Feat: AI 면접 완료 후 종합 리포트를 PDF 형태로 다운로드할 수 있는 기능 구현

src/InterviewAssistant.ApiService/Delegates/PdfDownloadDelegate.cs

@@ -0,0 +1,35 @@
+using InterviewAssistant.Common.Models;
+using InterviewAssistant.ApiService.Services;
+using Microsoft.AspNetCore.Mvc;
+
+namespace InterviewAssistant.ApiService.Delegates;
+
+/// <summary>
+/// PDF 다운로드를 처리하는 Delegate
+/// </summary>
+public static class PdfDownloadDelegate
+{
+    /// <summary>
+    /// 면접 결과 리포트를 PDF로 다운로드합니다.
+    /// </summary>
+    /// <param name="request">PDF 생성 요청 데이터</param>
+    /// <param name="pdfService">PDF 생성 서비스</param>
+    /// <returns>PDF 파일</returns>
+    public static async Task<IResult> DownloadInterviewReportPdfAsync(
+        [FromBody] PdfDownloadRequest request,
+        IPdfGenerationService pdfService)
+    {
+        try
+        {
+            var pdfBytes = await pdfService.GenerateInterviewReportPdfAsync(request.Report, request.ChatHistory);
+
+            var fileName = $"면접결과_{DateTime.Now:yyyyMMdd_HHmmss}.pdf";
+
+            return Results.File(pdfBytes, "application/pdf", fileName);
+        }
+        catch (Exception ex)
+        {
+            return Results.Problem($"PDF 생성 중 오류가 발생했습니다: {ex.Message}");
+        }
+    }
+}

src/InterviewAssistant.ApiService/Endpoints/PdfDownloadEndpoint.cs

@@ -0,0 +1,31 @@
+using InterviewAssistant.ApiService.Delegates;
+using InterviewAssistant.Common.Models;
+
+namespace InterviewAssistant.ApiService.Endpoints;
+
+/// <summary>
+/// PDF 다운로드 엔드포인트
+/// </summary>
+public static class PdfDownloadEndpoint
+{
+    /// <summary>
+    /// PDF 다운로드 엔드포인트를 등록합니다.
+    /// </summary>
+    /// <param name="app">웹 애플리케이션</param>
+    /// <returns>라우트 그룹 빌더</returns>
+    public static RouteGroupBuilder MapPdfDownloadEndpoints(this WebApplication app)
+    {
+        var group = app.MapGroup("/api/pdf");
+
+        group.MapPost("/download-report", PdfDownloadDelegate.DownloadInterviewReportPdfAsync)
+            .WithName("DownloadInterviewReportPdf")
+            .WithDisplayName("Download Interview Report PDF")
+            .WithDescription("면접 결과 리포트를 PDF로 다운로드합니다.")
+            .WithOpenApi()
+            .Produces<byte[]>(200, "application/pdf")
+            .ProducesValidationProblem()
+            .Accepts<PdfDownloadRequest>("application/json");
+
+        return group;
+    }
+}

src/InterviewAssistant.ApiService/InterviewAssistant.ApiService.csproj

@@ -15,6 +15,9 @@
     <PackageReference Include="Microsoft.SemanticKernel.Agents.core" Version="1.*" />
     <PackageReference Include="Microsoft.SemanticKernel.Yaml" Version="1.*" />
     <PackageReference Include="ModelContextProtocol" Version="0.*-*" />
+    <PackageReference Include="QuestPDF" Version="2024.*" />
+    <PackageReference Include="Markdig" Version="0.*" />
+    <PackageReference Include="SkiaSharp" Version="2.*" />
   </ItemGroup>
 
   <ItemGroup>

src/InterviewAssistant.ApiService/Program.cs

@@ -32,6 +32,7 @@
 
 builder.Services.AddScoped<IKernelService, KernelService>();
 builder.Services.AddScoped<IInterviewRepository, InterviewRepository>();
+builder.Services.AddScoped<IPdfGenerationService, PdfGenerationService>();
 
 //OpenAPI 설정
 builder.Services.AddOpenApi();
@@ -99,6 +100,9 @@
 // Chat Completion 엔드포인트 매핑
 app.MapChatCompletionEndpoint();
 
