// https://www.volcengine.com/docs/6561/1329505#%E7%A4%BA%E4%BE%8Bsamples

import { WebSocket } from 'ws';
import { EventEmitter } from 'eventemitter3';
import fs from 'fs/promises';
import { nanoid } from 'nanoid';
const uuidv4 = nanoid;
const PROTOCOL_VERSION = 0b0001;
const DEFAULT_HEADER_SIZE = 0b0001;

// Message Type:
const FULL_CLIENT_REQUEST = 0b0001;
const AUDIO_ONLY_RESPONSE = 0b1011;
const FULL_SERVER_RESPONSE = 0b1001;
const ERROR_INFORMATION = 0b1111;

// Message Type Specific Flags
const MsgTypeFlagNoSeq = 0b0000; // Non-terminal packet with no sequence
const MsgTypeFlagPositiveSeq = 0b1; // Non-terminal packet with sequence > 0
const MsgTypeFlagLastNoSeq = 0b10; // last packet with no sequence
const MsgTypeFlagNegativeSeq = 0b11; // Payload contains event number (int32)
const MsgTypeFlagWithEvent = 0b100;
// Message Serialization
const NO_SERIALIZATION = 0b0000;
const JSON_TYPE = 0b0001;
// Message Compression
const COMPRESSION_NO = 0b0000;
const COMPRESSION_GZIP = 0b0001;

const EVENT_NONE = 0;
const EVENT_Start_Connection = 1;
const EVENT_FinishConnection = 2;
const EVENT_ConnectionStarted = 50; // 成功建连
const EVENT_ConnectionFailed = 51; // 建连失败（可能是无法通过权限认证）
const EVENT_ConnectionFinished = 52; // 连接结束
// 上行Session事件
const EVENT_StartSession = 100;
const EVENT_FinishSession = 102;
// 下行Session事件
const EVENT_SessionStarted = 150;
const EVENT_SessionFinished = 152;
const EVENT_SessionFailed = 153;
// 上行通用事件
const EVENT_TaskRequest = 200;
// 下行TTS事件
const EVENT_TTSSentenceStart = 350;
const EVENT_TTSSentenceEnd = 351;
const EVENT_TTSResponse = 352;

class Header {
  headerSize: number;
  protocolVersion: number;
  messageType: number;
  messageTypeSpecificFlags: number;
  serialMethod: number;
  compressionType: number;
  reservedData: number;

  constructor(
    protocolVersion: number = PROTOCOL_VERSION,
    headerSize: number = DEFAULT_HEADER_SIZE,
    messageType: number = 0,
    messageTypeSpecificFlags: number = 0,
    serialMethod: number = NO_SERIALIZATION,
    compressionType: number = COMPRESSION_NO,
    reservedData: number = 0,
  ) {
    this.headerSize = headerSize;
    this.protocolVersion = protocolVersion;
    this.messageType = messageType;
    this.messageTypeSpecificFlags = messageTypeSpecificFlags;
    this.serialMethod = serialMethod;
    this.compressionType = compressionType;
    this.reservedData = reservedData;
  }

  asBytes(): Buffer {
    return Buffer.from([
      (this.protocolVersion << 4) | this.headerSize,
      (this.messageType << 4) | this.messageTypeSpecificFlags,
      (this.serialMethod << 4) | this.compressionType,
      this.reservedData,
    ]);
  }
}

class Optional {
  event: number;
  sessionId: string | null;
  errorCode: number;
  connectionId: string | null;
  responseMetaJson: string | null;
  sequence: number | null;

  constructor(event: number = EVENT_NONE, sessionId: string | null = null, sequence: number | null = null) {
    this.event = event;
    this.sessionId = sessionId;
    this.errorCode = 0;
    this.connectionId = null;
    this.responseMetaJson = null;
    this.sequence = sequence;
  }

  // 转成 byte 序列
  asBytes(): Buffer {
    const optionBytes = Buffer.alloc(0);
    let result = optionBytes;

    if (this.event !== EVENT_NONE) {
      const eventBuffer = Buffer.alloc(4);
      eventBuffer.writeInt32BE(this.event);
      result = Buffer.concat([result, eventBuffer]);
    }

    if (this.sessionId !== null) {
      const sessionIdBytes = Buffer.from(this.sessionId);
      const sizeBuffer = Buffer.alloc(4);
      sizeBuffer.writeInt32BE(sessionIdBytes.length);
      result = Buffer.concat([result, sizeBuffer, sessionIdBytes]);
    }

