update-youtube-weekly-playlist.js

// --- GLOBAL CONFIGURATION ---
var CACHE_DURATION_DAYS = 7;
var VIDEO_DURATION_THRESHOLD = 120; // 2 minutes

// NOTE: UPDATE THESE WITH YOUR ACTUAL IDs
var PLAYLIST_ID = 'ADD YOUR ID HERE'; 
var SPREADSHEET_ID = 'THE SPREADSHEET ID';
var CHANNEL_IDS = [
  'UCEJM4kRM01cY-2NeJ4-3nbw', 'UCZkGmgbBziqGCYI3x9hVQPg', 'UC5OdB-sGz9atv-tJINwWOTg',
  'UCtf6aq_atnqF6shEam6m1sQ', 'UCsphzld6v6ghCl_RyvihNgA', 'UC4ijq8Cg-8zQKx8OH12dUSw',
  'UCQdxE3tUpHOKQ5zK-_fOBjg' 
];


// =================================================================
// === 1. MAIN PLAYLIST UPDATE FUNCTION (for Scheduled Run 1) ===
// =================================================================

function updatePlaylist() {
  
  // Ensure the sheet structure is ready
  initializeSheet(SPREADSHEET_ID);
  
  var eightDaysAgo = new Date();
  eightDaysAgo.setDate(eightDaysAgo.getDate() - 8);
  
  try {
    var allVideos = [];
    for (var i = 0; i < CHANNEL_IDS.length; i++) {
      var videos = getLatestVideos(CHANNEL_IDS[i], eightDaysAgo);
      allVideos = allVideos.concat(videos);
    }
    
    var allVideoIds = allVideos.map(video => video.id.videoId);
    var videoDetails = getVideoDetailsInBatches(allVideoIds);
    var watchedVideos = getWatchedVideos(SPREADSHEET_ID);
    
    for (var i = 0; i < allVideos.length; i++) {
      var video = allVideos[i];
      var videoId = video.id.videoId;
      var details = videoDetails[videoId];
      
      // Merge all video data
      var fullVideoData = {
        id: videoId,
        channelName: video.snippet.channelTitle,
        title: video.snippet.title,
        publishedAt: video.snippet.publishedAt,
        durationInSeconds: details ? details.durationInSeconds : 0
      };
      
      if (fullVideoData.durationInSeconds > VIDEO_DURATION_THRESHOLD && 
          !watchedVideos.includes(videoId) && 
          !videoInPlaylist(videoId, PLAYLIST_ID)) {
        
        addToPlaylist(videoId, PLAYLIST_ID);
        addToWatchedList(fullVideoData, SPREADSHEET_ID); 
        Logger.log('Added video ' + videoId + ' to playlist and watched list');
      }
    }
  } catch (e) {
    console.error('An error occurred while updating the playlist:', e);
  }
}


// =================================================================
// === 2. CLEANUP FUNCTIONS (for Scheduled Run 2) ===
// =================================================================

// Wrapper function for trigger scheduling
function runPlaylistCleanup() {
  cleanPlaylist(PLAYLIST_ID, SPREADSHEET_ID);
}

function cleanPlaylist(playlistId, spreadsheetId) {
  Logger.log('Starting scheduled playlist cleanup...');
  
  // 1. Get the list of videos marked as watched in the Sheet
  var watchedVideoIds = getWatchedVideos(spreadsheetId);
  if (watchedVideoIds.length === 0) {
    Logger.log('No videos found in the Watched Videos sheet. Cleanup complete.');
    return;
  }
  
  // 2. Get all item IDs currently in the YouTube playlist
  var playlistItems = getAllPlaylistItems(playlistId); 
  
  // 3. Iterate and delete
  playlistItems.forEach(function(item) {
    var videoId = item.snippet.resourceId.videoId;
    
    // Check if the video is watched
    if (watchedVideoIds.includes(videoId)) {
      try {
        // Delete the item using its unique playlist item ID
        // Note: The delete operation costs 50 quota units.
        YouTube.PlaylistItems.remove(item.id); 
        Logger.log('Removed playlist item ' + item.id + ' (Video: ' + videoId + ')');
      } catch (e) {
        // Log error but continue with other deletions
        console.error('Error removing item ' + item.id + ': ' + e);
      }
    }
  });
  Logger.log('Playlist cleanup finished.');
}

// Helper function to handle paginated results for the playlist items (Cost: 1 unit per 50 items)
function getAllPlaylistItems(playlistId) {
  var allItems = [];
  var pageToken = '';

  do {
    // Request 'contentDetails' to get the videoId and 'snippet' to confirm.
    var response = YouTube.PlaylistItems.list('snippet,contentDetails', {
      playlistId: playlistId,
      maxResults: 50,
      pageToken: pageToken
    });
    
    allItems = allItems.concat(response.items);
    pageToken = response.nextPageToken;
    