+// PDF 다운로드 엔드포인트 매핑
+app.MapPdfDownloadEndpoints();
+
 // .NET Aspire 헬스체크 및 모니터링 엔드포인트 매핑
 app.MapDefaultEndpoints();
 

src/InterviewAssistant.ApiService/Services/PdfGenerationService.cs

@@ -0,0 +1,194 @@
+using InterviewAssistant.Common.Models;
+using QuestPDF.Fluent;
+using QuestPDF.Helpers;
+using QuestPDF.Infrastructure;
+using Markdig;
+using System.Text.RegularExpressions;
+
+namespace InterviewAssistant.ApiService.Services;
+
+/// <summary>
+/// PDF 생성 서비스 인터페이스
+/// </summary>
+public interface IPdfGenerationService
+{
+    /// <summary>
+    /// 면접 결과 리포트를 PDF로 생성합니다.
+    /// </summary>
+    /// <param name="report">면접 결과 리포트</param>
+    /// <param name="chatHistory">채팅 기록</param>
+    /// <returns>PDF 바이트 배열</returns>
+    Task<byte[]> GenerateInterviewReportPdfAsync(InterviewReportModel report, List<ChatMessage> chatHistory);
+}
+
+/// <summary>
+/// PDF 생성 서비스 구현
+/// </summary>
+public class PdfGenerationService : IPdfGenerationService
+{
+    public async Task<byte[]> GenerateInterviewReportPdfAsync(InterviewReportModel report, List<ChatMessage> chatHistory)
+    {
+        // QuestPDF 라이선스 설정 (Community 라이선스)
+        QuestPDF.Settings.License = LicenseType.Community;
+
+        return await Task.FromResult(Document.Create(container =>
+        {
+            container.Page(page =>
+            {
+                page.Size(PageSizes.A4);
+                page.Margin(2, Unit.Centimetre);
+                page.PageColor(Colors.White);
+                page.DefaultTextStyle(x => x.FontSize(11));
+
+                page.Header()
+                    .Text("면접 결과 리포트")
+                    .SemiBold().FontSize(20).FontColor(Colors.Blue.Medium);
+
+                page.Content()
+                    .PaddingVertical(1, Unit.Centimetre)
+                    .Column(column =>
+                    {
+                        column.Spacing(20);
+
+                        // 종합 분석 (마크다운 처리)
+                        column.Item().Text("종합 분석").SemiBold().FontSize(16);
+                        var overallFeedbackHtml = ConvertMarkdownToPlainText(report.OverallFeedback ?? "분석 결과가 없습니다.");
+                        column.Item().PaddingLeft(10).Text(overallFeedbackHtml);
+
+                        // 강점 (마크다운 처리)
+                        column.Item().Text("강점").SemiBold().FontSize(16);
+                        if (report.Strengths?.Any() == true)
+                        {
+                            foreach (var strength in report.Strengths)
+                            {
+                                var strengthText = ConvertMarkdownToPlainText(strength);
+                                column.Item().PaddingLeft(10).Text($"• {strengthText}");
+                            }
+                        }
+                        else
+                        {
+                            column.Item().PaddingLeft(10).Text("• 강점이 기록되지 않았습니다.");
+                        }
+
+                        // 개선점 (마크다운 처리)
+                        column.Item().Text("개선점").SemiBold().FontSize(16);
+                        if (report.Weaknesses?.Any() == true)
+                        {
+                            foreach (var weakness in report.Weaknesses)
+                            {
+                                var weaknessText = ConvertMarkdownToPlainText(weakness);
+                                column.Item().PaddingLeft(10).Text($"• {weaknessText}");
+                            }
+                        }
+                        else
+                        {
+                            column.Item().PaddingLeft(10).Text("• 개선점이 기록되지 않았습니다.");
+                        }
+
+                        // 질문 유형 분석 (원 그래프 형태로 표시)
+                        if (report.ChartData?.Labels?.Any() == true && report.ChartData?.Values?.Any() == true)
+                        {
+                            column.Item().Text("질문 유형 분석").SemiBold().FontSize(16);
+
+                            // 시각적 차트 표현
+                            column.Item().PaddingLeft(10).Column(chartColumn =>
+                            {
+                                var total = report.ChartData.Values.Sum();
+                                if (total > 0)
+                                {
+                                    chartColumn.Item().Text("📊 질문 유형별 분포").FontSize(12).SemiBold();
+                                    chartColumn.Item().PaddingVertical(5);
+
+                                    for (int i = 0; i < Math.Min(report.ChartData.Labels.Count, report.ChartData.Values.Count); i++)
+                                    {
+                                        var percentage = CalculatePercentage(report.ChartData.Values[i], total);
+                                        var barLength = (int)(percentage / 5); // 5%당 하나의 블록
+                                        var bar = new string('█', Math.Max(1, barLength));
+
+                                        chartColumn.Item().Row(row =>
+                                        {
+                                            row.ConstantItem(80).Text($"{report.ChartData.Labels[i]}:");
+                                            row.ConstantItem(150).Text(bar).FontColor(GetChartColor(i));
+                                            row.RelativeItem().Text($"{report.ChartData.Values[i]}개 ({percentage:F1}%)");
+                                        });
+                                    }
+                                }
+                            });
+                        }
+
+                        // 대화 기록 (마크다운 처리)
+                        if (chatHistory?.Any() == true)
+                        {
+                            column.Item().Text("대화 기록").SemiBold().FontSize(16);
+
+                            foreach (var message in chatHistory)
+                            {
+                                var roleText = message.Role switch
+                                {
+                                    MessageRoleType.User => "지원자",
+                                    MessageRoleType.Assistant => "면접관",
+                                    _ => message.Role.ToString()
+                                };
+
+                                var messageText = ConvertMarkdownToPlainText(message.Message ?? "");
+
+                                column.Item().PaddingLeft(10).Column(messageColumn =>
+                                {
+                                    messageColumn.Item().Text($"[{roleText}]").SemiBold().FontColor(
+                                        message.Role == MessageRoleType.User ? Colors.Blue.Medium : Colors.Green.Medium);
+                                    messageColumn.Item().PaddingLeft(10).Text(messageText);
+                                    messageColumn.Item().PaddingVertical(5);
+                                });
+                            }
+                        }
+                    });
+
+                page.Footer()
+                    .AlignCenter()
+                    .Text(x =>
+                    {
+                        x.Span("생성일: ");
+                        x.Span(DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss")).SemiBold();
+                    });
+            });
+        }).GeneratePdf());
+    }
+
+    /// <summary>
+    /// 마크다운을 일반 텍스트로 변환합니다.
+    /// </summary>
+    private static string ConvertMarkdownToPlainText(string markdown)
+    {
+        if (string.IsNullOrWhiteSpace(markdown))
+            return string.Empty;
+
+        // 마크다운을 HTML로 변환
+        var html = Markdown.ToHtml(markdown);
+
+        // HTML 태그 제거하여 일반 텍스트로 변환
+        var plainText = Regex.Replace(html, "<.*?>", string.Empty);
+
+        // HTML 엔티티 디코딩
+        plainText = System.Net.WebUtility.HtmlDecode(plainText);
+
+        return plainText.Trim();
+    }
+
+    /// <summary>
+    /// 차트 색상을 반환합니다.
+    /// </summary>
+    private static string GetChartColor(int index)
+    {
+        var colors = new[] { Colors.Blue.Medium, Colors.Green.Medium, Colors.Orange.Medium, Colors.Red.Medium, Colors.Purple.Medium };
+        return colors[index % colors.Length];
+    }
+
+    /// <summary>
+    /// 퍼센티지를 계산합니다.
+    /// </summary>
+    private static double CalculatePercentage(int value, int total)
+    {
+        if (total == 0) return 0;
+        return (double)value / total * 100;
+    }
+}

