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

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

        // EN: Setup UnitOfWork mock
        // VI: Thiết lập mock cho UnitOfWork
        _unitOfWorkMock
            .Setup(u => u.SaveEntitiesAsync(It.IsAny<CancellationToken>()))
            .ReturnsAsync(true);
        _groupRepositoryMock
            .Setup(r => r.UnitOfWork)
            .Returns(_unitOfWorkMock.Object);

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

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

        // EN: Override group's Id using reflection for testing (since Id is auto-generated)
        // VI: Sử dụng để test vì Id được tự động tạo
        var idProperty = typeof(Group).GetProperty("Id");
        idProperty?.SetValue(group, groupId);

        var command = new AddGroupMemberCommand(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().NotBeNull();
        result.GroupId.Should().Be(groupId);
        result.UserId.Should().Be(userId);
        result.Role.Should().Be("Member"); // Default role
        result.JoinedAt.Should().BeCloseTo(DateTime.UtcNow, TimeSpan.FromSeconds(1));
    }

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

        var command = new AddGroupMemberCommand(
            GroupId: groupId,
            UserId: userId,
            RoleId: GroupRole.Admin.Id); // Admin role

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

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

        // Assert
        result.Role.Should().Be("Admin");
    }

    [Fact]
    public async Task Handle_WithAddedByUser_TracksByWhoAdded()
    {
        // Arrange
        var groupId = Guid.NewGuid();
        var userId = Guid.NewGuid();
        var addedByUserId = Guid.NewGuid();
        var group = Group.Create(Guid.NewGuid(), "Test Group");

        var command = new AddGroupMemberCommand(
            GroupId: groupId,
            UserId: userId,
            AddedByUserId: addedByUserId);

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

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

        // Assert
        result.Should().NotBeNull();
        group.Members.First().AddedByUserId.Should().Be(addedByUserId);
    }

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

        var command = new AddGroupMemberCommand(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 AddGroupMemberCommand(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_UserAlreadyMember_ThrowsInvalidOperationException()
    {
        // Arrange
        var groupId = Guid.NewGuid();
        var userId = Guid.NewGuid();
        var group = Group.Create(Guid.NewGuid(), "Test Group");
        group.AddMember(userId); // User already added

        var command = new AddGroupMemberCommand(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("*already a member*");
    }

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

        var command = new AddGroupMemberCommand(
            GroupId: groupId,
            UserId: userId,
            RoleId: 999); // Invalid role ID

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

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

        // Assert
        result.Role.Should().Be("Member"); // Should fall back to Member
    }

    [Fact]
    public async Task Handle_CancellationRequested_PropagatesCancellation()
    {
        // Arrange
        var command = new AddGroupMemberCommand(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>();
    }
}