/**
 * @typedef {Object} Suggestion
 * @property {string} title
 * @property {string} id
 * @property {number=} duration
 * @property {boolean=} isShort
 * @property {string=} url
 * @property {string=} thumbnail
 * @property {string=} uploaderName
 * @property {string=} type
 */

function parseISODurationToSeconds(iso) {
  if (typeof iso !== 'string' || !iso) return 0;
  const match = iso.match(/PT(?:(\d+)H)?(?:(\d+)M)?(?:(\d+)S)?/);
  if (!match) return 0;
  const hours = Number(match[1] || 0);
  const minutes = Number(match[2] || 0);
  const seconds = Number(match[3] || 0);
  return (hours * 3600) + (minutes * 60) + seconds;
}

/** @type {{ id: 'yt', label: string, search: (q: string, opts: { limit: number, page?: number, sort?: 'relevance'|'date'|'views' }) => Promise<Suggestion[]> }} */
const handler = {
  id: 'yt',
  label: 'YouTube',
  async search(q, opts) {
    const { limit = 10, page = 1, sort = 'relevance' } = opts || {};
    try {
      const API_KEY = process.env.YOUTUBE_API_KEY;
      if (!API_KEY) {
        throw new Error('YOUTUBE_API_KEY not configured');
      }

      let order = 'relevance';
      if (sort === 'date') order = 'date';
      else if (sort === 'views') order = 'viewCount';

      // Iterate nextPageToken to reach the requested page (1-based)
      const perPage = Math.min(Math.max(1, Number(limit || 10)), 50);
      const targetPage = Math.max(1, Number(page || 1));
      let pageToken = '';
      let currentPage = 1;
      let lastItems = [];

      while (currentPage <= targetPage) {
        const params = new URLSearchParams({
          part: 'snippet',
          q: q,
          type: 'video',
          maxResults: String(perPage),
          key: API_KEY,
          order
        });
        if (pageToken) params.set('pageToken', pageToken);

        const response = await fetch(`https://www.googleapis.com/youtube/v3/search?` + params.toString());
        if (!response.ok) {
          throw new Error(`YouTube API error: ${response.status}`);
        }
        const data = await response.json();

        if (currentPage === targetPage) {
          lastItems = Array.isArray(data.items) ? data.items : [];
          break;
        }

        // Prepare for next iteration
        const next = data.nextPageToken;
        if (!next) {
          // No more pages; requested page beyond available results
          lastItems = [];
          break;
        }
        pageToken = String(next);
        currentPage++;
      }

      const videoIds = (lastItems || [])
        .map(item => item?.id?.videoId)
        .filter(Boolean);

      const detailsMap = new Map();
      if (videoIds.length > 0) {
        const detailsParams = new URLSearchParams({
          part: 'contentDetails,statistics',
          id: videoIds.join(','),
          key: API_KEY
        });

        const detailsResp = await fetch(`https://www.googleapis.com/youtube/v3/videos?${detailsParams.toString()}`);
        if (detailsResp.ok) {
          const detailsData = await detailsResp.json();
          for (const vid of detailsData?.items || []) {
            if (vid?.id) detailsMap.set(vid.id, vid);
          }
        }
      }

      return (lastItems || []).map(item => {
        const videoId = item?.id?.videoId;
        const snippet = item?.snippet || {};
        const thumb = snippet.thumbnails?.high?.url
          || snippet.thumbnails?.medium?.url
          || snippet.thumbnails?.default?.url
          || undefined;

        const details = videoId ? detailsMap.get(videoId) : null;
        const isoDuration = details?.contentDetails?.duration || '';
        const duration = parseISODurationToSeconds(isoDuration);
        const views = details?.statistics?.viewCount != null ? Number(details.statistics.viewCount) : undefined;

        return {
          title: snippet.title || '',
          id: videoId,
          url: videoId ? `https://www.youtube.com/watch?v=${videoId}` : undefined,
          thumbnail: thumb,
          uploaderName: snippet.channelTitle || undefined,
          type: 'video',
          duration: duration > 0 ? duration : undefined,
          views,
          publishedAt: snippet.publishedAt || undefined
        };
      });
    } catch (error) {
      console.error('YouTube search error:', error);
      return [];
    }
  }
};

export default handler;