feat: 账号管理新增使用统计功能

- 新增账号统计弹窗，展示30天使用数据
- 显示总费用、请求数、日均费用、日均请求等汇总指标
- 显示今日概览、最高费用日、最高请求日
- 包含费用与请求趋势图（双Y轴）
- 复用模型分布图组件展示模型使用分布
- 显示实际扣费和标准计费（标准计费以较淡颜色显示）

backend/cmd/server/wire_gen.go

@@ -83,7 +83,7 @@ func initializeApplication(buildInfo handler.BuildInfo) (*Application, error) {
 	accountUsageService := service.NewAccountUsageService(accountRepository, usageLogRepository, claudeUsageFetcher)
 	httpUpstream := repository.NewHTTPUpstream(configConfig)
 	accountTestService := service.NewAccountTestService(accountRepository, oAuthService, openAIOAuthService, httpUpstream)
-	accountHandler := admin.NewAccountHandler(adminService, oAuthService, openAIOAuthService, rateLimitService, accountUsageService, accountTestService)
+	accountHandler := admin.NewAccountHandler(adminService, oAuthService, openAIOAuthService, rateLimitService, accountUsageService, accountTestService, usageLogRepository)
 	oAuthHandler := admin.NewOAuthHandler(oAuthService)
 	openAIOAuthHandler := admin.NewOpenAIOAuthHandler(openAIOAuthService, adminService)
 	proxyHandler := admin.NewProxyHandler(adminService)

backend/internal/handler/admin/account_handler.go

@@ -6,6 +6,8 @@ import (
 	"sub2api/internal/pkg/claude"
 	"sub2api/internal/pkg/openai"
 	"sub2api/internal/pkg/response"
+	"sub2api/internal/pkg/timezone"
+	"sub2api/internal/repository"
 	"sub2api/internal/service"
 
 	"github.com/gin-gonic/gin"
@@ -31,10 +33,11 @@ type AccountHandler struct {
 	rateLimitService    *service.RateLimitService
 	accountUsageService *service.AccountUsageService
 	accountTestService  *service.AccountTestService
+	usageLogRepo        *repository.UsageLogRepository
 }
 
 // NewAccountHandler creates a new admin account handler
-func NewAccountHandler(adminService service.AdminService, oauthService *service.OAuthService, openaiOAuthService *service.OpenAIOAuthService, rateLimitService *service.RateLimitService, accountUsageService *service.AccountUsageService, accountTestService *service.AccountTestService) *AccountHandler {
+func NewAccountHandler(adminService service.AdminService, oauthService *service.OAuthService, openaiOAuthService *service.OpenAIOAuthService, rateLimitService *service.RateLimitService, accountUsageService *service.AccountUsageService, accountTestService *service.AccountTestService, usageLogRepo *repository.UsageLogRepository) *AccountHandler {
 	return &AccountHandler{
 		adminService:        adminService,
 		oauthService:        oauthService,
@@ -42,6 +45,7 @@ func NewAccountHandler(adminService service.AdminService, oauthService *service.
 		rateLimitService:    rateLimitService,
 		accountUsageService: accountUsageService,
 		accountTestService:  accountTestService,
+		usageLogRepo:        usageLogRepo,
 	}
 }
 
@@ -297,15 +301,26 @@ func (h *AccountHandler) GetStats(c *gin.Context) {
 		return
 	}
 
-	// Return mock data for now
-	_ = accountID
-	response.Success(c, gin.H{
-		"total_requests":        0,
-		"successful_requests":   0,
-		"failed_requests":       0,
-		"total_tokens":          0,
-		"average_response_time": 0,
-	})
+	// Parse days parameter (default 30)
+	days := 30
+	if daysStr := c.Query("days"); daysStr != "" {
+		if d, err := strconv.Atoi(daysStr); err == nil && d > 0 && d <= 90 {
+			days = d
+		}
+	}
+
+	// Calculate time range
+	now := timezone.Now()
+	endTime := timezone.StartOfDay(now.AddDate(0, 0, 1))
+	startTime := timezone.StartOfDay(now.AddDate(0, 0, -days+1))
+
+	stats, err := h.usageLogRepo.GetAccountUsageStats(c.Request.Context(), accountID, startTime, endTime)
+	if err != nil {
+		response.InternalError(c, "Failed to get account stats: "+err.Error())
+		return
+	}
+
+	response.Success(c, stats)
 }
 
 // ClearError handles clearing account error

backend/internal/handler/admin/dashboard_handler.go

@@ -175,7 +175,7 @@ func (h *DashboardHandler) GetModelStats(c *gin.Context) {
 		}
 	}
 
