// Copyright 2026 Arctel.net
// SPDX-License-Identifier: Apache-2.0

package handler

import (
	"net/http"
	"time"

	"github.com/Rain-kl/Wavelet/internal/apps/upload/shared"
	"github.com/Rain-kl/Wavelet/internal/common/response"
	"github.com/Rain-kl/Wavelet/internal/model"
	"github.com/gin-gonic/gin"
)

type trendItem struct {
	Date  string `json:"date"`
	Count int64  `json:"count"`
	Size  int64  `json:"size"`
}

type distributionItem struct {
	Name  string `json:"name"`
	Count int64  `json:"count"`
	Size  int64  `json:"size"`
}

type fileStatsResponse struct {
	TotalCount int64              `json:"total_count"`
	TotalSize  int64              `json:"total_size"`
	Trend      []trendItem        `json:"trend"`
	Categories []distributionItem `json:"categories"`
	Types      []distributionItem `json:"types"`
}

// GetFileStats 获取系统上传的文件统计数据
// @Summary 获取文件统计数据
// @Description 返回系统级的总文件数、占用大小、最近 7 天新增趋势、文件类型/格式分布等数据
// @Tags admin
// @Produce json
// @Security SessionCookie
// @Success 200 {object} response.Any{data=fileStatsResponse} "获取成功"
// @Failure 401 {object} response.Any "未登录"
// @Failure 403 {object} response.Any "无管理员权限"
// @Failure 500 {object} response.Any "内部错误"
// @Router /api/v1/admin/uploads/stats [get]
func GetFileStats(c *gin.Context) {
	ctx := c.Request.Context()

	stats, err := loadUploadStats(ctx)
	if err != nil {
		response.AbortBadRequest(c, err.Error())
		return
	}

	now := time.Now()
	trendDates := make([]string, 0, shared.FileStatsTrendDays)
	trendCountMap := make(map[string]int64, shared.FileStatsTrendDays)
	trendSizeMap := make(map[string]int64, shared.FileStatsTrendDays)
	for i := shared.FileStatsTrendDays - 1; i >= 0; i-- {
		date := now.AddDate(0, 0, -i).Format("2006-01-02")
		trendDates = append(trendDates, date)
		trendCountMap[date] = 0
		trendSizeMap[date] = 0
	}

	var (
		totalCount int64
		totalSize  int64
		types      []distributionItem
		categories []distributionItem
	)

	categoriesList := []string{"图片", "视频", "音频", "文档", "压缩包", "其他"}
	categoryMap := make(map[string]distributionItem, len(categoriesList))
	for _, cat := range categoriesList {
		categoryMap[cat] = distributionItem{Name: cat}
	}

	for _, stat := range stats {
		switch stat.Dimension {
		case model.UploadStatDimensionTotal:
			totalCount = stat.FileCount
			totalSize = stat.FileSize
		case model.UploadStatDimensionType:
			types = append(types, distributionItem{
				Name:  stat.StatKey,
				Count: stat.FileCount,
				Size:  stat.FileSize,
			})
		case model.UploadStatDimensionCategory:
			if item, ok := categoryMap[stat.StatKey]; ok {
				item.Count = stat.FileCount
				item.Size = stat.FileSize
				categoryMap[stat.StatKey] = item
			}
		case model.UploadStatDimensionTrend:
			if _, ok := trendCountMap[stat.StatKey]; ok {
				trendCountMap[stat.StatKey] = stat.FileCount
				trendSizeMap[stat.StatKey] = stat.FileSize
			}
		}
	}

	categories = make([]distributionItem, 0, len(categoriesList))
	for _, cat := range categoriesList {
		categories = append(categories, categoryMap[cat])
	}

	trend := make([]trendItem, 0, len(trendDates))
	for _, date := range trendDates {
		trend = append(trend, trendItem{
			Date:  date,
			Count: trendCountMap[date],
			Size:  trendSizeMap[date],
		})
	}

	c.JSON(http.StatusOK, response.OK(fileStatsResponse{
		TotalCount: totalCount,
		TotalSize:  totalSize,
		Trend:      trend,
		Categories: categories,
		Types:      types,
	}))
}