import express, { Request, Response } from 'express';
import path from 'path';
import fs from 'fs/promises';
import { createBackup, restoreBackup, listBackups, deleteBackup } from '../services/backup.service';
import multer from 'multer';

const router = express.Router();

// Configure multer for backup file uploads
const upload = multer({
  dest: '/tmp/basil-restore/',
  limits: {
    fileSize: 1024 * 1024 * 1024, // 1GB max
  },
});

// Get backup directory from env or use default
const getBackupDir = (): string => {
  return process.env.BACKUP_PATH || path.join(__dirname, '../../../backups');
};

/**
 * POST /api/backup
 * Creates a new backup of all data and files
 */
router.post('/', async (req: Request, res: Response) => {
  try {
    const backupDir = getBackupDir();
    await fs.mkdir(backupDir, { recursive: true });

    const backupPath = await createBackup(backupDir);
    const fileName = path.basename(backupPath);
    const stats = await fs.stat(backupPath);

    res.json({
      success: true,
      message: 'Backup created successfully',
      backup: {
        name: fileName,
        path: backupPath,
        size: stats.size,
        created: stats.birthtime,
      },
    });
  } catch (error) {
    console.error('Backup creation error:', error);
    res.status(500).json({
      success: false,
      error: 'Failed to create backup',
      message: error instanceof Error ? error.message : 'Unknown error',
    });
  }
});

/**
 * GET /api/backup
 * Lists all available backups
 */
router.get('/', async (req: Request, res: Response) => {
  try {
    const backupDir = getBackupDir();
    const backups = await listBackups(backupDir);

    res.json({
      success: true,
      backups,
    });
  } catch (error) {
    console.error('Error listing backups:', error);
    res.status(500).json({
      success: false,
      error: 'Failed to list backups',
      message: error instanceof Error ? error.message : 'Unknown error',
    });
  }
});

/**
 * GET /api/backup/:filename
 * Downloads a specific backup file
 */
router.get('/:filename', async (req: Request, res: Response) => {
  try {
    const { filename } = req.params;
    const backupDir = getBackupDir();
    const backupPath = path.join(backupDir, filename);

    // Security check: ensure the file is within the backup directory
    const resolvedPath = path.resolve(backupPath);
    const resolvedBackupDir = path.resolve(backupDir);
    if (!resolvedPath.startsWith(resolvedBackupDir)) {
      return res.status(403).json({
        success: false,
        error: 'Access denied',
      });
    }

    // Check if file exists
    try {
      await fs.access(backupPath);
    } catch {
      return res.status(404).json({
        success: false,
        error: 'Backup file not found',
      });
    }

    // Send file
    res.download(backupPath, filename, (err) => {
      if (err) {
        console.error('Error downloading backup:', err);
        if (!res.headersSent) {
          res.status(500).json({
            success: false,
            error: 'Failed to download backup',
          });
        }
      }
    });
  } catch (error) {
    console.error('Error downloading backup:', error);
    res.status(500).json({
      success: false,
      error: 'Failed to download backup',
      message: error instanceof Error ? error.message : 'Unknown error',
    });
  }
});

/**
 * POST /api/backup/restore
 * Restores data from a backup file
 * Accepts either:
 * - multipart/form-data with 'backup' file field
 * - JSON with 'filename' field (for existing backup in backup directory)
 */
router.post('/restore', upload.single('backup'), async (req: Request, res: Response) => {
  let backupPath: string | null = null;
  let isTemporaryFile = false;

  try {
    const backupDir = getBackupDir();

    // Check if file was uploaded or filename provided
    if (req.file) {
      backupPath = req.file.path;
      isTemporaryFile = true;
    } else if (req.body.filename) {
      backupPath = path.join(backupDir, req.body.filename);

      // Security check
      const resolvedPath = path.resolve(backupPath);
      const resolvedBackupDir = path.resolve(backupDir);
      if (!resolvedPath.startsWith(resolvedBackupDir)) {
        return res.status(403).json({
          success: false,
          error: 'Access denied',
        });
      }

      // Check if file exists
      try {
        await fs.access(backupPath);
      } catch {
        return res.status(404).json({
          success: false,
          error: 'Backup file not found',
        });
      }
    } else {
      return res.status(400).json({
        success: false,
        error: 'No backup file provided. Either upload a file or specify a filename.',
      });
    }

    // Perform restore
    const metadata = await restoreBackup(backupPath, backupDir);

    // Clean up temporary file if it was uploaded
    if (isTemporaryFile && backupPath) {
      try {
        await fs.unlink(backupPath);
      } catch (err) {
        console.warn('Failed to clean up temporary file:', err);
      }
    }

    res.json({
      success: true,
      message: 'Backup restored successfully',
      metadata,
    });
  } catch (error) {
    console.error('Restore error:', error);

    // Clean up temporary file on error
    if (isTemporaryFile && backupPath) {
      try {
        await fs.unlink(backupPath);
      } catch {}
    }

    res.status(500).json({
      success: false,
      error: 'Failed to restore backup',
      message: error instanceof Error ? error.message : 'Unknown error',
    });
  }
});

/**
 * DELETE /api/backup/:filename
 * Deletes a backup file
 */
router.delete('/:filename', async (req: Request, res: Response) => {
  try {
    const { filename } = req.params;
    const backupDir = getBackupDir();
    const backupPath = path.join(backupDir, filename);

    // Security check
    const resolvedPath = path.resolve(backupPath);
    const resolvedBackupDir = path.resolve(backupDir);
    if (!resolvedPath.startsWith(resolvedBackupDir)) {
      return res.status(403).json({
        success: false,
        error: 'Access denied',
      });
    }

    // Check if file exists
    try {
      await fs.access(backupPath);
    } catch {
      return res.status(404).json({
        success: false,
        error: 'Backup file not found',
      });
    }

    await deleteBackup(backupPath);

    res.json({
      success: true,
      message: 'Backup deleted successfully',
    });
  } catch (error) {
    console.error('Error deleting backup:', error);
    res.status(500).json({
      success: false,
      error: 'Failed to delete backup',
      message: error instanceof Error ? error.message : 'Unknown error',
    });
  }
});

export default router;