src/InterviewAssistant.Common/Models/PdfDownloadRequest.cs

@@ -0,0 +1,17 @@
+namespace InterviewAssistant.Common.Models;
+
+/// <summary>
+/// PDF 다운로드 요청 모델
+/// </summary>
+public class PdfDownloadRequest
+{
+    /// <summary>
+    /// 면접 결과 리포트
+    /// </summary>
+    public InterviewReportModel Report { get; set; } = new();
+
+    /// <summary>
+    /// 채팅 기록
+    /// </summary>
+    public List<ChatMessage> ChatHistory { get; set; } = new();
+}

src/InterviewAssistant.Web/Clients/ChatApiClient.cs

@@ -22,6 +22,14 @@ public interface IChatApiClient
     IAsyncEnumerable<ChatResponse> SendInterviewDataAsync(InterviewDataRequest request);
 
     Task<InterviewReportModel?> GenerateReportAsync(List<ChatMessage> messages);
+
+    /// <summary>
+    /// 면접 결과 리포트를 PDF로 다운로드합니다.
+    /// </summary>
+    /// <param name="report">면접 결과 리포트</param>
+    /// <param name="chatHistory">채팅 기록</param>
+    /// <returns>PDF 바이트 배열</returns>
+    Task<byte[]?> DownloadReportPdfAsync(InterviewReportModel report, List<ChatMessage> chatHistory);
 }
 
 /// <summary>
@@ -88,4 +96,25 @@ public async IAsyncEnumerable<ChatResponse> SendInterviewDataAsync(InterviewData
         _logger.LogError("리포트 생성 실패: {StatusCode}", httpResponse.StatusCode);
         return null;
     }
+
+    public async Task<byte[]?> DownloadReportPdfAsync(InterviewReportModel report, List<ChatMessage> chatHistory)
+    {
+        _logger.LogInformation("API에 PDF 다운로드 요청");
+
+        var request = new PdfDownloadRequest
+        {
+            Report = report,
+            ChatHistory = chatHistory
+        };
+
+        var httpResponse = await _http.PostAsJsonAsync("/api/pdf/download-report", request);
+
+        if (httpResponse.IsSuccessStatusCode)
+        {
+            return await httpResponse.Content.ReadAsByteArrayAsync();
+        }
+
+        _logger.LogError("PDF 다운로드 실패: {StatusCode}", httpResponse.StatusCode);
+        return null;
+    }
 }