    if (this.sequence !== null) {
      const sequenceBuffer = Buffer.alloc(4);
      sequenceBuffer.writeInt32BE(this.sequence);
      result = Buffer.concat([result, sequenceBuffer]);
    }

    return result;
  }
}

class Response {
  optional: Optional;
  header: Header;
  payload: Buffer | null;

  constructor(header: Header, optional: Optional) {
    this.optional = optional;
    this.header = header;
    this.payload = null;
  }

  toString(): string {
    return this.payload?.toString() || '';
  }
}

// 发送事件
async function sendEvent(ws: WebSocket, header: Buffer, optional: Buffer | null = null, payload: Buffer | null = null): Promise<void> {
  return new Promise((resolve, reject) => {
    const fullClientRequest: Buffer[] = [header];

    if (optional !== null) {
      fullClientRequest.push(optional);
    }

    if (payload !== null) {
      const payloadSizeBuffer = Buffer.alloc(4);
      payloadSizeBuffer.writeInt32BE(payload.length);
      fullClientRequest.push(payloadSizeBuffer, payload);
    }

    ws.send(Buffer.concat(fullClientRequest), (err) => {
      if (err) reject(err);
      else resolve();
    });
  });
}

// 读取 res 数组某段 字符串内容
function readResContent(res: Buffer, offset: number): [string, number] {
  const contentSize = res.readInt32BE(offset);
  offset += 4;
  const content = res.slice(offset, offset + contentSize).toString();
  offset += contentSize;
  return [content, offset];
}

// 读取 payload
function readResPayload(res: Buffer, offset: number): [Buffer, number] {
  const payloadSize = res.readInt32BE(offset);
  offset += 4;
  const payload = res.slice(offset, offset + payloadSize);
  offset += payloadSize;
  return [payload, offset];
}

// 解析响应结果
function parserResponse(res: Buffer | string): Response {
  if (typeof res === 'string') {
    throw new Error(res);
  }

  const response = new Response(new Header(), new Optional());
  // 解析结果
  // header
  const header = response.header;
  const num = 0b00001111;
  header.protocolVersion = (res[0] >> 4) & num;
  header.headerSize = res[0] & 0x0f;
  header.messageType = (res[1] >> 4) & num;
  header.messageTypeSpecificFlags = res[1] & 0x0f;
  header.serialMethod = (res[2] >> 4) & num;
  header.compressionType = res[2] & 0x0f;
  header.reservedData = res[3];

  let offset = 4;
  const optional = response.optional;

  if (header.messageType === FULL_SERVER_RESPONSE || header.messageType === AUDIO_ONLY_RESPONSE) {
    // read event
    if (header.messageTypeSpecificFlags === MsgTypeFlagWithEvent) {
      optional.event = res.readInt32BE(offset);
      offset += 4;

      if (optional.event === EVENT_NONE) {
        return response;
      }
      // read connectionId
      else if (optional.event === EVENT_ConnectionStarted) {
        [optional.connectionId, offset] = readResContent(res, offset);
      } else if (optional.event === EVENT_ConnectionFailed) {
        [optional.responseMetaJson, offset] = readResContent(res, offset);
      } else if (optional.event === EVENT_SessionStarted || optional.event === EVENT_SessionFailed || optional.event === EVENT_SessionFinished) {
        [optional.sessionId, offset] = readResContent(res, offset);
        [optional.responseMetaJson, offset] = readResContent(res, offset);
      } else {
        [optional.sessionId, offset] = readResContent(res, offset);
        [response.payload, offset] = readResPayload(res, offset);
      }
    }
  } else if (header.messageType === ERROR_INFORMATION) {
    optional.errorCode = res.readInt32BE(offset);
    offset += 4;
    [response.payload, offset] = readResPayload(res, offset);
  }

  return response;
}

function printResponse(res: Response, tag: string): void {
  // console.log(`===>${tag} header:`, res.header, res.optional.event);
  // console.log(`===>${tag} optional:`, res.optional);
}

function getPayloadBytes(
  uid: string = '1234',
  event: number = EVENT_NONE,
  text: string = '',
  speaker: string = '',
  audioFormat: string = 'mp3',
  audioSampleRate: number = 24000,
): Buffer {
  return Buffer.from(
    JSON.stringify({
      user: { uid },
      event,
      namespace: 'BidirectionalTTS',
      req_params: {
        text,
        speaker,
        audio_params: {
          format: audioFormat,
          sample_rate: audioSampleRate,
        },
      },
    }),
  );
}

