import * as plugins from './plugins.js';
import { RustBinaryLocator } from './classes.rustbinarylocator.js';
import { StreamingResponse } from './classes.streamingresponse.js';
import { StdioTransport } from './classes.stdiotransport.js';
import { SocketTransport } from './classes.sockettransport.js';
import type {
  IRustBridgeOptions,
  IRustBridgeLogger,
  ISocketConnectOptions,
  TCommandMap,
  IManagementRequest,
  IManagementResponse,
  IManagementEvent,
  TStreamingCommandKeys,
  TExtractChunk,
  IRustTransport,
} from './interfaces/index.js';

const defaultLogger: IRustBridgeLogger = {
  log() {},
};

/**
 * Generic bridge between TypeScript and a Rust binary.
 * Communicates via JSON-over-stdin/stdout IPC protocol (stdio mode)
 * or JSON-over-Unix-socket/named-pipe (socket mode).
 *
 * @typeParam TCommands - Map of command names to their param/result types
 */
export class RustBridge<TCommands extends TCommandMap = TCommandMap> extends plugins.events.EventEmitter {
  private locator: RustBinaryLocator;
  private options: Required<Pick<IRustBridgeOptions, 'cliArgs' | 'requestTimeoutMs' | 'readyTimeoutMs' | 'readyEventName' | 'maxPayloadSize'>> & IRustBridgeOptions;
  private logger: IRustBridgeLogger;
  private transport: IRustTransport | null = null;
  private pendingRequests = new Map<string, {
    resolve: (value: any) => void;
    reject: (error: Error) => void;
    timer: ReturnType<typeof setTimeout>;
    streaming?: StreamingResponse<any, any>;
  }>();
  private requestCounter = 0;
  private isRunning = false;
  private binaryPath: string | null = null;

  constructor(options: IRustBridgeOptions) {
    super();
    this.logger = options.logger || defaultLogger;
    this.options = {
      cliArgs: ['--management'],
      requestTimeoutMs: 30000,
      readyTimeoutMs: 10000,
      readyEventName: 'ready',
      maxPayloadSize: 50 * 1024 * 1024,
      ...options,
    };
    this.locator = new RustBinaryLocator(options, this.logger);
  }

  /**
   * Spawn the Rust binary and wait for it to signal readiness.
   * Returns true if the binary was found and spawned successfully.
   */
  public async spawn(): Promise<boolean> {
    this.binaryPath = await this.locator.findBinary();
    if (!this.binaryPath) {
      return false;
    }

    const transport = new StdioTransport({
      binaryPath: this.binaryPath,
      cliArgs: this.options.cliArgs,
      env: this.options.env,
      maxPayloadSize: this.options.maxPayloadSize,
      logger: this.logger,
    });

    return this.connectWithTransport(transport);
  }

  /**
   * Connect to an already-running Rust daemon via Unix socket or named pipe.
   * Returns true if the connection was established and the daemon signaled readiness.
   *
   * @param socketPath - Path to Unix socket or Windows named pipe
   * @param socketOptions - Optional socket connection options (reconnect, etc.)
   */
  public async connect(socketPath: string, socketOptions?: ISocketConnectOptions): Promise<boolean> {
    const transport = new SocketTransport({
      socketPath,
      maxPayloadSize: this.options.maxPayloadSize,
      logger: this.logger,
      autoReconnect: socketOptions?.autoReconnect,
      reconnectBaseDelayMs: socketOptions?.reconnectBaseDelayMs,
      reconnectMaxDelayMs: socketOptions?.reconnectMaxDelayMs,
      maxReconnectAttempts: socketOptions?.maxReconnectAttempts,
    });

    return this.connectWithTransport(transport);
  }

  /**
   * Internal: wire up any transport and wait for the ready handshake.
   */
  private connectWithTransport(transport: IRustTransport): Promise<boolean> {
    return new Promise<boolean>((resolve) => {
      try {
        this.transport = transport;

        // Wire transport events
        transport.on('line', (line: string) => this.handleLine(line));

        transport.on('stderr', (line: string) => {
          this.logger.log('debug', `[${this.options.binaryName}] ${line}`);
          this.emit('stderr', line);
        });

        transport.on('close', (...args: any[]) => {
          this.logger.log('info', `Transport closed`);
          this.cleanup();
          this.emit('exit', ...args);
        });

        transport.on('error', (err: Error) => {
          this.logger.log('error', `Transport error: ${err.message}`);
          this.cleanup();
          resolve(false);
        });

        transport.on('reconnected', () => {
          this.logger.log('info', 'Transport reconnected, waiting for ready event');
          this.emit('reconnected');
        });

        // Connect the transport
        transport.connect().then(() => {
          // Wait for the ready event from the protocol layer
          const readyTimeout = setTimeout(() => {
            this.logger.log('error', `Process did not send ready event within ${this.options.readyTimeoutMs}ms`);
            this.kill();
            resolve(false);
          }, this.options.readyTimeoutMs);

          this.once(`management:${this.options.readyEventName}`, () => {
            clearTimeout(readyTimeout);
            this.isRunning = true;
            this.logger.log('info', `Bridge connected to ${this.options.binaryName}`);
            this.emit('ready');
            resolve(true);
          });
        }).catch((err: Error) => {
          this.logger.log('error', `Transport connect failed: ${err.message}`);
          resolve(false);
        });
      } catch (err: any) {
        this.logger.log('error', `Failed to connect: ${err.message}`);
        resolve(false);
      }
    });
  }

