/**
 * Avatar Stream SDK
 *
 * SDK para streaming sincronizado de áudio e vídeo em tempo real.
 * Recebe frames JPEG e chunks de áudio PCM via WebSocket binário.
 *
 * @example
 * ```typescript
 * const avatar = new AvatarStreamSDK({
 *   wsUrl: 'ws://localhost:8080/ws',
 *   canvas: document.getElementById('canvas') as HTMLCanvasElement,
 *   onStatusChange: (status) => console.log('Status:', status),
 *   onMetricsUpdate: (metrics) => console.log('Metrics:', metrics),
 * });
 *
 * await avatar.connect();
 * await avatar.generate('Hello world!', 'tara');
 * ```
 */

// ============================================================================
// Types
// ============================================================================

export interface AvatarStreamConfig {
  /** WebSocket URL do servidor */
  wsUrl: string;

  /** Canvas onde os frames serão renderizados */
  canvas: HTMLCanvasElement;

  /** FPS alvo para renderização (default: 25) */
  targetFps?: number;

  /** Sample rate do áudio (default: 24000) */
  audioSampleRate?: number;

  /** Mínimo de frames antes de iniciar playback (default: 10) */
  minFramesBuffer?: number;

  /** Mínimo de chunks de áudio antes de iniciar playback (default: 2) */
  minAudioChunks?: number;

  /** Callback quando o status muda */
  onStatusChange?: (status: StreamStatus) => void;

  /** Callback quando as métricas são atualizadas */
  onMetricsUpdate?: (metrics: StreamMetrics) => void;

  /** Callback quando ocorre um erro */
  onError?: (error: Error) => void;

  /** Callback quando o stream termina */
  onComplete?: (summary: StreamSummary) => void;

  /** Callback quando o primeiro frame é recebido */
  onFirstFrame?: (latencyMs: number) => void;

  /** Callback quando o playback inicia */
  onPlaybackStart?: (latencyMs: number) => void;
}

export type StreamStatus =
  | 'disconnected'
  | 'connecting'
  | 'connected'
  | 'generating'
  | 'buffering'
  | 'playing'
  | 'completed'
  | 'error';

export interface StreamMetrics {
  /** Frames recebidos do servidor */
  framesReceived: number;

  /** Frames renderizados no canvas */
  framesRendered: number;

  /** Frames no buffer aguardando renderização */
  bufferSize: number;

  /** Bytes totais recebidos */
  bytesReceived: number;

  /** Duração do vídeo em segundos (frames / fps) */
  videoDuration: number;

  /** Duração do áudio em segundos (samples / sampleRate) */
  audioDuration: number;

  /** Diferença entre áudio e vídeo (audioDuration - videoDuration) */
  syncDiff: number;

  /** FPS atual da renderização */
  currentFps: number;

  /** Bandwidth em KB/s */
  bandwidthKBps: number;

  /** Chunks de áudio recebidos */
  audioChunksReceived: number;

  /** Latência até o primeiro frame (ms) */
  firstFrameLatencyMs: number | null;

  /** Latência até o início do playback (ms) */
  playbackLatencyMs: number | null;
}

export interface StreamSummary {
  /** Total de frames renderizados */
  totalFrames: number;

  /** Duração total em segundos */
  durationSeconds: number;

  /** Bytes totais transferidos */
  totalBytes: number;

  /** Duração do vídeo */
  videoDuration: number;

  /** Duração do áudio */
  audioDuration: number;

  /** Diferença de sincronização final */
  finalSyncDiff: number;
}

interface FrameData {
  url: string;
  index: number;
}

// ============================================================================
// Constants
// ============================================================================

/** Tipos de mensagem binária (devem corresponder ao servidor) */
const MSG_FRAME = 0x01;
const MSG_AUDIO = 0x02;
const MSG_AUDIO_CHUNK = 0x03;

