const DEFAULT_TIMEOUT_MS = Number(process.env.CHANNEL_FETCH_TIMEOUT_MS || 6000);

// Fournisseur de token Twitch branché par server/index.mjs (qui gère le cache
// et le renouvellement via TWITCH_CLIENT_ID/SECRET). Sans lui, les chaînes
// Twitch retombent sur des métadonnées vides (titre/avatar null -> pas de logo).
let twitchTokenProvider = null;
export function setTwitchTokenProvider(fn) {
  twitchTokenProvider = typeof fn === 'function' ? fn : null;
}

async function getTwitchToken() {
  try {
    if (twitchTokenProvider) {
      const t = await twitchTokenProvider();
      if (t) return t;
    }
  } catch {}
  return process.env.TWITCH_APP_ACCESS_TOKEN || null;
}

async function fetchWithTimeout(url, options = {}) {
  const { timeout = DEFAULT_TIMEOUT_MS, transform, ...init } = options || {};
  const controller = new AbortController();
  const timer = setTimeout(() => controller.abort(), timeout);
  try {
    const resp = await fetch(url, { ...init, signal: controller.signal });
    if (!resp.ok) throw new Error(`fetch_failed_${resp.status}`);
    const data = transform ? await transform(resp) : await resp.json();
    return data;
  } finally {
    clearTimeout(timer);
  }
}

function safeMeta(meta = {}, fallback = {}) {
  return {
    provider: fallback.provider,
    externalId: fallback.externalId,
    title: meta.title ?? fallback.title,
    handle: meta.handle ?? fallback.handle,
    avatarUrl: meta.avatarUrl ?? fallback.avatarUrl,
    url: meta.url ?? fallback.url,
    subsCount: typeof meta.subsCount === 'number' ? meta.subsCount : fallback.subsCount,
    verified: typeof meta.verified === 'boolean'
      ? meta.verified
      : (typeof fallback.verified === 'boolean' ? fallback.verified : false),
  };
}

async function fetchYoutubeChannel(externalId) {
  const key = process.env.YOUTUBE_API_KEY;
  if (!key) {
    return { provider: 'yt', externalId, url: `https://www.youtube.com/channel/${externalId}` };
  }
  try {
    const params = new URLSearchParams({
      part: 'snippet,statistics,brandingSettings',
      id: externalId,
      key,
    });
    const data = await fetchWithTimeout(`https://www.googleapis.com/youtube/v3/channels?${params.toString()}`);
    const item = data?.items?.[0];
    if (!item) throw new Error('channel_not_found');
    const snippet = item.snippet || {};
    const thumbnails = snippet.thumbnails || {};
    const stats = item.statistics || {};
    const branding = item.brandingSettings || {};
    const avatars = thumbnails.high?.url || thumbnails.medium?.url || thumbnails.default?.url;
    const url = branding.channel?.customUrl
      ? `https://www.youtube.com/${branding.channel.customUrl}`
      : `https://www.youtube.com/channel/${externalId}`;
    return {
      provider: 'yt',
      externalId,
      title: snippet.title || branding.channel?.title,
      handle: snippet.customUrl ? `@${snippet.customUrl.replace(/^@/, '')}` : undefined,
      avatarUrl: avatars,
      url,
      subsCount: stats.subscriberCount ? Number(stats.subscriberCount) : undefined,
      verified: Array.isArray(snippet.badges) ? snippet.badges.includes('verified') : undefined,
    };
  } catch {
    return { provider: 'yt', externalId, url: `https://www.youtube.com/channel/${externalId}` };
  }
}

async function fetchDailymotionChannel(externalId) {
  try {
    // NOTE : `avatar_url` n'est pas un champ valide de l'API user (400 sur
    // toute la requête) — seuls avatar_720_url / avatar_medium_url le sont.
    const params = new URLSearchParams({
      fields: 'id,username,screenname,avatar_720_url,avatar_medium_url,url,followers_total,verified',
    });
    const data = await fetchWithTimeout(`https://api.dailymotion.com/user/${externalId}?${params.toString()}`);
    const username = data.username || externalId;
    return safeMeta({
      title: data.screenname || data.username,
      handle: data.username ? `@${data.username}` : undefined,
      avatarUrl: data.avatar_720_url || data.avatar_medium_url,
      url: `https://www.dailymotion.com/user/${username}`,
      subsCount: typeof data.followers_total === 'number' ? data.followers_total : undefined,
      verified: Boolean(data.verified),
    }, { provider: 'dm', externalId, url: `https://www.dailymotion.com/user/${externalId}` });
  } catch {
    return { provider: 'dm', externalId, url: `https://www.dailymotion.com/user/${externalId}` };
  }
}

