import * as zlib from 'node:zlib';
import { promisify } from 'node:util';
import { nanoid } from 'nanoid';
import { VolcEngineBase, uuid } from './base.ts';

// Promisify zlib methods
const gzipPromise = promisify(zlib.gzip);
const gunzipPromise = promisify(zlib.gunzip);

// Protocol constants
const PROTOCOL_VERSION = 0b0001;
const DEFAULT_HEADER_SIZE = 0b0001;

// Message Type
const FULL_CLIENT_REQUEST = 0b0001;
const AUDIO_ONLY_REQUEST = 0b0010;
const FULL_SERVER_RESPONSE = 0b1001;
const SERVER_ACK = 0b1011;
const SERVER_ERROR_RESPONSE = 0b1111;

// Message Type Specific Flags
const NO_SEQUENCE = 0b0000; // no check sequence
const POS_SEQUENCE = 0b0001;
const NEG_SEQUENCE = 0b0010;
const NEG_WITH_SEQUENCE = 0b0011;
const NEG_SEQUENCE_1 = 0b0011;

// Message Serialization
const NO_SERIALIZATION = 0b0000;
const JSON_SERIALIZATION = 0b0001;

// Message Compression
const NO_COMPRESSION = 0b0000;
const GZIP_COMPRESSION = 0b0001;

/**
 * Generate header for the WebSocket request
 */
function generateHeader(
  messageType = FULL_CLIENT_REQUEST,
  messageTypeSpecificFlags = NO_SEQUENCE,
  serialMethod = JSON_SERIALIZATION,
  compressionType = GZIP_COMPRESSION,
  reservedData = 0x00,
): Buffer {
  const header = Buffer.alloc(4);
  const headerSize = 1;
  header[0] = (PROTOCOL_VERSION << 4) | headerSize;
  header[1] = (messageType << 4) | messageTypeSpecificFlags;
  header[2] = (serialMethod << 4) | compressionType;
  header[3] = reservedData;
  return header;
}

/**
 * Generate the sequence part of the request
 */
function generateBeforePayload(sequence: number): Buffer {
  const beforePayload = Buffer.alloc(4);
  beforePayload.writeInt32BE(sequence);
  return beforePayload;
}

export type ParsedMessage = {
  isLastPackage: boolean;
  payloadSequence?: number;
  payloadMsg?: {
    audio_info?: {
      duration: number;
    };
    result?: {
      additions?: {
        log_id?: string;
      };
      text?: string;
      utterances?: Array<{
        additions?: {
          fixed_prefix_result?: string;
        };
        definite?: boolean;
        end_time?: number;
        start_time?: number;
        text?: string;
        words?: Array<{
          end_time: number;
          start_time: number;
          text: string;
        }>;
      }>;
    };
    error?: any;
  };
  payloadSize?: number;
  code?: number;
  seq?: number;
};
/**
 * Parse response from the WebSocket server
 */
function parseResponse(res: Buffer): any {
  const protocolVersion = res[0] >> 4;
  const headerSize = res[0] & 0x0f;
  const messageType = res[1] >> 4;
  const messageTypeSpecificFlags = res[1] & 0x0f;
  const serializationMethod = res[2] >> 4;
  const messageCompression = res[2] & 0x0f;
  const reserved = res[3];
  const headerExtensions = res.slice(4, headerSize * 4);
  const payload = res.slice(headerSize * 4);

  const result: any = {
    isLastPackage: false,
  };

  let payloadMsg = null;
  let payloadSize = 0;
  let offset = 0;

  if (messageTypeSpecificFlags & 0x01) {
    // receive frame with sequence
    const seq = payload.readInt32BE(0);
    result.payloadSequence = seq;
    offset += 4;
  }

  if (messageTypeSpecificFlags & 0x02) {
    // receive last package
    result.isLastPackage = true;
  }

  const remainingPayload = payload.slice(offset);

  if (messageType === FULL_SERVER_RESPONSE) {
    payloadSize = remainingPayload.readInt32BE(0);
    payloadMsg = remainingPayload.slice(4);
  } else if (messageType === SERVER_ACK) {
    const seq = remainingPayload.readInt32BE(0);
    result.seq = seq;
    if (remainingPayload.length >= 8) {
      payloadSize = remainingPayload.readUInt32BE(4);
      payloadMsg = remainingPayload.slice(8);
    }
  } else if (messageType === SERVER_ERROR_RESPONSE) {
    const code = remainingPayload.readUInt32BE(0);
    result.code = code;
    payloadSize = remainingPayload.readUInt32BE(4);
    payloadMsg = remainingPayload.slice(8);
  }

  if (!payloadMsg) {
    return result;
  }

  if (messageCompression === GZIP_COMPRESSION) {
    try {
      const decompressed = zlib.gunzipSync(payloadMsg);
      payloadMsg = decompressed;
    } catch (error) {
      console.error('Error decompressing payload:', error);
    }
  }

  if (serializationMethod === JSON_SERIALIZATION) {
    try {
      payloadMsg = JSON.parse(payloadMsg.toString('utf-8'));
    } catch (error) {
      console.error('Error parsing JSON payload:', error);
    }
  } else if (serializationMethod !== NO_SERIALIZATION) {
    payloadMsg = payloadMsg.toString('utf-8');
  }

  result.payloadMsg = payloadMsg;
  result.payloadSize = payloadSize;
  return result;
}

