import { WORKS_SQUARE_CONFIG } from '../api/works-config';
import { proxyAwareFetch } from '../utils/proxy-fetch';
import { getValidWorksSquareAccessToken } from './works-square-session';

const MAX_AUDIO_BYTES = 26_214_400;
const MAX_TRANSCRIPT_LENGTH = 16_000;

export type LearningSpeechRequest = {
  audio: Uint8Array;
  fileName: string;
  mimeType: string;
  language?: string;
};

type Dependencies = {
  fetchImpl?: typeof fetch;
  getAccessToken?: typeof getValidWorksSquareAccessToken;
  apiBaseUrl?: string;
};

export function createLearningSpeechClient(dependencies: Dependencies = {}) {
  const fetchImpl = dependencies.fetchImpl ?? proxyAwareFetch;
  const getAccessToken = dependencies.getAccessToken ?? getValidWorksSquareAccessToken;
  const apiBaseUrl = (dependencies.apiBaseUrl ?? WORKS_SQUARE_CONFIG.apiBaseUrl).replace(/\/+$/, '');

  async function transcribe(
    input: LearningSpeechRequest,
    assertCurrentAccount: () => void = () => undefined,
  ): Promise<{ text: string }> {
    const audio = input.audio instanceof Uint8Array ? input.audio : new Uint8Array(input.audio);
    if (!audio.byteLength || audio.byteLength > MAX_AUDIO_BYTES) throw new Error('语音长度不符合要求');
    assertCurrentAccount();
    const token = await getAccessToken({ fetchImpl }).catch(() => { throw new Error('语音识别失败'); });
    assertCurrentAccount();
    if (!token) throw new Error('请先登录');
    const form = new FormData();
    form.set('audio', new Blob([audio], { type: input.mimeType || 'audio/webm' }), input.fileName || 'voice.webm');
    if (input.language?.trim()) form.set('language', input.language.trim());
    const request = (accessToken: string) => {
      assertCurrentAccount();
      return fetchImpl(`${apiBaseUrl}/api/speech/transcriptions`, {
      method: 'POST',
      headers: { Authorization: `Bearer ${accessToken}` },
      body: form,
      });
    };
    let response = await request(token).catch(() => { throw new Error('语音识别失败'); });
    assertCurrentAccount();
    if (response.status === 401) {
      await response.body?.cancel().catch(() => undefined);
      assertCurrentAccount();
      const refreshed = await getAccessToken({ fetchImpl, forceRefresh: true }).catch(() => null);
      assertCurrentAccount();
      if (refreshed) {
        response = await request(refreshed).catch(() => { throw new Error('语音识别失败'); });
        assertCurrentAccount();
      }
    }
    const payload = await response.json().catch(() => null) as { text?: unknown; detail?: unknown } | null;
    const text = typeof payload?.text === 'string' ? payload.text.trim() : '';
    if (!response.ok || !text || text.length > MAX_TRANSCRIPT_LENGTH) throw new Error('语音识别失败');
    return { text };
  }

  return { transcribe };
}