.send(content);
    
  } catch (error) {
    const code = typeof error?.status === 'number' ? error.status : 500;
    console.error('GET /api/files error:', error);
    res.status(code).json({ error: 'Internal server error' });
  }
});

// PUT file content with If-Match check and size limit (10MB)
app.put('/api/files', express.json({ limit: '10mb' }), express.text({ limit: '10mb', type: 'text/markdown' }), (req, res) => {
  try {
    const pathParam = req.query.path;
    if (!pathParam || typeof pathParam !== 'string') {
      return res.status(400).json({ error: 'Missing or invalid path query parameter' });
    }

    const rel = decodeURIComponent(pathParam);
    const abs = resolveVaultPath(rel);

    // Check if the path is a directory (reject directory operations)
    if (fs.existsSync(abs) && fs.statSync(abs).isDirectory()) {
      return res.status(400).json({ error: 'Cannot write to directory path. Specify a file path.' });
    }

    const dir = path.dirname(abs);
    if (!fs.existsSync(dir)) {
      // Create parent directories if they don't exist
      try {
        fs.mkdirSync(dir, { recursive: true });
      } catch (mkdirError) {
        console.error('[PUT /api/files] Failed to create directory:', mkdirError);
        return res.status(500).json({ error: 'Failed to create parent directories' });
      }
    }

    const contentType = (req.headers['content-type'] || '').split(';')[0];
    const base = path.basename(abs).toLowerCase();
    const isExcalidrawMd = base.endsWith('.excalidraw.md');

    let finalContent;
    let existingFrontMatter = null;
    console.log('[PUT /api/files] path=%s contentType=%s isExcalidrawMd=%s', rel, contentType, isExcalidrawMd);

    // Extract existing front matter if file exists
    if (fs.existsSync(abs) && isExcalidrawMd) {
      try {
        const existing = fs.readFileSync(abs, 'utf-8');
        existingFrontMatter = extractFrontMatter(existing);
      } catch (readError) {
        console.warn('[PUT /api/files] Failed to read existing file for frontmatter:', readError);
      }
    }

    // Handle JSON payload (Excalidraw scene)
    if (contentType === 'application/json') {
      const body = req.body;
      const parsed = excalidrawSceneSchema.safeParse(body);

      if (!parsed.success) {
        console.warn('[PUT /api/files] invalid scene schema', parsed.error?.issues?.slice(0,3));
        return res.status(400).json({
          error: 'Invalid Excalidraw scene',
          issues: parsed.error.issues?.slice(0, 5)
        });
      }

      // Convert to Obsidian format if target is .excalidraw.md
      if (isExcalidrawMd) {
        finalContent = toObsidianExcalidrawMd(parsed.data, existingFrontMatter);
      } else {
        // Plain JSON for .excalidraw or .json files
        finalContent = JSON.stringify(parsed.data, null, 2);
      }
    }
    // Handle text/markdown payload (already formatted)
    else if (contentType === 'text/markdown') {
      finalContent = typeof req.body === 'string' ? req.body : String(req.body);
    }
    else {
      console.warn('[PUT /api/files] unsupported content-type', contentType);
      return res.status(400).json({ error: 'Unsupported content type. Use application/json for Excalidraw or text/markdown for text files.' });
    }

    // Check size limit
    if (Buffer.byteLength(finalContent, 'utf-8') > 10 * 1024 * 1024) {
      console.warn('[PUT /api/files] payload too large path=%s size=%d', rel, Buffer.byteLength(finalContent, 'utf-8'));
      return res.status(413).json({ error: 'Payload too large (max 10MB)' });
    }

    // Check for conflicts with If-Match
    const hasExisting = fs.existsSync(abs);
    const ifMatch = req.headers['if-match'];
    if (hasExisting && ifMatch) {
      const current = fs.readFileSync(abs, 'utf-8');
      const currentRev = calculateSimpleHash(current);
      if (ifMatch !== currentRev) {
        console.warn('[PUT /api/files] conflict path=%s ifMatch=%s current=%s', rel, ifMatch, currentRev);
        return res.status(409).json({ error: 'Conflict detected. File was modified externally.' });
      }
    }

