from functools import wraps
from flask import jsonify, request
from decimal import Decimal, ROUND_HALF_UP, InvalidOperation, DecimalException
from datetime import datetime

def validate_json(*required_fields):
    def decorator(f):
        @wraps(f)
        def decorated_function(*args, **kwargs):
            if not request.is_json:
                return jsonify({'message': 'Missing JSON in request'}), 400
            
            data = request.get_json()
            missing_fields = [field for field in required_fields if field not in data]
            
            if missing_fields:
                return jsonify({
                    'message': f'Missing required fields: {", ".join(missing_fields)}'
                }), 400
                
            return f(*args, **kwargs)
        return decorated_function
    return decorator

def validate_decimal(value):
    """验证并转换decimal类型的值"""
    try:
        if value is None:
            return None
        # 转换为Decimal并保留2位小数
        return Decimal(str(value)).quantize(Decimal('0.01'), rounding=ROUND_HALF_UP)
    except (TypeError, InvalidOperation, DecimalException):
        return None

def validate_date(date_str):
    try:
        return datetime.strptime(date_str, '%Y-%m-%d').date()
    except:
        return None