async function fetchTwitchChannel(externalId) {
  try {
    const clientId = process.env.TWITCH_CLIENT_ID;
    const token = await getTwitchToken();
    if (clientId && token) {
      // Les anciens abonnements peuvent stocker l'id numérique : Helix exige
      // ?id= dans ce cas (?login= ne matche que le login).
      const byId = /^\d+$/.test(String(externalId || ''));
      const data = await fetchWithTimeout(
        `https://api.twitch.tv/helix/users?${byId ? 'id' : 'login'}=${encodeURIComponent(externalId)}`,
        {
          headers: {
            'Client-ID': clientId,
            'Authorization': `Bearer ${token}`,
          },
        }
      );
      const user = data?.data?.[0];
      if (user) {
        return safeMeta({
          title: user.display_name,
          handle: `@${user.login}`,
          avatarUrl: user.profile_image_url,
          url: `https://www.twitch.tv/${user.login}`,
          subsCount: typeof user.view_count === 'number' ? user.view_count : undefined,
        }, { provider: 'tw', externalId, url: `https://www.twitch.tv/${externalId}` });
      }
    }
  } catch {}
  return { provider: 'tw', externalId, url: `https://www.twitch.tv/${externalId}` };
}

function parsePeerTubeExternalId(externalId) {
  const [instance, channel] = String(externalId).split('|');
  if (!channel) return { instance: null, channel: externalId };
  return { instance, channel };
}

async function fetchPeerTubeChannel(externalId) {
  const { instance, channel } = parsePeerTubeExternalId(externalId);
  if (!instance) {
    return { provider: 'pt', externalId, url: `https://${externalId}` };
  }
  try {
    const data = await fetchWithTimeout(`https://${instance}/api/v1/video-channels/${encodeURIComponent(channel)}`);
    return safeMeta({
      title: data.displayName || data.name,
      handle: data.host ? `@${data.name}@${data.host}` : undefined,
      avatarUrl: data?.avatar?.path ? `https://${instance}${data.avatar.path}` : undefined,
      url: data?.url || `https://${instance}/video-channels/${channel}`,
      subsCount: typeof data.followersCount === 'number' ? data.followersCount : undefined,
      verified: Boolean(data.ownerAccount?.verified)
    }, { provider: 'pt', externalId, url: `https://${instance}/video-channels/${channel}` });
  } catch {
    return { provider: 'pt', externalId, url: instance ? `https://${instance}/video-channels/${channel}` : undefined };
  }
}

async function fetchOdyseeChannel(externalId) {
  try {
    const body = {
      jsonrpc: '2.0',
      method: 'resolve',
      params: { urls: [externalId.startsWith('@') ? externalId : `@${externalId}`] },
      id: 1
    };
    const resp = await fetchWithTimeout('https://api.na-backend.odysee.com/api/v1/proxy?m=resolve', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify(body),
      transform: res => res.json(),
      timeout: DEFAULT_TIMEOUT_MS
    });
    const result = resp?.result;
    const key = result ? Object.keys(result)[0] : null;
    const meta = key ? result[key] : null;
    if (meta?.value) {
      const value = meta.value;
      return safeMeta({
        title: value?.title,
        handle: meta.short_url ? meta.short_url.replace('https://odysee.com/', '') : undefined,
        avatarUrl: meta?.thumbnail?.url,
        url: meta.short_url,
        subsCount: typeof meta?.meta?.effective_amount === 'number' ? meta.meta.effective_amount : undefined,
      }, { provider: 'od', externalId, url: meta.short_url });
    }
  } catch {}
  return { provider: 'od', externalId, url: `https://odysee.com/${externalId.replace(/^@/, '')}` };
}

async function fetchRumbleChannel(externalId) {
  try {
    const data = await fetchWithTimeout(`https://rumble.com/${externalId}`, {
      transform: async (res) => res.text()
    });
    const titleMatch = /<title>([^<]+)<\/title>/i.exec(data);
    const avatarMatch = /property="og:image" content="([^"]+)"/i.exec(data);
    const name = titleMatch ? titleMatch[1].replace(/ on Rumble.*$/i, '').trim() : undefined;
    return safeMeta({
      title: name,
      avatarUrl: avatarMatch ? avatarMatch[1] : undefined,
      url: `https://rumble.com/${externalId}`,
    }, { provider: 'ru', externalId, url: `https://rumble.com/${externalId}` });
  } catch {
    return { provider: 'ru', externalId, url: `https://rumble.com/${externalId}` };
  }
}

export const channelRegistry = {
  yt: { fetchChannelById: fetchYoutubeChannel },
  dm: { fetchChannelById: fetchDailymotionChannel },
  tw: { fetchChannelById: fetchTwitchChannel },
  pt: { fetchChannelById: fetchPeerTubeChannel },
  od: { fetchChannelById: fetchOdyseeChannel },
  ru: { fetchChannelById: fetchRumbleChannel },
};

export function getChannelAdapter(provider) {
  return channelRegistry[provider];
}

export default channelRegistry;