package dispute

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) Create(c *gin.Context) {
	userID, ok := currentUserID(c)
	if !ok {
		response.Unauthorized(c, "缺少用户上下文")
		return
	}
	orderID, ok := parseID(c)
	if !ok {
		return
	}
	var req CreateRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		response.BadRequest(c, "申诉信息不完整")
		return
	}
	item, err := h.service.Create(userID, orderID, req)
	if err != nil {
		writeDisputeError(c, err)
		return
	}
	response.Created(c, item)
}

func (h *Handler) List(c *gin.Context) {
	userID, ok := currentUserID(c)
	if !ok {
		response.Unauthorized(c, "缺少用户上下文")
		return
	}
	page, pageSize := parsePagination(c)
	result, err := h.service.ListForUser(userID, page, pageSize)
	if err != nil {
		writeDisputeError(c, err)
		return
	}
	response.OK(c, result)
}

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

func (h *Handler) AdminList(c *gin.Context) {
	page, pageSize := parsePagination(c)
	result, err := h.service.ListAdmin(page, pageSize)
	if err != nil {
		writeDisputeError(c, err)
		return
	}
	response.OK(c, result)
}

func (h *Handler) AdminArbitrate(c *gin.Context) {
	adminID, ok := currentAdminID(c)
	if !ok {
		response.Unauthorized(c, "缺少管理员上下文")
		return
	}
	id, ok := parseID(c)
	if !ok {
		return
	}
	var req ArbitrateRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		response.BadRequest(c, "仲裁结果和备注不能为空")
		return
	}
	item, err := h.service.Arbitrate(adminID, id, req, auditMeta(c))
	if err != nil {
		writeDisputeError(c, err)
		return
	}
	response.OK(c, item)
}

func auditMeta(c *gin.Context) AuditMeta {
	return AuditMeta{
		IP:        c.ClientIP(),
		UserAgent: c.GetHeader("User-Agent"),
		RequestID: middleware.GetRequestID(c),
	}
}

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

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

func parseID(c *gin.Context) (uint64, bool) {
	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
	if err != nil || id == 0 {
		response.BadRequest(c, "ID 不正确")
		return 0, false
	}
	return id, true
}

func parsePagination(c *gin.Context) (int, int) {
	page, _ := strconv.Atoi(c.DefaultQuery("page", "1"))
	pageSize, _ := strconv.Atoi(c.DefaultQuery("page_size", "20"))
	if page < 1 {
		page = 1
	}
	if pageSize < 1 {
		pageSize = 20
	}
	if pageSize > 100 {
		pageSize = 100
	}
	return page, pageSize
}

func writeDisputeError(c *gin.Context, err error) {
	switch {
	case errors.Is(err, ErrDependencyUnavailable):
		response.ServiceUnavailable(c, "数据库未连接")
	case errors.Is(err, ErrInvalidDispute):
		response.BadRequest(c, "申诉信息不符合规则")
	case errors.Is(err, ErrDisputeExists):
		response.Error(c, http.StatusConflict, "dispute_exists", "该订单已有处理中申诉")
	case errors.Is(err, ErrDisputeCannotHandle):
		response.Error(c, http.StatusConflict, "dispute_cannot_handle", "当前申诉不能仲裁")
	case errors.Is(err, ErrPermissionDenied):
		response.Error(c, http.StatusForbidden, "permission_denied", "无权操作该申诉")
	case IsNotFound(err):
		response.Error(c, http.StatusNotFound, "not_found", "申诉不存在")
	default:
		response.Error(c, http.StatusInternalServerError, "internal_error", "申诉服务暂时不可用")
	}
}
