SPMS.Application/DTOs/Stats/DashboardResponseDto.cs

@@ -46,6 +46,15 @@ public class DashboardKpiDto
     [JsonPropertyName("active_service_count")]
     public int ActiveServiceCount { get; set; }
 
+    [JsonPropertyName("success_rate_change")]
+    public double SuccessRateChange { get; set; }
+
+    [JsonPropertyName("device_count_change")]
+    public int DeviceCountChange { get; set; }
+
+    [JsonPropertyName("today_sent_change_rate")]
+    public double TodaySentChangeRate { get; set; }
+
     [JsonPropertyName("today")]
     public PeriodStatDto Today { get; set; } = new();
 

SPMS.Application/Services/StatsService.cs

@@ -433,6 +433,44 @@ public class StatsService : IStatsService
         var activeServiceCount = await _serviceRepository.CountAsync(s => s.Status == ServiceStatus.Active && !s.IsDeleted);
         var topMessages = await _messageRepository.GetTopBySendCountAsync(serviceId, 5);
 
+        // KPI 변화량 계산
+        var (startDate, endDate) = ParseDateRange(request.StartDate, request.EndDate);
+
+        // 1) success_rate_change: 직전 동일 기간 대비 성공률 변화 (pp)
+        var duration = endDate.DayNumber - startDate.DayNumber + 1;
+        var prevEnd = startDate.AddDays(-1);
+        var prevStart = prevEnd.AddDays(-(duration - 1));
+        var prevStats = await _dailyStatRepository.GetByDateRangeAsync(serviceId, prevStart, prevEnd);
+
+        var currentSend = daily.Summary.TotalSend;
+        var currentSuccess = daily.Summary.TotalSuccess;
+        var prevSend = prevStats.Sum(s => (long)s.SentCnt);
+        var prevSuccess = prevStats.Sum(s => (long)s.SuccessCnt);
+
+        var currentRate = currentSend > 0 ? (double)currentSuccess / currentSend * 100 : 0;
+        var prevRate = prevSend > 0 ? (double)prevSuccess / prevSend * 100 : 0;
+        var successRateChange = prevSend > 0 ? Math.Round(currentRate - prevRate, 1) : 0;
+
+        // 2) device_count_change: 오늘 신규 등록 디바이스 수
+        var todayDateTime = DateTime.UtcNow.Date;
+        var tomorrowDateTime = todayDateTime.AddDays(1);
+        var deviceCountChange = serviceId.HasValue
+            ? await _deviceRepository.CountAsync(d => d.ServiceId == serviceId.Value
+                && d.CreatedAt >= todayDateTime && d.CreatedAt < tomorrowDateTime)
+            : await _deviceRepository.CountAsync(d =>
+                d.CreatedAt >= todayDateTime && d.CreatedAt < tomorrowDateTime);
+
+        // 3) today_sent_change_rate: 오늘 vs 어제 발송 수 변화율 (%)
+        var today = DateOnly.FromDateTime(DateTime.UtcNow);
+        var yesterday = today.AddDays(-1);
+        var yesterdayStats = await _dailyStatRepository.GetByDateRangeAsync(serviceId, yesterday, yesterday);
+        var yesterdaySent = yesterdayStats.Sum(s => s.SentCnt);
+        var todaySent = summary.Today.SendCount;
+
+        var todaySentChangeRate = yesterdaySent > 0
+            ? Math.Round((double)(todaySent - yesterdaySent) / yesterdaySent * 100, 1)
+            : 0;
+
         return new DashboardResponseDto
         {
             Kpi = new DashboardKpiDto
@@ -445,6 +483,9 @@ public class StatsService : IStatsService
                 TotalOpen = summary.TotalOpen,
                 AvgCtr = summary.AvgCtr,
                 ActiveServiceCount = activeServiceCount,
+                SuccessRateChange = successRateChange,
+                DeviceCountChange = deviceCountChange,
+                TodaySentChangeRate = todaySentChangeRate,
                 Today = summary.Today,
                 ThisMonth = summary.ThisMonth
             },