/**
 * HarborForge Monitor Plugin for OpenClaw
 * 
 * Registers with OpenClaw Gateway and manages sidecar lifecycle.
 * Sidecar runs as separate Node process to avoid blocking Gateway.
 */
import { spawn } from 'child_process';
import { fileURLToPath } from 'url';
import { dirname, join } from 'path';
import { existsSync } from 'fs';

const __filename = fileURLToPath(import.meta.url);
const __dirname = dirname(__filename);

/** @type {import('openclaw').Plugin} */
export default function register(api, config) {
  const logger = api.logger || { 
    info: (...args) => console.log('[HF-Monitor]', ...args),
    error: (...args) => console.error('[HF-Monitor]', ...args),
    debug: (...args) => console.debug('[HF-Monitor]', ...args)
  };

  if (!config?.enabled) {
    logger.info('HarborForge Monitor plugin disabled');
    return;
  }

  // Validate required config
  if (!config.challengeUuid) {
    logger.error('Missing required config: challengeUuid');
    logger.error('Please register server in HarborForge Monitor first');
    return;
  }

  const sidecarPath = join(__dirname, 'sidecar', 'server.mjs');
  
  if (!existsSync(sidecarPath)) {
    logger.error('Sidecar not found:', sidecarPath);
    return;
  }

  /** @type {import('child_process').ChildProcess|null} */
  let sidecar = null;

  /**
   * Start the sidecar server
   */
  function startSidecar() {
    if (sidecar) {
      logger.debug('Sidecar already running');
      return;
    }

    logger.info('Starting HarborForge Monitor sidecar...');
    
    // Prepare environment for sidecar
    const env = {
      ...process.env,
      HF_MONITOR_BACKEND_URL: config.backendUrl || 'https://monitor.hangman-lab.top',
      HF_MONITOR_IDENTIFIER: config.identifier || '',
      HF_MONITOR_CHALLENGE_UUID: config.challengeUuid,
      HF_MONITOR_REPORT_INTERVAL: String(config.reportIntervalSec || 30),
      HF_MONITOR_HTTP_FALLBACK_INTERVAL: String(config.httpFallbackIntervalSec || 60),
      HF_MONITOR_LOG_LEVEL: config.logLevel || 'info',
      // Pass OpenClaw info for metrics
      OPENCLAW_PATH: process.env.OPENCLAW_PATH || join(process.env.HOME || '/root', '.openclaw'),
      OPENCLAW_VERSION: api.version || 'unknown',
    };

    // Spawn sidecar as detached process so it survives Gateway briefly during restart
    sidecar = spawn('node', [sidecarPath], {
      env,
      detached: false, // Keep attached for logging, but could be true for full detachment
      stdio: ['ignore', 'pipe', 'pipe']
    });

    sidecar.stdout?.on('data', (data) => {
      logger.info('[sidecar]', data.toString().trim());
    });

    sidecar.stderr?.on('data', (data) => {
      logger.error('[sidecar]', data.toString().trim());
    });

    sidecar.on('exit', (code, signal) => {
      logger.info(`Sidecar exited (code: ${code}, signal: ${signal})`);
      sidecar = null;
    });

    sidecar.on('error', (err) => {
      logger.error('Failed to start sidecar:', err.message);
      sidecar = null;
    });

    logger.info('Sidecar started with PID:', sidecar.pid);
  }

  /**
   * Stop the sidecar server
   */
  function stopSidecar() {
    if (!sidecar) {
      logger.debug('Sidecar not running');
      return;
    }

    logger.info('Stopping HarborForge Monitor sidecar...');
    
    // Graceful shutdown
    sidecar.kill('SIGTERM');
    
    // Force kill after timeout
    const timeout = setTimeout(() => {
      if (sidecar && !sidecar.killed) {
        logger.warn('Sidecar did not exit gracefully, forcing kill');
        sidecar.kill('SIGKILL');
      }
    }, 5000);

    sidecar.on('exit', () => {
      clearTimeout(timeout);
    });
  }

  // Hook into Gateway lifecycle
  api.on('gateway:start', () => {
    logger.info('Gateway starting, starting monitor sidecar...');
    startSidecar();
  });

  api.on('gateway:stop', () => {
    logger.info('Gateway stopping, stopping monitor sidecar...');
    stopSidecar();
  });

  // Also handle process signals directly
  process.on('SIGTERM', () => {
    stopSidecar();
  });

  process.on('SIGINT', () => {
    stopSidecar();
  });

  // Start immediately if Gateway is already running
  if (api.isRunning?.()) {
    startSidecar();
  } else {
    // Delay start slightly to ensure Gateway is fully up
    setTimeout(() => {
      startSidecar();
    }, 1000);
  }

  // Register status tool
  api.registerTool(() => ({
    name: 'harborforge_monitor_status',
    description: 'Get HarborForge Monitor plugin status',
    parameters: {
      type: 'object',
      properties: {}
    },
    async execute() {
      return {
        enabled: true,
        sidecarRunning: sidecar !== null && sidecar.exitCode === null,
        pid: sidecar?.pid || null,
        config: {
          backendUrl: config.backendUrl,
          identifier: config.identifier || 'auto-detected',
          reportIntervalSec: config.reportIntervalSec
        }
      };
    }
  }));

  logger.info('HarborForge Monitor plugin registered');
}