import { spawn, ChildProcess } from 'child_process';
import { app } from 'electron';
import path from 'path';
import log from 'electron-log';
import { appConfig } from '../config';

const HEALTH_CHECK_TIMEOUT = 2000;

class OpenCodeService {
  private process: ChildProcess | null = null;
  private healthCheckTimer: NodeJS.Timeout | null = null;
  private restartAttempts = 0;
  private _isRunning = false;

  get port(): number {
    return appConfig.opencode.port;
  }

  get healthCheckInterval(): number {
    return appConfig.opencode.healthCheckInterval;
  }

  get maxRestartAttempts(): number {
    return appConfig.opencode.maxRestartAttempts;
  }

  isRunning(): boolean {
    return this._isRunning;
  }

  getStatus(): { running: boolean; port: number; restartAttempts: number } {
    return {
      running: this._isRunning,
      port: this.port,
      restartAttempts: this.restartAttempts,
    };
  }

  private getOpenCodePath(): string {
    if (appConfig.opencode.mode === 'exe') {
      const basePath = app.isPackaged
        ? path.dirname(app.getPath('exe'))
        : path.join(process.cwd(), 'bin');
      return path.join(basePath, appConfig.opencode.exePath);
    }
    return 'opencode';
  }

  private getOpenCodeArgs(): string[] {
    if (appConfig.opencode.mode === 'exe') {
      return ['serve'];
    }
    return ['serve'];
  }

  private getAuthHeaders(): Record<string, string> {
    const password = 'xc_opencode_password';
    const encoded = Buffer.from(`:${password}`).toString('base64');
    return {
      'Authorization': `Basic ${encoded}`,
    };
  }

  private async checkHealth(): Promise<boolean> {
    try {
      const response = await fetch(`http://127.0.0.1:${this.port}/session`, {
        method: 'GET',
        headers: this.getAuthHeaders(),
        signal: AbortSignal.timeout(HEALTH_CHECK_TIMEOUT),
      });
      return response.ok;
    } catch (error) {
      log.warn('[OpenCodeService] Health check failed:', error);
      return false;
    }
  }

  private async restart(): Promise<void> {
    if (this.restartAttempts >= this.maxRestartAttempts) {
      log.error('[OpenCodeService] Max restart attempts reached, giving up');
      this._isRunning = false;
      return;
    }

    this.restartAttempts++;
    log.info(`[OpenCodeService] Attempting restart (${this.restartAttempts}/${this.maxRestartAttempts})...`);

    await this.stop();
    await this.start();
  }

  private startHealthCheck(): void {
    if (this.healthCheckTimer) {
      clearInterval(this.healthCheckTimer);
    }

    this.healthCheckTimer = setInterval(async () => {
      const isHealthy = await this.checkHealth();
      if (!isHealthy && this._isRunning) {
        log.warn('[OpenCodeService] Health check failed, attempting restart...');
        await this.restart();
      }
    }, this.healthCheckInterval);
  }

  async start(): Promise<{ success: boolean; error?: string }> {
    if (this._isRunning && this.process) {
      log.info('[OpenCodeService] Already running');
      return { success: true };
    }

    try {
      const opencodePath = this.getOpenCodePath();
      const opencodeArgs = this.getOpenCodeArgs();
      const mode = appConfig.opencode.mode;

      log.info(`[OpenCodeService] Starting OpenCode server (mode: ${mode})...`);
      log.info(`[OpenCodeService] Path: ${opencodePath}`);

      this.process = spawn(opencodePath, opencodeArgs, {
        stdio: 'pipe',
        shell: true,
        detached: false,
      });

      this.process.stdout?.on('data', (data) => {
        log.info(`[OpenCode] ${data}`);
      });

      this.process.stderr?.on('data', (data) => {
        log.error(`[OpenCode error] ${data}`);
      });

      this.process.on('error', (err) => {
        log.error('[OpenCodeService] Process error:', err);
        this._isRunning = false;
        this.process = null;
      });

      this.process.on('exit', (code) => {
        log.info(`[OpenCodeService] Process exited with code ${code}`);
        this._isRunning = false;
        this.process = null;
      });

      await new Promise<void>((resolve) => {
        setTimeout(resolve, 2000);
      });

      const isHealthy = await this.checkHealth();
      if (!isHealthy) {
        log.warn('[OpenCodeService] Server started but health check failed, waiting longer...');
        await new Promise<void>((resolve) => setTimeout(resolve, 3000));
      }

      this._isRunning = true;
      this.restartAttempts = 0;
      this.startHealthCheck();

      log.info(`[OpenCodeService] Started successfully on port ${this.port}`);
      return { success: true };
    } catch (error: any) {
      log.error('[OpenCodeService] Failed to start:', error);
      this._isRunning = false;
      return { success: false, error: error.message };
    }
  }

  async stop(): Promise<{ success: boolean; error?: string }> {
    if (this.healthCheckTimer) {
      clearInterval(this.healthCheckTimer);
      this.healthCheckTimer = null;
    }

    if (!this.process) {
      log.info('[OpenCodeService] Not running');
      return { success: true };
    }

    try {
      log.info('[OpenCodeService] Stopping...');

      this.process.kill('SIGTERM');
      
      await new Promise<void>((resolve) => {
        setTimeout(resolve, 1000);
      });

      if (this.process && !this.process.killed) {
        this.process.kill('SIGKILL');
      }

      this.process = null;
      this._isRunning = false;
      this.restartAttempts = 0;

      log.info('[OpenCodeService] Stopped');
      return { success: true };
    } catch (error: any) {
      log.error('[OpenCodeService] Failed to stop:', error);
      return { success: false, error: error.message };
    }
  }
}

export const opencodeService = new OpenCodeService();