package callback

import (
	"context"
	"encoding/xml"
	"fmt"
	"net/http"
	"net/url"
	"strings"

	"github.com/gofiber/fiber/v2"
	"github.com/valyala/fasthttp/fasthttpadaptor"

	"github.com/break/junhong_cmp_fiber/internal/model"
	orderService "github.com/break/junhong_cmp_fiber/internal/service/order"
	rechargeService "github.com/break/junhong_cmp_fiber/internal/service/recharge"
	"github.com/break/junhong_cmp_fiber/pkg/constants"
	"github.com/break/junhong_cmp_fiber/pkg/errors"
	"github.com/break/junhong_cmp_fiber/pkg/fuiou"
	"github.com/break/junhong_cmp_fiber/pkg/response"
	"github.com/break/junhong_cmp_fiber/pkg/wechat"
)

// AgentRechargeServiceInterface 代理充值服务接口
type AgentRechargeServiceInterface interface {
	HandlePaymentCallback(ctx context.Context, rechargeNo string, paymentMethod string, paymentTransactionID string) error
}

type PaymentHandler struct {
	orderService         *orderService.Service
	rechargeService      *rechargeService.Service
	agentRechargeService AgentRechargeServiceInterface
	wechatPayment        wechat.PaymentServiceInterface
}

func NewPaymentHandler(
	orderService *orderService.Service,
	rechargeService *rechargeService.Service,
	agentRechargeService AgentRechargeServiceInterface,
	wechatPayment wechat.PaymentServiceInterface,
) *PaymentHandler {
	return &PaymentHandler{
		orderService:         orderService,
		rechargeService:      rechargeService,
		agentRechargeService: agentRechargeService,
		wechatPayment:        wechatPayment,
	}
}

// WechatPayCallback 微信支付回调（带签名验证）
// POST /api/callback/wechat-pay
func (h *PaymentHandler) WechatPayCallback(c *fiber.Ctx) error {
	if h.wechatPayment == nil {
		return errors.New(errors.CodeWechatCallbackInvalid, "微信支付服务未配置")
	}

	var httpReq http.Request
	fasthttpadaptor.ConvertRequest(c.Context(), &httpReq, true)

	ctx := context.Background()
	_, err := h.wechatPayment.HandlePaymentNotify(&httpReq, func(result *wechat.PaymentNotifyResult) error {
		if result.TradeState != "SUCCESS" {
			return nil
		}

		// TODO: 按 payment_config_id 加载配置验签（当前留桩，仍用 wechatPayment 单例验签）

		// 按订单号前缀分发
		outTradeNo := result.OutTradeNo
		switch {
		case strings.HasPrefix(outTradeNo, "ORD"):
			return h.orderService.HandlePaymentCallback(ctx, outTradeNo, model.PaymentMethodWechat)
		case strings.HasPrefix(outTradeNo, constants.AssetRechargeOrderPrefix):
			return h.rechargeService.HandlePaymentCallback(ctx, outTradeNo, model.PaymentMethodWechat, result.TransactionID)
		case strings.HasPrefix(outTradeNo, constants.AgentRechargeOrderPrefix):
			if h.agentRechargeService != nil {
				return h.agentRechargeService.HandlePaymentCallback(ctx, outTradeNo, model.PaymentMethodWechat, result.TransactionID)
			}
			return fmt.Errorf("代理充值服务未配置，无法处理订单: %s", outTradeNo)
		default:
			return fmt.Errorf("未知订单号前缀: %s", outTradeNo)
		}
	})

	if err != nil {
		return errors.Wrap(errors.CodeWechatCallbackInvalid, err, "处理微信支付回调失败")
	}

	return response.Success(c, map[string]string{"return_code": "SUCCESS"})
}

type AlipayCallbackRequest struct {
	OrderNo string `json:"out_trade_no" form:"out_trade_no"`
}

// AlipayCallback 支付宝回调
// POST /api/callback/alipay
func (h *PaymentHandler) AlipayCallback(c *fiber.Ctx) error {
	var req AlipayCallbackRequest
	if err := c.BodyParser(&req); err != nil {
		return errors.New(errors.CodeInvalidParam, "请求参数解析失败")
	}

	if req.OrderNo == "" {
		return errors.New(errors.CodeInvalidParam, "订单号不能为空")
	}

	ctx := c.UserContext()

