/**
 * Geofence Notification Service
 * Handles sending email notifications for geofence events
 */

import { emailService } from './email-service';
import {
  renderGeofenceEnterEmail,
  renderGeofenceExitEmail,
  GeofenceEmailData,
} from './email-renderer';
import { geofenceDb } from './geofence-db';
import type { GeofenceEvent } from './types';
import Database from 'better-sqlite3';
import path from 'path';

const dbPath = path.join(process.cwd(), 'data', 'database.sqlite');

interface DeviceInfo {
  id: string;
  name: string;
  ownerId: string;
}

interface UserInfo {
  id: string;
  username: string;
  email: string | null;
}

interface GeofenceInfo {
  id: string;
  name: string;
  owner_id: string;
}

/**
 * Get device information from database
 */
function getDevice(deviceId: string): DeviceInfo | null {
  const db = new Database(dbPath);
  try {
    const stmt = db.prepare('SELECT id, name, ownerId FROM Device WHERE id = ?');
    return stmt.get(deviceId) as DeviceInfo | null;
  } finally {
    db.close();
  }
}

/**
 * Get user information from database
 */
function getUser(userId: string): UserInfo | null {
  const db = new Database(dbPath);
  try {
    const stmt = db.prepare('SELECT id, username, email FROM User WHERE id = ?');
    return stmt.get(userId) as UserInfo | null;
  } finally {
    db.close();
  }
}

/**
 * Send notification for a single geofence event
 */
async function sendEventNotification(event: GeofenceEvent): Promise<void> {
  try {
    // Get geofence details
    const geofence = geofenceDb.findById(event.geofence_id);
    if (!geofence) {
      throw new Error(`Geofence not found: ${event.geofence_id}`);
    }

    // Get device details
    const device = getDevice(event.device_id);
    if (!device) {
      throw new Error(`Device not found: ${event.device_id}`);
    }

    // Get owner details
    const owner = getUser(geofence.owner_id);
    if (!owner || !owner.email) {
      console.log(`[GeofenceNotification] No email for owner ${geofence.owner_id}, skipping notification`);
      geofenceDb.markNotificationSent(event.id!, true); // Mark as "sent" (no email needed)
      return;
    }

    // Prepare email data
    const emailData: GeofenceEmailData = {
      username: owner.username,
      deviceName: device.name,
      geofenceName: geofence.name,
      timestamp: event.timestamp,
      latitude: event.latitude,
      longitude: event.longitude,
      distanceFromCenter: event.distance_from_center || 0,
      // Optional: Add map URL later
      // mapUrl: `${process.env.NEXT_PUBLIC_URL}/map?lat=${event.latitude}&lon=${event.longitude}`
    };

    // Render and send email
    let html: string;
    let subject: string;

    if (event.event_type === 'enter') {
      html = await renderGeofenceEnterEmail(emailData);
      subject = `${device.name} hat ${geofence.name} betreten`;
    } else {
      html = await renderGeofenceExitEmail(emailData);
      subject = `${device.name} hat ${geofence.name} verlassen`;
    }

    // Send via existing email service
    await emailService['sendEmail'](owner.email, subject, html);

    // Mark notification as sent
    geofenceDb.markNotificationSent(event.id!, true);

    console.log(`[GeofenceNotification] Sent ${event.event_type} notification for geofence ${geofence.name} to ${owner.email}`);
  } catch (error) {
    console.error('[GeofenceNotification] Failed to send notification:', error);

    // Mark notification as failed
    const errorMessage = error instanceof Error ? error.message : 'Unknown error';
    geofenceDb.markNotificationSent(event.id!, false, errorMessage);

    throw error;
  }
}

/**
 * Send notifications for multiple geofence events
 * Processes events sequentially to avoid overwhelming SMTP server
 */
export async function sendGeofenceNotifications(events: GeofenceEvent[]): Promise<void> {
  if (events.length === 0) {
    return;
  }

  console.log(`[GeofenceNotification] Processing ${events.length} geofence event(s)`);

  for (const event of events) {
    try {
      await sendEventNotification(event);
    } catch (error) {
      // Log error but continue with other notifications
      console.error(`[GeofenceNotification] Failed to send notification for event ${event.id}:`, error);
    }
  }
}