package handler

import (
	"encoding/json"
	"net/http"
	"strconv"

	"affiliate_dash/internal/middleware"
	"affiliate_dash/internal/model"
	"affiliate_dash/internal/pkg/response"
	"affiliate_dash/internal/service"

	"github.com/gin-gonic/gin"
)

// OpenV1Handler 提供面向商户系统和履约器的通用开放接口。
type OpenV1Handler struct {
	merchantSvc    *service.MerchantService
	fulfillmentSvc *service.FulfillmentService
}

func NewOpenV1Handler(merchantSvc *service.MerchantService, fulfillmentSvc *service.FulfillmentService) *OpenV1Handler {
	return &OpenV1Handler{merchantSvc: merchantSvc, fulfillmentSvc: fulfillmentSvc}
}

func (h *OpenV1Handler) ListProducts(c *gin.Context) {
	page, _ := strconv.Atoi(c.DefaultQuery("page", "1"))
	size, _ := strconv.Atoi(c.DefaultQuery("size", "20"))
	list, total, err := h.merchantSvc.ListMerchantProducts(middleware.GetMerchantID(c), page, size, true)
	if err != nil {
		response.ServerError(c, err.Error())
		return
	}
	response.Page(c, list, total, page, size)
}

type openCreateOrderReq struct {
	ClientOrderNo  string          `json:"client_order_no" binding:"required"`
	SKU            string          `json:"sku" binding:"required"`
	Quantity       int64           `json:"quantity"`
	BuyerReference string          `json:"buyer_reference"`
	Data           json.RawMessage `json:"data"`
}

func (h *OpenV1Handler) CreateOrder(c *gin.Context) {
	var req openCreateOrderReq
	if err := c.ShouldBindJSON(&req); err != nil {
		response.BadRequest(c, "参数错误：client_order_no 与 sku 必填")
		return
	}
	if key := c.GetHeader("Idempotency-Key"); key != "" && key != req.ClientOrderNo {
		response.BadRequest(c, "Idempotency-Key 必须与 client_order_no 一致")
		return
	}
	var data interface{}
	if len(req.Data) > 0 {
		var decoded interface{}
		if err := json.Unmarshal(req.Data, &decoded); err != nil {
			response.BadRequest(c, "data 必须是有效 JSON")
			return
		}
		data = decoded
	}
	client := middleware.GetAPIClient(c)
	result, err := h.fulfillmentSvc.CreateOrder(service.CreateFulfillmentOrderInput{
		MerchantID:     middleware.GetMerchantID(c),
		APIClientID:    client.ID,
		ClientOrderNo:  req.ClientOrderNo,
		SKU:            req.SKU,
		Quantity:       req.Quantity,
		BuyerReference: req.BuyerReference,
		RequestData:    data,
	})
	if err != nil {
		response.BadRequest(c, err.Error())
		return
	}
	status := http.StatusOK
	if !result.Idempotent {
		status = http.StatusCreated
	}
	c.JSON(status, response.Body{
		Code:    0,
		Message: "ok",
		Data: gin.H{
			"order":      buildOpenOrderResponse(result.Order),
			"idempotent": result.Idempotent,
		},
	})
}

func (h *OpenV1Handler) QueryOrder(c *gin.Context) {
	order, err := h.fulfillmentSvc.GetOrder(middleware.GetMerchantID(c), c.Param("order_no"))
	if err != nil {
		if err.Error() == "订单不存在" {
			response.NotFound(c, err.Error())
			return
		}
		response.ServerError(c, err.Error())
		return
	}
	response.OK(c, buildOpenOrderResponse(order))
}