  } while (pageToken);
  
  return allItems;
}


// =================================================================
// === 3. HELPER FUNCTIONS ===
// =================================================================

function exponentialBackoff(func, maxRetries = 5) {
  for (let i = 0; i < maxRetries; i++) {
    try {
      return func();
    } catch (e) {
      if (i === maxRetries - 1) throw e;
      
      const waitTime = Math.pow(2, i) * 1000 + Math.random() * 1000;
      Utilities.sleep(waitTime);
    }
  }
}

function initializeSheet(spreadsheetId) {
  var ss = SpreadsheetApp.openById(spreadsheetId);
  var sheet = ss.getSheetByName('Watched Videos');
  
  if (!sheet) {
    sheet = ss.insertSheet('Watched Videos');
  }
  
  // Set headers if the first cell is empty or doesn't match
  var headerRange = sheet.getRange('A1:D1');
  if (headerRange.getValues()[0][0] !== 'Video ID') {
    headerRange.setValues([['Video ID', 'Channel Name', 'Video Title', 'Publication Date/Time']]).setFontWeight('bold');
  }
}

function getLatestVideos(channelId, publishedAfter, pageToken) {
  return exponentialBackoff(() => {
    var options = {
      channelId: channelId,
      type: 'video',
      order: 'date',
      publishedAfter: publishedAfter.toISOString(),
      maxResults: 10
    };
    if (pageToken) options.pageToken = pageToken;
    
    try {
      // 'snippet' is essential here for title, channel name, and date
      var results = YouTube.Search.list('id,snippet', options); 
      return results.items;
    } catch (e) {
      console.error('Error fetching latest videos:', e);
      throw e;
    }
  });
}

function getVideoDetailsInBatches(videoIds) {
  var cache = CacheService.getScriptCache();
  var videoDetails = {};
  var uncachedIds = [];
  
  videoIds.forEach(function(videoId) {
    var cachedData = cache.get(videoId);
    if (cachedData) {
      videoDetails[videoId] = JSON.parse(cachedData);
    } else {
      uncachedIds.push(videoId);
    }
  });
  
  for (var i = 0; i < uncachedIds.length; i += 50) {
    var batch = uncachedIds.slice(i, i + 50);
    exponentialBackoff(() => {
      try {
        var response = YouTube.Videos.list('contentDetails', {id: batch.join(',')});
        response.items.forEach(function(item) {
          var durationInSeconds = parseDuration(item.contentDetails.duration);
          videoDetails[item.id] = {durationInSeconds: durationInSeconds};
          cache.put(item.id, JSON.stringify({durationInSeconds: durationInSeconds}), 21600);
        });
      } catch (e) {
        console.error('Error fetching video details:', e);
        throw e;
      }
    });
  }
  
  return videoDetails;
}

function parseDuration(duration) {
  var match = duration.match(/PT(\d+H)?(\d+M)?(\d+S)?/);
  if (!match) return 0; 
  
  var hours = parseInt(match[1]) ? parseInt(match[1].replace('H','')) : 0;
  var minutes = parseInt(match[2]) ? parseInt(match[2].replace('M','')) : 0;
  var seconds = parseInt(match[3]) ? parseInt(match[3].replace('S','')) : 0;
  return hours * 3600 + minutes * 60 + seconds;
}


function getWatchedVideos(spreadsheetId) {
  var sheet = SpreadsheetApp.openById(spreadsheetId).getSheetByName('Watched Videos');
  if (!sheet) return []; 
  // Get all IDs from Column A starting from row 2
  return sheet.getRange('A2:A').getValues().flat().filter(String);
}

function videoInPlaylist(videoId, playlistId) {
  return exponentialBackoff(() => {
    var cache = CacheService.getScriptCache();
    var cacheKey = 'playlist_' + videoId;
    var cachedResult = cache.get(cacheKey);
    
    if (cachedResult !== null) {
      return cachedResult === 'true';
    }
    
    try {
      var playlistItems = YouTube.PlaylistItems.list('snippet', {
        playlistId: playlistId,
        videoId: videoId,
        maxResults: 1
      });
      
      var result = playlistItems.items && playlistItems.items.length > 0;
      cache.put(cacheKey, result.toString(), 21600);
      return result;
    } catch (e) {
      console.error('Error checking video in playlist:', e);
      throw e;
    }
  });
}

function addToPlaylist(videoId, playlistId) {
  return exponentialBackoff(() => {
    try {
      YouTube.PlaylistItems.insert({
        snippet: {
          playlistId: playlistId,
          resourceId: {
            kind: 'youtube#video',
            videoId: videoId
          }
        }
      }, 'snippet');
    } catch (e) {
      console.error('Error adding video to playlist:', e);
      throw e;
    }
  });
}

function addToWatchedList(videoData, spreadsheetId) {
  var sheet = SpreadsheetApp.openById(spreadsheetId).getSheetByName('Watched Videos');
  
  // A: Video ID, B: Channel Name, C: Video Title, D: Publication Date/Time
  var row = [
    videoData.id,
    videoData.channelName,
    videoData.title,
    videoData.publishedAt 
  ];
  sheet.appendRow(row);
}