// ============================================================
// AUDIO BACKUP — IndexedDB-based audio recording backup
// Saves audio blobs locally so failed transcriptions can be retried
// ============================================================

(function() {
  var DB_NAME = 'PedScribeAudioBackup';
  var STORE_NAME = 'recordings';
  var DB_VERSION = 1;
  var MAX_AGE_MS = 24 * 60 * 60 * 1000; // 24 hours

  var _db = null;

  function openDB() {
    if (_db) return Promise.resolve(_db);
    return new Promise(function(resolve, reject) {
      var request = indexedDB.open(DB_NAME, DB_VERSION);
      request.onupgradeneeded = function(e) {
        var db = e.target.result;
        if (!db.objectStoreNames.contains(STORE_NAME)) {
          var store = db.createObjectStore(STORE_NAME, { keyPath: 'id', autoIncrement: true });
          store.createIndex('timestamp', 'timestamp', { unique: false });
        }
      };
      request.onsuccess = function(e) { _db = e.target.result; resolve(_db); };
      request.onerror = function() { reject(new Error('IndexedDB open failed')); };
    });
  }

  // Save audio blob with metadata
  window.saveAudioBackup = function(blob, module) {
    return openDB().then(function(db) {
      return new Promise(function(resolve, reject) {
        var tx = db.transaction(STORE_NAME, 'readwrite');
        var store = tx.objectStore(STORE_NAME);
        var record = {
          blob: blob,
          module: module || 'unknown',
          timestamp: Date.now(),
          size: blob.size,
          mimeType: blob.type
        };
        var req = store.add(record);
        req.onsuccess = function() { resolve(req.result); }; // returns ID
        req.onerror = function() { reject(new Error('Failed to save audio backup')); };
      });
    }).then(function(id) {
      window._lastAudioBackupId = id;
      cleanupOldBackups();
      return id;
    }).catch(function(err) {
      console.warn('[AudioBackup] Save failed:', err.message);
      return null;
    });
  };

  // Delete a specific backup
  window.deleteAudioBackup = function(id) {
    return openDB().then(function(db) {
      return new Promise(function(resolve) {
        var tx = db.transaction(STORE_NAME, 'readwrite');
        tx.objectStore(STORE_NAME).delete(id);
        tx.oncomplete = function() { resolve(); };
        tx.onerror = function() { resolve(); };
      });
    }).catch(function() {});
  };

  // Get all backups (for UI listing)
  window.getAudioBackups = function() {
    return openDB().then(function(db) {
      return new Promise(function(resolve) {
        var tx = db.transaction(STORE_NAME, 'readonly');
        var store = tx.objectStore(STORE_NAME);
        var req = store.getAll();
        req.onsuccess = function() {
          var records = (req.result || []).filter(function(r) {
            return (Date.now() - r.timestamp) < MAX_AGE_MS;
          });
          resolve(records);
        };
        req.onerror = function() { resolve([]); };
      });
    }).catch(function() { return []; });
  };

  // Retry transcription from backup
  window.retryAudioBackup = function(id) {
    return openDB().then(function(db) {
      return new Promise(function(resolve, reject) {
        var tx = db.transaction(STORE_NAME, 'readonly');
        var req = tx.objectStore(STORE_NAME).get(id);
        req.onsuccess = function() {
          if (!req.result) { reject(new Error('Backup not found')); return; }
          resolve(req.result);
        };
        req.onerror = function() { reject(new Error('Failed to read backup')); };
      });
    }).then(function(record) {
      showLoading('Re-transcribing audio backup...');
      window._lastAudioBackupId = id;
      return transcribeAudio(record.blob).then(function(data) {
        hideLoading();
        if (data.success) {
          showToast('Backup transcribed successfully!', 'success');
          // Copy to clipboard
          if (navigator.clipboard && navigator.clipboard.writeText) {
            navigator.clipboard.writeText(data.text);
            showToast('Transcript copied to clipboard', 'info');
          }
        } else {
          showToast('Retry failed: ' + (data.error || 'unknown'), 'error');
        }
        return data;
      });
    });
  };

  // Clean up old backups
  function cleanupOldBackups() {
    openDB().then(function(db) {
      var tx = db.transaction(STORE_NAME, 'readwrite');
      var store = tx.objectStore(STORE_NAME);
      var index = store.index('timestamp');
      var cutoff = Date.now() - MAX_AGE_MS;
      var range = IDBKeyRange.upperBound(cutoff);
      var req = index.openCursor(range);
      req.onsuccess = function(e) {
        var cursor = e.target.result;
        if (cursor) {
          cursor.delete();
          cursor.continue();
        }
      };
    }).catch(function() {});
  }

  // Render audio backups list in settings
  window.renderAudioBackups = function() {
    var container = document.getElementById('audio-backups-list');
    if (!container) return;
    getAudioBackups().then(function(backups) {
      if (backups.length === 0) {
        container.innerHTML = '<p style="color:var(--g400);font-size:13px;">No audio backups. Recordings are saved here automatically and kept for 24 hours.</p>';
        return;
      }
      container.innerHTML = backups.map(function(b) {
        var date = new Date(b.timestamp);
        var sizeKb = Math.round(b.size / 1024);
        var age = Math.round((Date.now() - b.timestamp) / 60000);
        var ageStr = age < 60 ? age + 'm ago' : Math.round(age / 60) + 'h ago';
        return '<div class="saved-enc-item" style="padding:8px 12px;">' +
          '<div style="flex:1;">' +
            '<div style="font-weight:600;font-size:13px;">' + esc(b.module) + ' recording</div>' +
            '<div style="font-size:11px;color:var(--g500);">' + date.toLocaleString() + ' · ' + sizeKb + ' KB · ' + ageStr + '</div>' +
          '</div>' +
          '<button class="btn-sm btn-primary audio-backup-retry" data-id="' + b.id + '"><i class="fas fa-rotate-right"></i> Retry</button>' +
          '<button class="btn-sm btn-ghost audio-backup-delete" data-id="' + b.id + '" style="color:var(--red);"><i class="fas fa-trash"></i></button>' +
        '</div>';
      }).join('');
      container.querySelectorAll('.audio-backup-retry').forEach(function(btn) {
        btn.addEventListener('click', function() { retryAudioBackup(parseInt(btn.dataset.id)); });
      });
      container.querySelectorAll('.audio-backup-delete').forEach(function(btn) {
        btn.addEventListener('click', function() {
          deleteAudioBackup(parseInt(btn.dataset.id)).then(function() {
            showToast('Backup deleted', 'info');
            renderAudioBackups();
          });
        });
      });
    });
  };

  function esc(str) {
    if (!str) return '';
    return String(str).replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;');
  }

  // Clean up on load
  cleanupOldBackups();

  console.log('Audio backup system loaded');
})();