DocumentService/DocumentService.Tests/Unit/Client/SwissQrCodeClientTests.cs

using DocumentService.Application.Common.DTOs;
using DocumentService.Client.Clients;
using DocumentService.Client.Interfaces;
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="SwissQrCodeClient"/>.
/// All tests use a fake <see cref="MockHttpMessageHandler"/> — no real HTTP calls are made.
/// </summary>
public class SwissQrCodeClientTests
{
    // ?? helpers ????????????????????????????????????????????????????????????

    private static (SwissQrCodeClient client, MockHttpMessageHandler handler) Build<T>(T body)
    {
        var handler = MockHttpMessageHandler.ReturningJson(body);
        var httpClient = new HttpClient(handler) { BaseAddress = new Uri("http://localhost") };
        var client = new SwissQrCodeClient(httpClient, NullLogger<SwissQrCodeClient>.Instance);
        return (client, handler);
    }

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

    // ?? ExtractSwissQrCodeAsync (Stream) — parsed Bill ??????????????????????

    [Fact]
    public async Task ExtractSwissQrCodeAsync_Stream_ParsedMode_SendsMultipartToCorrectEndpoint()
    {
        // Arrange
        var expected = new SwissQrCodeExtractionResult(
            Bill: new SwissQrBillDto
            {
                Version = "V2_0",
                Currency = "CHF",
                Account = "CH9300762011623852957",
                Creditor = new AddressDto { Name = "Test AG", Town = "Bern", CountryCode = "CH", Type = "S", PostalCode = "3000" },
                ReferenceType = "NON"
            },
            RawLines: []
        );
        var (client, handler) = Build(expected);

        // Act
        var result = await client.ExtractSwissQrCodeAsync(new MemoryStream(FakePdfBytes()), raw: false);

        // Assert
        result.Should().NotBeNull();
        handler.LastRequest!.RequestUri!.PathAndQuery.Should().Be("/api/pdf/qr-code/extract-swiss?raw=False");
        handler.LastRequest.Content.Should().BeOfType<MultipartFormDataContent>();
    }

    [Fact]
    public async Task ExtractSwissQrCodeAsync_Stream_RawMode_SendsRawFlagInUrl()
    {
        // Arrange
        var expected = new SwissQrCodeExtractionResult(Bill: null, RawLines: ["SPC", "0200", "1"]);
        var (client, handler) = Build(expected);

        // Act
        var result = await client.ExtractSwissQrCodeAsync(new MemoryStream(FakePdfBytes()), raw: true);

        // Assert
        result.RawLines.Should().HaveCount(3).And.StartWith("SPC");
        handler.LastRequest!.RequestUri!.PathAndQuery.Should().Be("/api/pdf/qr-code/extract-swiss?raw=True");
    }

    // ?? ExtractSwissQrCodeAsync (byte[]) ????????????????????????????????????

    [Fact]
    public async Task ExtractSwissQrCodeAsync_Bytes_SendsJsonWithBase64()
    {
        // Arrange
        var expected = new SwissQrCodeExtractionResult(Bill: null, RawLines: []);
        var (client, handler) = Build(expected);

        // Act
        await client.ExtractSwissQrCodeAsync(FakePdfBytes(), raw: false);

        // 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();
    }

    [Fact]
    public async Task ExtractSwissQrCodeAsync_Bytes_RawMode_IncludesRawFlagInUrl()
    {
        // Arrange
        var expected = new SwissQrCodeExtractionResult(Bill: null, RawLines: ["SPC"]);
        var (client, handler) = Build(expected);

        // Act
        await client.ExtractSwissQrCodeAsync(FakePdfBytes(), raw: true);

        // Assert
        handler.LastRequest!.RequestUri!.PathAndQuery.Should().Be("/api/pdf/qr-code/extract-swiss?raw=True");
    }

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

    [Fact]
    public async Task ExtractSwissQrCodeAsync_WhenApiReturns404_ThrowsHttpRequestException()
    {
        // Arrange
        var handler = MockHttpMessageHandler.ReturningStatus(HttpStatusCode.NotFound);
        var httpClient = new HttpClient(handler) { BaseAddress = new Uri("http://localhost") };
        var client = new SwissQrCodeClient(httpClient, NullLogger<SwissQrCodeClient>.Instance);

        // Act & Assert
        await client.Invoking(c => c.ExtractSwissQrCodeAsync(new MemoryStream(FakePdfBytes())))
            .Should().ThrowAsync<HttpRequestException>();
    }

    [Fact]
    public async Task ExtractSwissQrCodeAsync_WhenApiReturns500_ThrowsHttpRequestException()
    {
        // Arrange
        var handler = MockHttpMessageHandler.ReturningStatus(HttpStatusCode.InternalServerError);
        var httpClient = new HttpClient(handler) { BaseAddress = new Uri("http://localhost") };
        var client = new SwissQrCodeClient(httpClient, NullLogger<SwissQrCodeClient>.Instance);

        // Act & Assert
        await client.Invoking(c => c.ExtractSwissQrCodeAsync(FakePdfBytes()))
            .Should().ThrowAsync<HttpRequestException>();
    }
}