import * as plugins from './plugins.js';
import * as paths from './paths.js';
import { Tspm } from './classes.tspm.js';
import type {
  IpcMethodMap,
  RequestForMethod,
  ResponseForMethod,
  DaemonStatusResponse,
  HeartbeatResponse,
} from './ipc.types.js';

/**
 * Central daemon server that manages all TSPM processes
 */
export class TspmDaemon {
  private tspmInstance: Tspm;
  private ipcServer: plugins.smartipc.IpcServer;
  private startTime: number;
  private isShuttingDown: boolean = false;
  private socketPath: string;
  private heartbeatInterval: NodeJS.Timeout | null = null;
  private daemonPidFile: string;

  constructor() {
    this.tspmInstance = new Tspm();
    this.socketPath = plugins.path.join(paths.tspmDir, 'tspm.sock');
    this.daemonPidFile = plugins.path.join(paths.tspmDir, 'daemon.pid');
    this.startTime = Date.now();
  }

  /**
   * Start the daemon server
   */
  public async start(): Promise<void> {
    console.log('Starting TSPM daemon...');

    // Check if another daemon is already running
    if (await this.isDaemonRunning()) {
      throw new Error('Another TSPM daemon instance is already running');
    }

    // Initialize IPC server
    this.ipcServer = new plugins.smartipc.IpcServer({
      id: 'tspm-daemon',
      socketPath: this.socketPath,
    });

    // Register message handlers
    this.registerHandlers();

    // Start the IPC server
    await this.ipcServer.start();

    // Write PID file
    await this.writePidFile();

    // Start heartbeat monitoring
    this.startHeartbeatMonitoring();

    // Load existing process configurations
    await this.tspmInstance.loadProcessConfigs();

    // Set up graceful shutdown handlers
    this.setupShutdownHandlers();

    console.log(`TSPM daemon started successfully on ${this.socketPath}`);
    console.log(`PID: ${process.pid}`);
  }

  /**
   * Register all IPC message handlers
   */
  private registerHandlers(): void {
    // Process management handlers
    this.ipcServer.on<RequestForMethod<'start'>>(
      'start',
      async (request) => {
        try {
          await this.tspmInstance.start(request.config);
          const processInfo = this.tspmInstance.processInfo.get(
            request.config.id,
          );
          return {
            processId: request.config.id,
            pid: processInfo?.pid,
            status: processInfo?.status || 'stopped',
          };
        } catch (error) {
          throw new Error(`Failed to start process: ${error.message}`);
        }
      },
    );

    this.ipcServer.on<RequestForMethod<'stop'>>(
      'stop',
      async (request) => {
        try {
          await this.tspmInstance.stop(request.id);
          return {
            success: true,
            message: `Process ${request.id} stopped successfully`,
          };
        } catch (error) {
          throw new Error(`Failed to stop process: ${error.message}`);
        }
      },
    );

    this.ipcServer.on<RequestForMethod<'restart'>>('restart', async (request) => {
      try {
        await this.tspmInstance.restart(request.id);
        const processInfo = this.tspmInstance.processInfo.get(request.id);
        return {
          processId: request.id,
          pid: processInfo?.pid,
          status: processInfo?.status || 'stopped',
        };
      } catch (error) {
        throw new Error(`Failed to restart process: ${error.message}`);
      }
    });

    this.ipcServer.on<RequestForMethod<'delete'>>(
      'delete',
      async (request) => {
        try {
          await this.tspmInstance.delete(request.id);
          return {
            success: true,
            message: `Process ${request.id} deleted successfully`,
          };
        } catch (error) {
          throw new Error(`Failed to delete process: ${error.message}`);
        }
      },
    );

    // Query handlers
    this.ipcServer.on<RequestForMethod<'list'>>(
      'list',
      async () => {
        const processes = await this.tspmInstance.list();
        return { processes };
      },
    );

    this.ipcServer.on<RequestForMethod<'describe'>>('describe', async (request) => {
      const processInfo = await this.tspmInstance.describe(request.id);
      const config = this.tspmInstance.processConfigs.get(request.id);

      if (!processInfo || !config) {
        throw new Error(`Process ${request.id} not found`);
      }

      return {
        processInfo,
        config,
      };
    });

    this.ipcServer.on<RequestForMethod<'getLogs'>>('getLogs', async (request) => {
      const logs = await this.tspmInstance.getLogs(request.id);
      return { logs };
    });

    // Batch operations handlers
    this.ipcServer.on<RequestForMethod<'startAll'>>('startAll', async () => {
      const started: string[] = [];
      const failed: Array<{ id: string; error: string }> = [];

      await this.tspmInstance.startAll();

      // Get status of all processes
      for (const [id, processInfo] of this.tspmInstance.processInfo) {
        if (processInfo.status === 'online') {
          started.push(id);
        } else {
          failed.push({ id, error: 'Failed to start' });
        }
      }

      return { started, failed };
    });

    this.ipcServer.on<RequestForMethod<'stopAll'>>('stopAll', async () => {
      const stopped: string[] = [];
      const failed: Array<{ id: string; error: string }> = [];

      await this.tspmInstance.stopAll();

      // Get status of all processes
      for (const [id, processInfo] of this.tspmInstance.processInfo) {
        if (processInfo.status === 'stopped') {
          stopped.push(id);
        } else {
          failed.push({ id, error: 'Failed to stop' });
        }
      }

      return { stopped, failed };
    });

    this.ipcServer.on<RequestForMethod<'restartAll'>>('restartAll', async () => {
      const restarted: string[] = [];
      const failed: Array<{ id: string; error: string }> = [];

      await this.tspmInstance.restartAll();

