using Xunit;
using Moq;
using FluentAssertions;
using Microsoft.Extensions.Logging;
using IamService.API.Application.Commands.Groups;
using IamService.Domain.AggregatesModel.GroupAggregate;
using IamService.Domain.Exceptions;
using IamService.Domain.SeedWork;

namespace IamService.UnitTests.Application.Commands.Groups;

/// <summary>
/// EN: Unit tests for RemoveGroupMemberCommandHandler.
/// VI: Unit tests cho RemoveGroupMemberCommandHandler.
/// </summary>
public class RemoveGroupMemberCommandHandlerTests
{
    private readonly Mock<IGroupRepository> _groupRepositoryMock;
    private readonly Mock<ILogger<RemoveGroupMemberCommandHandler>> _loggerMock;
    private readonly Mock<IUnitOfWork> _unitOfWorkMock;
    private readonly RemoveGroupMemberCommandHandler _handler;

    public RemoveGroupMemberCommandHandlerTests()
    {
        _groupRepositoryMock = new Mock<IGroupRepository>();
        _loggerMock = new Mock<ILogger<RemoveGroupMemberCommandHandler>>();
        _unitOfWorkMock = new Mock<IUnitOfWork>();

        _unitOfWorkMock
            .Setup(u => u.SaveEntitiesAsync(It.IsAny<CancellationToken>()))
            .ReturnsAsync(true);
        _groupRepositoryMock
            .Setup(r => r.UnitOfWork)
            .Returns(_unitOfWorkMock.Object);

        _handler = new RemoveGroupMemberCommandHandler(
            _groupRepositoryMock.Object,
            _loggerMock.Object);
    }

    [Fact]
    public async Task Handle_ValidCommand_RemovesMemberFromGroup()
    {
        // Arrange
        var groupId = Guid.NewGuid();
        var userId = Guid.NewGuid();
        var group = Group.Create(Guid.NewGuid(), "Test Group");
        group.AddMember(userId);
        
        var command = new RemoveGroupMemberCommand(groupId, userId);

        _groupRepositoryMock
            .Setup(r => r.GetByIdWithMembersAsync(groupId, It.IsAny<CancellationToken>()))
            .ReturnsAsync(group);

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

        // Assert
        result.Should().BeTrue();
        group.Members.Should().NotContain(m => m.UserId == userId);
    }

    [Fact]
    public async Task Handle_ValidCommand_PersistsChanges()
    {
        // Arrange
        var groupId = Guid.NewGuid();
        var userId = Guid.NewGuid();
        var group = Group.Create(Guid.NewGuid(), "Test Group");
        group.AddMember(userId);
        
        var command = new RemoveGroupMemberCommand(groupId, userId);

        _groupRepositoryMock
            .Setup(r => r.GetByIdWithMembersAsync(groupId, It.IsAny<CancellationToken>()))
            .ReturnsAsync(group);

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

        // Assert
        _groupRepositoryMock.Verify(r => r.Update(group), Times.Once);
        _unitOfWorkMock.Verify(u => u.SaveEntitiesAsync(It.IsAny<CancellationToken>()), Times.Once);
    }

    [Fact]
    public async Task Handle_GroupNotFound_ThrowsDomainException()
    {
        // Arrange
        var command = new RemoveGroupMemberCommand(Guid.NewGuid(), Guid.NewGuid());

        _groupRepositoryMock
            .Setup(r => r.GetByIdWithMembersAsync(It.IsAny<Guid>(), It.IsAny<CancellationToken>()))
            .ReturnsAsync((Group?)null);

        // Act
        var act = async () => await _handler.Handle(command, CancellationToken.None);

        // Assert
        await act.Should().ThrowAsync<DomainException>()
            .WithMessage("*Group*not found*");

        _groupRepositoryMock.Verify(r => r.Update(It.IsAny<Group>()), Times.Never);
    }

    [Fact]
    public async Task Handle_MemberNotInGroup_ThrowsInvalidOperationException()
    {
        // Arrange
        var groupId = Guid.NewGuid();
        var userId = Guid.NewGuid();
        var group = Group.Create(Guid.NewGuid(), "Test Group");
        // NOT adding userId to group
        
        var command = new RemoveGroupMemberCommand(groupId, userId);

        _groupRepositoryMock
            .Setup(r => r.GetByIdWithMembersAsync(groupId, It.IsAny<CancellationToken>()))
            .ReturnsAsync(group);

        // Act
        var act = async () => await _handler.Handle(command, CancellationToken.None);

        // Assert
        await act.Should().ThrowAsync<InvalidOperationException>()
            .WithMessage("*not a member*");
    }

    [Fact]
    public async Task Handle_CancellationRequested_PropagatesCancellation()
    {
        // Arrange
        var command = new RemoveGroupMemberCommand(Guid.NewGuid(), Guid.NewGuid());
        var cts = new CancellationTokenSource();
        cts.Cancel();

        _groupRepositoryMock
            .Setup(r => r.GetByIdWithMembersAsync(It.IsAny<Guid>(), It.IsAny<CancellationToken>()))
            .ThrowsAsync(new OperationCanceledException());

        // Act
        var act = async () => await _handler.Handle(command, cts.Token);

        // Assert
        await act.Should().ThrowAsync<OperationCanceledException>();
    }
}