    // Atomic write with backup
    const temp = abs + '.tmp';
    const backup = abs + '.bak';

    try {
      if (hasExisting && enableBackups) fs.copyFileSync(abs, backup);
      fs.writeFileSync(temp, finalContent, 'utf-8');
      fs.renameSync(temp, abs);
      console.log('[PUT /api/files] wrote file path=%s bytes=%d', rel, Buffer.byteLength(finalContent, 'utf-8'));
    } catch (e) {
      // Cleanup temp file
      if (fs.existsSync(temp)) try { fs.unlinkSync(temp); } catch {}
      // Restore backup if it exists
      if (hasExisting && fs.existsSync(backup)) try { fs.copyFileSync(backup, abs); } catch {}
      console.error('[PUT /api/files] write error path=%s', rel, e);
      return res.status(500).json({ error: 'Failed to write file. Check file permissions and disk space.' });
    }

    // Cleanup backup
    if (fs.existsSync(backup)) {
      try { fs.unlinkSync(backup); } catch {}
    }

    const rev = calculateSimpleHash(finalContent);
    res.setHeader('ETag', rev);
    res.json({ rev, path: rel, size: Buffer.byteLength(finalContent, 'utf-8') });

  } catch (error) {
    const code = typeof error?.status === 'number' ? error.status : 500;
    console.error('PUT /api/files error:', error);
    res.status(code).json({
      error: 'Internal server error',
      message: error.message || 'An unexpected error occurred while saving the file.'
    });
  }
});

// PUT binary sidecar (e.g., PNG/SVG)
app.put('/api/files/blob', (req, res) => {
  try {
    const pathParam = req.query.path;
    if (!pathParam || typeof pathParam !== 'string') {
      return res.status(400).json({ error: 'Missing path query parameter' });
    }
    
    const rel = decodeURIComponent(pathParam);
    const abs = resolveVaultPath(rel);
    const dir = path.dirname(abs);
    if (!fs.existsSync(dir)) fs.mkdirSync(dir, { recursive: true });

    // Collect raw body
    const chunks = [];
    req.on('data', (chunk) => {
      chunks.push(chunk);
      const size = chunks.reduce((a, b) => a + b.length, 0);
      if (size > 10 * 1024 * 1024) { // 10MB limit
        req.destroy();
      }
    });
    req.on('end', () => {
      const buf = Buffer.concat(chunks);
      // Basic allowlist
      const ext = path.extname(abs).toLowerCase();
      if (!['.png', '.svg'].includes(ext)) {
        return res.status(415).json({ error: 'unsupported_media_type' });
      }
      fs.writeFileSync(abs, buf);
      res.json({ ok: true });
    });
    req.on('error', (err) => {
      console.error('Blob upload error:', err);
      res.status(500).json({ error: 'internal_error' });
    });
  } catch (error) {
    const code = typeof error?.status === 'number' ? error.status : 500;
    console.error('PUT /api/files/blob error:', error);
    res.status(code).json({ error: 'internal_error' });
  }
});

function ensureBookmarksStorage() {
  const obsidianDir = path.join(vaultDir, '.obsidian');
  if (!fs.existsSync(obsidianDir)) {
    fs.mkdirSync(obsidianDir, { recursive: true });
  }

  const bookmarksPath = path.join(obsidianDir, 'bookmarks.json');
  if (!fs.existsSync(bookmarksPath)) {
    const emptyDoc = { items: [] };
    const initialContent = JSON.stringify(emptyDoc, null, 2);
    fs.writeFileSync(bookmarksPath, initialContent, 'utf-8');
  }

  return { obsidianDir, bookmarksPath };
}

// Ensure bookmarks storage is ready on startup
ensureBookmarksStorage();