// ============================================================================
// SDK Class
// ============================================================================

export class AvatarStreamSDK {
  // Configuration
  private config: Required<AvatarStreamConfig>;
  private ctx: CanvasRenderingContext2D;

  // WebSocket
  private ws: WebSocket | null = null;

  // State
  private status: StreamStatus = 'disconnected';
  private startTime: number = 0;
  private streamDone: boolean = false;
  private playbackStarted: boolean = false;

  // Frame management
  private allFrames: FrameData[] = [];
  private frameQueue: FrameData[] = [];
  private renderedFrames: number = 0;
  private renderInterval: number | null = null;
  private lastRenderTime: number = 0;
  private totalBytes: number = 0;

  // Audio management
  private audioContext: AudioContext | null = null;
  private audioChunks: Uint8Array[] = [];
  private audioChunksComplete: boolean = false;
  private nextAudioTime: number = 0;
  private audioScheduledChunks: number = 0;
  private totalAudioSamples: number = 0;

  // Metrics
  private firstFrameLatencyMs: number | null = null;
  private playbackLatencyMs: number | null = null;

  // Heartbeat
  private heartbeatInterval: number | null = null;

  constructor(config: AvatarStreamConfig) {
    // Validate required config
    if (!config.wsUrl) throw new Error('wsUrl is required');
    if (!config.canvas) throw new Error('canvas is required');

    const ctx = config.canvas.getContext('2d');
    if (!ctx) throw new Error('Could not get 2D context from canvas');
    this.ctx = ctx;

    // Apply defaults
    this.config = {
      wsUrl: config.wsUrl,
      canvas: config.canvas,
      targetFps: config.targetFps ?? 25,
      audioSampleRate: config.audioSampleRate ?? 24000,
      minFramesBuffer: config.minFramesBuffer ?? 10,
      minAudioChunks: config.minAudioChunks ?? 2,
      onStatusChange: config.onStatusChange ?? (() => {}),
      onMetricsUpdate: config.onMetricsUpdate ?? (() => {}),
      onError: config.onError ?? (() => {}),
      onComplete: config.onComplete ?? (() => {}),
      onFirstFrame: config.onFirstFrame ?? (() => {}),
      onPlaybackStart: config.onPlaybackStart ?? (() => {}),
    };
  }

  // ==========================================================================
  // Public API
  // ==========================================================================

  /**
   * Conecta ao servidor WebSocket
   */
  async connect(): Promise<void> {
    if (this.ws?.readyState === WebSocket.OPEN) {
      return;
    }

    return new Promise((resolve, reject) => {
      this.setStatus('connecting');

      this.ws = new WebSocket(this.config.wsUrl);
      this.ws.binaryType = 'arraybuffer';

      this.ws.onopen = () => {
        this.setStatus('connected');
        this.startHeartbeat();
        resolve();
      };

      this.ws.onmessage = (event) => {
        if (event.data instanceof ArrayBuffer) {
          this.handleBinaryMessage(event.data);
        } else {
          try {
            const data = JSON.parse(event.data);
            this.handleJsonMessage(data);
          } catch (e) {
            this.config.onError(new Error(`Invalid JSON: ${e}`));
          }
        }
      };

      this.ws.onclose = () => {
        this.setStatus('disconnected');
        this.stopHeartbeat();
      };

      this.ws.onerror = () => {
        const error = new Error('WebSocket connection failed');
        this.config.onError(error);
        reject(error);
      };
    });
  }

  /**
   * Desconecta do servidor
   */
  disconnect(): void {
    this.stop();
    this.stopHeartbeat();

    if (this.ws) {
      this.ws.close();
      this.ws = null;
    }

    this.setStatus('disconnected');
  }

  /**
   * Gera um avatar falando o texto especificado
   */
  async generate(text: string, voice: string = 'tara'): Promise<void> {
    if (!this.ws || this.ws.readyState !== WebSocket.OPEN) {
      throw new Error('WebSocket not connected. Call connect() first.');
    }

    if (!text.trim()) {
      throw new Error('Text cannot be empty');
    }

    // Reset state
    this.resetState();
    this.startTime = Date.now();
    this.setStatus('generating');