async function startConnection(websocket: WebSocket): Promise<void> {
  const header = new Header(PROTOCOL_VERSION, DEFAULT_HEADER_SIZE, FULL_CLIENT_REQUEST, MsgTypeFlagWithEvent).asBytes();

  const optional = new Optional(EVENT_Start_Connection).asBytes();
  const payload = Buffer.from('{}');
  return await sendEvent(websocket, header, optional, payload);
}

async function startSession(websocket: WebSocket, speaker: string, sessionId: string): Promise<void> {
  const header = new Header(PROTOCOL_VERSION, DEFAULT_HEADER_SIZE, FULL_CLIENT_REQUEST, MsgTypeFlagWithEvent, JSON_TYPE).asBytes();

  const optional = new Optional(EVENT_StartSession, sessionId).asBytes();
  const payload = getPayloadBytes('1234', EVENT_StartSession, '', speaker);
  return await sendEvent(websocket, header, optional, payload);
}

async function sendText(ws: WebSocket, speaker: string, text: string, sessionId: string): Promise<void> {
  const header = new Header(PROTOCOL_VERSION, DEFAULT_HEADER_SIZE, FULL_CLIENT_REQUEST, MsgTypeFlagWithEvent, JSON_TYPE).asBytes();
  console.log('sendText=========', text);
  const optional = new Optional(EVENT_TaskRequest, sessionId).asBytes();
  const payload = getPayloadBytes('1234', EVENT_TaskRequest, text, speaker);
  return await sendEvent(ws, header, optional, payload);
}

async function finishSession(ws: WebSocket, sessionId: string): Promise<void> {
  const header = new Header(PROTOCOL_VERSION, DEFAULT_HEADER_SIZE, FULL_CLIENT_REQUEST, MsgTypeFlagWithEvent, JSON_TYPE).asBytes();

  const optional = new Optional(EVENT_FinishSession, sessionId).asBytes();
  const payload = Buffer.from('{}');
  return await sendEvent(ws, header, optional, payload);
}

async function finishConnection(ws: WebSocket): Promise<void> {
  const header = new Header(PROTOCOL_VERSION, DEFAULT_HEADER_SIZE, FULL_CLIENT_REQUEST, MsgTypeFlagWithEvent, JSON_TYPE).asBytes();

  const optional = new Optional(EVENT_FinishConnection).asBytes();
  const payload = Buffer.from('{}');
  return await sendEvent(ws, header, optional, payload);
}

type RunOptions = {
  id?: string;
  autoEnd?: boolean;
};
export async function runDemo(
  appId: string,
  token: string,
  speaker: string,
  text: string,
  outputPath: string,
  emitter?: EventEmitter,
  opts: RunOptions = {},
): Promise<void> {
  const autoEnd = opts.autoEnd ?? true;
  return new Promise((resolve, reject) => {
    const wsHeader = {
      'X-Api-App-Key': appId,
      'X-Api-Access-Key': token,
      'X-Api-Resource-Id': 'volc.service_type.10029',
      'X-Api-Connect-Id': uuidv4(),
    };

    const url = 'wss://openspeech.bytedance.com/api/v3/tts/bidirection';
    const ws = new WebSocket(url, { headers: wsHeader });
    const filename = outputPath.split('/').pop() || '';
    // 开始连接
    let isBegin = true;
    const writeFileEmitter = (data: Buffer) => {
      const value: TTSWriteType = {
        type: 'tts-mix',
        filename,
        data,
      };
      if (isBegin) {
        value.isBegin = true;
        isBegin = false;
      }
      emitter?.emit?.('writeFile', value);
    };
    const finishEmitter = () => {
      emitter?.emit?.('writeFile', {
        type: 'tts-mix',
        isEnd: true,
        data: Buffer.from(''),
        filename,
      });
    };