// Graph config API - reads/writes <vault>/.obsidian/graph.json
function ensureGraphStorage() {
  const obsidianDir = path.join(vaultDir, '.obsidian');
  if (!fs.existsSync(obsidianDir)) {
    fs.mkdirSync(obsidianDir, { recursive: true });
  }

  const graphPath = path.join(obsidianDir, 'graph.json');
  if (!fs.existsSync(graphPath)) {
    // Create default graph config matching Obsidian defaults
    const defaultConfig = {
      'collapse-filter': false,
      search: '',
      showTags: false,
      showAttachments: false,
      hideUnresolved: false,
      showOrphans: true,
      'collapse-color-groups': false,
      colorGroups: [],
      'collapse-display': false,
      showArrow: false,
      textFadeMultiplier: 0,
      nodeSizeMultiplier: 1,
      lineSizeMultiplier: 1,
      'collapse-forces': false,
      centerStrength: 0.3,
      repelStrength: 17,
      linkStrength: 0.5,
      linkDistance: 200,
      scale: 1,
      close: false
    };
    const initialContent = JSON.stringify(defaultConfig, null, 2);
    fs.writeFileSync(graphPath, initialContent, 'utf-8');
  }

  return { obsidianDir, graphPath };
}

// Ensure graph storage is ready on startup
ensureGraphStorage();

app.get('/api/vault/graph', (req, res) => {
  try {
    const { graphPath } = ensureGraphStorage();
    const content = fs.readFileSync(graphPath, 'utf-8');
    const config = JSON.parse(content);
    const rev = calculateSimpleHash(content);

    res.json({ config, rev });
  } catch (error) {
    console.error('Failed to load graph config:', error);
    res.status(500).json({ error: 'Unable to load graph config.' });
  }
});

app.put('/api/vault/graph', (req, res) => {
  try {
    const { graphPath } = ensureGraphStorage();
    const ifMatch = req.headers['if-match'];

    // Check for conflicts if If-Match header is present
    if (ifMatch) {
      const currentContent = fs.readFileSync(graphPath, 'utf-8');
      const currentRev = calculateSimpleHash(currentContent);

      if (ifMatch !== currentRev) {
        return res.status(409).json({ error: 'Conflict: File modified externally' });
      }
    }

    // Create backup before writing
    const backupPath = graphPath + '.bak';
    if (enableBackups && fs.existsSync(graphPath)) {
      fs.copyFileSync(graphPath, backupPath);
    }

    // Atomic write: write to temp file, then rename
    const tempPath = graphPath + '.tmp';
    const content = JSON.stringify(req.body, null, 2);
    
    try {
      fs.writeFileSync(tempPath, content, 'utf-8');
      fs.renameSync(tempPath, graphPath);
    } catch (writeError) {
      // If write failed, restore backup if it exists
      if (fs.existsSync(backupPath)) {
        fs.copyFileSync(backupPath, graphPath);
      }
      throw writeError;
    }

    const newRev = calculateSimpleHash(content);
    res.json({ rev: newRev });
  } catch (error) {
    console.error('Failed to save graph config:', error);
    res.status(500).json({ error: 'Unable to save graph config.' });
  }
});

app.get('/api/vault/bookmarks', (req, res) => {
  try {
    const { bookmarksPath } = ensureBookmarksStorage();
    const content = fs.readFileSync(bookmarksPath, 'utf-8');
    const doc = JSON.parse(content);
    const rev = calculateSimpleHash(content);

    res.json({ ...doc, rev });
  } catch (error) {
    console.error('Failed to load bookmarks:', error);
    res.status(500).json({ error: 'Unable to load bookmarks.' });
  }
});

app.put('/api/vault/bookmarks', (req, res) => {
  try {
    const { bookmarksPath } = ensureBookmarksStorage();
    const ifMatch = req.headers['if-match'];