      // Get status of all processes
      for (const [id, processInfo] of this.tspmInstance.processInfo) {
        if (processInfo.status === 'online') {
          restarted.push(id);
        } else {
          failed.push({ id, error: 'Failed to restart' });
        }
      }

      return { restarted, failed };
    });

    // Daemon management handlers
    this.ipcServer.on<RequestForMethod<'daemon:status'>>('daemon:status', async () => {
      const memUsage = process.memoryUsage();
      return {
        status: 'running',
        pid: process.pid,
        uptime: Date.now() - this.startTime,
        processCount: this.tspmInstance.processes.size,
        memoryUsage: memUsage.heapUsed,
        cpuUsage: process.cpuUsage().user / 1000000, // Convert to seconds
      };
    });

    this.ipcServer.on<RequestForMethod<'daemon:shutdown'>>('daemon:shutdown', async (request) => {
      if (this.isShuttingDown) {
        return {
          success: false,
          message: 'Daemon is already shutting down',
        };
      }

      // Schedule shutdown
      const graceful = request.graceful !== false;
      const timeout = request.timeout || 10000;

      if (graceful) {
        setTimeout(() => this.shutdown(true), 100);
      } else {
        setTimeout(() => this.shutdown(false), 100);
      }

      return {
        success: true,
        message: `Daemon will shutdown ${graceful ? 'gracefully' : 'immediately'} in ${timeout}ms`,
      };
    });

    // Heartbeat handler
    this.ipcServer.on<RequestForMethod<'heartbeat'>>('heartbeat', async () => {
      return {
        timestamp: Date.now(),
        status: this.isShuttingDown ? 'degraded' : 'healthy',
      };
    });
  }

  /**
   * Start heartbeat monitoring
   */
  private startHeartbeatMonitoring(): void {
    // Send heartbeat every 30 seconds
    this.heartbeatInterval = setInterval(() => {
      // This is where we could implement health checks
      // For now, just log that the daemon is alive
      const uptime = Math.floor((Date.now() - this.startTime) / 1000);
      console.log(
        `[Heartbeat] Daemon alive - Uptime: ${uptime}s, Processes: ${this.tspmInstance.processes.size}`,
      );
    }, 30000);
  }

  /**
   * Set up graceful shutdown handlers
   */
  private setupShutdownHandlers(): void {
    const shutdownHandler = async (signal: string) => {
      console.log(`\nReceived ${signal}, initiating graceful shutdown...`);
      await this.shutdown(true);
    };

    process.on('SIGTERM', () => shutdownHandler('SIGTERM'));
    process.on('SIGINT', () => shutdownHandler('SIGINT'));
    process.on('SIGHUP', () => shutdownHandler('SIGHUP'));

    // Handle uncaught errors
    process.on('uncaughtException', (error) => {
      console.error('Uncaught exception:', error);
      this.shutdown(false);
    });

    process.on('unhandledRejection', (reason, promise) => {
      console.error('Unhandled rejection at:', promise, 'reason:', reason);
      // Don't exit on unhandled rejection, just log it
    });
  }

  /**
   * Shutdown the daemon
   */
  public async shutdown(graceful: boolean = true): Promise<void> {
    if (this.isShuttingDown) {
      return;
    }

    this.isShuttingDown = true;
    console.log('Shutting down TSPM daemon...');

    // Clear heartbeat interval
    if (this.heartbeatInterval) {
      clearInterval(this.heartbeatInterval);
      this.heartbeatInterval = null;
    }

    if (graceful) {
      // Stop all processes gracefully
      try {
        console.log('Stopping all managed processes...');
        await this.tspmInstance.stopAll();
      } catch (error) {
        console.error('Error stopping processes:', error);
      }
    }

    // Stop IPC server
    if (this.ipcServer) {
      try {
        await this.ipcServer.stop();
      } catch (error) {
        console.error('Error stopping IPC server:', error);
      }
    }

    // Remove PID file
    await this.removePidFile();

    // Remove socket file if it exists
    try {
      const fs = await import('fs');
      await fs.promises.unlink(this.socketPath).catch(() => {});
    } catch (error) {
      // Ignore errors
    }

    console.log('TSPM daemon shutdown complete');
    process.exit(0);
  }

  /**
   * Check if another daemon instance is running
   */
  private async isDaemonRunning(): Promise<boolean> {
    try {
      const fs = await import('fs');
      const pidContent = await fs.promises.readFile(
        this.daemonPidFile,
        'utf-8',
      );
      const pid = parseInt(pidContent.trim(), 10);

      // Check if process is running
      try {
        process.kill(pid, 0);
        return true; // Process exists
      } catch {
        // Process doesn't exist, clean up stale PID file
        await this.removePidFile();
        return false;
      }
    } catch {
      // PID file doesn't exist
      return false;
    }
  }

  /**
   * Write the daemon PID to a file
   */
  private async writePidFile(): Promise<void> {
    const fs = await import('fs');
    await fs.promises.writeFile(this.daemonPidFile, process.pid.toString());
  }

  /**
   * Remove the daemon PID file
   */
  private async removePidFile(): Promise<void> {
    try {
      const fs = await import('fs');
      await fs.promises.unlink(this.daemonPidFile);
    } catch {
      // Ignore if file doesn't exist
    }
  }
}

/**
 * Main entry point for the daemon
 */
export const startDaemon = async (): Promise<void> => {
  const daemon = new TspmDaemon();
  await daemon.start();

  // Keep the process alive
  await new Promise(() => {});
};