/** 치지직 라이브/채널 URL에서 channelId 추출 */
export function parseChzzkChannelId(input: string): string | null {
  const raw = input.trim();
  if (!raw) return null;

  // 해시만 붙여 넣은 경우
  if (/^[a-f0-9]{32}$/i.test(raw)) return raw.toLowerCase();

  try {
    const url = new URL(raw.startsWith('http') ? raw : `https://${raw}`);
    if (!url.hostname.includes('chzzk.naver.com')) return null;
    const parts = url.pathname.split('/').filter(Boolean);
    // /live/{id} | /{id} | /channel/{id}
    const liveIdx = parts.indexOf('live');
    if (liveIdx >= 0 && parts[liveIdx + 1]) {
      const id = parts[liveIdx + 1];
      return /^[a-f0-9]{32}$/i.test(id) ? id.toLowerCase() : null;
    }
    const channelIdx = parts.indexOf('channel');
    if (channelIdx >= 0 && parts[channelIdx + 1]) {
      const id = parts[channelIdx + 1];
      return /^[a-f0-9]{32}$/i.test(id) ? id.toLowerCase() : null;
    }
    if (parts[0] && /^[a-f0-9]{32}$/i.test(parts[0])) {
      return parts[0].toLowerCase();
    }
  } catch {
    return null;
  }
  return null;
}

const CHZZK_API = 'https://api.chzzk.naver.com';
const GAME_API = 'https://comm-api.game.naver.com/nng_main';

const DEFAULT_HEADERS = {
  Accept: 'application/json',
  'User-Agent':
    'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/122.0.0.0 Safari/537.36',
  Origin: 'https://chzzk.naver.com',
  Referer: 'https://chzzk.naver.com/',
};

async function getJson<T>(url: string): Promise<T> {
  const res = await fetch(url, {
    headers: DEFAULT_HEADERS,
    cache: 'no-store',
  });
  if (!res.ok) {
    throw new Error(`치지직 API 오류 (${res.status})`);
  }
  return (await res.json()) as T;
}

export type ChannelInfo = {
  channelId: string;
  channelName: string | null;
};

export async function fetchChannelInfo(channelId: string): Promise<ChannelInfo> {
  const data = await getJson<{
    content?: { channelId?: string; channelName?: string };
  }>(`${CHZZK_API}/service/v1/channels/${channelId}`);
  return {
    channelId: data.content?.channelId || channelId,
    channelName: data.content?.channelName ?? null,
  };
}

export type LiveChatInfo = {
  chatChannelId: string;
  liveTitle: string | null;
  status: string | null;
};

/** 방송 중일 때 chatChannelId를 얻는다. */
export async function fetchLiveChatInfo(channelId: string): Promise<LiveChatInfo> {
  // polling live-status 우선
  try {
    const status = await getJson<{
      content?: { chatChannelId?: string; status?: string; liveTitle?: string };
    }>(`${CHZZK_API}/polling/v2/channels/${channelId}/live-status`);
    if (status.content?.chatChannelId) {
      return {
        chatChannelId: status.content.chatChannelId,
        liveTitle: status.content.liveTitle ?? null,
        status: status.content.status ?? null,
      };
    }
  } catch {
    // fallback below
  }

  const detail = await getJson<{
    content?: { chatChannelId?: string; liveTitle?: string; status?: string };
  }>(`${CHZZK_API}/service/v3/channels/${channelId}/live-detail`);

  if (!detail.content?.chatChannelId) {
    throw new Error('방송이 꺼져 있거나 chatChannelId를 찾지 못했습니다.');
  }

  return {
    chatChannelId: detail.content.chatChannelId,
    liveTitle: detail.content.liveTitle ?? null,
    status: detail.content.status ?? null,
  };
}

export async function fetchChatAccessToken(chatChannelId: string): Promise<string> {
  const data = await getJson<{
    code?: number;
    message?: string;
    content?: { accessToken?: string };
  }>(
    `${GAME_API}/v1/chats/access-token?channelId=${encodeURIComponent(chatChannelId)}&chatType=STREAMING`,
  );

  if (data.code === 42601) {
    throw new Error('연령 제한 방송이라 익명 채팅 토큰을 받을 수 없습니다.');
  }
  const token = data.content?.accessToken;
  if (!token) {
    throw new Error(data.message || '채팅 accessToken을 받지 못했습니다.');
  }
  return token;
}

export function chatServerUrl(chatChannelId: string) {
  const sum = chatChannelId
    .split('')
    .map((c) => c.charCodeAt(0))
    .reduce((a, b) => a + b, 0);
  const serverId = (Math.abs(sum) % 9) + 1;
  return `wss://kr-ss${serverId}.chat.naver.com/chat`;
}