/**
 * Read WAV file information
 */
async function readWavInfo(data: Buffer): Promise<{
  channels: number;
  sampleWidth: number;
  sampleRate: number;
  frames: number;
  audioData: Buffer;
}> {
  // This is a simplified WAV parser - in production you should use a proper library
  if (data.length < 44) {
    throw new Error('Invalid WAV file: too short');
  }

  // Check WAV header
  if (data.slice(0, 4).toString() !== 'RIFF' || data.slice(8, 12).toString() !== 'WAVE') {
    throw new Error('Invalid WAV file: not a WAV format');
  }

  // Parse header information
  const channels = data.readUInt16LE(22);
  const sampleRate = data.readUInt32LE(24);
  const bitsPerSample = data.readUInt16LE(34);
  const sampleWidth = bitsPerSample / 8;

  // Find data chunk
  let offset = 12; // Start after "WAVE"
  let dataSize = 0;
  let audioData: Buffer = Buffer.alloc(0);

  while (offset < data.length) {
    const chunkType = data.slice(offset, offset + 4).toString();
    const chunkSize = data.readUInt32LE(offset + 4);

    if (chunkType === 'data') {
      dataSize = chunkSize;
      audioData = data.slice(offset + 8, offset + 8 + chunkSize);
      break;
    }

    offset += 8 + chunkSize;
  }

  const frames = dataSize / (channels * sampleWidth);

  return {
    channels,
    sampleWidth,
    sampleRate,
    frames,
    audioData,
  };
}

/**
 * Check if data is a valid WAV file
 */
function judgeWav(data: Buffer): boolean {
  if (data.length < 44) {
    return false;
  }
  return data.slice(0, 4).toString() === 'RIFF' && data.slice(8, 12).toString() === 'WAVE';
}

/**
 * Slice data into chunks
 */
function* sliceData(data: Buffer, chunkSize: number): Generator<[Buffer, boolean]> {
  const dataLen = data.length;
  let offset = 0;

  while (offset + chunkSize < dataLen) {
    yield [data.slice(offset, offset + chunkSize), false];
    offset += chunkSize;
  }

  yield [data.slice(offset, dataLen), true];
}
const format = ['wav', 'mp3', 'pcm'] as const;
type AsrClientFormat = (typeof format)[number];
interface AsrClientOptions {
  segDuration?: number;
  wsUrl?: string;
  uid?: string;
  format?: AsrClientFormat;
  rate?: number;
  bits?: number;
  channel?: number;
  codec?: string;
  authMethod?: string;
  hotWords?: string[];
  streaming?: boolean;
  mp3SegSize?: number;

  resourceId?: string;
  token?: string;
  appid?: string;
}

interface AudioItem {
  id: string | number;
  path: string;
}

/**
 * ASR WebSocket Client
 */
export class AsrWsClient extends VolcEngineBase {
  private successCode: number = 1000;
  private segDuration: number;
  private format: string;
  private rate: number;
  private bits: number;
  private channel: number;
  private codec: string;
  private hotWords: string[] | null;
  private mp3SegSize: number;
  private reqEvent: number = 1;
  private uid: string;
  private seq: number = 1;
  private hasSendFullClientRequest: boolean = false;

  constructor(options: AsrClientOptions = {}) {
    super({
      url: options.wsUrl || 'wss://openspeech.bytedance.com/api/v3/sauc/bigmodel',
      onConnect: () => this.onWsConnect(),
      wsOptions: {
        headers: {
          'X-Api-Resource-Id': options.resourceId || 'volc.bigasr.sauc.duration',
          'X-Api-Access-Key': options.token || '',
          'X-Api-App-Key': options.appid || '',
          'X-Api-Request-Id': uuid(),
        },
      },
    });

    this.segDuration = options.segDuration || 200;
    this.uid = options.uid || 'test';
    this.format = options.format || 'wav';
    this.rate = options.rate || 16000;
    this.bits = options.bits || 16;
    this.channel = options.channel || 1;
    this.codec = options.codec || 'raw';
    this.hotWords = options.hotWords || null;
    this.mp3SegSize = options.mp3SegSize || 1000;
  }

  private onWsConnect() {
    console.log('ASR Big Model WebSocket connected');
  }

  /**
   * Construct request parameters
   */
  private constructRequest(reqId: string, data?: any): any {
    return {
      user: {
        uid: this.uid,
      },
      audio: {
        format: this.format,
        sample_rate: this.rate,
        bits: this.bits,
        channel: this.channel,
        codec: this.codec,
      },
      request: {
        model_name: 'bigmodel',
        enable_punc: true,
        // result_type: 'single', // all, single
        result_type: 'all',
      },
    };
  }
  async sendFullClientRequest() {
    if (this.hasSendFullClientRequest) {
      return;
    }
    this.seq = 1;
    const seq = this.seq;
    const reqId = nanoid();
    const requestParams = this.constructRequest(reqId);

