from flask import Blueprint, request, jsonify
from backend.models import db, Category

bp = Blueprint('categories', __name__, url_prefix='/api/categories')


@bp.route('', methods=['GET'])
def list_categories():
    """Get all categories"""
    categories = Category.query.order_by(Category.name).all()
    return jsonify([c.to_dict() for c in categories]), 200


@bp.route('/<int:category_id>', methods=['GET'])
def get_category(category_id):
    """Get a single category by ID"""
    category = Category.query.get_or_404(category_id)
    return jsonify(category.to_dict()), 200


@bp.route('', methods=['POST'])
def create_category():
    """Create a new category"""
    data = request.get_json()
    if not data:
        return jsonify({'error': 'No data provided'}), 400

    name = data.get('name', '').strip()
    if not name:
        return jsonify({'error': 'Category name is required'}), 400

    # Check if category already exists
    existing = Category.query.filter_by(name=name).first()
    if existing:
        return jsonify({'error': 'Category already exists'}), 409

    try:
        category = Category(name=name)
        db.session.add(category)
        db.session.commit()

        return jsonify(category.to_dict()), 201

    except Exception as e:
        db.session.rollback()
        return jsonify({'error': str(e)}), 500


@bp.route('/<int:category_id>', methods=['PUT'])
def update_category(category_id):
    """Update an existing category"""
    category = Category.query.get_or_404(category_id)
    data = request.get_json()

    if not data:
        return jsonify({'error': 'No data provided'}), 400

    name = data.get('name', '').strip()
    if not name:
        return jsonify({'error': 'Category name is required'}), 400

    # Check if another category with this name exists
    existing = Category.query.filter(Category.name == name, Category.id != category_id).first()
    if existing:
        return jsonify({'error': 'Category already exists'}), 409

    try:
        category.name = name
        db.session.commit()

        return jsonify(category.to_dict()), 200

    except Exception as e:
        db.session.rollback()
        return jsonify({'error': str(e)}), 500


@bp.route('/<int:category_id>', methods=['DELETE'])
def delete_category(category_id):
    """Delete a category"""
    category = Category.query.get_or_404(category_id)

    try:
        db.session.delete(category)
        db.session.commit()

        return jsonify({'message': 'Category deleted successfully'}), 200

    except Exception as e:
        db.session.rollback()
        return jsonify({'error': str(e)}), 500