/**
 * SIEM (Security Information and Event Management) API Routes
 * Provides access to centralized log aggregation, security intelligence,
 * anomaly detection, and real-time alerts
 */

const express = require('express');
const router = express.Router();
const { authenticate } = require('../middleware/auth');
const { requirePermission } = require('../middleware/rbac');
const { validatePagination, validateIdParam } = require('../middleware/inputValidation');
const logAggregator = require('../utils/logAggregator');
const securityIntelligence = require('../utils/securityIntelligence');
const alertSystem = require('../utils/alertSystem');
const logger = require('../utils/logger');

/**
 * GET /api/siem/logs
 * Query aggregated logs with filtering
 */
router.get('/logs',
  authenticate,
  requirePermission('security.view_audit'),
  validatePagination,
  async (req, res) => {
    try {
      const filters = {
        source: req.query.source,
        level: req.query.level,
        category: req.query.category,
        userId: req.query.userId ? parseInt(req.query.userId) : undefined,
        startDate: req.query.startDate,
        endDate: req.query.endDate,
        limit: req.query.limit ? parseInt(req.query.limit) : 100,
        offset: req.query.offset ? parseInt(req.query.offset) : 0
      };

      const logs = await logAggregator.query(filters);

      logAggregator.aggregate('siem', 'info', 'access', 'SIEM logs queried', {
        userId: req.user.id,
        filters
      });

      res.json({
        success: true,
        data: logs,
        filters,
        count: logs.length
      });
    } catch (error) {
      logger.error('[SIEM API] Error querying logs:', error);
      res.status(500).json({
        success: false,
        message: 'Failed to query logs',
        error: error.message
      });
    }
  }
);

/**
 * POST /api/siem/logs/verify
 * Verify log integrity (check for tampering)
 */
router.post('/logs/verify',
  authenticate,
  requirePermission('security.manage'),
  async (req, res) => {
    try {
      const logIds = req.body.logIds || [];
      const result = await logAggregator.verifyIntegrity(logIds.length > 0 ? logIds : null);

      logAggregator.aggregate('siem', 'info', 'security', 'Log integrity verification performed', {
        userId: req.user.id,
        checkedCount: result.total,
        tamperedCount: result.tampered
      });

      res.json({
        success: true,
        data: result
      });
    } catch (error) {
      logger.error('[SIEM API] Error verifying logs:', error);
      res.status(500).json({
        success: false,
        message: 'Failed to verify log integrity',
        error: error.message
      });
    }
  }
);

/**
 * GET /api/siem/statistics
 * Get log statistics
 */
router.get('/statistics',
  authenticate,
  requirePermission('security.view_audit'),
  async (req, res) => {
    try {
      const timeRange = req.query.timeRange ? parseInt(req.query.timeRange) : 24;
      const stats = await logAggregator.getStatistics(timeRange);

      res.json({
        success: true,
        data: stats,
        timeRange: `${timeRange} hours`
      });
    } catch (error) {
      logger.error('[SIEM API] Error getting statistics:', error);
      res.status(500).json({
        success: false,
        message: 'Failed to get statistics',
        error: error.message
      });
    }
  }
);

/**
 * GET /api/siem/export
 * Export logs in JSON or CSV format
 */
router.get('/export',
  authenticate,
  requirePermission('security.manage'),
  async (req, res) => {
    try {
      const format = req.query.format || 'json';
      const filters = {
        source: req.query.source,
        level: req.query.level,
        startDate: req.query.startDate,
        endDate: req.query.endDate
      };

      const exportData = await logAggregator.export(filters, format);

      logAggregator.aggregate('siem', 'info', 'security', 'Logs exported', {
        userId: req.user.id,
        format,
        filters
      });

      const contentType = format === 'csv' ? 'text/csv' : 'application/json';
      const filename = `siem_export_${Date.now()}.${format}`;

      res.setHeader('Content-Type', contentType);
      res.setHeader('Content-Disposition', `attachment; filename="${filename}"`);
      res.send(exportData);
    } catch (error) {
      logger.error('[SIEM API] Error exporting logs:', error);
      res.status(500).json({
        success: false,
        message: 'Failed to export logs',
        error: error.message
      });
    }
  }
);

/**
 * GET /api/siem/anomalies
 * Get detected anomalies
 */
router.get('/anomalies',
  authenticate,
  requirePermission('security.view_audit'),
  validatePagination,
  async (req, res) => {
    try {
      const filters = {
        status: req.query.status || 'open',
        severity: req.query.severity,
        type: req.query.type,
        limit: req.query.limit ? parseInt(req.query.limit) : 100,
        offset: req.query.offset ? parseInt(req.query.offset) : 0
      };

      const anomalies = await securityIntelligence.getAnomalies(filters);

      res.json({
        success: true,
        data: anomalies,
        count: anomalies.length
      });
    } catch (error) {
      logger.error('[SIEM API] Error getting anomalies:', error);
      res.status(500).json({
        success: false,
        message: 'Failed to get anomalies',
        error: error.message
      });
    }
  }
);