    // Check for conflicts if If-Match header is present
    if (ifMatch) {
      const currentContent = fs.readFileSync(bookmarksPath, 'utf-8');
      const currentRev = calculateSimpleHash(currentContent);

      if (ifMatch !== currentRev) {
        return res.status(409).json({ error: 'Conflict: File modified externally' });
      }
    }

    // Create backup before writing
    const backupPath = bookmarksPath + '.bak';
    if (enableBackups && fs.existsSync(bookmarksPath)) {
      fs.copyFileSync(bookmarksPath, backupPath);
    }

    // Atomic write: write to temp file, then rename
    const tempPath = bookmarksPath + '.tmp';
    const content = JSON.stringify(req.body, null, 2);
    
    try {
      fs.writeFileSync(tempPath, content, 'utf-8');
      fs.renameSync(tempPath, bookmarksPath);
    } catch (writeError) {
      // If write failed, restore backup if it exists
      if (fs.existsSync(backupPath)) {
        fs.copyFileSync(backupPath, bookmarksPath);
      }
      throw writeError;
    }

    const newRev = calculateSimpleHash(content);
    res.json({ rev: newRev });
  } catch (error) {
    console.error('Failed to save bookmarks:', error);
    res.status(500).json({ error: 'Unable to save bookmarks.' });
  }
});

// Simple hash function for rev generation
function calculateSimpleHash(content) {
  let hash = 0;
  for (let i = 0; i < content.length; i++) {
    const char = content.charCodeAt(i);
    hash = (hash << 5) - hash + char;
    hash = hash & hash;
  }
  return Math.abs(hash).toString(36) + '-' + content.length;
}

// Meilisearch API endpoints
app.get('/api/search', async (req, res) => {
  try {
    const { q = '', limit = '20', offset = '0', sort, highlight = 'true' } = req.query;
    
    // Parse Obsidian-style query to Meilisearch format
    const parsedQuery = mapObsidianQueryToMeili(String(q));
    
    // Build search parameters
    const searchParams = buildSearchParams(parsedQuery, {
      limit: Number(limit),
      offset: Number(offset),
      sort,
      highlight: highlight === 'true'
    });
    
    // Execute search
    const client = meiliClient();
    const indexUid = vaultIndexName(vaultDir);
    const index = await ensureIndexSettings(client, indexUid);
    const result = await index.search(searchParams.q, searchParams);
    
    // Return results
    res.json({
      hits: result.hits,
      estimatedTotalHits: result.estimatedTotalHits,
      facetDistribution: result.facetDistribution,
      processingTimeMs: result.processingTimeMs,
      query: q
    });
  } catch (error) {
    console.error('[Meili] Search failed:', error);
    res.status(500).json({ 
      error: 'search_failed',
      message: error.message 
    });
  }
});

// PUT /api/notes/:idOrPath/tags - Update tags for a specific note
// Accepts either a slug id or a vault-relative path (with or without .md), including slashes
app.put(/^\/api\/notes\/(.+?)\/tags$/, express.json(), async (req, res) => {
  try {
    const rawParam = req.params[0];
    const noteParam = decodeURIComponent(rawParam || '');
    const { tags } = req.body;
    
    if (!Array.isArray(tags)) {
      return res.status(400).json({ error: 'tags must be an array' });
    }
    
    // Find note by id or by path
    const notes = await loadVaultNotes(vaultDir);
    let note = notes.find(n => n.id === noteParam);

    if (!note) {
      // Try by originalPath (without .md)
      const withoutExt = noteParam.replace(/\.md$/i, '');
      note = notes.find(n => n.originalPath === withoutExt);
    }

    if (!note) {
      // Try by filePath (with .md)
      const withExt = /\.md$/i.test(noteParam) ? noteParam : `${noteParam}.md`;
      // Normalize slashes
      const normalized = withExt.replace(/\\/g, '/');
      note = notes.find(n => n.filePath === normalized || n.filePath === normalized.replace(/^\//, ''));
    }
    
    if (!note || !note.filePath) {
      return res.status(404).json({ error: 'Note not found' });
    }
    
    const absolutePath = path.join(vaultDir, note.filePath);
    
    if (!fs.existsSync(absolutePath)) {
      return res.status(404).json({ error: 'File not found on disk' });
    }
    
