feat: implement comprehensive backup and restore system with S3 support

- Add S3/MinIO storage adapter with multipart upload support
- Implement database backup service for SQLite and PostgreSQL
- Create backup manifest generator for tracking backup contents
- Enhance backup service with S3 integration and incremental backups
- Add restore service with safety measures and rollback capability
- Create comprehensive test suite for all backup functionality
- Add admin API endpoints for backup/restore management
- Implement frontend UI with dashboard, configuration, and restore wizard
- Add roadmap section to README with implemented backup feature

This implementation provides:
- Multiple backup destinations (local, rsync, S3/MinIO)
- Intelligent change detection to minimize backup frequency
- Full database backups with compression
- Manifest-based restore with integrity validation
- Pre-restore safety backups with rollback
- Comprehensive error handling and monitoring
- User-friendly admin interface

🤖 Generated with Claude Code

Co-Authored-By: Claude <noreply@anthropic.com>

backend/src/services/__tests__/databaseBackup.test.js

@@ -0,0 +1,251 @@
+const { DatabaseBackupService } = require('../databaseBackup');
+const { db } = require('../../database/db');
+const fs = require('fs').promises;
+const path = require('path');
+const crypto = require('crypto');
+
+// Mock dependencies
+jest.mock('../../database/db');
+jest.mock('../../utils/logger');
+jest.mock('../emailProcessor');
+jest.mock('child_process');
+
+describe('DatabaseBackupService', () => {
+  let service;
+  let mockExecAsync;
+
+  beforeEach(() => {
+    service = new DatabaseBackupService();
+    mockExecAsync = jest.fn();
+    
+    // Reset mocks
+    jest.clearAllMocks();
+    
+    // Mock execAsync
+    const childProcess = require('child_process');
+    childProcess.exec = jest.fn((cmd, opts, callback) => {
+      if (callback) {
+        callback(null, { stdout: 'ok', stderr: '' });
+      }
+    });
+  });
+
+  afterEach(async () => {
+    // Cleanup test files
+    try {
+      await fs.rmdir('/tmp/test-backup', { recursive: true });
+    } catch (e) {
+      // Ignore
+    }
+  });
+
+  describe('calculateChecksum', () => {
+    it('should calculate SHA256 checksum of a file', async () => {
+      const testFile = '/tmp/test-checksum.txt';
+      const testContent = 'Hello, World!';
+      await fs.writeFile(testFile, testContent);
+
+      const checksum = await service.calculateChecksum(testFile);
+      
+      // Expected checksum for "Hello, World!"
+      const expectedChecksum = crypto
+        .createHash('sha256')
+        .update(testContent)
+        .digest('hex');
+      
+      expect(checksum).toBe(expectedChecksum);
+      
+      await fs.unlink(testFile);
+    });
+  });
+
+  describe('getTableChecksums', () => {
+    it('should get checksums for all tables', async () => {
+      // Mock getTables
+      service.getTables = jest.fn().mockResolvedValue(['events', 'photos']);
+      
+      // Mock SQLite response
+      db.raw = jest.fn()
+        .mockResolvedValueOnce([{ row_count: 10, data_sum: 1000 }])
+        .mockResolvedValueOnce([{ row_count: 20, data_sum: 2000 }]);
+      
+      const checksums = await service.getTableChecksums();
+      
+      expect(checksums).toHaveProperty('events');
+      expect(checksums).toHaveProperty('photos');
+      expect(checksums.events.rowCount).toBe(10);
+      expect(checksums.photos.rowCount).toBe(20);
+      expect(checksums.events.checksum).toBeDefined();
+      expect(checksums.photos.checksum).toBeDefined();
+    });
+  });
+
+  describe('getTables', () => {
+    it('should get list of tables for SQLite', async () => {
+      service.dbType = 'sqlite';
+      
+      db.raw = jest.fn().mockResolvedValue([
+        { name: 'events' },
+        { name: 'photos' },
+        { name: 'admin_users' }
+      ]);
+      
+      const tables = await service.getTables();
+      
+      expect(tables).toEqual(['events', 'photos', 'admin_users']);
+      expect(db.raw).toHaveBeenCalledWith(expect.stringContaining('sqlite_master'));
+    });
+
+    it('should get list of tables for PostgreSQL', async () => {
+      service.dbType = 'postgresql';
+      
+      db.raw = jest.fn().mockResolvedValue({
+        rows: [
+          { table_name: 'events' },
+          { table_name: 'photos' },
+          { table_name: 'admin_users' }
+        ]
+      });
+      
+      const tables = await service.getTables();
+      
+      expect(tables).toEqual(['events', 'photos', 'admin_users']);
