// Shared playlist utility functions
// Used by both popup.js and background.js

const PlaylistUtils = {
  /**
   * Extract video ID from YouTube URL
   * @param {string} url - YouTube URL
   * @returns {string|null} - Video ID or null if not found
   */
  extractVideoId(url) {
    try {
      const urlObj = new URL(url);
      return urlObj.searchParams.get("v");
    } catch (e) {
      return null;
    }
  },

  /**
   * Normalize a YouTube watch URL down to just the `v` (video ID) param,
   * stripping queue/playlist params like `list`, `index`, and `pp` so that
   * navigating to the stored URL later doesn't drop the user back into
   * whatever queue or playlist they originally watched it from.
   * @param {string} url - YouTube URL
   * @returns {string} - Clean watch URL, or the original url if no video ID is found
   */
  cleanVideoUrl(url) {
    const videoId = this.extractVideoId(url);
    return videoId ? `https://www.youtube.com/watch?v=${videoId}` : url;
  },

  /**
   * Find a video in all playlists by URL
   * @param {Object} playlists - All playlists object
   * @param {string} url - Video URL to search for
   * @returns {Array|false} - [playlistName, videoIndex, isLastVideo] or false if not found
   */
  findVideoInPlaylists(playlists, url) {
    const videoId = this.extractVideoId(url);

    if (!videoId) {
      return false;
    }

    // Check each playlist
    for (const playlistName in playlists) {
      const videos = playlists[playlistName];

      // Check each video in the playlist
      for (let i = 0; i < videos.length; i++) {
        const itemVideoId = this.extractVideoId(videos[i].url);

        // If the video IDs match, return playlist info
        if (itemVideoId === videoId) {
          const isLastVideo = i === videos.length - 1;
          return [playlistName, i, isLastVideo];
        }
      }
    }

    return false;
  },

  /**
   * Find which playlist contains a video by URL
   * @param {Object} playlists - All playlists object
   * @param {string} url - Video URL to search for
   * @returns {string|false} - Playlist name or false if not found
   */
  findPlaylist(playlists, url) {
    const result = this.findVideoInPlaylists(playlists, url);
    return result ? result[0] : false;
  },

  /**
   * Add a video to a playlist if it's not already present in any playlist
   * @param {string} playlistName - Name of playlist to add to
   * @param {Object} video - Video object with url and title properties
   * @returns {Promise<boolean>} - True if added, false if already exists
   */
  async addVideoToPlaylist(playlistName, video) {
    const { playlists: currentPlaylists } =
      await browser.storage.local.get("playlists");

    const cleanedVideo = { ...video, url: this.cleanVideoUrl(video.url) };

    const alreadyExists = this.findPlaylist(
      currentPlaylists,
      cleanedVideo.url,
    );

    if (alreadyExists) {
      console.log("Video already exists in playlist:", alreadyExists);
      return false;
    }

    // Add video to the specified playlist
    const updatedPlaylist = [...currentPlaylists[playlistName], cleanedVideo];
    const updatedPlaylists = {
      ...currentPlaylists,
      [playlistName]: updatedPlaylist,
    };

    await browser.storage.local.set({ playlists: updatedPlaylists });
    console.log("Added video to playlist:", playlistName);
    return true;
  },

  /**
   * Legacy function for backward compatibility with context menu
   * @param {string} playlistName - Name of playlist to add to
   * @param {Object} item - Context menu item with linkUrl and linkText
   * @returns {Promise<boolean>} - True if added, false if already exists
   */
  async addLinkToPlaylist(playlistName, item) {
    const video = {
      url: item.linkUrl,
      title: item.linkText,
    };

    return await this.addVideoToPlaylist(playlistName, video);
  },
};