package pointsmall

import (
	"errors"
	"net/http"
	"strconv"

	"hfb_sys/backend/internal/middleware"
	"hfb_sys/backend/pkg/response"

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

type Handler struct {
	service *Service
}

func NewHandler(service *Service) *Handler {
	return &Handler{service: service}
}

func (h *Handler) Summary(c *gin.Context) {
	userID, ok := currentUserID(c)
	if !ok {
		response.Unauthorized(c, "缺少用户上下文")
		return
	}
	item, err := h.service.Summary(c.Request.Context(), userID)
	if err != nil {
		writeError(c, err)
		return
	}
	response.OK(c, item)
}

func (h *Handler) Ledger(c *gin.Context) {
	userID, ok := currentUserID(c)
	if !ok {
		response.Unauthorized(c, "缺少用户上下文")
		return
	}
	items, err := h.service.Ledger(c.Request.Context(), userID, parseLimit(c.Query("limit")))
	if err != nil {
		writeError(c, err)
		return
	}
	response.OK(c, items)
}

func (h *Handler) Products(c *gin.Context) {
	items, err := h.service.ListProducts(c.Request.Context(), false)
	if err != nil {
		writeError(c, err)
		return
	}
	response.OK(c, items)
}

func (h *Handler) AdminProducts(c *gin.Context) {
	items, err := h.service.ListProducts(c.Request.Context(), true)
	if err != nil {
		writeError(c, err)
		return
	}
	response.OK(c, items)
}

func (h *Handler) CreateProduct(c *gin.Context) {
	var req ProductRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		response.BadRequest(c, "积分商品参数不正确")
		return
	}
	item, err := h.service.CreateProduct(c.Request.Context(), req)
	if err != nil {
		writeError(c, err)
		return
	}
	response.OK(c, item)
}

func (h *Handler) UpdateProduct(c *gin.Context) {
	id, _ := strconv.ParseUint(c.Param("id"), 10, 64)
	if id == 0 {
		response.BadRequest(c, "商品 ID 不正确")
		return
	}
	var req ProductRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		response.BadRequest(c, "积分商品参数不正确")
		return
	}
	item, err := h.service.UpdateProduct(c.Request.Context(), id, req)
	if err != nil {
		writeError(c, err)
		return
	}
	response.OK(c, item)
}

func (h *Handler) Redeem(c *gin.Context) {
	userID, ok := currentUserID(c)
	if !ok {
		response.Unauthorized(c, "缺少用户上下文")
		return
	}
	productID, _ := strconv.ParseUint(c.Param("id"), 10, 64)
	var req RedeemRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		response.BadRequest(c, "请填写联系人、正确的手机号和兑换数量")
		return
	}
	item, err := h.service.Redeem(c.Request.Context(), userID, productID, req)
	if err != nil {
		writeError(c, err)
		return
	}
	response.OK(c, item)
}

func (h *Handler) MyRedemptions(c *gin.Context) {
	userID, ok := currentUserID(c)
	if !ok {
		response.Unauthorized(c, "缺少用户上下文")
		return
	}
	items, err := h.service.ListRedemptions(c.Request.Context(), userID, false)
	if err != nil {
		writeError(c, err)
		return
	}
	response.OK(c, items)
}

func (h *Handler) AdminRedemptions(c *gin.Context) {
	items, err := h.service.ListRedemptions(c.Request.Context(), 0, true)
	if err != nil {
		writeError(c, err)
		return
	}
	response.OK(c, items)
}

func (h *Handler) CompleteRedemption(c *gin.Context) {
	adminID, ok := currentAdminID(c)
	if !ok {
		response.Unauthorized(c, "缺少管理员上下文")
		return
	}
	id, _ := strconv.ParseUint(c.Param("id"), 10, 64)
	var req CompleteRedemptionRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		response.BadRequest(c, "处理备注不正确")
		return
	}
	item, err := h.service.CompleteRedemption(c.Request.Context(), adminID, id, req.Remark)
	if err != nil {
		writeError(c, err)
		return
	}
	response.OK(c, item)
}

func currentUserID(c *gin.Context) (uint64, bool) {
	value, ok := c.Get(middleware.ContextUserID)
	if !ok {
		return 0, false
	}
	id, ok := value.(uint64)
	return id, ok
}

func currentAdminID(c *gin.Context) (uint64, bool) {
	value, ok := c.Get(middleware.ContextAdminID)
	if !ok {
		return 0, false
	}
	id, ok := value.(uint64)
	return id, ok
}

func parseLimit(value string) int {
	limit, err := strconv.Atoi(value)
	if err != nil {
		return 100
	}
	return limit
}

func writeError(c *gin.Context, err error) {
	response.RecordError(c, err)
	switch {
	case errors.Is(err, ErrInvalidInput):
		response.BadRequest(c, "积分商城参数不正确")
	case errors.Is(err, ErrProductUnavailable):
		response.Error(c, http.StatusConflict, "points_product_unavailable", "商品已下架或库存不足")
	case errors.Is(err, ErrInsufficientPoints):
		response.Error(c, http.StatusConflict, "insufficient_points", "可用积分不足")
	case errors.Is(err, ErrRedeemLimitExceeded):
		response.Error(c, http.StatusConflict, "points_redeem_limit", "已超过该商品限兑数量")
	case errors.Is(err, ErrRedemptionNotPending):
		response.Error(c, http.StatusConflict, "points_redemption_processed", "该兑换记录已处理")
	case IsNotFound(err):
		response.Error(c, http.StatusNotFound, "not_found", "积分商城数据不存在")
	default:
		response.Error(c, http.StatusInternalServerError, "internal_error", "积分商城服务暂时不可用")
	}
}