DocumentService/DocumentOperator.Tests/Unit/Client/PdfOperationsClientTests.cs

using DocumentService.Client.Clients;
using DocumentService.Client.Interfaces;
using DocumentService.Client.Models.Requests;
using DocumentService.Client.Models.ValueObjects;
using FluentAssertions;
using Microsoft.Extensions.Logging.Abstractions;
using System.Net;
using System.Net.Http;
using System.Text.Json;

namespace DocumentService.Tests.Unit.Client;

/// <summary>
/// Unit tests for <see cref="PdfOperationsClient"/>.
/// All tests use a fake <see cref="MockHttpMessageHandler"/> — no real HTTP calls are made.
/// </summary>
public class PdfOperationsClientTests
{
    // ?? helpers ?????????????????????????????????????????????????????????????

    private static (PdfOperationsClient client, MockHttpMessageHandler handler) BuildBytes(byte[] bytes = null!)
    {
        var handler = MockHttpMessageHandler.ReturningBytes(bytes ?? "merged-pdf"u8.ToArray(), "application/pdf");
        var httpClient = new HttpClient(handler) { BaseAddress = new Uri("http://localhost") };
        var client = new PdfOperationsClient(httpClient, NullLogger<PdfOperationsClient>.Instance);
        return (client, handler);
    }

    private static byte[] FakePdfBytes() => "fake-pdf-content"u8.ToArray();

    private static AddAnnotationBase64Request FakeAnnotationRequest() => new()
    {
        Base64Pdf    = string.Empty,
        AnnotationType = AnnotationType.TextMarkup,
        PageNumber   = 1,
        X1 = 10, Y1 = 20, Width = 100, Height = 30,
        Color        = "FFFF00",
        TextMarkupStyle = TextMarkupStyle.Highlight,
        Origin       = AnnotationOrigin.TopLeft
    };

    private static AddStampBase64Request FakeStampRequest() => new()
    {
        Base64Pdf  = string.Empty,
        StampType  = StampType.Text,
        X = 100, Y = 50,
        Text       = "CONFIDENTIAL",
        FontSize   = 24,
        Color      = "FF0000",
        Opacity    = 0.5,
        Placement  = StampPlacement.Foreground,
        Origin     = AnnotationOrigin.BottomLeft
    };

    // ?? MergeAsync (Streams) ?????????????????????????????????????????????????

    [Fact]
    public async Task MergeAsync_Streams_SendsMultipartWithAllFiles()
    {
        // Arrange
        var (client, handler) = BuildBytes();
        var streams = new List<Stream>
        {
            new MemoryStream(FakePdfBytes()),
            new MemoryStream(FakePdfBytes())
        };

        // Act
        using var result = await client.MergeAsync(streams);

        // Assert
        result.Should().NotBeNull();
        handler.LastRequest!.RequestUri!.PathAndQuery.Should().Be("/api/pdf/operations/merge");
        handler.LastRequest.Content.Should().BeOfType<MultipartFormDataContent>();

        foreach (var s in streams) s.Dispose();
    }

    [Fact]
    public async Task MergeAsync_Streams_ReturnsMergedPdfStream()
    {
        // Arrange
        var expectedBytes = "merged-content"u8.ToArray();
        var (client, _) = BuildBytes(expectedBytes);

        // Act
        using var result = await client.MergeAsync(new[] { new MemoryStream(FakePdfBytes()), new MemoryStream(FakePdfBytes()) });
        var actualBytes = await result.ReadAllBytesAsync();

        // Assert
        actualBytes.Should().BeEquivalentTo(expectedBytes);
    }

    // ?? MergeAsync (byte[][]) ????????????????????????????????????????????????

    [Fact]
    public async Task MergeAsync_ByteArrays_SendsJsonWithBase64List()
    {
        // Arrange
        var (client, handler) = BuildBytes();

        // Act
        using var result = await client.MergeAsync(new[] { FakePdfBytes(), FakePdfBytes() });

        // Assert
        handler.LastRequest!.Content.Should().NotBeNull();
        handler.LastRequest.Content!.Headers.ContentType!.MediaType.Should().Be("application/json");
        var body = await handler.LastRequest.Content!.ReadAsStringAsync();
        var doc = JsonDocument.Parse(body);
        doc.RootElement.GetProperty("base64Pdfs").GetArrayLength().Should().Be(2);
    }

    [Fact]
    public async Task MergeAsync_ByteArrays_WithPageRanges_IncludesPageRangesInJson()
    {
        // Arrange
        var (client, handler) = BuildBytes();
        var pageRanges = new List<string?> { "1-2", null };

        // Act
        await client.MergeAsync(new[] { FakePdfBytes(), FakePdfBytes() }, pageRanges);

        // Assert
        handler.LastRequest!.Content.Should().NotBeNull();
        var body = await handler.LastRequest!.Content!.ReadAsStringAsync();
        var doc = JsonDocument.Parse(body);
        doc.RootElement.GetProperty("pageRanges").GetArrayLength().Should().Be(2);
    }

    // ?? AnnotateAsync (Stream) ????????????????????????????????????????????????

