package handler

import (
	"net/http"
	"time"

	"github.com/gin-gonic/gin"

	"nex/backend/internal/config"
)

// StatsHandler 统计处理器
type StatsHandler struct{}

// NewStatsHandler 创建统计处理器
func NewStatsHandler() *StatsHandler {
	return &StatsHandler{}
}

// GetStats 查询统计
func (h *StatsHandler) GetStats(c *gin.Context) {
	// 解析查询参数
	providerID := c.Query("provider_id")
	modelName := c.Query("model_name")
	startDateStr := c.Query("start_date")
	endDateStr := c.Query("end_date")

	var startDate, endDate *time.Time

	// 解析日期
	if startDateStr != "" {
		t, err := time.Parse("2006-01-02", startDateStr)
		if err != nil {
			c.JSON(http.StatusBadRequest, gin.H{
				"error": "无效的 start_date 格式，应为 YYYY-MM-DD",
			})
			return
		}
		startDate = &t
	}

	if endDateStr != "" {
		t, err := time.Parse("2006-01-02", endDateStr)
		if err != nil {
			c.JSON(http.StatusBadRequest, gin.H{
				"error": "无效的 end_date 格式，应为 YYYY-MM-DD",
			})
			return
		}
		endDate = &t
	}

	// 查询统计
	stats, err := config.GetStats(providerID, modelName, startDate, endDate)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{
			"error": "查询统计失败: " + err.Error(),
		})
		return
	}

	c.JSON(http.StatusOK, stats)
}

// AggregateStats 聚合统计
func (h *StatsHandler) AggregateStats(c *gin.Context) {
	// 解析查询参数
	providerID := c.Query("provider_id")
	modelName := c.Query("model_name")
	startDateStr := c.Query("start_date")
	endDateStr := c.Query("end_date")
	groupBy := c.Query("group_by") // "provider", "model", "date"

	var startDate, endDate *time.Time

	// 解析日期
	if startDateStr != "" {
		t, err := time.Parse("2006-01-02", startDateStr)
		if err != nil {
			c.JSON(http.StatusBadRequest, gin.H{
				"error": "无效的 start_date 格式，应为 YYYY-MM-DD",
			})
			return
		}
		startDate = &t
	}

	if endDateStr != "" {
		t, err := time.Parse("2006-01-02", endDateStr)
		if err != nil {
			c.JSON(http.StatusBadRequest, gin.H{
				"error": "无效的 end_date 格式，应为 YYYY-MM-DD",
			})
			return
		}
		endDate = &t
	}

	// 查询统计
	stats, err := config.GetStats(providerID, modelName, startDate, endDate)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{
			"error": "查询统计失败: " + err.Error(),
		})
		return
	}

	// 聚合
	result := h.aggregate(stats, groupBy)

	c.JSON(http.StatusOK, result)
}

// aggregate 执行聚合
func (h *StatsHandler) aggregate(stats []config.UsageStats, groupBy string) []map[string]interface{} {
	switch groupBy {
	case "provider":
		return h.aggregateByProvider(stats)
	case "model":
		return h.aggregateByModel(stats)
	case "date":
		return h.aggregateByDate(stats)
	default:
		// 默认按供应商聚合
		return h.aggregateByProvider(stats)
	}
}

// aggregateByProvider 按供应商聚合
func (h *StatsHandler) aggregateByProvider(stats []config.UsageStats) []map[string]interface{} {
	aggregated := make(map[string]int)
	for _, stat := range stats {
		aggregated[stat.ProviderID] += stat.RequestCount
	}

	result := make([]map[string]interface{}, 0, len(aggregated))
	for providerID, count := range aggregated {
		result = append(result, map[string]interface{}{
			"provider_id":   providerID,
			"request_count": count,
		})
	}

	return result
}

// aggregateByModel 按模型聚合
func (h *StatsHandler) aggregateByModel(stats []config.UsageStats) []map[string]interface{} {
	aggregated := make(map[string]int)
	for _, stat := range stats {
		key := stat.ProviderID + "/" + stat.ModelName
		aggregated[key] += stat.RequestCount
	}

	result := make([]map[string]interface{}, 0, len(aggregated))
	for key, count := range aggregated {
		result = append(result, map[string]interface{}{
			"provider_id":   key[:len(key)/2],
			"model_name":    key[len(key)/2+1:],
			"request_count": count,
		})
	}

	return result
}

// aggregateByDate 按日期聚合
func (h *StatsHandler) aggregateByDate(stats []config.UsageStats) []map[string]interface{} {
	aggregated := make(map[string]int)
	for _, stat := range stats {
		key := stat.Date.Format("2006-01-02")
		aggregated[key] += stat.RequestCount
	}

	result := make([]map[string]interface{}, 0, len(aggregated))
	for date, count := range aggregated {
		result = append(result, map[string]interface{}{
			"date":          date,
			"request_count": count,
		})
	}

	return result
}