    // Send request
    this.ws.send(JSON.stringify({
      action: 'generate',
      text: text.trim(),
      voice,
    }));
  }

  /**
   * Para a geração atual
   */
  stop(): void {
    if (this.ws?.readyState === WebSocket.OPEN) {
      this.ws.send(JSON.stringify({ action: 'stop' }));
    }

    this.cleanup();
    this.setStatus('connected');
  }

  /**
   * Retorna o status atual
   */
  getStatus(): StreamStatus {
    return this.status;
  }

  /**
   * Retorna as métricas atuais
   */
  getMetrics(): StreamMetrics {
    const elapsed = (Date.now() - this.startTime) / 1000;
    const videoDuration = this.allFrames.length / this.config.targetFps;
    const audioDuration = this.totalAudioSamples / this.config.audioSampleRate;

    return {
      framesReceived: this.allFrames.length,
      framesRendered: this.renderedFrames,
      bufferSize: this.frameQueue.length,
      bytesReceived: this.totalBytes,
      videoDuration,
      audioDuration,
      syncDiff: audioDuration - videoDuration,
      currentFps: this.lastRenderTime > 0 ? 1000 / (performance.now() - this.lastRenderTime) : 0,
      bandwidthKBps: elapsed > 0 ? (this.totalBytes / 1024 / elapsed) : 0,
      audioChunksReceived: this.audioChunks.length,
      firstFrameLatencyMs: this.firstFrameLatencyMs,
      playbackLatencyMs: this.playbackLatencyMs,
    };
  }

  /**
   * Verifica se está conectado
   */
  isConnected(): boolean {
    return this.ws?.readyState === WebSocket.OPEN;
  }

  /**
   * Verifica se está reproduzindo
   */
  isPlaying(): boolean {
    return this.playbackStarted && !this.streamDone;
  }

  // ==========================================================================
  // Private Methods - Message Handling
  // ==========================================================================

  private handleBinaryMessage(buffer: ArrayBuffer): void {
    const view = new DataView(buffer);
    const msgType = view.getUint8(0);

    this.totalBytes += buffer.byteLength;

    if (msgType === MSG_FRAME) {
      const frameIndex = view.getUint32(1, true);
      const dataSize = view.getUint32(5, true);
      const frameData = new Uint8Array(buffer, 9, dataSize);
      this.handleFrame(frameData, frameIndex);

    } else if (msgType === MSG_AUDIO) {
      const sampleRate = view.getUint32(1, true);
      const dataSize = view.getUint32(5, true);
      const audioData = new Uint8Array(buffer, 9, dataSize);
      this.handleAudioComplete(audioData, sampleRate);

    } else if (msgType === MSG_AUDIO_CHUNK) {
      const chunkIndex = view.getUint32(1, true);
      const isLast = view.getUint8(5) === 1;
      const dataSize = view.getUint32(6, true);
      const chunkData = new Uint8Array(buffer, 10, dataSize);
      this.handleAudioChunk(chunkData, chunkIndex, isLast);
    }

    this.emitMetrics();
  }

  private handleJsonMessage(data: any): void {
    switch (data.type) {
      case 'first_frame':
        // Server-side first frame latency
        break;

      case 'done':
        this.streamDone = true;
        this.tryStartStreamingPlayback();
        break;

      case 'status':
        // Status message from server
        break;

      case 'error':
        this.config.onError(new Error(data.message));
        this.cleanup();
        this.setStatus('error');
        break;
    }
  }