/**
 * POST /api/siem/anomalies/:id/resolve
 * Resolve an anomaly
 */
router.post('/anomalies/:id/resolve',
  authenticate,
  requirePermission('security.manage'),
  validateIdParam,
  async (req, res) => {
    try {
      const anomalyId = req.params.id;
      const notes = req.body.notes || '';

      await securityIntelligence.resolveAnomaly(anomalyId, req.user.id, notes);

      logAggregator.aggregate('siem', 'info', 'security', 'Anomaly resolved', {
        userId: req.user.id,
        anomalyId,
        notes
      });

      res.json({
        success: true,
        message: 'Anomaly resolved successfully'
      });
    } catch (error) {
      logger.error('[SIEM API] Error resolving anomaly:', error);
      res.status(500).json({
        success: false,
        message: 'Failed to resolve anomaly',
        error: error.message
      });
    }
  }
);

/**
 * GET /api/siem/threats
 * Get threat intelligence data
 */
router.get('/threats',
  authenticate,
  requirePermission('security.view_audit'),
  validatePagination,
  async (req, res) => {
    try {
      const filters = {
        level: req.query.level,
        type: req.query.type,
        limit: req.query.limit ? parseInt(req.query.limit) : 100
      };

      const threats = await securityIntelligence.getThreatIntelligence(filters);

      res.json({
        success: true,
        data: threats,
        count: threats.length
      });
    } catch (error) {
      logger.error('[SIEM API] Error getting threats:', error);
      res.status(500).json({
        success: false,
        message: 'Failed to get threat intelligence',
        error: error.message
      });
    }
  }
);

/**
 * GET /api/siem/alerts
 * Get active security alerts
 */
router.get('/alerts',
  authenticate,
  requirePermission('security.view_audit'),
  validatePagination,
  async (req, res) => {
    try {
      const filters = {
        status: req.query.status || 'active',
        severity: req.query.severity,
        limit: req.query.limit ? parseInt(req.query.limit) : 100,
        offset: req.query.offset ? parseInt(req.query.offset) : 0
      };

      const alerts = await alertSystem.getAlerts(filters);

      res.json({
        success: true,
        data: alerts,
        count: alerts.length
      });
    } catch (error) {
      logger.error('[SIEM API] Error getting alerts:', error);
      res.status(500).json({
        success: false,
        message: 'Failed to get alerts',
        error: error.message
      });
    }
  }
);

/**
 * POST /api/siem/alerts/:id/acknowledge
 * Acknowledge an alert
 */
router.post('/alerts/:id/acknowledge',
  authenticate,
  requirePermission('security.view_audit'),
  validateIdParam,
  async (req, res) => {
    try {
      const alertId = req.params.id;
      const notes = req.body.notes || '';

      await alertSystem.acknowledgeAlert(alertId, req.user.id, notes);

      res.json({
        success: true,
        message: 'Alert acknowledged successfully'
      });
    } catch (error) {
      logger.error('[SIEM API] Error acknowledging alert:', error);
      res.status(500).json({
        success: false,
        message: 'Failed to acknowledge alert',
        error: error.message
      });
    }
  }
);

/**
 * POST /api/siem/alerts/:id/resolve
 * Resolve an alert
 */
router.post('/alerts/:id/resolve',
  authenticate,
  requirePermission('security.manage'),
  validateIdParam,
  async (req, res) => {
    try {
      const alertId = req.params.id;
      const notes = req.body.notes;

      await alertSystem.resolveAlert(alertId, req.user.id, notes);

      res.json({
        success: true,
        message: 'Alert resolved successfully'
      });
    } catch (error) {
      logger.error('[SIEM API] Error resolving alert:', error);
      res.status(500).json({
        success: false,
        message: 'Failed to resolve alert',
        error: error.message
      });
    }
  }
);

/**
 * GET /api/siem/dashboard
 * Get comprehensive security intelligence dashboard data
 */
router.get('/dashboard',
  authenticate,
  requirePermission('security.view_audit'),
  async (req, res) => {
    try {
      const [dashboardData, alertStats] = await Promise.all([
        securityIntelligence.getDashboardData(),
        alertSystem.getStatistics()
      ]);

      res.json({
        success: true,
        data: {
          ...dashboardData,
          alertStats
        }
      });
    } catch (error) {
      logger.error('[SIEM API] Error getting dashboard data:', error);
      res.status(500).json({
        success: false,
        message: 'Failed to get dashboard data',
        error: error.message
      });
    }
  }
);

/**
 * GET /api/siem/alert-rules
 * Get configured alert rules
 */
router.get('/alert-rules',
  authenticate,
  requirePermission('security.manage'),
  async (req, res) => {
    try {
      const rules = Array.from(alertSystem.alertRules.values());

      res.json({
        success: true,
        data: rules,
        count: rules.length
      });
    } catch (error) {
      logger.error('[SIEM API] Error getting alert rules:', error);
      res.status(500).json({
        success: false,
        message: 'Failed to get alert rules',
        error: error.message
      });
    }
  }
);

module.exports = router;