package handler

import (
	"errors"
	"net/http"
	"strings"
	"time"

	"github.com/gin-gonic/gin"

	"wx_service/internal/middleware"
	"wx_service/internal/model"
	smokeservice "wx_service/internal/smoke/service"
)

func (h *SmokeHandler) Stats(c *gin.Context) {
	user := middleware.MustCurrentUser(c)

	rangeType := strings.ToLower(strings.TrimSpace(c.DefaultQuery("range", "week")))
	asOf := time.Now().In(time.Local)
	if v := strings.TrimSpace(c.Query("date")); v != "" {
		parsed, err := time.ParseInLocation(dateLayout, v, time.Local)
		if err != nil {
			c.JSON(http.StatusBadRequest, model.Error(http.StatusBadRequest, "date 格式错误，应为 YYYY-MM-DD"))
			return
		}
		asOf = time.Date(parsed.Year(), parsed.Month(), parsed.Day(), 23, 59, 59, 0, time.Local)
	}

	req, err := buildStatsRequest(rangeType, asOf)
	if err != nil {
		c.JSON(http.StatusBadRequest, model.Error(http.StatusBadRequest, err.Error()))
		return
	}

	profile, err := h.smokeProfileService.Get(c.Request.Context(), int(user.ID))
	if err != nil {
		c.JSON(http.StatusInternalServerError, model.Error(http.StatusInternalServerError, "获取基础信息失败，请稍后重试"))
		return
	}

	result, err := h.smokeLogService.Stats(c.Request.Context(), int(user.ID), req, profile)
	if err != nil {
		c.JSON(http.StatusInternalServerError, model.Error(http.StatusInternalServerError, "获取统计数据失败，请稍后重试"))
		return
	}

	c.JSON(http.StatusOK, model.Success(result))
}

func buildStatsRequest(rangeType string, anchor time.Time) (smokeservice.SmokeStatsRequest, error) {
	local := anchor.In(time.Local)
	switch rangeType {
	case "week":
		start, end := weekRange(local)
		return smokeservice.SmokeStatsRequest{
			Range:     "week",
			Start:     start,
			End:       end,
			PrevStart: start.AddDate(0, 0, -7),
			PrevEnd:   end.AddDate(0, 0, -7),
			TrendUnit: "day",
			AsOf:      local,
		}, nil
	case "month":
		start := time.Date(local.Year(), local.Month(), 1, 0, 0, 0, 0, time.Local)
		end := start.AddDate(0, 1, 0).AddDate(0, 0, -1)
		prevEnd := start.AddDate(0, 0, -1)
		prevStart := time.Date(prevEnd.Year(), prevEnd.Month(), 1, 0, 0, 0, 0, time.Local)
		return smokeservice.SmokeStatsRequest{
			Range:     "month",
			Start:     start,
			End:       end,
			PrevStart: prevStart,
			PrevEnd:   prevEnd,
			TrendUnit: "day",
			AsOf:      local,
		}, nil
	case "year":
		start := time.Date(local.Year(), time.January, 1, 0, 0, 0, 0, time.Local)
		end := time.Date(local.Year(), time.December, 31, 0, 0, 0, 0, time.Local)
		prevStart := time.Date(local.Year()-1, time.January, 1, 0, 0, 0, 0, time.Local)
		prevEnd := time.Date(local.Year()-1, time.December, 31, 0, 0, 0, 0, time.Local)
		return smokeservice.SmokeStatsRequest{
			Range:     "year",
			Start:     start,
			End:       end,
			PrevStart: prevStart,
			PrevEnd:   prevEnd,
			TrendUnit: "month",
			AsOf:      local,
		}, nil
	default:
		return smokeservice.SmokeStatsRequest{}, errors.New("range 应为 week|month|year")
	}
}

func weekRange(anchor time.Time) (time.Time, time.Time) {
	local := anchor.In(time.Local)
	weekday := local.Weekday()
	daysSinceMonday := int(weekday) - int(time.Monday)
	if daysSinceMonday < 0 {
		daysSinceMonday += 7
	}
	start := time.Date(local.Year(), local.Month(), local.Day(), 0, 0, 0, 0, time.Local).
		AddDate(0, 0, -daysSinceMonday)
	end := start.AddDate(0, 0, 6)
	return start, end
}