type openCancelOrderReq struct {
	Reason string `json:"reason"`
}

func (h *OpenV1Handler) CancelOrder(c *gin.Context) {
	var req openCancelOrderReq
	if err := c.ShouldBindJSON(&req); err != nil {
		response.BadRequest(c, "参数错误")
		return
	}
	client := middleware.GetAPIClient(c)
	order, err := h.fulfillmentSvc.CancelOrder(middleware.GetMerchantID(c), client.ID, c.Param("order_no"), req.Reason)
	if err != nil {
		response.BadRequest(c, err.Error())
		return
	}
	response.OK(c, buildOpenOrderResponse(order))
}

type openShipNotifyReq struct {
	OrderNo         string          `json:"order_no"`
	ShipStatus      string          `json:"ship_status" binding:"required"`
	ProviderOrderNo string          `json:"provider_order_no"`
	FailReason      string          `json:"fail_reason"`
	Result          json.RawMessage `json:"result"`
}

func (h *OpenV1Handler) ShipNotify(c *gin.Context) {
	var req openShipNotifyReq
	if err := c.ShouldBindJSON(&req); err != nil {
		response.BadRequest(c, "参数错误：ship_status 必填")
		return
	}
	status := ""
	switch req.ShipStatus {
	case "processing":
		status = model.FulfillmentStatusProcessing
	case "success":
		status = model.FulfillmentStatusSucceeded
	case "failed":
		status = model.FulfillmentStatusFailed
	default:
		response.BadRequest(c, "ship_status 仅支持 processing、success、failed")
		return
	}
	var result interface{}
	if len(req.Result) > 0 {
		if err := json.Unmarshal(req.Result, &result); err != nil {
			response.BadRequest(c, "result 必须是有效 JSON")
			return
		}
	}
	client := middleware.GetAPIClient(c)
	orderNo := c.Param("order_no")
	if orderNo == "" {
		orderNo = req.OrderNo
	}
	if orderNo == "" {
		response.BadRequest(c, "order_no 必填")
		return
	}
	order, err := h.fulfillmentSvc.UpdateFulfillment(service.FulfillmentUpdateInput{
		MerchantID:      middleware.GetMerchantID(c),
		APIClientID:     client.ID,
		OrderNo:         orderNo,
		Status:          status,
		ProviderOrderNo: req.ProviderOrderNo,
		FailureReason:   req.FailReason,
		ResultData:      result,
	})
	if err != nil {
		response.BadRequest(c, err.Error())
		return
	}
	response.OK(c, buildOpenOrderResponse(order))
}

func (h *OpenV1Handler) GetWallet(c *gin.Context) {
	wallet, err := h.fulfillmentSvc.GetWallet(middleware.GetMerchantID(c))
	if err != nil {
		response.ServerError(c, err.Error())
		return
	}
	response.OK(c, wallet)
}

func buildOpenOrderResponse(order *model.FulfillmentOrder) gin.H {
	canFulfill, reason := service.CanFulfill(order)
	data := gin.H{
		"order_no":              order.OrderNo,
		"client_order_no":       order.ClientOrderNo,
		"payment_status":        order.PaymentStatus,
		"fulfillment_status":    order.FulfillmentStatus,
		"can_fulfill":           canFulfill,
		"cannot_fulfill_reason": reason,
		"product": gin.H{
			"sku":  order.ProductSKU,
			"name": order.ProductName,
		},
		"quantity":          order.Quantity,
		"base_amount":       order.BaseAmount,
		"fee_type":          order.FeeType,
		"service_fee_amount": order.ServiceFeeAmount,
		"amount":            order.Amount,
		"currency":          order.Currency,
		"buyer_reference":   order.BuyerReference,
		"provider_order_no": order.ProviderOrderNo,
		"failure_reason":    order.FailureReason,
		"created_at":        order.CreatedAt,
		"delivered_at":      order.DeliveredAt,
		"cancelled_at":      order.CancelledAt,
	}
	if json.Valid([]byte(order.RequestData)) {
		data["data"] = json.RawMessage(order.RequestData)
	}
	if json.Valid([]byte(order.ResultData)) {
		data["result"] = json.RawMessage(order.ResultData)
	}
	return data
}