smartserve/ts/adapters/adapter.bun.ts

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

// Bun types (for type checking without requiring Bun runtime)
declare const Bun: {
  serve(options: any): { stop(): void; port: number; hostname: string };
  file(path: string): any;
};

/**
 * Bun adapter - zero overhead, native Request/Response
 */
export class BunAdapter extends BaseAdapter {
  private server: { stop(): void; port: number; hostname: string } | null = null;

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

  get characteristics(): IAdapterCharacteristics {
    return {
      zeroCopyStreaming: true,
      http2Support: false, // Bun currently HTTP/1.1 only
      maxConnections: 'unlimited',
      nativeWebSocket: true,
    };
  }

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

  async start(handler: TRequestHandler): Promise<ISmartServeInstance> {
    if (!this.isSupported()) {
      throw new Error('Bun 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',
      fetch: async (request: Request, server: any) => {
        this.stats.requestsTotal++;
        this.stats.requestsActive++;

        try {
          // Handle WebSocket upgrade
          if (this.options.websocket && request.headers.get('upgrade') === 'websocket') {
            const upgraded = server.upgrade(request);
            if (upgraded) {
              return undefined; // Bun handles the upgrade
            }
          }

          // Create connection info
          const connectionInfo: IConnectionInfo = {
            remoteAddr: server.requestIP(request)?.address ?? 'unknown',
            remotePort: 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--;
        }
      },
    };

    // Add TLS if configured
    if (this.options.tls) {
      serveOptions.tls = {
        cert: typeof this.options.tls.cert === 'string'
          ? Bun.file(this.options.tls.cert)
          : this.options.tls.cert,
        key: typeof this.options.tls.key === 'string'
          ? Bun.file(this.options.tls.key)
          : this.options.tls.key,
        passphrase: this.options.tls.passphrase,
      };
    }

    // Add WebSocket handlers if configured
    if (this.options.websocket) {
      serveOptions.websocket = this.createWebSocketHandler();
    }

    this.server = Bun.serve(serveOptions);
    return this.createInstance();
  }

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

  private createWebSocketHandler(): any {
    const hooks = this.options.websocket;
    if (!hooks) return undefined;

    return {
      open: (ws: any) => {
        const peer = this.wrapBunWebSocket(ws);
        hooks.onOpen?.(peer);
      },
      message: (ws: any, message: string | ArrayBuffer) => {
        const peer = this.wrapBunWebSocket(ws);
        const msg = {
          type: typeof message === 'string' ? 'text' as const : 'binary' as const,
          text: typeof message === 'string' ? message : undefined,
          data: message instanceof ArrayBuffer ? new Uint8Array(message) : undefined,
          size: typeof message === 'string' ? message.length : (message as ArrayBuffer).byteLength,
        };
        hooks.onMessage?.(peer, msg);
      },
      close: (ws: any, code: number, reason: string) => {
        const peer = this.wrapBunWebSocket(ws);
        hooks.onClose?.(peer, code, reason);
      },
      error: (ws: any, error: Error) => {
        const peer = this.wrapBunWebSocket(ws);
        hooks.onError?.(peer, error);
      },
      ping: (ws: any, data: ArrayBuffer) => {
        const peer = this.wrapBunWebSocket(ws);
        hooks.onPing?.(peer, new Uint8Array(data));
      },
      pong: (ws: any, data: ArrayBuffer) => {
        const peer = this.wrapBunWebSocket(ws);
        hooks.onPong?.(peer, new Uint8Array(data));
      },
    };
  }

  private wrapBunWebSocket(ws: any): any {
    return {
      id: ws.data?.id ?? crypto.randomUUID(),
      url: ws.data?.url ?? '',
      get readyState() { return ws.readyState; },
      protocol: ws.protocol ?? '',
      extensions: ws.extensions ?? '',
      send: (data: string) => ws.send(data),
      sendBinary: (data: Uint8Array | ArrayBuffer) => ws.send(data),
      close: (code?: number, reason?: string) => ws.close(code, reason),
      ping: (data?: Uint8Array) => ws.ping(data),
      terminate: () => ws.terminate(),
      context: {} as any,
      data: ws.data?.customData ?? new Map(),
    };
  }
}