DocumentService/DocumentService.Tests/Unit/Application/Features/AddStamp/AddStampHandlerTests.cs

using DocumentService.Application.AddStamp;
using DocumentService.Application.Common.Interfaces;
using DocumentService.Domain.Common.Exceptions;
using DocumentService.Domain.Models.ValueObjects;
using FluentAssertions;
using Moq;
using Xunit;

namespace DocumentService.Tests.Unit.Application.Features.AddStamp;

public class AddStampHandlerTests
{
    private readonly Mock<IPdfProcessor> _mockProcessor;
    private readonly AddStampHandler _handler;
    private static readonly byte[] FakePdfBytes = "%PDF"u8.ToArray();

    public AddStampHandlerTests()
    {
        _mockProcessor = new Mock<IPdfProcessor>();
        _handler = new AddStampHandler(_mockProcessor.Object);
    }

    [Fact]
    public async Task Handle_TextStamp_ReturnsStampedBytes()
    {
        // Arrange
        var command = new AddStampCommand
        {
            PdfStream = new MemoryStream(FakePdfBytes),
            StampType = StampType.Text,
            Position = (100, 200),
            Text = "CONFIDENTIAL"
        };
        var expected = new byte[] { 0x25, 0x50, 0x44, 0x46, 0x03 };
        _mockProcessor.Setup(x => x.AddStampAsync(
                It.IsAny<Stream>(), StampType.Text, null,
                It.IsAny<(double, double)>(), null,
                AnnotationOrigin.BottomLeft, "CONFIDENTIAL",
                null, null, null, null, null,
                StampPlacement.Foreground, null, null))
            .ReturnsAsync(expected);

        // Act
        var result = await _handler.Handle(command, CancellationToken.None);

        // Assert
        result.Should().BeEquivalentTo(expected);
        _mockProcessor.Verify(x => x.AddStampAsync(
            It.IsAny<Stream>(), StampType.Text, null,
            It.IsAny<(double, double)>(), null,
            AnnotationOrigin.BottomLeft, "CONFIDENTIAL",
            null, null, null, null, null,
            StampPlacement.Foreground, null, null), Times.Once);
    }

    [Fact]
    public async Task Handle_PredefinedStamp_PassesPredefinedTypeToProcessor()
    {
        // Arrange
        var command = new AddStampCommand
        {
            PdfStream = new MemoryStream(FakePdfBytes),
            StampType = StampType.Predefined,
            Position = (50, 50),
            PredefinedType = PredefinedStampType.Approved,
            Opacity = 0.8
        };
        var expected = new byte[] { 0x25, 0x50, 0x44, 0x46, 0x04 };
        _mockProcessor.Setup(x => x.AddStampAsync(
                It.IsAny<Stream>(), StampType.Predefined, null,
                It.IsAny<(double, double)>(), null,
                AnnotationOrigin.BottomLeft, null, null, null, null,
                0.8, null, StampPlacement.Foreground, null, PredefinedStampType.Approved))
            .ReturnsAsync(expected);

        // Act
        var result = await _handler.Handle(command, CancellationToken.None);

        // Assert
        result.Should().BeEquivalentTo(expected);
    }

    [Fact]
    public async Task Handle_ProcessorThrowsBadRequest_PropagatesException()
    {
        // Arrange
        var command = new AddStampCommand
        {
            PdfStream = new MemoryStream(FakePdfBytes),
            StampType = StampType.Text,
            Position = (0, 0),
            Text = "DRAFT",
            Opacity = 2.0  // invalid
        };
        _mockProcessor.Setup(x => x.AddStampAsync(
                It.IsAny<Stream>(), It.IsAny<StampType>(), It.IsAny<int[]?>(),
                It.IsAny<(double, double)>(), It.IsAny<(double, double)?>(),
                It.IsAny<AnnotationOrigin>(), It.IsAny<string?>(), It.IsAny<string?>(),
                It.IsAny<double?>(), It.IsAny<string?>(), It.IsAny<double?>(),
                It.IsAny<double?>(), It.IsAny<StampPlacement>(),
                It.IsAny<byte[]?>(), It.IsAny<PredefinedStampType?>()))
            .ThrowsAsync(new BadRequestException("Opacity must be between 0.0 and 1.0"));

        // Act & Assert
        var ex = await Assert.ThrowsAsync<BadRequestException>(
            () => _handler.Handle(command, CancellationToken.None));
        ex.Message.Should().Contain("Opacity");
    }

    [Fact]
    public async Task Handle_ProcessorThrowsGenericException_PropagatesException()
    {
        // Arrange
        var command = new AddStampCommand
        {
            PdfStream = new MemoryStream(FakePdfBytes),
            StampType = StampType.Text,
            Position = (0, 0),
            Text = "TEST"
        };
        _mockProcessor.Setup(x => x.AddStampAsync(
                It.IsAny<Stream>(), It.IsAny<StampType>(), It.IsAny<int[]?>(),
                It.IsAny<(double, double)>(), It.IsAny<(double, double)?>(),
                It.IsAny<AnnotationOrigin>(), It.IsAny<string?>(), It.IsAny<string?>(),
                It.IsAny<double?>(), It.IsAny<string?>(), It.IsAny<double?>(),
                It.IsAny<double?>(), It.IsAny<StampPlacement>(),
                It.IsAny<byte[]?>(), It.IsAny<PredefinedStampType?>()))
            .ThrowsAsync(new Exception("Unexpected"));

        // Act & Assert
        await Assert.ThrowsAsync<Exception>(() => _handler.Handle(command, CancellationToken.None));
    }
}