    // Read current content
    const currentContent = fs.readFileSync(absolutePath, 'utf-8');
    
    // Rewrite with new tags
    const updatedContent = rewriteTagsFrontmatter(currentContent, tags);
    
    // Write back to disk (atomic with backup)
    const tempPath = absolutePath + '.tmp';
    const backupPath = absolutePath + '.bak';
    
    try {
      if (enableBackups) {
        fs.copyFileSync(absolutePath, backupPath);
      }
      
      // Write to temp file
      fs.writeFileSync(tempPath, updatedContent, 'utf-8');
      
      // Atomic rename
      fs.renameSync(tempPath, absolutePath);
      
      console.log(`[Tags] Updated tags for note ${note.id} (${note.filePath})`);
      
      // Extract final tags from updated content
      const finalTags = extractTagsFromFrontmatter(updatedContent);
      
      // Trigger Meilisearch reindex for this file
      try {
        await upsertFile(note.filePath);
      } catch (indexError) {
        console.warn('[Tags] Failed to reindex after tag update:', indexError);
      }
      
      res.json({ 
        ok: true,
        tags: finalTags,
        noteId: note.id
      });
      
    } catch (writeError) {
      // Restore from backup on error
      if (fs.existsSync(tempPath)) {
        try { fs.unlinkSync(tempPath); } catch {}
      }
      if (fs.existsSync(backupPath)) {
        try { fs.copyFileSync(backupPath, absolutePath); } catch {}
      }
      throw writeError;
    }
    
  } catch (error) {
    console.error('[Tags] Update failed:', error);
    res.status(500).json({ 
      error: 'Failed to update tags',
      message: error.message 
    });
  }
});

app.post('/api/reindex', async (_req, res) => {
  try {
    console.log('[Meili] Manual reindex triggered');
    const result = await fullReindex();
    res.json({ 
      ok: true,
      ...result
    });
  } catch (error) {
    console.error('[Meili] Reindex failed:', error);
    res.status(500).json({ 
      error: 'reindex_failed',
      message: error.message
    });
  }
});

// Get counts for Quick Links (favorites, templates, tasks, drafts, archive)
app.get('/api/quick-links/counts', async (req, res) => {
  try {
    const client = meiliClient();
    const indexUid = vaultIndexName(vaultDir);
    const index = await ensureIndexSettings(client, indexUid);
    
    // Get counts for each filter
    const [favoritesResult, templatesResult, tasksResult, draftsResult, archiveResult] = await Promise.all([
      index.search('', { filter: 'favoris = true', limit: 0 }),
      index.search('', { filter: 'template = true', limit: 0 }),
      index.search('', { filter: 'task = true', limit: 0 }),
      index.search('', { filter: 'draft = true', limit: 0 }),
      index.search('', { filter: 'archive = true', limit: 0 })
    ]);
    
    res.json({
      favorites: favoritesResult.estimatedTotalHits || 0,
      templates: templatesResult.estimatedTotalHits || 0,
      tasks: tasksResult.estimatedTotalHits || 0,
      drafts: draftsResult.estimatedTotalHits || 0,
      archive: archiveResult.estimatedTotalHits || 0
    });
  } catch (error) {
    console.error('[Quick Links] Failed to get counts:', error);
    res.status(500).json({ 
      error: 'Failed to get counts',
      message: error.message 
    });
  }
});

// Servir l'index.html pour toutes les routes (SPA)
const sendIndex = (req, res) => {
  const indexPath = path.join(distDir, 'index.html');
  if (!fs.existsSync(indexPath)) {
    return res
      .status(500)
      .send('Application build missing. Please run `npm run build` before starting the server.');
  }
  res.sendFile(indexPath);
};

