Phase 3 Step 7: Scan Comparison Features & UX Improvements

Implemented comprehensive scan comparison functionality with historical
analysis and improved user experience for scan triggering.

Features Added:
- Scan comparison engine with ports, services, and certificates analysis
- Drift score calculation (0.0-1.0 scale) for infrastructure changes
- Side-by-side comparison UI with color-coded changes (added/removed/changed)
- Historical trend charts showing port counts over time
- "Compare with Previous" button on scan detail pages
- Scan history API endpoint for trending data

API Endpoints:
- GET /api/scans/<id1>/compare/<id2> - Compare two scans
- GET /api/stats/scan-history/<id> - Historical scan data for charts

UI Improvements:
- Replaced config file text inputs with dropdown selectors
- Added config file selection to dashboard and scans pages
- Improved delete scan confirmation with proper async handling
- Enhanced error messages with detailed validation feedback
- Added 2-second delay before redirect to ensure deletion completes

Comparison Features:
- Port changes: tracks added, removed, and unchanged ports
- Service changes: detects version updates and service modifications
- Certificate changes: monitors SSL/TLS certificate updates
- Interactive historical charts with clickable data points
- Automatic detection of previous scan for comparison

Bug Fixes:
- Fixed scan deletion UI alert appearing on successful deletion
- Prevented config file path duplication (configs/configs/...)
- Improved error handling for failed API responses
- Added proper JSON response parsing with fallback handling

Testing:
- Created comprehensive test suite for comparison functionality
- Tests cover comparison API, service methods, and drift scoring
- Added edge case tests for identical scans and missing data

web/api/stats.py

@@ -149,3 +149,110 @@ def summary():
     except Exception as e:
         logger.error(f"Error in summary: {str(e)}")
         return jsonify({'error': 'An error occurred'}), 500
+
+
+@bp.route('/scan-history/<int:scan_id>', methods=['GET'])
+@api_auth_required
+def scan_history(scan_id):
+    """
+    Get historical trend data for scans with the same config file.
+
+    Returns port counts and other metrics over time for the same
+    configuration/target as the specified scan.
+
+    Args:
+        scan_id: Reference scan ID
+
+    Query params:
+        limit: Maximum number of historical scans to include (default: 10, max: 50)
+
+    Returns:
+        JSON response with historical scan data
+        {
+            "scans": [
+                {
+                    "id": 123,
+                    "timestamp": "2025-01-01T12:00:00",
+                    "title": "Scan title",
+                    "port_count": 25,
+                    "ip_count": 5
+                },
+                ...
+            ],
+            "labels": ["2025-01-01", ...],
+            "port_counts": [25, 26, 24, ...]
+        }
+    """
+    try:
+        # Get query parameters
+        limit = request.args.get('limit', 10, type=int)
+        if limit > 50:
+            limit = 50
+
+        db_session = current_app.db_session
+
+        # Get the reference scan to find its config file
+        from web.models import ScanPort
+        reference_scan = db_session.query(Scan).filter(Scan.id == scan_id).first()
+
+        if not reference_scan:
+            return jsonify({'error': 'Scan not found'}), 404
+
+        config_file = reference_scan.config_file
+
+        # Query historical scans with the same config file
+        historical_scans = (
+            db_session.query(Scan)
+            .filter(Scan.config_file == config_file)
+            .filter(Scan.status == 'completed')
+            .order_by(Scan.timestamp.desc())
+            .limit(limit)
+            .all()
+        )
+
+        # Build result data
+        scans_data = []
+        labels = []
+        port_counts = []
+
+        for scan in reversed(historical_scans):  # Reverse to get chronological order
+            # Count ports for this scan
+            port_count = (
+                db_session.query(func.count(ScanPort.id))
+                .filter(ScanPort.scan_id == scan.id)
+                .scalar() or 0
+            )
+
+            # Count unique IPs for this scan
+            from web.models import ScanIP
+            ip_count = (
+                db_session.query(func.count(ScanIP.id))
+                .filter(ScanIP.scan_id == scan.id)
+                .scalar() or 0
+            )
+
+            scans_data.append({
+                'id': scan.id,
+                'timestamp': scan.timestamp.isoformat() if scan.timestamp else None,
+                'title': scan.title,
+                'port_count': port_count,
+                'ip_count': ip_count
+            })
+
+            # For chart data
+            labels.append(scan.timestamp.strftime('%Y-%m-%d %H:%M') if scan.timestamp else '')
+            port_counts.append(port_count)
+
+        return jsonify({
+            'scans': scans_data,
+            'labels': labels,
+            'port_counts': port_counts,
+            'config_file': config_file
+        }), 200
+
+    except SQLAlchemyError as e:
+        logger.error(f"Database error in scan_history: {str(e)}")
+        return jsonify({'error': 'Database error occurred'}), 500
+    except Exception as e:
+        logger.error(f"Error in scan_history: {str(e)}")
+        return jsonify({'error': 'An error occurred'}), 500