from flask import current_app
from models import db, User, Order, Transaction
from datetime import datetime
import uuid
from sqlalchemy import desc

class OrderService:
    @staticmethod
    def _generate_order_no():
        """生成订单号"""
        return f"ORD{datetime.utcnow().strftime('%Y%m%d%H%M%S')}{uuid.uuid4().hex[:8].upper()}"

    @staticmethod
    def create_order(user_id, data):
        """创建充值订单"""
        user = User.query.get(user_id)
        
        if not user:
            return {'error': '用户不存在'}, 404
        
        amount = data.get('amount')
        payment_method = data.get('payment_method', 'alipay')  # alipay, wechat
        
        # 验证金额
        if not amount or amount <= 0:
            return {'error': '充值金额必须大于0'}, 400
        
        # 验证支付方式
        if payment_method not in ['alipay', 'wechat']:
            return {'error': '不支持的支付方式'}, 400
        
        # 创建订单
        order = Order(
            order_no=OrderService._generate_order_no(),
            user_id=user_id,
            amount=amount,
            payment_method=payment_method,
            status='pending'
        )
        
        try:
            db.session.add(order)
            db.session.commit()
            
            # TODO: 调用支付接口
            # 这里返回支付参数，前端跳转到支付页面
            payment_params = {
                'order_no': order.order_no,
                'amount': order.amount,
                'payment_method': payment_method,
                # 实际项目中应返回支付宝或微信的支付参数
                'qr_code': f'https://payment.example.com/qr/{order.order_no}',
                'payment_url': f'https://payment.example.com/pay/{order.order_no}'
            }
            
            return {
                'message': '订单创建成功',
                'order': order.to_dict(),
                'payment': payment_params
            }, 201
        except Exception as e:
            db.session.rollback()
            return {'error': '订单创建失败'}, 500

    @staticmethod
    def get_orders(user_id, page=1, per_page=20, status=None):
        """获取订单列表"""
        query = Order.query.filter_by(user_id=user_id)
        
        if status:
            query = query.filter_by(status=status)
        
        # 分页查询
        pagination = query.order_by(desc(Order.created_at))\
            .paginate(page=page, per_page=per_page, error_out=False)
        
        return {
            'orders': [order.to_dict() for order in pagination.items],
            'total': pagination.total,
            'page': page,
            'per_page': per_page,
            'pages': pagination.pages
        }, 200

    @staticmethod
    def get_order(user_id, order_id):
        """获取订单详情"""
        order = Order.query.filter_by(id=order_id, user_id=user_id).first()
        
        if not order:
            return {'error': '订单不存在'}, 404
        
        return order.to_dict(), 200

    @staticmethod
    def alipay_callback(data):
        """支付宝支付回调（预留接口）"""
        # TODO: 实现支付宝回调逻辑
        return {'message': '处理成功'}, 200

    @staticmethod
    def wechat_callback(data):
        """微信支付回调（预留接口）"""
        # TODO: 实现微信支付回调逻辑
        return {'message': '处理成功'}, 200

    @staticmethod
    def payment_notify(order_no):
        """模拟支付通知（仅用于测试）"""
        order = Order.query.filter_by(order_no=order_no).first()
        
        if not order:
            return {'error': '订单不存在'}, 404
        
        if order.status != 'pending':
            return {'error': '订单状态不正确'}, 400
        
        try:
            # 更新订单状态
            order.status = 'paid'
            order.paid_at = datetime.utcnow()
            order.transaction_id = f"TXN{uuid.uuid4().hex[:16].upper()}"
            
            # 增加用户余额
            user = User.query.get(order.user_id)
            balance_before = user.balance
            user.balance += order.amount
            balance_after = user.balance
            
            # 创建交易记录
            transaction = Transaction(
                user_id=user.id,
                type='recharge',
                amount=order.amount,
                balance_before=balance_before,
                balance_after=balance_after,
                description=f'充值 - 订单号: {order.order_no}',
                order_id=order.id
            )
            
            db.session.add(transaction)
            db.session.commit()
            
            return {
                'message': '支付成功',
                'order': order.to_dict()
            }, 200
        except Exception as e:
            db.session.rollback()
            return {'error': '支付处理失败'}, 500