Initial commit

app/routes/budget.py

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+"""
+Budget Alerts API
+Provides budget status, alerts, and notification management
+Security: All queries filtered by user_id
+"""
+from flask import Blueprint, request, jsonify
+from flask_login import login_required, current_user
+from app.models import Category, Expense
+from app import db
+from datetime import datetime, timedelta
+from sqlalchemy import func
+
+bp = Blueprint('budget', __name__, url_prefix='/api/budget')
+
+
+@bp.route('/status', methods=['GET'])
+@login_required
+def get_budget_status():
+    """
+    Get budget status for all user categories and overall monthly budget
+    Security: Only returns current user's data
+    
+    Returns:
+    - overall: Total spending vs monthly budget
+    - categories: Per-category budget status
+    - alerts: Active budget alerts
+    """
+    # Get current month date range
+    now = datetime.utcnow()
+    start_of_month = now.replace(day=1, hour=0, minute=0, second=0, microsecond=0)
+    
+    # Calculate overall monthly spending - Security: filter by user_id
+    total_spent = db.session.query(func.sum(Expense.amount)).filter(
+        Expense.user_id == current_user.id,
+        Expense.date >= start_of_month
+    ).scalar() or 0.0
+    
+    overall_status = {
+        'spent': float(total_spent),
+        'budget': current_user.monthly_budget or 0,
+        'remaining': (current_user.monthly_budget or 0) - float(total_spent),
+        'percentage': 0 if not current_user.monthly_budget else round((float(total_spent) / current_user.monthly_budget) * 100, 1),
+        'alert_level': 'none'
+    }
+    
+    # Determine overall alert level
+    if current_user.monthly_budget and current_user.monthly_budget > 0:
+        if overall_status['percentage'] >= 100:
+            overall_status['alert_level'] = 'exceeded'
+        elif overall_status['percentage'] >= 90:
+            overall_status['alert_level'] = 'danger'
+        elif overall_status['percentage'] >= 80:
+            overall_status['alert_level'] = 'warning'
+    
+    # Get category budgets - Security: filter by user_id
+    categories = Category.query.filter_by(user_id=current_user.id).all()
+    category_statuses = []
+    active_alerts = []
+    
+    for category in categories:
+        if category.monthly_budget and category.monthly_budget > 0:
+            status = category.get_budget_status()
+            category_statuses.append({
+                'category_id': category.id,
+                'category_name': category.name,
+                'category_color': category.color,
+                'category_icon': category.icon,
+                **status
+            })
+            
+            # Add to alerts if over threshold
+            if status['alert_level'] in ['warning', 'danger', 'exceeded']:
+                active_alerts.append({
+                    'category_id': category.id,
+                    'category_name': category.name,
+                    'category_color': category.color,
+                    'alert_level': status['alert_level'],
+                    'percentage': status['percentage'],
+                    'spent': status['spent'],
+                    'budget': status['budget'],
+                    'remaining': status['remaining']
+                })
+    
+    # Sort alerts by severity
+    alert_order = {'exceeded': 0, 'danger': 1, 'warning': 2}
+    active_alerts.sort(key=lambda x: (alert_order[x['alert_level']], -x['percentage']))
+    
+    return jsonify({
+        'success': True,
+        'overall': overall_status,
+        'categories': category_statuses,
+        'alerts': active_alerts,
+        'alert_count': len(active_alerts)
+    })
+
+
+@bp.route('/weekly-summary', methods=['GET'])
+@login_required
+def get_weekly_summary():
+    """
+    Get weekly spending summary for notification
+    Security: Only returns current user's data
+    
+    Returns:
+    - week_total: Total spent this week
+    - daily_average: Average per day
+    - top_category: Highest spending category
+    - comparison: vs previous week
+    """
+    now = datetime.utcnow()
+    week_start = now - timedelta(days=now.weekday())  # Monday
+    week_start = week_start.replace(hour=0, minute=0, second=0, microsecond=0)
+    
+    prev_week_start = week_start - timedelta(days=7)
+    
+    # Current week spending - Security: filter by user_id
+    current_week_expenses = Expense.query.filter(
+        Expense.user_id == current_user.id,
+        Expense.date >= week_start
+    ).all()
+    
+    week_total = sum(e.amount for e in current_week_expenses)
+    daily_average = week_total / max(1, (now - week_start).days + 1)
+    
+    # Previous week for comparison
+    prev_week_expenses = Expense.query.filter(
+        Expense.user_id == current_user.id,
+        Expense.date >= prev_week_start,
+        Expense.date < week_start
+    ).all()
+    
+    prev_week_total = sum(e.amount for e in prev_week_expenses)
+    change_percent = 0
+    if prev_week_total > 0:
+        change_percent = ((week_total - prev_week_total) / prev_week_total) * 100
+    
+    # Find top category
+    category_totals = {}
+    for expense in current_week_expenses:
+        if expense.category:
+            category_totals[expense.category.name] = category_totals.get(expense.category.name, 0) + expense.amount
+    
+    top_category = max(category_totals.items(), key=lambda x: x[1]) if category_totals else (None, 0)
+    
+    return jsonify({
+        'success': True,
+        'week_total': float(week_total),
+        'daily_average': float(daily_average),
+        'previous_week_total': float(prev_week_total),
+        'change_percent': round(change_percent, 1),
+        'top_category': top_category[0] if top_category[0] else 'None',
+        'top_category_amount': float(top_category[1]),
+        'expense_count': len(current_week_expenses),
+        'week_start': week_start.isoformat(),
+        'currency': current_user.currency
+    })
+
+
+@bp.route('/category/<int:category_id>/budget', methods=['PUT'])
+@login_required
+def update_category_budget(category_id):
+    """
+    Update budget settings for a category
+    Security: Verify category belongs to current user
+    """
+    # Security check: ensure category belongs to current user
+    category = Category.query.filter_by(id=category_id, user_id=current_user.id).first()
+    
+    if not category:
+        return jsonify({'success': False, 'message': 'Category not found'}), 404
+    
+    data = request.get_json()
+    
+    try:
+        if 'monthly_budget' in data:
+            budget = float(data['monthly_budget']) if data['monthly_budget'] else None
+            if budget is not None and budget < 0:
+                return jsonify({'success': False, 'message': 'Budget cannot be negative'}), 400
+            category.monthly_budget = budget
+        
+        if 'budget_alert_threshold' in data:
+            threshold = float(data['budget_alert_threshold'])
+            if threshold < 0.5 or threshold > 2.0:
+                return jsonify({'success': False, 'message': 'Threshold must be between 0.5 (50%) and 2.0 (200%)'}), 400
+            category.budget_alert_threshold = threshold
+        
+        db.session.commit()
+        
+        return jsonify({
+            'success': True,
+            'message': 'Budget updated successfully',
+            'category': category.to_dict()
+        })
+    except ValueError as e:
+        return jsonify({'success': False, 'message': f'Invalid data: {str(e)}'}), 400
+    except Exception as e:
+        db.session.rollback()
+        return jsonify({'success': False, 'message': f'Error updating budget: {str(e)}'}), 500