	// 按订单号前缀分发
	switch {
	case strings.HasPrefix(req.OrderNo, "ORD"):
		if err := h.orderService.HandlePaymentCallback(ctx, req.OrderNo, model.PaymentMethodAlipay); err != nil {
			return err
		}
	case strings.HasPrefix(req.OrderNo, constants.AssetRechargeOrderPrefix):
		if err := h.rechargeService.HandlePaymentCallback(ctx, req.OrderNo, model.PaymentMethodAlipay, ""); err != nil {
			return err
		}
	case strings.HasPrefix(req.OrderNo, constants.AgentRechargeOrderPrefix):
		if h.agentRechargeService != nil {
			if err := h.agentRechargeService.HandlePaymentCallback(ctx, req.OrderNo, model.PaymentMethodAlipay, ""); err != nil {
				return err
			}
		}
	default:
		return errors.New(errors.CodeInvalidParam, "未知订单号前缀")
	}

	return c.SendString("success")
}

// FuiouPayCallback 富友支付回调
// POST /api/callback/fuiou-pay
func (h *PaymentHandler) FuiouPayCallback(c *fiber.Ctx) error {
	body := c.Body()
	if len(body) == 0 {
		return errors.New(errors.CodeFuiouCallbackInvalid, "回调请求体为空")
	}

	ctx := c.UserContext()

	// TODO: 按 payment_config_id 加载配置创建 fuiou.Client 验签
	// 当前留桩：解析但不验签

	// 解析 req= 参数
	formValue := string(body)
	if strings.HasPrefix(formValue, "req=") {
		formValue = formValue[4:]
	}

	decoded, err := url.QueryUnescape(formValue)
	if err != nil {
		return errors.New(errors.CodeFuiouCallbackInvalid, "回调数据解码失败")
	}

	utf8Data, err := fuiou.GBKToUTF8([]byte(decoded))
	if err != nil {
		return errors.New(errors.CodeFuiouCallbackInvalid, "GBK 转 UTF-8 失败")
	}

	xmlStr := strings.Replace(string(utf8Data), `encoding="GBK"`, `encoding="UTF-8"`, 1)

	var notify fuiou.NotifyRequest
	if err := xml.Unmarshal([]byte(xmlStr), &notify); err != nil {
		return errors.New(errors.CodeFuiouCallbackInvalid, "解析回调 XML 失败")
	}

	if notify.ResultCode != "000000" {
		c.Set("Content-Type", "text/xml; charset=gbk")
		return c.Send(fuiou.BuildNotifySuccessResponse())
	}

	// 按订单号前缀分发
	orderNo := notify.MchntOrderNo
	switch {
	case strings.HasPrefix(orderNo, "ORD"):
		if err := h.orderService.HandlePaymentCallback(ctx, orderNo, "fuiou"); err != nil {
			c.Set("Content-Type", "text/xml; charset=gbk")
			return c.Send(fuiou.BuildNotifyFailResponse(err.Error()))
		}
	case strings.HasPrefix(orderNo, constants.AssetRechargeOrderPrefix):
		if err := h.rechargeService.HandlePaymentCallback(ctx, orderNo, "fuiou", notify.TransactionId); err != nil {
			c.Set("Content-Type", "text/xml; charset=gbk")
			return c.Send(fuiou.BuildNotifyFailResponse(err.Error()))
		}
	case strings.HasPrefix(orderNo, constants.AgentRechargeOrderPrefix):
		if h.agentRechargeService != nil {
			if err := h.agentRechargeService.HandlePaymentCallback(ctx, orderNo, "fuiou", notify.TransactionId); err != nil {
				c.Set("Content-Type", "text/xml; charset=gbk")
				return c.Send(fuiou.BuildNotifyFailResponse(err.Error()))
			}
		}
	default:
		c.Set("Content-Type", "text/xml; charset=gbk")
		return c.Send(fuiou.BuildNotifyFailResponse("unknown order prefix"))
	}

	c.Set("Content-Type", "text/xml; charset=gbk")
	return c.Send(fuiou.BuildNotifySuccessResponse())
}