-	stats, err := h.usageRepo.GetModelStatsWithFilters(c.Request.Context(), startTime, endTime, userID, apiKeyID)
+	stats, err := h.usageRepo.GetModelStatsWithFilters(c.Request.Context(), startTime, endTime, userID, apiKeyID, 0)
 	if err != nil {
 		response.Error(c, 500, "Failed to get model statistics")
 		return

backend/internal/repository/usage_log_repo.go

@@ -937,7 +937,7 @@ func (r *UsageLogRepository) GetUsageTrendWithFilters(ctx context.Context, start
 }
 
 // GetModelStatsWithFilters returns model statistics with optional user/api_key filters
-func (r *UsageLogRepository) GetModelStatsWithFilters(ctx context.Context, startTime, endTime time.Time, userID, apiKeyID int64) ([]ModelStat, error) {
+func (r *UsageLogRepository) GetModelStatsWithFilters(ctx context.Context, startTime, endTime time.Time, userID, apiKeyID, accountID int64) ([]ModelStat, error) {
 	var results []ModelStat
 
 	db := r.db.WithContext(ctx).Model(&model.UsageLog{}).
@@ -958,6 +958,9 @@ func (r *UsageLogRepository) GetModelStatsWithFilters(ctx context.Context, start
 	if apiKeyID > 0 {
 		db = db.Where("api_key_id = ?", apiKeyID)
 	}
+	if accountID > 0 {
+		db = db.Where("account_id = ?", accountID)
+	}
 