    [Fact]
    public async Task AnnotateAsync_Stream_SendsMultipartWithAnnotationFields()
    {
        // Arrange
        var (client, handler) = BuildBytes();
        var request = FakeAnnotationRequest();

        // Act
        using var result = await client.AnnotateAsync(new MemoryStream(FakePdfBytes()), request);

        // Assert
        result.Should().NotBeNull();
        handler.LastRequest!.RequestUri!.PathAndQuery.Should().Be("/api/pdf/operations/annotate");
        handler.LastRequest.Content.Should().BeOfType<MultipartFormDataContent>();
    }

    // ?? AnnotateAsync (byte[]) ????????????????????????????????????????????????

    [Fact]
    public async Task AnnotateAsync_Bytes_SendsJsonWithBase64Pdf()
    {
        // Arrange
        var (client, handler) = BuildBytes();
        var request = FakeAnnotationRequest();

        // Act
        await client.AnnotateAsync(FakePdfBytes(), request);

        // Assert
        handler.LastRequest!.Content.Should().NotBeNull();
        handler.LastRequest.Content!.Headers.ContentType!.MediaType.Should().Be("application/json");
        var body = await handler.LastRequest.Content!.ReadAsStringAsync();
        var doc = JsonDocument.Parse(body);
        doc.RootElement.GetProperty("base64Pdf").GetString().Should().NotBeNullOrEmpty();
        // annotationType serializes as integer by default (TextMarkup = 0)
        doc.RootElement.GetProperty("annotationType").GetInt32().Should().Be((int)AnnotationType.TextMarkup);
    }

    // ?? StampAsync (Stream) ???????????????????????????????????????????????????

    [Fact]
    public async Task StampAsync_Stream_SendsMultipartWithStampFields()
    {
        // Arrange
        var (client, handler) = BuildBytes();
        var request = FakeStampRequest();

        // Act
        using var result = await client.StampAsync(new MemoryStream(FakePdfBytes()), request);

        // Assert
        result.Should().NotBeNull();
        handler.LastRequest!.RequestUri!.PathAndQuery.Should().Be("/api/pdf/operations/stamp");
        handler.LastRequest.Content.Should().BeOfType<MultipartFormDataContent>();
    }

    // ?? StampAsync (byte[]) ???????????????????????????????????????????????????

    [Fact]
    public async Task StampAsync_Bytes_SendsJsonWithBase64Pdf()
    {
        // Arrange
        var (client, handler) = BuildBytes();
        var request = FakeStampRequest();

        // Act
        await client.StampAsync(FakePdfBytes(), request);

        // Assert
        handler.LastRequest!.Content.Should().NotBeNull();
        handler.LastRequest.Content!.Headers.ContentType!.MediaType.Should().Be("application/json");
        var body = await handler.LastRequest.Content!.ReadAsStringAsync();
        var doc = JsonDocument.Parse(body);
        doc.RootElement.GetProperty("base64Pdf").GetString().Should().NotBeNullOrEmpty();
        // stampType serializes as integer by default (Text = 0)
        doc.RootElement.GetProperty("stampType").GetInt32().Should().Be((int)StampType.Text);
    }

    // ?? HTTP error propagation ???????????????????????????????????????????????

    [Fact]
    public async Task MergeAsync_WhenApiReturns400_ThrowsHttpRequestException()
    {
        // Arrange
        var handler = MockHttpMessageHandler.ReturningStatus(HttpStatusCode.BadRequest);
        var httpClient = new HttpClient(handler) { BaseAddress = new Uri("http://localhost") };
        var client = new PdfOperationsClient(httpClient, NullLogger<PdfOperationsClient>.Instance);

        // Act & Assert
        await client.Invoking(c => c.MergeAsync(new[] { new MemoryStream(FakePdfBytes()), new MemoryStream(FakePdfBytes()) }))
            .Should().ThrowAsync<HttpRequestException>();
    }
}

// ?? local helper extension ???????????????????????????????????????????????????

file static class StreamHelper
{
    public static async Task<byte[]> ReadAllBytesAsync(this Stream stream)
    {
        using var ms = new MemoryStream();
        await stream.CopyToAsync(ms);
        return ms.ToArray();
    }
}