const ASR_URL = '/mobile/jd-asr/asr';
const APPLICATION_ID = 'db5c6297-4d8e-44af-ba77-f36154447dae';
const ASR_PROTOCOL = 3;
const NET_STATE = 2; // WIFI
const APPLICATOR = 1; // 外部业务方

interface ASRResponse {
  request_id: string;
  status: number;
  index: number;
  message: string;
  content?: Array<{
    text: string;
    text_type?: 'final' | 'partial';
  }>;
}

export type OnRecognitionResult = (result: {
  text: string;
  textType: 'partial' | 'final';
  isComplete: boolean;
}) => void;

export interface StreamPackageParams {
  audioData: ArrayBuffer;
  requestId: string;
  sequenceId: number;
  isFirstPackage?: boolean;
  isLastPackage?: boolean;
  onResult?: OnRecognitionResult;
}

const ERROR_MESSAGES: Record<number, string> = {
  0: '成功',
  31001: '语音数据为空',
  31002: '语音数据过长，一次请求音频不能超过一分钟',
  31003: '请求参数出错',
  31004: '音频头部格式解析错误',
  31005: '音频采样率或通道数错误',
  31006: '音频格式错误',
  32001: '服务内部音频解码错误',
  32002: '服务内部模块错误',
  32003: '服务内部连接错误',
  33001: '服务内部模块错误',
  33002: '语音识别解码失败',
};

export function generateUUID(): string {
  if (typeof crypto !== 'undefined' && crypto.randomUUID) {
    return crypto.randomUUID();
  }
  return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, c => {
    const r = (Math.random() * 16) | 0;
    const v = c === 'x' ? r : (r & 0x3) | 0x8;
    return v.toString(16);
  });
}

function getPlatformInfo(): string {
  if (typeof navigator === 'undefined') return 'Web&Browser&Unknown';
  const ua = navigator.userAgent;

  if (ua.includes('iPhone') || ua.includes('iPad')) {
    const m = ua.match(/OS (\d+[._]\d+)/);
    const ver = m ? m[1].replace(/_/g, '.') : 'Unknown';
    const dev = ua.includes('iPad') ? 'iPad' : 'iPhone';
    return `iOS&${dev}&${ver}`;
  }
  if (ua.includes('Android')) {
    const m = ua.match(/Android (\d+\.\d+)/);
    return `Android&Mobile&${m ? m[1] : 'Unknown'}`;
  }
  if (ua.includes('Mac OS')) {
    const m = ua.match(/Mac OS X (\d+[._]\d+[._]\d+)/);
    return `macOS&Mac&${m ? m[1].replace(/_/g, '.') : 'Unknown'}`;
  }
  if (ua.includes('Windows')) {
    const m = ua.match(/Windows NT (\d+\.\d+)/);
    return `Windows&PC&${m ? m[1] : 'Unknown'}`;
  }
  return 'Web&Browser&Unknown';
}

function buildStreamingProperty(): string {
  return JSON.stringify({
    autoend: false,
    platform: getPlatformInfo(),
    version: '1.0.0',
    longspeech: true,
    encode: {
      channel: 1,
      format: 'wav',
      sample_rate: 16000,
      post_process: -1,
      partial_result: 1,
      punc_end_process: 1,
      punc_partial_process: 1,
      dynamic_lm: 1,
    },
  });
}

/**
 * Send a single streaming audio package to JD ASR.
 * Sequence-Id protocol: first=1, middle=N, last=-N.
 * Property header is included on first and last packages.
 */
export async function sendStreamPackage(params: StreamPackageParams): Promise<ASRResponse> {
  const {
    audioData,
    requestId,
    sequenceId,
    isFirstPackage = false,
    isLastPackage = false,
    onResult,
  } = params;

  if ((!audioData || audioData.byteLength === 0) && !isLastPackage) {
    return { request_id: requestId, status: 0, index: 0, message: '成功', content: [] };
  }

  const headers: Record<string, string> = {
    'Content-Type': 'application/octet-stream',
    Domain: 'general',
    'Application-Id': APPLICATION_ID,
    'Request-Id': requestId,
    'Sequence-Id': isLastPackage ? `-${sequenceId}` : String(sequenceId),
    'Asr-Protocol': String(ASR_PROTOCOL),
    'Net-State': String(NET_STATE),
    Applicator: String(APPLICATOR),
  };

  if (isFirstPackage || isLastPackage) {
    headers.Property = buildStreamingProperty();
  }

  const response = await fetch(ASR_URL, {
    method: 'POST',
    headers,
    body: audioData,
  });

  if (!response.ok) {
    throw new Error(`语音识别请求失败 (HTTP ${response.status})`);
  }

  const result: ASRResponse = await response.json();

  if (result.status !== 0) {
    const msg = ERROR_MESSAGES[result.status] || result.message || '未知错误';
    throw new Error(`语音识别失败: ${msg}`);
  }

  if (result.content && result.content.length > 0 && onResult) {
    for (const item of result.content) {
      if (item.text) {
        const textType = item.text_type || (isLastPackage ? 'final' : 'partial');
        onResult({
          text: item.text,
          textType: textType as 'partial' | 'final',
          isComplete: isLastPackage && textType === 'final',
        });
      }
    }
  }

  return result;
}

/**
 * Send WAV audio data to JD ASR API and return the recognized text.
 * Uses single-package upload (Sequence-Id: -1).
 */
export async function recognizeSpeech(audioData: ArrayBuffer): Promise<string> {
  if (!audioData || audioData.byteLength === 0) {
    return '';
  }

  const requestId = generateUUID();

  const property = JSON.stringify({
    autoend: false,
    platform: getPlatformInfo(),
    version: '1.0.0',
    longspeech: false,
    encode: {
      channel: 1,
      format: 'wav',
      sample_rate: 16000,
      post_process: -1,
      partial_result: -1,
      punc_end_process: 1,
      punc_partial_process: -1,
      dynamic_lm: 1,
    },
  });

  const headers: Record<string, string> = {
    'Content-Type': 'application/octet-stream',
    Domain: 'general',
    'Application-Id': APPLICATION_ID,
    'Request-Id': requestId,
    'Sequence-Id': '-1',
    'Asr-Protocol': String(ASR_PROTOCOL),
    'Net-State': String(NET_STATE),
    Applicator: String(APPLICATOR),
    Property: property,
  };

  const response = await fetch(ASR_URL, {
    method: 'POST',
    headers,
    body: audioData,
  });

  if (!response.ok) {
    throw new Error(`语音识别请求失败 (HTTP ${response.status})`);
  }

  const result: ASRResponse = await response.json();

  if (result.status !== 0) {
    const msg = ERROR_MESSAGES[result.status] || result.message || '未知错误';
    throw new Error(`语音识别失败: ${msg}`);
  }

  if (result.content && result.content.length > 0) {
    return result.content.map(c => c.text).join('');
  }

  return '';
}