// Phase 3: Setup performance monitoring endpoint (must be before catch-all)
setupPerformanceEndpoint(app, performanceMonitor, metadataCache, meilisearchCircuitBreaker);

// Setup create note endpoint (must be before catch-all)
setupCreateNoteEndpoint(app, vaultDir);

// Setup update and delete note endpoints (must be before catch-all)
setupUpdateNoteEndpoint(app, vaultDir);
setupDeleteNoteEndpoint(app, vaultDir);

// SSE endpoint for vault events (folder rename, delete, etc.)
app.get('/api/vault/events', (req, res) => {
  res.setHeader('Content-Type', 'text/event-stream');
  res.setHeader('Cache-Control', 'no-cache');
  res.setHeader('Connection', 'keep-alive');
  res.setHeader('Access-Control-Allow-Origin', '*');

  const client = registerVaultEventClient(res);

  req.on('close', () => {
    unregisterVaultEventClient(client);
  });
});

// Setup rename folder endpoint (must be before catch-all)
setupRenameFolderEndpoint(app, vaultDir, broadcastVaultEvent, metadataCache);

// Setup rename file endpoint (must be before catch-all)
setupRenameFileEndpoint(app, vaultDir, broadcastVaultEvent, metadataCache);

// Setup move note endpoint (must be before catch-all)
setupMoveNoteEndpoint(app, vaultDir, broadcastVaultEvent, metadataCache);

// Setup delete folder endpoint (must be before catch-all)
setupDeleteFolderEndpoint(app, vaultDir, broadcastVaultEvent, metadataCache);

// Setup create folder endpoint (must be before catch-all)
setupCreateFolderEndpoint(app, vaultDir, broadcastVaultEvent, metadataCache);

app.get('/', sendIndex);
app.use((req, res) => {
  if (req.path.startsWith('/api/')) {
    return res.status(404).json({ error: 'Not found' });
  }
  return sendIndex(req, res);
});

// Créer le répertoire de la voûte s'il n'existe pas
if (!fs.existsSync(vaultDir)) {
  fs.mkdirSync(vaultDir, { recursive: true });
  console.log('Created vault directory:', vaultDir);
}

// Phase 3: Deferred Meilisearch indexing (non-blocking)
let indexingState = { inProgress: false, completed: false };
const scheduleIndexing = async () => {
  if (indexingState.inProgress) return;
  indexingState.inProgress = true;
  
  setImmediate(async () => {
    try {
      console.time('[Meilisearch] Background indexing');
      await fullReindex(vaultDir);
      console.timeEnd('[Meilisearch] Background indexing');
      indexingState.completed = true;
      console.log('[Meilisearch] ✅ Background indexing completed');
    } catch (error) {
      console.error('[Meilisearch] ❌ Background indexing failed:', error.message);
      indexingState.completed = false;
      // Retry after 5 minutes
      setTimeout(() => {
        indexingState.inProgress = false;
        scheduleIndexing();
      }, 5 * 60 * 1000);
    }
  });
};

const server = app.listen(PORT, '0.0.0.0', () => {
  console.log(`🚀 ObsiViewer server running on http://0.0.0.0:${PORT}`);
  console.log(`📁 Vault directory: ${vaultDir}`);
  console.log(`📊 Performance monitoring: http://0.0.0.0:${PORT}/__perf`);
  
  // Schedule background indexing (non-blocking)
  scheduleIndexing();
  console.log('✅ Server ready - Meilisearch indexing in background');
});

// Error handlers
process.on('uncaughtException', (err) => {
  console.error('Uncaught Exception:', err);
  process.exit(1);
});

process.on('unhandledRejection', (reason, promise) => {
  console.error('Unhandled Rejection at:', promise, 'reason:', reason);
  process.exit(1);
});

// Graceful shutdown
process.on('SIGINT', () => {
  console.log('\n🛑 Shutting down server...');
  server.close(() => {
    console.log('✅ Server shutdown complete');
    process.exit(0);
  });
});