// Synchronization Utilities
// Handles sync logic and conflict resolution

(function() {
  'use strict';

  const SyncUtils = {
    
    // Sync mode descriptions
    MODES: {
      'bi-directional': {
        name: 'Bi-Directional',
        description: 'Keep both versions; additions/updates replicate both ways',
        deleteFromLinkding: true,
        keepBothOnUpdate: true
      },
      'write-only': {
        name: 'Write-Only',
        description: 'Browser is authoritative; updates push to Linkding only',
        deleteFromLinkding: true,
        keepBothOnUpdate: false
      },
      'read-only': {
        name: 'Read-Only',
        description: 'Linkding is authoritative; download from Linkding only',
        deleteFromLinkding: false,
        keepBothOnUpdate: false
      }
    },
    
    // Get sync mode config
    getModeConfig(mode) {
      return this.MODES[mode] || this.MODES['bi-directional'];
    },
    
    // Determine sync action based on mode
    determineSyncAction(mode, action) {
      const config = this.getModeConfig(mode);
      
      switch (action) {
        case 'create':
          // New bookmark in browser
          if (config.deleteFromLinkding) {
            return { action: 'create', deleteFromLinkding: false };
          }
          return { action: 'create' };
          
        case 'update':
          // Existing bookmark with changes
          if (config.keepBothOnUpdate) {
            return { action: 'update', keepBoth: true };
          }
          return { action: 'update' };
          
        case 'delete':
          // Bookmark deleted from browser
          if (config.deleteFromLinkding) {
            return { action: 'delete' };
          }
          return { action: 'ignore' };
          
        default:
          return { action: 'none' };
      }
    },
    
    // Resolve conflict when same URL exists in different folders
    resolveConflict(browserBookmark, linkdingBookmark, browserNotes, linkdingNotes, mode) {
      const config = this.getModeConfig(mode);
      
      if (config.keepBothOnUpdate) {
        // Bi-directional: keep both, use Linkding notes as primary
        const mergedNotes = {
          path: browserNotes.path || linkdingNotes.path,
          userNotes: config.keepBothOnUpdate ? linkdingNotes.userNotes : browserNotes.userNotes,
          autoTags: []
        };
        
        return {
          action: 'update',
          notes: mergedNotes,
          note: 'Updated with browser path; Linkding notes preserved'
        };
      }
      
      // Write-only or read-only: use browser data
      return {
        action: 'update',
        notes: browserNotes,
        note: 'Updated from browser'
      };
    },
    
    // Check if bookmark needs sync
    needsSync(browserBookmark, linkdingBookmark, browserNotes, linkdingNotes) {
      // Check if URLs match
      if (browserBookmark.url !== linkdingBookmark.url) {
        return true;
      }
      
      // Check if path changed
      if (browserNotes.path !== linkdingNotes.path) {
        return true;
      }
      
      // Check if notes changed
      if (browserNotes.userNotes !== linkdingNotes.userNotes) {
        return true;
      }
      
      // Check if tags changed
      const browserTags = browserNotes.autoTags.map(t => t.name);
      const linkdingTags = linkdingNotes.autoTags.map(t => t.name);
      
      if (JSON.stringify(browserTags) !== JSON.stringify(linkdingTags)) {
        return true;
      }
      
      return false;
    },
    
    // Get last sync timestamp
    getLastSyncTime() {
      return new Date().toISOString();
    },
    
    // Format sync timestamp for display
    formatTimestamp(timestamp) {
      if (!timestamp) return 'Never';
      
      const date = new Date(timestamp);
      const options = {
        year: 'numeric',
        month: 'short',
        day: 'numeric',
        hour: '2-digit',
        minute: '2-digit',
        timeZoneName: 'short'
      };
      
      return date.toLocaleDateString('en-US', options);
    }
  };

  // Export for use in other scripts
  window.SyncUtils = SyncUtils;

})();