feat: Add specialized client implementations for PDF operations

DocumentService.Client/Clients/PdfAttachmentClient.cs

@@ -0,0 +1,124 @@
+using DocumentService.Client.Interfaces;
+using DocumentService.Client.Models.Requests;
+using Microsoft.Extensions.Logging;
+using System.IO.Compression;
+using System.Net.Http;
+
+namespace DocumentService.Client.Clients;
+
+/// <summary>
+/// Implementation of PDF attachment client.
+/// </summary>
+public class PdfAttachmentClient(HttpClient httpClient, ILogger<PdfAttachmentClient> logger)
+    : BaseDocumentClient(httpClient, logger), IPdfAttachmentClient
+{
+    /// <inheritdoc />
+    public async Task<AttachmentCheckResult> CheckAttachmentsAsync(Stream pdfStream, CancellationToken cancellationToken = default)
+    {
+        Logger.LogDebug("Checking PDF attachments from stream (multipart)");
+
+        var result = await SendMultipartAsync<AttachmentCheckResult>(
+            "/api/pdf/attachments/check",
+            pdfStream,
+            "document.pdf",
+            cancellationToken);
+
+        return result ?? throw new InvalidOperationException("API returned null response");
+    }
+
+    /// <inheritdoc />
+    public async Task<AttachmentCheckResult> CheckAttachmentsAsync(byte[] pdfBytes, CancellationToken cancellationToken = default)
+    {
+        Logger.LogDebug("Checking PDF attachments from byte array (Base64 JSON)");
+
+        var request = new CheckPdfAttachmentsRequest { Base64Pdf = ToBase64(pdfBytes) };
+
+        var result = await SendJsonAsync<CheckPdfAttachmentsRequest, AttachmentCheckResult>(
+            "/api/pdf/attachments/check",
+            request,
+            cancellationToken);
+
+        return result ?? throw new InvalidOperationException("API returned null response");
+    }
+
+    /// <inheritdoc />
+    public async Task<Dictionary<string, Stream>> ExtractAttachmentsAsync(Stream pdfStream, CancellationToken cancellationToken = default)
+    {
+        Logger.LogDebug("Extracting PDF attachments from stream (multipart)");
+
+        var zipStream = await SendMultipartForStreamAsync(
+            "/api/pdf/attachments/extract",
+            pdfStream,
+            "document.pdf",
+            cancellationToken);
+
+        return UnzipToStreams(zipStream);
+    }
+
+    /// <inheritdoc />
+    public async Task<Dictionary<string, Stream>> ExtractAttachmentsAsync(byte[] pdfBytes, CancellationToken cancellationToken = default)
+    {
+        Logger.LogDebug("Extracting PDF attachments from byte array (Base64 JSON)");
+
+        var request = new ExtractPdfAttachmentsRequest { Base64Pdf = ToBase64(pdfBytes) };
+
+        var zipStream = await SendJsonForStreamAsync(
+            "/api/pdf/attachments/extract",
+            request,
+            cancellationToken);
+
+        return UnzipToStreams(zipStream);
+    }
+
+    /// <inheritdoc />
+    [Obsolete("API endpoint not implemented yet")]
+    public Task<Stream> AddAttachmentsAsync(Stream pdfStream, List<AttachmentRequestDto> attachments, CancellationToken cancellationToken = default)
+    {
+        Logger.LogWarning("AddAttachments endpoint is not implemented yet in API");
+        throw new NotImplementedException("API endpoint /api/pdf/attachments/add is not implemented yet");
+    }
+
+    /// <inheritdoc />
+    [Obsolete("API endpoint not implemented yet")]
+    public Task<Stream> AddAttachmentsAsync(byte[] pdfBytes, List<AttachmentRequestDto> attachments, CancellationToken cancellationToken = default)
+    {
+        Logger.LogWarning("AddAttachments endpoint is not implemented yet in API");
+        throw new NotImplementedException("API endpoint /api/pdf/attachments/add is not implemented yet");
+    }
+
+    // ?????????????????????????????????????????????????????????????????????????
+    // Private helpers
+    // ?????????????????????????????????????????????????????????????????????????
+
+    /// <summary>
+    /// Reads a ZIP stream and returns a dictionary mapping each entry's full name
+    /// to an in-memory <see cref="MemoryStream"/> containing the decompressed bytes.
+    /// The caller owns the returned streams and is responsible for disposing them.
+    /// </summary>
+    private static Dictionary<string, Stream> UnzipToStreams(Stream zipStream)
+    {
+        var result = new Dictionary<string, Stream>(StringComparer.OrdinalIgnoreCase);
+
+        using var archive = new ZipArchive(zipStream, ZipArchiveMode.Read, leaveOpen: false);
+
+        foreach (var entry in archive.Entries)
+        {
+            // Skip directory entries (name ends with '/')
+            if (string.IsNullOrEmpty(entry.Name))
+                continue;
+
+            var ms = new MemoryStream((int)entry.Length);
+
+            using (var entryStream = entry.Open())
+            {
+                entryStream.CopyTo(ms);
+            }
+
+            ms.Position = 0;
+            result[entry.FullName] = ms;
+        }
+
+        return result;
+    }
+}
+