  /**
   * Send a typed command to the Rust process and wait for the response.
   */
  public async sendCommand<K extends string & keyof TCommands>(
    method: K,
    params: TCommands[K]['params'],
  ): Promise<TCommands[K]['result']> {
    if (!this.transport?.connected || !this.isRunning) {
      throw new Error(`${this.options.binaryName} bridge is not running`);
    }

    const id = `req_${++this.requestCounter}`;
    const request: IManagementRequest = { id, method, params };
    const json = JSON.stringify(request);

    // Check outbound payload size
    const byteLength = Buffer.byteLength(json, 'utf8');
    if (byteLength > this.options.maxPayloadSize) {
      throw new Error(
        `Outbound message exceeds maxPayloadSize (${byteLength} > ${this.options.maxPayloadSize})`
      );
    }

    return new Promise<TCommands[K]['result']>((resolve, reject) => {
      const timer = setTimeout(() => {
        this.pendingRequests.delete(id);
        reject(new Error(`Command '${method}' timed out after ${this.options.requestTimeoutMs}ms`));
      }, this.options.requestTimeoutMs);

      this.pendingRequests.set(id, { resolve, reject, timer });

      this.transport!.write(json + '\n').catch((err) => {
        clearTimeout(timer);
        this.pendingRequests.delete(id);
        reject(new Error(`Failed to write to transport: ${err.message}`));
      });
    });
  }

  /**
   * Send a streaming command to the Rust process.
   * Returns a StreamingResponse that yields chunks via `for await...of`
   * and exposes `.result` for the final response.
   */
  public sendCommandStreaming<K extends string & TStreamingCommandKeys<TCommands>>(
    method: K,
    params: TCommands[K]['params'],
  ): StreamingResponse<TExtractChunk<TCommands[K]>, TCommands[K]['result']> {
    const streaming = new StreamingResponse<TExtractChunk<TCommands[K]>, TCommands[K]['result']>();

    if (!this.transport?.connected || !this.isRunning) {
      streaming.fail(new Error(`${this.options.binaryName} bridge is not running`));
      return streaming;
    }

    const id = `req_${++this.requestCounter}`;
    const request: IManagementRequest = { id, method, params };
    const json = JSON.stringify(request);

    const byteLength = Buffer.byteLength(json, 'utf8');
    if (byteLength > this.options.maxPayloadSize) {
      streaming.fail(
        new Error(`Outbound message exceeds maxPayloadSize (${byteLength} > ${this.options.maxPayloadSize})`)
      );
      return streaming;
    }

    const timeoutMs = this.options.streamTimeoutMs ?? this.options.requestTimeoutMs;
    const timer = setTimeout(() => {
      this.pendingRequests.delete(id);
      streaming.fail(new Error(`Streaming command '${method}' timed out after ${timeoutMs}ms`));
    }, timeoutMs);

    this.pendingRequests.set(id, {
      resolve: (result: any) => streaming.finish(result),
      reject: (error: Error) => streaming.fail(error),
      timer,
      streaming,
    });

    this.transport!.write(json + '\n').catch((err) => {
      clearTimeout(timer);
      this.pendingRequests.delete(id);
      streaming.fail(new Error(`Failed to write to transport: ${err.message}`));
    });

    return streaming;
  }

  /**
   * Kill the connection and clean up all resources.
   * For stdio: kills the child process (SIGTERM, then SIGKILL).
   * For socket: closes the socket connection (does NOT kill the daemon).
   */
  public kill(): void {
    if (this.transport) {
      const transport = this.transport;
      this.transport = null;
      this.isRunning = false;

      // Reject pending requests
      for (const [, pending] of this.pendingRequests) {
        clearTimeout(pending.timer);
        pending.reject(new Error(`${this.options.binaryName} process killed`));
      }
      this.pendingRequests.clear();

      transport.removeAllListeners();
      transport.disconnect();
    }
  }

  /**
   * Whether the bridge is currently running.
   */
  public get running(): boolean {
    return this.isRunning;
  }

  private handleLine(line: string): void {
    if (!line) return;

    let parsed: any;
    try {
      parsed = JSON.parse(line);
    } catch {
      this.logger.log('warn', `Non-JSON output: ${line}`);
      return;
    }

    // Check if it's an event (has 'event' field, no 'id')
    if ('event' in parsed && !('id' in parsed)) {
      const event = parsed as IManagementEvent;
      this.emit(`management:${event.event}`, event.data);
      return;
    }

    // Stream chunk (has 'id' + stream === true + 'data')
    if ('id' in parsed && parsed.stream === true && 'data' in parsed) {
      const pending = this.pendingRequests.get(parsed.id);
      if (pending?.streaming) {
        // Reset inactivity timeout
        clearTimeout(pending.timer);
        const timeoutMs = this.options.streamTimeoutMs ?? this.options.requestTimeoutMs;
        pending.timer = setTimeout(() => {
          this.pendingRequests.delete(parsed.id);
          pending.reject(new Error(`Streaming command timed out after ${timeoutMs}ms of inactivity`));
        }, timeoutMs);
        pending.streaming.pushChunk(parsed.data);
      }
      return;
    }

    // Otherwise it's a response (has 'id' field)
    if ('id' in parsed) {
      const response = parsed as IManagementResponse;
      const pending = this.pendingRequests.get(response.id);
      if (pending) {
        clearTimeout(pending.timer);
        this.pendingRequests.delete(response.id);
        if (response.success) {
          pending.resolve(response.result);
        } else {
          pending.reject(new Error(response.error || 'Unknown error from Rust process'));
        }
      }
    }
  }

  private cleanup(): void {
    this.isRunning = false;
    this.transport = null;

    // Reject all pending requests
    for (const [, pending] of this.pendingRequests) {
      clearTimeout(pending.timer);
      pending.reject(new Error(`${this.options.binaryName} process exited`));
    }
    this.pendingRequests.clear();
  }
}