import type { PlatformSource, FetchRecentContentOptions } from './platform-source';
import type {
  Channel,
  PlatformSourceMetadata,
  PlatformContentMetadata,
} from '../types/index';
import { Platform, ContentType } from '../types/index';
import { execYtDlp, parseSingleJson, parseJsonLines } from './yt-dlp';

// ── URL Validation ──

/**
 * Accept SoundCloud artist-level URLs.
 * Reject track and set URLs (which contain /tracks/ or /sets/).
 */
export function isSoundCloudChannelUrl(url: string): boolean {
  if (!/^https?:\/\/(www\.)?soundcloud\.com\//.test(url)) return false;
  if (/\/(tracks|sets)\//.test(url)) return false;
  return true;
}

// ── Implementation ──

export class SoundCloudSource implements PlatformSource {
  async resolveChannel(url: string): Promise<PlatformSourceMetadata> {
    const result = await execYtDlp(
      ['--dump-single-json', '--playlist-items', '0', '--flat-playlist', url],
      { timeout: 30_000 }
    );

    const data = parseSingleJson(result.stdout) as Record<string, unknown>;

    // SoundCloud uses uploader/uploader_id/uploader_url instead of channel fields
    const channelName =
      (data.uploader as string) ??
      (data.channel as string) ??
      'Unknown Artist';
    const uploaderId = (data.uploader_id as string) ?? '';
    const uploaderUrl =
      (data.uploader_url as string) ??
      (data.channel_url as string) ??
      url;

    // Pick best available thumbnail
    const thumbnails = data.thumbnails as Array<{ url?: string }> | undefined;
    const imageUrl = thumbnails?.length
      ? (thumbnails[thumbnails.length - 1]?.url ?? null)
      : null;

    // Extract enrichment metadata (limited availability on SoundCloud)
    const description = typeof data.description === 'string' ? data.description : null;
    const subscriberCount = typeof data.channel_follower_count === 'number'
      ? data.channel_follower_count
      : typeof data.uploader_follower_count === 'number'
        ? data.uploader_follower_count
        : null;

    return {
      name: channelName,
      platformId: uploaderId,
      imageUrl,
      url: uploaderUrl,
      platform: Platform.SoundCloud,
      bannerUrl: null, // SoundCloud doesn't provide banner URLs via yt-dlp
      description,
      subscriberCount,
    };
  }

  async fetchRecentContent(
    channel: Channel,
    options?: FetchRecentContentOptions
  ): Promise<PlatformContentMetadata[]> {
    const limit = options?.limit ?? 50;
    const result = await execYtDlp(
      [
        '--flat-playlist',
        '--dump-json',
        '--playlist-items',
        `1:${limit}`,
        '--sleep-requests',
        '2', // SoundCloud rate limit mitigation
        channel.url,
      ],
      { timeout: 120_000 } // Longer timeout due to sleep-requests
    );

    const entries = parseJsonLines(result.stdout);

    return entries.map((entry) => {
      const e = entry as Record<string, unknown>;
      return {
        platformContentId: (e.id as string) ?? '',
        title: (e.title as string) ?? 'Untitled',
        url: (e.url as string) ?? (e.webpage_url as string) ?? '',
        contentType: ContentType.Audio, // SoundCloud defaults to audio
        duration: typeof e.duration === 'number' ? e.duration : null,
        thumbnailUrl: extractThumbnailUrl(e),
        publishedAt: null, // populated in T02 from upload_date
      };
    });
  }
}

// ── Helpers ──

function extractThumbnailUrl(entry: Record<string, unknown>): string | null {
  if (typeof entry.thumbnail === 'string') return entry.thumbnail;
  const thumbnails = entry.thumbnails as Array<{ url?: string }> | undefined;
  if (thumbnails?.length) {
    return thumbnails[thumbnails.length - 1]?.url ?? null;
  }
  return null;
}