package admin

import (
	"net/http"
	"strconv"

	"bindbox-game/internal/code"
	"bindbox-game/internal/pkg/core"
	"bindbox-game/internal/pkg/validation"
)

type activityRankingsRequest struct {
	SortBy   string `form:"sort_by"`
	Page     int    `form:"page"`
	PageSize int    `form:"page_size"`
}

type activityRankingItem struct {
	Rank        int64  `json:"rank"`
	UserID      int64  `json:"user_id"`
	Nickname    string `json:"nickname"`
	Avatar      string `json:"avatar"`
	TotalAmount int64  `json:"total_amount"`
	OrderCount  int64  `json:"order_count"`
}

type activityRankingsResponse struct {
	Page     int                   `json:"page"`
	PageSize int                   `json:"page_size"`
	Total    int64                 `json:"total"`
	List     []activityRankingItem `json:"list"`
}

// GetActivityRankings 获取活动内用户消费/订单排行榜
// @Summary 活动排行榜
// @Description 按活动维度统计用户消费总额与订单数排行榜
// @Tags 管理端.活动
// @Accept json
// @Produce json
// @Param activity_id path int true "活动ID"
// @Param sort_by query string false "排序字段: amount|orders"
// @Param page query int false "页码" default(1)
// @Param page_size query int false "每页条数(最大100)" default(20)
// @Success 200 {object} activityRankingsResponse
// @Failure 400 {object} code.Failure
// @Router /api/admin/activities/{activity_id}/rankings [get]
// @Security LoginVerifyToken
func (h *handler) GetActivityRankings() core.HandlerFunc {
	return func(ctx core.Context) {
		activityID, err := strconv.ParseInt(ctx.Param("activity_id"), 10, 64)
		if err != nil || activityID <= 0 {
			ctx.AbortWithError(core.Error(http.StatusBadRequest, code.ParamBindError, "无效的活动ID"))
			return
		}

		req := new(activityRankingsRequest)
		if err := ctx.ShouldBindForm(req); err != nil {
			ctx.AbortWithError(core.Error(http.StatusBadRequest, code.ParamBindError, validation.Error(err)))
			return
		}

		if req.Page <= 0 {
			req.Page = 1
		}
		if req.PageSize <= 0 {
			req.PageSize = 20
		}
		if req.PageSize > 100 {
			req.PageSize = 100
		}
		if req.SortBy != "orders" {
			req.SortBy = "amount"
		}

		baseQuery := h.repo.GetDbR().WithContext(ctx.RequestContext()).
			Table("orders").
			Joins(`
				JOIN (
					SELECT DISTINCT activity_draw_logs.order_id, activity_issues.activity_id
					FROM activity_draw_logs
					JOIN activity_issues ON activity_issues.id = activity_draw_logs.issue_id
				) AS order_activities ON order_activities.order_id = orders.id
			`).
			Where("order_activities.activity_id = ?", activityID).
			Where("orders.status = ?", 2)

		userSubQuery := baseQuery.
			Select("orders.user_id").
			Group("orders.user_id")

		var total int64
		if err := h.repo.GetDbR().WithContext(ctx.RequestContext()).
			Table("(?) AS ranked_users", userSubQuery).
			Count(&total).Error; err != nil {
			ctx.AbortWithError(core.Error(http.StatusInternalServerError, code.ServerError, err.Error()))
			return
		}

		type rankingRow struct {
			UserID      int64
			Nickname    string
			Avatar      string
			TotalAmount int64
			OrderCount  int64
		}
		var rows []rankingRow

		listQuery := h.repo.GetDbR().WithContext(ctx.RequestContext()).
			Table("orders").
			Joins(`
				JOIN (
					SELECT DISTINCT activity_draw_logs.order_id, activity_issues.activity_id
					FROM activity_draw_logs
					JOIN activity_issues ON activity_issues.id = activity_draw_logs.issue_id
				) AS order_activities ON order_activities.order_id = orders.id
			`).
			Joins("LEFT JOIN users ON users.id = orders.user_id").
			Where("order_activities.activity_id = ?", activityID).
			Where("orders.status = ?", 2).
			Select(`
				orders.user_id,
				COALESCE(users.nickname, '') AS nickname,
				COALESCE(users.avatar, '') AS avatar,
				CAST(SUM(orders.actual_amount + orders.discount_amount) AS SIGNED) AS total_amount,
				COUNT(DISTINCT orders.id) AS order_count
			`).
			Group("orders.user_id, users.nickname, users.avatar")

		if req.SortBy == "orders" {
			listQuery = listQuery.Order("order_count DESC").Order("total_amount DESC").Order("orders.user_id ASC")
		} else {
			listQuery = listQuery.Order("total_amount DESC").Order("order_count DESC").Order("orders.user_id ASC")
		}

		offset := (req.Page - 1) * req.PageSize
		if err := listQuery.Offset(offset).Limit(req.PageSize).Scan(&rows).Error; err != nil {
			ctx.AbortWithError(core.Error(http.StatusInternalServerError, code.ServerError, err.Error()))
			return
		}

		res := activityRankingsResponse{
			Page:     req.Page,
			PageSize: req.PageSize,
			Total:    total,
			List:     make([]activityRankingItem, 0, len(rows)),
		}
		for i, row := range rows {
			res.List = append(res.List, activityRankingItem{
				Rank:        int64(offset + i + 1),
				UserID:      row.UserID,
				Nickname:    row.Nickname,
				Avatar:      row.Avatar,
				TotalAmount: row.TotalAmount,
				OrderCount:  row.OrderCount,
			})
		}

		ctx.Payload(res)
	}
}