  // ==========================================================================
  // Private Methods - Frame Handling
  // ==========================================================================

  private handleFrame(frameData: Uint8Array, frameIndex: number): void {
    const blob = new Blob([frameData], { type: 'image/jpeg' });
    const url = URL.createObjectURL(blob);

    this.allFrames.push({ url, index: frameIndex });

    if (this.playbackStarted) {
      this.frameQueue.push({ url, index: frameIndex });
    }

    if (this.allFrames.length === 1) {
      this.firstFrameLatencyMs = Date.now() - this.startTime;
      this.config.onFirstFrame(this.firstFrameLatencyMs);
      this.setStatus('buffering');
    }

    this.tryStartStreamingPlayback();
  }

  private startRendering(): void {
    if (this.renderInterval !== null) return;

    this.lastRenderTime = performance.now();
    const frameInterval = 1000 / this.config.targetFps;

    this.renderInterval = window.setInterval(() => {
      this.renderNextFrame();
    }, frameInterval);
  }

  private renderNextFrame(): void {
    if (this.frameQueue.length === 0) {
      if (this.streamDone) {
        this.finishPlayback();
      }
      return;
    }

    const frame = this.frameQueue.shift()!;

    const img = new Image();
    img.onload = () => {
      if (this.config.canvas.width !== img.width ||
          this.config.canvas.height !== img.height) {
        this.config.canvas.width = img.width;
        this.config.canvas.height = img.height;
      }

      this.ctx.drawImage(img, 0, 0);
      URL.revokeObjectURL(frame.url);
      this.renderedFrames++;
      this.emitMetrics();
    };
    img.src = frame.url;

    this.lastRenderTime = performance.now();
  }

  // ==========================================================================
  // Private Methods - Audio Handling
  // ==========================================================================

  private initAudioContext(): void {
    if (!this.audioContext) {
      this.audioContext = new (window.AudioContext || (window as any).webkitAudioContext)({
        sampleRate: this.config.audioSampleRate,
      });
    }
    this.nextAudioTime = this.audioContext.currentTime + 0.05;
    this.audioScheduledChunks = 0;
  }

  private handleAudioChunk(chunkData: Uint8Array, chunkIndex: number, isLast: boolean): void {
    if (this.audioChunks.length === 0 && chunkData.length > 0) {
      this.initAudioContext();
    }

    if (chunkData.length > 0) {
      this.audioChunks.push(chunkData);
      this.scheduleAudioChunk(chunkData);
    }

    if (isLast) {
      this.audioChunksComplete = true;
    }

    this.tryStartStreamingPlayback();
  }

  private scheduleAudioChunk(chunkData: Uint8Array): void {
    if (!this.audioContext) return;

    try {
      // Convert PCM int16 to float32
      const alignedBuffer = new ArrayBuffer(chunkData.length);
      new Uint8Array(alignedBuffer).set(chunkData);
      const samples = new Int16Array(alignedBuffer);
      const floatSamples = new Float32Array(samples.length);

      for (let i = 0; i < samples.length; i++) {
        floatSamples[i] = samples[i] / 32768;
      }

      this.totalAudioSamples += samples.length;

      // Create audio buffer
      const chunkBuffer = this.audioContext.createBuffer(
        1,
        floatSamples.length,
        this.config.audioSampleRate
      );
      chunkBuffer.getChannelData(0).set(floatSamples);

      // Create and schedule source
      const source = this.audioContext.createBufferSource();
      source.buffer = chunkBuffer;
      source.connect(this.audioContext.destination);

      if (this.nextAudioTime < this.audioContext.currentTime) {
        this.nextAudioTime = this.audioContext.currentTime + 0.01;
      }

      source.start(this.nextAudioTime);

      const chunkDuration = floatSamples.length / this.config.audioSampleRate;
      this.nextAudioTime += chunkDuration;
      this.audioScheduledChunks++;