    // Prepare and send initial request
    const payloadStr = JSON.stringify(requestParams);
    const compressedPayload = await gzipPromise(Buffer.from(payloadStr));

    const fullClientRequest = Buffer.concat([
      generateHeader(FULL_CLIENT_REQUEST, POS_SEQUENCE),
      generateBeforePayload(seq),
      Buffer.alloc(4),
      compressedPayload,
    ]);

    // Set payload size
    fullClientRequest.writeUInt32BE(compressedPayload.length, 8);

    // Send initial request
    (this as any).ws.send(fullClientRequest);
    this.hasSendFullClientRequest = true;
  }
  /**
   * Process audio data in segments
   */
  private async segmentDataProcessor(audioData: Buffer, segmentSize: number): Promise<any> {
    await this.sendFullClientRequest();
    const that = this;
    if (this.isError) {
      return;
    }
    const sendVoice = async (audioData: Buffer, segmentSize: number) => {
      that.setCanSend(false);
      for (const [chunk, last] of sliceData(audioData, segmentSize)) {
        that.seq += 1;
        const isEnd = that.isEnd && last; // 结束了，而且是语音的最后一包
        console.log('chunkSize', Buffer.byteLength(chunk), segmentSize, 'last', last);
        if (isEnd) {
          that.seq = -that.seq;
        }
        const seq = that.seq;
        const compressedChunk = await gzipPromise(chunk);

        const messageType = AUDIO_ONLY_REQUEST;
        const flags = isEnd ? NEG_WITH_SEQUENCE : POS_SEQUENCE;

        const audioRequest = Buffer.concat([generateHeader(messageType, flags), generateBeforePayload(seq), Buffer.alloc(4), compressedChunk]);

        // Set payload size
        audioRequest.writeUInt32BE(compressedChunk.length, 8);
        // Send audio chunk
        this.ws.send(audioRequest);
        // 待测试， 是否需要等待
        // const chunkResponse = await new Promise<any>((resolveChunk) => {
        //   const onChunkMessage = (chunkEvent: MessageEvent) => {
        //     (this as any).ws.removeEventListener('message', onChunkMessage);
        //     const parsed = parseResponse(Buffer.from(chunkEvent.data as ArrayBuffer));
        //     resolveChunk(parsed);
        //   };
        //   (this as any).ws.addEventListener('message', onChunkMessage, { once: true });
        // });
        // if (last) {
        //   console.log('last', JSON.stringify(chunkResponse));
        //   break;
        // }
      }
      that.setCanSend(true);
    };
    // Wait for response
    await sendVoice(audioData, segmentSize);
  }

  async onMessage(event: MessageEvent) {
    try {
      const parsed = parseResponse(Buffer.from(event.data as ArrayBuffer));
      // console.log(`Seq ${parsed.payloadSequence} response:`, parsed);
      if (typeof event.data === 'string') {
        throw new Error('event.data is string: ' + event.data);
      }
      // console.log('parsed', parsed.payloadSequence, parsed.payloadMsg.result.text);
      if (parsed?.payloadMsg?.error) {
        this.emitter.emit('error', parsed);
        this.isError = true;
      }
      this.emitter.emit('message', parsed);
      if (parsed.isLastPackage) {
        this.emitter.emit('end', parsed);
      }
    } catch (error) {
      console.error('Error processing response:', error);
    }
  }
  public async sendVoiceFile(data: Buffer) {
    try {
      if (this.format === 'mp3') {
        const segmentSize = this.mp3SegSize;
        return await this.segmentDataProcessor(data, segmentSize);
      }

      if (this.format === 'wav') {
        const wavInfo = await readWavInfo(data);
        const sizePerSec = wavInfo.channels * wavInfo.sampleWidth * wavInfo.sampleRate;
        const segmentSize = Math.floor((sizePerSec * this.segDuration) / 1000);
        // 3200
        return await this.segmentDataProcessor(data, segmentSize);
      }

      if (this.format === 'pcm') {
        const segmentSize = Math.floor((this.rate * 2 * this.channel * this.segDuration) / 500);
        return await this.segmentDataProcessor(data, segmentSize);
      }

      throw new Error('Unsupported format');
    } catch (error) {
      console.error('Error executing ASR:', error);
      throw error;
    }
  }
  async setIsEnd(isEnd: boolean) {
      super.setIsEnd(isEnd);
      if (isEnd) {
        // 发送空白包
        const emptyBuffer = Buffer.alloc(10000);
        this.sendVoiceStream(emptyBuffer);
      }
  }
  /**
   * 发送语音流, 最小10000
   * @param data
   * @returns
   */
  public async sendVoiceStream(data: Buffer) {
    let segmentSize = Buffer.byteLength(data);

    return await this.segmentDataProcessor(data, segmentSize);
  }
}