import * as fs from 'fs/promises';
import * as path from 'path';
import * as zlib from 'zlib';
import * as util from 'util';
import { Readable } from 'stream';
import { promisify } from '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;
}

/**
 * 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];
}

interface AsrClientOptions {
  segDuration?: number;
  wsUrl?: string;
  uid?: string;
  format?: string;
  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 audioPath: string;
  private successCode: number = 1000;
  private segDuration: number;
  private format: string;
  private rate: number;
  private bits: number;
  private channel: number;
  private codec: string;
  private authMethod: string;
  private hotWords: string[] | null;
  private streaming: boolean;
  private mp3SegSize: number;
  private reqEvent: number = 1;
  private uid: string;
  private seq: number = 1;
  private hasSendFullClientRequest: boolean = false;

  constructor(audioPath: string, 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.audioPath = audioPath;
    this.segDuration = options.segDuration || 100;
    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.authMethod = options.authMethod || 'none';
    this.hotWords = options.hotWords || null;
    this.streaming = options.streaming !== undefined ? options.streaming : true;
    this.mp3SegSize = options.mp3SegSize || 1000;
  }

  private onWsConnect() {
    console.log('ASR 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,
      },
    };
  }
  private 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;
    // Wait for response
    const result = await new Promise<any>((resolve, reject) => {
      const onMessage = async (event: MessageEvent) => {
        try {
          const response = parseResponse(Buffer.from(event.data as ArrayBuffer));
          console.log('Initial response:', response);

          // Process audio chunks
          for (const [chunk, last] of sliceData(audioData, segmentSize)) {
            that.seq += 1;
            if (last) {
              that.seq = -that.seq;
            }
            const seq = that.seq;

            const start = Date.now();
            const compressedChunk = await gzipPromise(chunk);

            const messageType = AUDIO_ONLY_REQUEST;
            const flags = last ? 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 as any).ws.send(audioRequest);

            // Wait for each response
            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));
                console.log(`Seq ${seq} response:`, parsed);
                resolveChunk(parsed);
              };

              (this as any).ws.addEventListener('message', onChunkMessage, { once: true });
            });

            // If streaming, add delay to simulate real-time
            if (this.streaming) {
              const elapsed = Date.now() - start;
              const sleepTime = Math.max(0, this.segDuration - elapsed);
              await new Promise((r) => setTimeout(r, sleepTime));
            }

            // If this is the last chunk, resolve with final result
            if (last) {
              resolve(chunkResponse);
              break;
            }
          }

          (this as any).ws.removeEventListener('message', onMessage);
        } catch (error) {
          console.error('Error processing response:', error);
          reject(error);
        }
      };

      (this as any).ws.addEventListener('message', onMessage, { once: true });

      (this as any).ws.addEventListener(
        'error',
        (error) => {
          console.error('WebSocket error:', error);
          reject(error);
        },
        { once: true },
      );
    });

    return result;
  }

  /**
   * Execute ASR on the audio file
   */
  public async execute(): Promise<any> {
    try {
      const data = await fs.readFile(this.audioPath);

      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;
    }
  }

  /**
   * Send OPUS data for processing
   */
  public async sendOpusData(audioData: Buffer): Promise<any> {
    const segmentSize = Math.floor((this.rate * 2 * this.channel * this.segDuration) / 500);
    return await this.segmentDataProcessor(audioData, segmentSize);
  }
}

/**
 * Execute ASR on a single audio file
 */
export async function executeOne(audioItem: AudioItem, options: AsrClientOptions = {}): Promise<any> {
  if (!audioItem.id || !audioItem.path) {
    throw new Error('Audio item must have id and path properties');
  }

  const audioId = audioItem.id;
  const audioPath = path.resolve(process.cwd(), audioItem.path);

  const asrClient = new AsrWsClient(audioPath, options);
  await new Promise((resolve) => setTimeout(resolve, 2000));

  return asrClient.execute().then((result) => {
    return {
      id: audioId,
      path: audioPath,
      result: result,
    };
  });
}

/**
 * Test stream processing
 */
export const testStream = async () => {
  console.log('测试流式');
  const audioPath = 'videos/asr_example.wav';

  const res = await executeOne({
    id: 1,
    path: audioPath,
  })
    .then((result) => {
      console.log('====end test=====');
      console.log(result);
      return result;
    })
    .catch((error) => {
      console.error('Test error:', error);
      return '';
    });
};

/**
 * Handle audio data directly
 */
export async function handleAudioData(audioData: Buffer, options: AsrClientOptions = {}): Promise<any> {
  const asrClient = new AsrWsClient('', options);
  return await asrClient.sendOpusData(audioData);
}