feat: 통계 리포트 다운로드 API 구현 (#138)

- POST /v1/in/stats/export (EXP-01)
- 일별/시간대별/플랫폼별 통계를 엑셀(.xlsx) 3시트로 생성
- ClosedXML 패키지 추가

Closes #138

SPMS.API/Controllers/StatsController.cs

@@ -63,6 +63,16 @@ public class StatsController : ControllerBase
         return Ok(ApiResponse<DeviceStatResponseDto>.Success(result, "조회 성공"));
     }
 
+    [HttpPost("export")]
+    [SwaggerOperation(Summary = "통계 리포트 다운로드", Description = "일별/시간대별/플랫폼별 통계를 엑셀(.xlsx) 파일로 다운로드합니다.")]
+    public async Task<IActionResult> ExportReportAsync([FromBody] StatsExportRequestDto request)
+    {
+        var serviceId = GetServiceId();
+        var fileBytes = await _statsService.ExportReportAsync(serviceId, request);
+        var fileName = $"stats_report_{request.StartDate}_{request.EndDate}.xlsx";
+        return File(fileBytes, "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet", fileName);
+    }
+
     [HttpPost("send-log")]
     [SwaggerOperation(Summary = "발송 상세 로그 조회", Description = "특정 메시지의 개별 디바이스별 발송 상세 로그를 조회합니다.")]
     public async Task<IActionResult> GetSendLogDetailAsync([FromBody] SendLogDetailRequestDto request)

SPMS.Application/DTOs/Stats/StatsExportRequestDto.cs

@@ -0,0 +1,15 @@
+using System.ComponentModel.DataAnnotations;
+using System.Text.Json.Serialization;
+
+namespace SPMS.Application.DTOs.Stats;
+
+public class StatsExportRequestDto
+{
+    [Required(ErrorMessage = "start_date는 필수입니다.")]
+    [JsonPropertyName("start_date")]
+    public string StartDate { get; set; } = string.Empty;
+
+    [Required(ErrorMessage = "end_date는 필수입니다.")]
+    [JsonPropertyName("end_date")]
+    public string EndDate { get; set; } = string.Empty;
+}

SPMS.Application/Interfaces/IStatsService.cs

@@ -10,4 +10,5 @@ public interface IStatsService
     Task<HourlyStatResponseDto> GetHourlyAsync(long serviceId, HourlyStatRequestDto request);
     Task<DeviceStatResponseDto> GetDeviceStatAsync(long serviceId);
     Task<SendLogDetailResponseDto> GetSendLogDetailAsync(long serviceId, SendLogDetailRequestDto request);
+    Task<byte[]> ExportReportAsync(long serviceId, StatsExportRequestDto request);
 }

SPMS.Application/SPMS.Application.csproj

@@ -13,6 +13,7 @@
 
     <ItemGroup>
       <PackageReference Include="BCrypt.Net-Next" Version="4.0.3" />
+      <PackageReference Include="ClosedXML" Version="0.105.0" />
       <PackageReference Include="Microsoft.Extensions.DependencyInjection.Abstractions" Version="10.0.2" />
       <PackageReference Include="Microsoft.Extensions.Options" Version="10.0.2" />
     </ItemGroup>

SPMS.Application/Services/StatsService.cs

@@ -1,4 +1,5 @@
 using System.Globalization;
+using ClosedXML.Excel;
 using SPMS.Application.DTOs.Stats;
 using SPMS.Application.Interfaces;
 using SPMS.Domain.Common;
@@ -290,6 +291,88 @@ public class StatsService : IStatsService
         };
     }
 
