package notification

import (
	"errors"
	"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 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 (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)
	siteCode := parseSiteCode(c)
	result, err := h.service.List(c.Request.Context(), userID, page, pageSize, siteCode)
	if err != nil {
		writeNotificationError(c, err)
		return
	}
	response.OK(c, result)
}

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

func (h *Handler) MarkAllRead(c *gin.Context) {
	userID, ok := currentUserID(c)
	if !ok {
		response.Unauthorized(c, "缺少用户上下文")
		return
	}
	siteCode := parseSiteCode(c)
	count, err := h.service.MarkAllRead(c.Request.Context(), userID, siteCode)
	if err != nil {
		writeNotificationError(c, err)
		return
	}
	response.OK(c, gin.H{"read_count": count})
}

func (h *Handler) MarkRead(c *gin.Context) {
	userID, ok := currentUserID(c)
	if !ok {
		response.Unauthorized(c, "缺少用户上下文")
		return
	}
	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
	if err != nil || id == 0 {
		response.BadRequest(c, "ID 不正确")
		return
	}
	siteCode := parseSiteCode(c)
	if err := h.service.MarkRead(c.Request.Context(), userID, id, siteCode); err != nil {
		writeNotificationError(c, err)
		return
	}
	response.OK(c, gin.H{"read": true})
}

func parseSiteCode(c *gin.Context) string {
	siteCode := c.Query("distribution_site_code")
	if siteCode == "" {
		siteCode = c.Query("site_code")
	}
	if siteCode == "" {
		siteCode = c.GetHeader("X-Distribution-Site-Code")
	}
	if siteCode == "" {
		siteCode = c.GetHeader("X-Site-Code")
	}
	return siteCode
}

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 writeNotificationError(c *gin.Context, err error) {
	response.RecordError(c, err)
	switch {
	case errors.Is(err, ErrDependencyUnavailable):
		response.ServiceUnavailable(c, "数据库未连接")
	case errors.Is(err, ErrNotificationNotFound):
		response.NotFound(c, "通知不存在")
	default:
		response.ServiceUnavailable(c, "通知服务暂时不可用")
	}
}