 	err := db.Group("model").Order("total_tokens DESC").Scan(&results).Error
 	if err != nil {
@@ -1007,3 +1010,209 @@ func (r *UsageLogRepository) GetGlobalStats(ctx context.Context, startTime, endT
 		AverageDurationMs: stats.AverageDurationMs,
 	}, nil
 }
+
+// AccountUsageHistory represents daily usage history for an account
+type AccountUsageHistory struct {
+	Date       string  `json:"date"`
+	Label      string  `json:"label"`
+	Requests   int64   `json:"requests"`
+	Tokens     int64   `json:"tokens"`
+	Cost       float64 `json:"cost"`
+	ActualCost float64 `json:"actual_cost"`
+}
+
+// AccountUsageSummary represents summary statistics for an account
+type AccountUsageSummary struct {
+	Days              int     `json:"days"`
+	ActualDaysUsed    int     `json:"actual_days_used"`
+	TotalCost         float64 `json:"total_cost"`
+	TotalStandardCost float64 `json:"total_standard_cost"`
+	TotalRequests     int64   `json:"total_requests"`
+	TotalTokens       int64   `json:"total_tokens"`
+	AvgDailyCost      float64 `json:"avg_daily_cost"`
+	AvgDailyRequests  float64 `json:"avg_daily_requests"`
+	AvgDailyTokens    float64 `json:"avg_daily_tokens"`
+	AvgDurationMs     float64 `json:"avg_duration_ms"`
+	Today             *struct {
+		Date     string  `json:"date"`
+		Cost     float64 `json:"cost"`
+		Requests int64   `json:"requests"`
+		Tokens   int64   `json:"tokens"`
+	} `json:"today"`
+	HighestCostDay *struct {
+		Date     string  `json:"date"`
+		Label    string  `json:"label"`
+		Cost     float64 `json:"cost"`
+		Requests int64   `json:"requests"`
+	} `json:"highest_cost_day"`
+	HighestRequestDay *struct {
+		Date     string  `json:"date"`
+		Label    string  `json:"label"`
+		Requests int64   `json:"requests"`
+		Cost     float64 `json:"cost"`
+	} `json:"highest_request_day"`
+}
+
+// AccountUsageStatsResponse represents the full usage statistics response for an account
+type AccountUsageStatsResponse struct {
+	History []AccountUsageHistory `json:"history"`
+	Summary AccountUsageSummary   `json:"summary"`
+	Models  []ModelStat           `json:"models"`
+}
+
+// GetAccountUsageStats returns comprehensive usage statistics for an account over a time range
+func (r *UsageLogRepository) GetAccountUsageStats(ctx context.Context, accountID int64, startTime, endTime time.Time) (*AccountUsageStatsResponse, error) {
+	daysCount := int(endTime.Sub(startTime).Hours()/24) + 1
+	if daysCount <= 0 {
+		daysCount = 30
+	}
+
+	// Get daily history
+	var historyResults []struct {
+		Date       string  `gorm:"column:date"`
+		Requests   int64   `gorm:"column:requests"`
+		Tokens     int64   `gorm:"column:tokens"`
+		Cost       float64 `gorm:"column:cost"`
+		ActualCost float64 `gorm:"column:actual_cost"`
+	}
+
+	err := r.db.WithContext(ctx).Model(&model.UsageLog{}).
+		Select(`
+			TO_CHAR(created_at, 'YYYY-MM-DD') as date,
+			COUNT(*) as requests,
+			COALESCE(SUM(input_tokens + output_tokens + cache_creation_tokens + cache_read_tokens), 0) as tokens,
+			COALESCE(SUM(total_cost), 0) as cost,
+			COALESCE(SUM(actual_cost), 0) as actual_cost
+		`).
+		Where("account_id = ? AND created_at >= ? AND created_at < ?", accountID, startTime, endTime).
+		Group("date").
+		Order("date ASC").
+		Scan(&historyResults).Error
+	if err != nil {
+		return nil, err
+	}
+
+	// Build history with labels
+	history := make([]AccountUsageHistory, 0, len(historyResults))
+	for _, h := range historyResults {
+		// Parse date to get label (MM/DD)
+		t, _ := time.Parse("2006-01-02", h.Date)
+		label := t.Format("01/02")
+		history = append(history, AccountUsageHistory{
+			Date:       h.Date,
+			Label:      label,
+			Requests:   h.Requests,
+			Tokens:     h.Tokens,
+			Cost:       h.Cost,
+			ActualCost: h.ActualCost,
+		})
+	}
+
+	// Calculate summary
+	var totalActualCost, totalStandardCost float64
+	var totalRequests, totalTokens int64
+	var highestCostDay, highestRequestDay *AccountUsageHistory
+
+	for i := range history {
+		h := &history[i]
+		totalActualCost += h.ActualCost
+		totalStandardCost += h.Cost
+		totalRequests += h.Requests
+		totalTokens += h.Tokens
+
+		if highestCostDay == nil || h.ActualCost > highestCostDay.ActualCost {
+			highestCostDay = h
+		}
+		if highestRequestDay == nil || h.Requests > highestRequestDay.Requests {
+			highestRequestDay = h
+		}
+	}
+
+	actualDaysUsed := len(history)
+	if actualDaysUsed == 0 {
+		actualDaysUsed = 1
+	}
+
+	// Get average duration
+	var avgDuration struct {
+		AvgDurationMs float64 `gorm:"column:avg_duration_ms"`
+	}
+	r.db.WithContext(ctx).Model(&model.UsageLog{}).
+		Select("COALESCE(AVG(duration_ms), 0) as avg_duration_ms").
+		Where("account_id = ? AND created_at >= ? AND created_at < ?", accountID, startTime, endTime).
+		Scan(&avgDuration)
+
+	summary := AccountUsageSummary{
+		Days:              daysCount,
+		ActualDaysUsed:    actualDaysUsed,
+		TotalCost:         totalActualCost,
+		TotalStandardCost: totalStandardCost,
+		TotalRequests:     totalRequests,
+		TotalTokens:       totalTokens,
+		AvgDailyCost:      totalActualCost / float64(actualDaysUsed),
+		AvgDailyRequests:  float64(totalRequests) / float64(actualDaysUsed),
+		AvgDailyTokens:    float64(totalTokens) / float64(actualDaysUsed),
+		AvgDurationMs:     avgDuration.AvgDurationMs,
+	}
+
+	// Set today's stats
+	todayStr := timezone.Now().Format("2006-01-02")
+	for i := range history {
+		if history[i].Date == todayStr {
+			summary.Today = &struct {
+				Date     string  `json:"date"`
+				Cost     float64 `json:"cost"`
+				Requests int64   `json:"requests"`
+				Tokens   int64   `json:"tokens"`
+			}{
+				Date:     history[i].Date,
+				Cost:     history[i].ActualCost,
+				Requests: history[i].Requests,
+				Tokens:   history[i].Tokens,
+			}
+			break
+		}
+	}
+
+	// Set highest cost day
+	if highestCostDay != nil {
+		summary.HighestCostDay = &struct {
+			Date     string  `json:"date"`
+			Label    string  `json:"label"`
+			Cost     float64 `json:"cost"`
+			Requests int64   `json:"requests"`
+		}{
+			Date:     highestCostDay.Date,
+			Label:    highestCostDay.Label,
+			Cost:     highestCostDay.ActualCost,
+			Requests: highestCostDay.Requests,
+		}
+	}
+
+	// Set highest request day
+	if highestRequestDay != nil {
+		summary.HighestRequestDay = &struct {
+			Date     string  `json:"date"`
+			Label    string  `json:"label"`
+			Requests int64   `json:"requests"`
+			Cost     float64 `json:"cost"`
+		}{
+			Date:     highestRequestDay.Date,
+			Label:    highestRequestDay.Label,
+			Requests: highestRequestDay.Requests,
+			Cost:     highestRequestDay.ActualCost,
+		}
+	}
+
+	// Get model statistics using the unified method
+	models, err := r.GetModelStatsWithFilters(ctx, startTime, endTime, 0, 0, accountID)
+	if err != nil {
+		models = []ModelStat{}
+	}
+
+	return &AccountUsageStatsResponse{
+		History: history,
+		Summary: summary,
+		Models:  models,
+	}, nil
+}