+    public async Task<byte[]> ExportReportAsync(long serviceId, StatsExportRequestDto request)
+    {
+        var (startDate, endDate) = ParseDateRange(request.StartDate, request.EndDate);
+
+        using var workbook = new XLWorkbook();
+
+        // Sheet 1: 일별 통계
+        var dailyStats = await _dailyStatRepository.GetByDateRangeAsync(serviceId, startDate, endDate);
+        var ws1 = workbook.Worksheets.Add("일별 통계");
+        ws1.Cell(1, 1).Value = "날짜";
+        ws1.Cell(1, 2).Value = "발송";
+        ws1.Cell(1, 3).Value = "성공";
+        ws1.Cell(1, 4).Value = "실패";
+        ws1.Cell(1, 5).Value = "열람";
+        ws1.Cell(1, 6).Value = "CTR(%)";
+        ws1.Row(1).Style.Font.Bold = true;
+
+        var row = 2;
+        foreach (var s in dailyStats.OrderBy(s => s.StatDate))
+        {
+            ws1.Cell(row, 1).Value = s.StatDate.ToString("yyyy-MM-dd");
+            ws1.Cell(row, 2).Value = s.SentCnt;
+            ws1.Cell(row, 3).Value = s.SuccessCnt;
+            ws1.Cell(row, 4).Value = s.FailCnt;
+            ws1.Cell(row, 5).Value = s.OpenCnt;
+            ws1.Cell(row, 6).Value = CalcCtr(s.OpenCnt, s.SuccessCnt);
+            row++;
+        }
+        ws1.Columns().AdjustToContents();
+
+        // Sheet 2: 시간대별 통계
+        var startDateTime = startDate.ToDateTime(TimeOnly.MinValue);
+        var endDateTime = endDate.ToDateTime(TimeOnly.MinValue).AddDays(1);
+        var hourlyStats = await _pushSendLogRepository.GetHourlyStatsAsync(serviceId, startDateTime, endDateTime);
+
+        var ws2 = workbook.Worksheets.Add("시간대별 통계");
+        ws2.Cell(1, 1).Value = "시간";
+        ws2.Cell(1, 2).Value = "발송";
+        ws2.Cell(1, 3).Value = "성공";
+        ws2.Cell(1, 4).Value = "실패";
+        ws2.Row(1).Style.Font.Bold = true;
+
+        for (var hour = 0; hour < 24; hour++)
+        {
+            var stat = hourlyStats.FirstOrDefault(h => h.Hour == hour);
+            ws2.Cell(hour + 2, 1).Value = $"{hour:D2}:00";
+            ws2.Cell(hour + 2, 2).Value = stat?.SendCount ?? 0;
+            ws2.Cell(hour + 2, 3).Value = stat?.SuccessCount ?? 0;
+            ws2.Cell(hour + 2, 4).Value = stat?.FailCount ?? 0;
+        }
+        ws2.Columns().AdjustToContents();
+
+        // Sheet 3: 플랫폼별 통계
+        var devices = await _deviceRepository.FindAsync(d => d.ServiceId == serviceId && d.IsActive);
+        var total = devices.Count;
+
+        var ws3 = workbook.Worksheets.Add("플랫폼별 통계");
+        ws3.Cell(1, 1).Value = "플랫폼";
+        ws3.Cell(1, 2).Value = "수량";
+        ws3.Cell(1, 3).Value = "비율(%)";
+        ws3.Row(1).Style.Font.Bold = true;
+
+        var platformGroups = devices
+            .GroupBy(d => d.Platform)
+            .OrderByDescending(g => g.Count())
+            .ToList();
+
+        row = 2;
+        foreach (var g in platformGroups)
+        {
+            ws3.Cell(row, 1).Value = g.Key.ToString();
+            ws3.Cell(row, 2).Value = g.Count();
+            ws3.Cell(row, 3).Value = total > 0 ? Math.Round((double)g.Count() / total * 100, 2) : 0;
+            row++;
+        }
+        ws3.Columns().AdjustToContents();
+
+        using var stream = new MemoryStream();
+        workbook.SaveAs(stream);
+        return stream.ToArray();
+    }
+
     private static double CalcCtr(int openCount, int successCount)
     {
         return successCount > 0 ? Math.Round((double)openCount / successCount * 100, 2) : 0;