    } catch (e) {
      console.error('Error scheduling audio chunk:', e);
    }
  }

  private handleAudioComplete(audioData: Uint8Array, sampleRate: number): void {
    // Fallback for complete audio mode
    try {
      if (!this.audioContext) {
        this.audioContext = new (window.AudioContext || (window as any).webkitAudioContext)({
          sampleRate,
        });
      }

      const alignedBuffer = new ArrayBuffer(audioData.length);
      new Uint8Array(alignedBuffer).set(audioData);
      const samples = new Int16Array(alignedBuffer);
      const floatSamples = new Float32Array(samples.length);

      for (let i = 0; i < samples.length; i++) {
        floatSamples[i] = samples[i] / 32768;
      }

      this.totalAudioSamples = samples.length;
      this.audioChunksComplete = true;

      const audioBuffer = this.audioContext.createBuffer(1, floatSamples.length, sampleRate);
      audioBuffer.getChannelData(0).set(floatSamples);

      const source = this.audioContext.createBufferSource();
      source.buffer = audioBuffer;
      source.connect(this.audioContext.destination);
      source.start();

      this.tryStartStreamingPlayback();

    } catch (e) {
      this.config.onError(new Error(`Audio processing error: ${e}`));
    }
  }

  // ==========================================================================
  // Private Methods - Playback Control
  // ==========================================================================

  private tryStartStreamingPlayback(): void {
    if (this.playbackStarted) return;

    if (this.allFrames.length < this.config.minFramesBuffer) {
      return;
    }

    if (this.audioScheduledChunks < this.config.minAudioChunks) {
      return;
    }

    // Ready to start
    this.playbackStarted = true;
    this.playbackLatencyMs = Date.now() - this.startTime;
    this.config.onPlaybackStart(this.playbackLatencyMs);

    this.frameQueue = [...this.allFrames];
    this.startRendering();
    this.setStatus('playing');
  }

  private finishPlayback(): void {
    if (this.renderInterval !== null) {
      clearInterval(this.renderInterval);
      this.renderInterval = null;
    }

    const elapsed = (Date.now() - this.startTime) / 1000;
    const videoDuration = this.allFrames.length / this.config.targetFps;
    const audioDuration = this.totalAudioSamples / this.config.audioSampleRate;

    const summary: StreamSummary = {
      totalFrames: this.renderedFrames,
      durationSeconds: elapsed,
      totalBytes: this.totalBytes,
      videoDuration,
      audioDuration,
      finalSyncDiff: audioDuration - videoDuration,
    };

    this.config.onComplete(summary);
    this.setStatus('completed');
  }

  // ==========================================================================
  // Private Methods - Utilities
  // ==========================================================================

  private setStatus(status: StreamStatus): void {
    this.status = status;
    this.config.onStatusChange(status);
  }

  private emitMetrics(): void {
    this.config.onMetricsUpdate(this.getMetrics());
  }

  private resetState(): void {
    this.cleanup();

    this.allFrames = [];
    this.frameQueue = [];
    this.renderedFrames = 0;
    this.totalBytes = 0;
    this.startTime = 0;
    this.streamDone = false;
    this.playbackStarted = false;

    this.audioChunks = [];
    this.audioChunksComplete = false;
    this.nextAudioTime = 0;
    this.audioScheduledChunks = 0;
    this.totalAudioSamples = 0;

    this.firstFrameLatencyMs = null;
    this.playbackLatencyMs = null;
  }

  private cleanup(): void {
    if (this.renderInterval !== null) {
      clearInterval(this.renderInterval);
      this.renderInterval = null;
    }

    // Release blob URLs
    this.frameQueue.forEach(f => URL.revokeObjectURL(f.url));
    this.allFrames.forEach(f => URL.revokeObjectURL(f.url));
  }

  private startHeartbeat(): void {
    this.heartbeatInterval = window.setInterval(() => {
      if (this.ws?.readyState === WebSocket.OPEN) {
        this.ws.send(JSON.stringify({ action: 'ping' }));
      }
    }, 30000);
  }

  private stopHeartbeat(): void {
    if (this.heartbeatInterval !== null) {
      clearInterval(this.heartbeatInterval);
      this.heartbeatInterval = null;
    }
  }
}

// Export default
export default AvatarStreamSDK;