from fastapi import HTTPException
from datetime import datetime
from ..db import get_connection
from ..utils.jwt_handler import verify_token

def get_user_coupons_service(token: str):
    """获取用户所有优惠券"""
    try:
        payload = verify_token(token)
        # 新增：通过phone_number查询用户ID
        connection = get_connection()
        cursor = connection.cursor(dictionary=True)
        cursor.execute("SELECT user_id FROM users WHERE phone_number = %s", (payload["sub"],))
        user = cursor.fetchone()
        if not user:
            raise HTTPException(status_code=404, detail="用户不存在")
        user_id = user['user_id']

        # 获取有效期内且未被使用的优惠券
        cursor.execute("""
            SELECT c.* 
            FROM user_coupons uc
            JOIN coupons c ON uc.coupon_id = c.coupon_id
            WHERE uc.user_id = %s 
            AND c.valid_from <= NOW() 
            AND c.valid_to >= NOW()
        """, (user_id,))

        coupons = []
        for coupon in cursor.fetchall():
            # 生成描述文字
            if coupon['discount_type'] == 'fixed':
                desc = f"满{coupon['min_order_amount'] or 0}元，减{coupon['discount_amount']}元"
            else:
                # 转换百分比折扣为中文（如85 -> 八五折）
                discount = int(coupon['discount_amount'])
                chinese_num = ''.join(['〇一二三四五六七八九'[int(d)] for d in str(discount)])
                desc = f"满{coupon['min_order_amount'] or 0}元，打{chinese_num}折"

            coupons.append({
                "coupon_id": coupon['coupon_id'],
                "description": desc
            })

        return coupons

    except Exception as e:
        raise HTTPException(status_code=500, detail=str(e))

def apply_coupon_service(token: str, coupon_id: int, order_id: float):
    """使用优惠券计算价格"""
    try:

        payload = verify_token(token)
        # 新增：通过phone_number查询用户ID
        connection = get_connection()
        cursor = connection.cursor(dictionary=True)
        cursor.execute("SELECT user_id FROM users WHERE phone_number = %s", (payload["sub"],))
        user = cursor.fetchone()
        if not user:
            raise HTTPException(status_code=404, detail="用户不存在")
        user_id = user['user_id']

        # 验证优惠券归属
        cursor.execute("""
            SELECT c.* 
            FROM user_coupons uc
            JOIN coupons c ON uc.coupon_id = c.coupon_id
            WHERE uc.user_id = %s 
            AND uc.coupon_id = %s
            AND c.valid_from <= NOW() 
            AND c.valid_to >= NOW()
            LIMIT 1
        """, (user_id, coupon_id))

        coupon = cursor.fetchone()
        if not coupon:
            raise HTTPException(status_code=400, detail="无效优惠券")
        # print(coupon)
        discount_amount = float(coupon['discount_amount'])
        min_order_amount = float(coupon['min_order_amount']) if coupon['min_order_amount'] else None

        # discount_amount = 0.0
        # min_order_amount = 0.0


        cursor.execute("""
                        SELECT payable_price 
                        FROM orders 
                        WHERE order_id = %s 
                        AND user_id = %s
                        AND order_status = 'pending'
                    """, (order_id, user['user_id']))
        order = cursor.fetchone()

        price = float(order['payable_price'])

        # 检查最低消费
        if coupon['min_order_amount'] and price < min_order_amount:
            raise HTTPException(status_code=400, detail="未达到最低消费金额")
        # 计算折扣
        if coupon['discount_type'] == 'fixed':
            final_price = max(price - discount_amount, 0)
        else:
            discount = price * (discount_amount / 100)
            final_price = max(discount, 0)

        return {"final_price": round(final_price, 2)}

    except Exception as e:
        raise HTTPException(status_code=500, detail=str(e))
    finally:
        cursor.close()
        connection.close()