import cron from "node-cron";
import fs from "fs";
import path from "path";
import { storage } from "../storage";
import { backupDatabaseToPath } from "../services/databaseBackupService";

// Local backup folder in the app root (apps/Backend/backups)
const LOCAL_BACKUP_DIR = path.resolve(process.cwd(), "backups");

// Name of the USB backup subfolder the user creates on their drive
const USB_BACKUP_FOLDER_NAME = "USB Backup";

function ensureLocalBackupDir() {
  if (!fs.existsSync(LOCAL_BACKUP_DIR)) {
    fs.mkdirSync(LOCAL_BACKUP_DIR, { recursive: true });
  }
}

async function getAdminUser() {
  const batchSize = 100;
  let offset = 0;
  while (true) {
    const users = await storage.getUsers(batchSize, offset);
    if (!users || users.length === 0) break;
    const admin = users.find((u) => u.username === "admin");
    if (admin) return admin;
    offset += batchSize;
  }
  return null;
}

export const startBackupCron = () => {
  // ============================================================
  // 8 PM — Local automatic backup to apps/Backend/backups/
  // ============================================================
  cron.schedule("0 20 * * *", async () => {
    console.log("🔄 [8 PM] Running local auto-backup...");
    ensureLocalBackupDir();

    const admin = await getAdminUser();
    if (!admin) {
      console.warn("No admin user found, skipping local backup.");
      return;
    }

    if (!admin.autoBackupEnabled) {
      console.log("✅ [8 PM] Auto-backup is disabled for admin, skipped.");
      return;
    }

    try {
      const filename = `dental_backup_${Date.now()}.sql`;
      await backupDatabaseToPath({ destinationPath: LOCAL_BACKUP_DIR, filename });
      await storage.createBackup(admin.id);
      await storage.deleteNotificationsByType(admin.id, "BACKUP");
      console.log(`✅ Local backup done → ${filename}`);
    } catch (err) {
      console.error("Local backup failed:", err);
      await storage.createNotification(
        admin.id,
        "BACKUP",
        "❌ Automatic backup failed. Please check the server backup folder."
      );
    }

    console.log("✅ [8 PM] Local backup complete.");
  });

  // ============================================================
  // 9 PM — USB backup to the "USB Backup" folder on the drive
  // ============================================================
  cron.schedule("0 21 * * *", async () => {
    console.log("🔄 [9 PM] Running USB backup...");

    const admin = await getAdminUser();
    if (!admin) {
      console.warn("No admin user found, skipping USB backup.");
      return;
    }

    if (!admin.usbBackupEnabled) {
      console.log("✅ [9 PM] USB backup is disabled for admin, skipped.");
      return;
    }

    const destination = await storage.getActiveBackupDestination(admin.id);
    if (!destination) {
      await storage.createNotification(
        admin.id,
        "BACKUP",
        "❌ USB backup failed: no backup destination configured."
      );
      return;
    }

    const usbBackupPath = path.join(destination.path, USB_BACKUP_FOLDER_NAME);

    if (!fs.existsSync(usbBackupPath)) {
      await storage.createNotification(
        admin.id,
        "BACKUP",
        `❌ USB backup failed: folder "${USB_BACKUP_FOLDER_NAME}" not found on the drive. Make sure the USB drive is connected and the folder exists.`
      );
      return;
    }

    try {
      const filename = `dental_backup_usb_${Date.now()}.sql`;
      await backupDatabaseToPath({ destinationPath: usbBackupPath, filename });
      await storage.createBackup(admin.id);
      await storage.deleteNotificationsByType(admin.id, "BACKUP");
      console.log(`✅ USB backup done → ${usbBackupPath}/${filename}`);
    } catch (err) {
      console.error("USB backup failed:", err);
      await storage.createNotification(
        admin.id,
        "BACKUP",
        "❌ USB backup failed. Please check the USB drive and try again."
      );
    }

    console.log("✅ [9 PM] USB backup complete.");
  });
};