+      expect(db.raw).toHaveBeenCalledWith(expect.stringContaining('information_schema.tables'));
+    });
+  });
+
+  describe('getDatabaseSize', () => {
+    it('should get database size for SQLite', async () => {
+      service.dbType = 'sqlite';
+      const mockSize = 1024 * 1024 * 10; // 10MB
+      
+      // Mock fs.stat
+      const originalStat = fs.stat;
+      fs.stat = jest.fn().mockResolvedValue({ size: mockSize });
+      
+      const size = await service.getDatabaseSize();
+      
+      expect(size).toBe(mockSize);
+      
+      fs.stat = originalStat;
+    });
+
+    it('should get database size for PostgreSQL', async () => {
+      service.dbType = 'postgresql';
+      const mockSize = 1024 * 1024 * 100; // 100MB
+      
+      db.raw = jest.fn().mockResolvedValue({
+        rows: [{ size: mockSize.toString() }]
+      });
+      
+      const size = await service.getDatabaseSize();
+      
+      expect(size).toBe(mockSize);
+      expect(db.raw).toHaveBeenCalledWith(expect.stringContaining('pg_database_size'));
+    });
+  });
+
+  describe('compressFile', () => {
+    it('should compress file and return stats', async () => {
+      const testFile = '/tmp/test-compress.txt';
+      const compressedFile = '/tmp/test-compress.txt.gz';
+      
+      // Create test file with repetitive content (compresses well)
+      const testContent = 'Hello, World! '.repeat(1000);
+      await fs.writeFile(testFile, testContent);
+      
+      const stats = await service.compressFile(testFile, compressedFile);
+      
+      expect(stats.originalSize).toBeGreaterThan(0);
+      expect(stats.compressedSize).toBeGreaterThan(0);
+      expect(stats.compressedSize).toBeLessThan(stats.originalSize);
+      expect(parseFloat(stats.compressionRatio)).toBeGreaterThan(0);
+      
+      // Cleanup
+      await fs.unlink(testFile);
+      await fs.unlink(compressedFile);
+    });
+  });
+
+  describe('backup configuration', () => {
+    it('should get backup configuration from database', async () => {
+      const mockConfig = [
+        { setting_key: 'database_backup_enabled', setting_value: 'true' },
+        { setting_key: 'database_backup_compress', setting_value: 'true' },
+        { setting_key: 'database_backup_retention_days', setting_value: '30' }
+      ];
+      
+      db.mockReturnValue({
+        where: jest.fn().mockReturnThis(),
+        select: jest.fn().mockResolvedValue(mockConfig)
+      });
+      
+      const config = await service.getBackupConfig();
+      
+      expect(config.database_backup_enabled).toBe(true);
+      expect(config.database_backup_compress).toBe(true);
+      expect(config.database_backup_retention_days).toBe(30);
+    });
+  });
+
+  describe('cleanupOldBackups', () => {
+    it('should delete old backup files and records', async () => {
+      const oldBackups = [
+        { id: 1, file_path: '/backup/old1.sql.gz' },
+        { id: 2, file_path: '/backup/old2.sql.gz' }
+      ];
+      
+      db.mockReturnValue({
+        where: jest.fn().mockReturnThis(),
+        select: jest.fn().mockResolvedValue(oldBackups),
+        delete: jest.fn().mockResolvedValue(1)
+      });
+      
+      // Mock fs.unlink
+      fs.unlink = jest.fn().mockResolvedValue(undefined);
+      
+      await service.cleanupOldBackups(30);
+      
+      expect(fs.unlink).toHaveBeenCalledTimes(2);
+      expect(fs.unlink).toHaveBeenCalledWith('/backup/old1.sql.gz');
+      expect(fs.unlink).toHaveBeenCalledWith('/backup/old2.sql.gz');
+    });
+  });
+
+  describe('progress tracking', () => {
+    it('should update and retrieve progress', () => {
+      expect(service.getProgress()).toBeNull();
+      
+      service.updateProgress('Testing...', { step: 1 });
+      
+      const progress = service.getProgress();
+      expect(progress.message).toBe('Testing...');
+      expect(progress.details.step).toBe(1);
+      expect(progress.timestamp).toBeDefined();
+    });
+  });
+
+  describe('backup history', () => {
+    it('should retrieve backup history', async () => {
+      const mockHistory = [
+        {
+          id: 1,
+          started_at: new Date(),
+          completed_at: new Date(),
+          status: 'completed',
+          file_size_bytes: 1024000
+        }
+      ];
+      
+      db.mockReturnValue({
+        orderBy: jest.fn().mockReturnThis(),
+        limit: jest.fn().mockResolvedValue(mockHistory)
+      });
+      
+      const history = await service.getBackupHistory(10);
+      
+      expect(history).toEqual(mockHistory);
+      expect(history.length).toBe(1);
+    });
+  });
+});