import type { ISmartServeInstance, IConnectionInfo } from '../core/smartserve.interfaces.js';
import { BaseAdapter, type IAdapterCharacteristics, type TRequestHandler } from './adapter.base.js';

// Deno types (for type checking without requiring Deno runtime)
declare const Deno: {
  serve(options: any, handler?: any): { shutdown(): Promise<void>; finished: Promise<void> };
  upgradeWebSocket(request: Request): { socket: WebSocket; response: Response };
};

/**
 * Deno adapter - zero overhead, native Request/Response
 */
export class DenoAdapter extends BaseAdapter {
  private server: { shutdown(): Promise<void>; finished: Promise<void> } | null = null;

  get name(): 'deno' {
    return 'deno';
  }

  get characteristics(): IAdapterCharacteristics {
    return {
      zeroCopyStreaming: true,
      http2Support: true,
      maxConnections: 'unlimited',
      nativeWebSocket: true,
    };
  }

  isSupported(): boolean {
    return typeof (globalThis as any).Deno !== 'undefined';
  }

  async start(handler: TRequestHandler): Promise<ISmartServeInstance> {
    if (!this.isSupported()) {
      throw new Error('Deno runtime is not available');
    }

    this.handler = handler;
    this.startTime = Date.now();

    const serveOptions: any = {
      port: this.options.port,
      hostname: this.options.hostname ?? '0.0.0.0',
    };

    // Add TLS if configured
    if (this.options.tls) {
      serveOptions.cert = this.options.tls.cert;
      serveOptions.key = this.options.tls.key;
    }

    this.server = Deno.serve(serveOptions, async (request: Request, info: any) => {
      this.stats.requestsTotal++;
      this.stats.requestsActive++;

      try {
        // Handle WebSocket upgrade
        if (this.options.websocket && request.headers.get('upgrade') === 'websocket') {
          const { socket, response } = Deno.upgradeWebSocket(request);
          this.attachWebSocketHooks(socket, request);
          return response;
        }

        // Create connection info
        const connectionInfo: IConnectionInfo = {
          remoteAddr: info?.remoteAddr?.hostname ?? 'unknown',
          remotePort: info?.remoteAddr?.port ?? 0,
          localAddr: this.options.hostname ?? '0.0.0.0',
          localPort: this.options.port,
          encrypted: !!this.options.tls,
        };

        return await handler(request, connectionInfo);
      } catch (error) {
        if (this.options.onError) {
          return this.options.onError(error as Error, request);
        }
        return new Response('Internal Server Error', { status: 500 });
      } finally {
        this.stats.requestsActive--;
      }
    });

    return this.createInstance();
  }

  async stop(): Promise<void> {
    if (this.server) {
      await this.server.shutdown();
      await this.server.finished;
      this.server = null;
    }
  }

  private attachWebSocketHooks(socket: WebSocket, request: Request): void {
    const hooks = this.options.websocket;
    if (!hooks) return;

    const peer = this.createWebSocketPeer(socket, request);

    socket.onopen = () => {
      hooks.onOpen?.(peer);
    };

    socket.onmessage = (event) => {
      const message = {
        type: typeof event.data === 'string' ? 'text' as const : 'binary' as const,
        text: typeof event.data === 'string' ? event.data : undefined,
        data: event.data instanceof Uint8Array ? event.data : undefined,
        size: typeof event.data === 'string' ? event.data.length : (event.data as ArrayBuffer).byteLength,
      };
      hooks.onMessage?.(peer, message);
    };

    socket.onclose = (event) => {
      hooks.onClose?.(peer, event.code, event.reason);
    };

    socket.onerror = (event) => {
      hooks.onError?.(peer, new Error('WebSocket error'));
    };
  }

  private createWebSocketPeer(socket: WebSocket, request: Request): any {
    const url = this.parseUrl(request);
    return {
      id: crypto.randomUUID(),
      url: url.pathname,
      get readyState() { return socket.readyState; },
      protocol: socket.protocol,
      extensions: socket.extensions,
      send: (data: string) => socket.send(data),
      sendBinary: (data: Uint8Array | ArrayBuffer) => socket.send(data),
      close: (code?: number, reason?: string) => socket.close(code, reason),
      ping: () => { /* Deno handles ping/pong automatically */ },
      terminate: () => socket.close(),
      context: {} as any, // Will be populated with IRequestContext
      data: new Map(),
    };
  }
}