    ws.on('open', async () => {
      try {
        await startConnection(ws);
        let fileHandle: fs.FileHandle | null = null;
        let sessionId: string = '';
        let isFirstResponse = true;
        let cacheText = '';
        const emitOk = (id: string, code = 200) => {
          emitter.emit(id, { code, msg: 'ok' });
        };
        emitter.on('text', async ({ text, id }) => {
          await sendText(ws, speaker, text, sessionId);
          emitOk(id);
        });
        emitter.on('textEnd', async ({ id }) => {
          console.log('text end');
          await finishSession(ws, sessionId);
          emitOk(id);
        });
        ws.on('message', async (data) => {
          try {
            const res = parserResponse(data as Buffer);
            printResponse(res, 'message res:');
            if (res.optional.event === EVENT_ConnectionStarted) {
              sessionId = uuidv4().replace(/-/g, '');
              await startSession(ws, speaker, sessionId);
              return;
            } else if (res.optional.event === EVENT_ConnectionFinished) {
              ws.close();
              resolve();
              return;
            }
            if (res.optional.event === EVENT_SessionStarted && isFirstResponse) {
              isFirstResponse = false;
              console.log('start session', sessionId, autoEnd);
              emitter.emit('isConnect', sessionId);
              text && (await sendText(ws, speaker, text, sessionId));
              autoEnd && (await finishSession(ws, sessionId));
              fileHandle = await fs.open(outputPath, 'w');
            } else if (!isFirstResponse) {
              if (res.optional.event === EVENT_TTSResponse && res.header.messageType === AUDIO_ONLY_RESPONSE && res.payload && fileHandle) {
                await fileHandle.write(res.payload);
                writeFileEmitter(res.payload);
              } else if (res.optional.event === EVENT_TTSSentenceStart || res.optional.event === EVENT_TTSSentenceEnd) {
                // continue
              } else {
                // 152
                if (fileHandle) {
                  await fileHandle.close();
                  fileHandle = null;
                }
                await finishConnection(ws);
                finishEmitter();
              }
            }
          } catch (err) {
            ws.close();
            reject(err);
          }
        });
      } catch (err) {
        ws.close();
        reject(err);
      }
    });

    ws.on('error', (err) => {
      reject(err);
    });
  });
}

type TTSWriteType = {
  type: 'tts-mix';
  filename: string;
  data?: Buffer;
  isBegin?: boolean;
  isEnd?: boolean;
  index?: number;
};

export class TtsMix {
  appId: string;
  token: string;
  emitter: EventEmitter;
  isStart = false;
  constructor(appId: string, token: string) {
    this.appId = appId;
    this.token = token;
    this.emitter = new EventEmitter();
    this.emitter.on('isConnect', () => {
      this.isStart = true;
    });
  }
  /**
   * 获取语音
   * @param speaker 说话人
   * @param text 文本
   * @param outputPath 输出路径
   * @returns
   */
  async getVoiceDemo(speaker: string, text: string, outputPath: string, autoEnd = true): Promise<void> {
    const id = nanoid();
    const listenId = 'text' + id;
    return runDemo(this.appId, this.token, speaker, text, outputPath, this.emitter, { autoEnd, id: listenId });
  }
  async isConnect() {
    if (this.isStart) {
      return Promise.resolve(true);
    }
    return new Promise((resolve) => {
      this.emitter.once('isConnect', resolve);
    });
  }
  async sendText(text: string): Promise<{ code?: number; msg?: string }> {
    const id = nanoid();
    return new Promise((resolve) => {
      this.emitter.once(id, resolve);
      this.emitter.emit('text', { text, id });
    });
  }
  async sendTextEnd() {
    const id = nanoid();
    return new Promise((resolve) => {
      this.emitter.once(id, resolve);
      this.emitter.emit('textEnd', { id });
    });
  }
  /**
   * 写入文件的时候同步的流监听
   * @param callback
   * @returns
   */
  onWriteFile(callback: (data: TTSWriteType) => void) {
    this.emitter.on('writeFile', callback);
    return () => {
      this.emitter.off?.('writeFile', callback);
    };
  }
  /**
   * 缓冲区写入
   * @TIPS 如果数据过小，音频在前端播放的时候，会卡顿
   * @param callback
   * @returns
   */
  onWriteFileBuffer(callback: (data: TTSWriteType) => void, opts?: { chunkSize?: number }) {
    let index = 0;
    let sendBuffer: Buffer = Buffer.alloc(0);
    let chunkSize = opts?.chunkSize || 1024 * 50; // 50kb
    const callbackBuff = (data: TTSWriteType) => {
      index++;
      if (data.isBegin) {
        callback(data);
        return;
      }
      const { data: videoBuffer } = data;
      const sendValue = {
        ...data,
        index,
      };
      sendBuffer = Buffer.concat([sendBuffer, videoBuffer]);
      const sendBufferLenght = Buffer.byteLength(sendBuffer);
      if (sendBufferLenght > chunkSize) {
        sendValue.data = sendBuffer;
        callback(sendValue);
        sendBuffer = Buffer.alloc(0);
      } else if (data.isEnd) {
        sendValue.data = sendBuffer;
        callback(sendValue);
        sendBuffer = Buffer.alloc(0);
      }
    };
    this.emitter.on('writeFile', callbackBuff);
    return () => {
      this.emitter.off?.('writeFile', callbackBuff);
    };
  }
}