using ErrorOr;
using Musify.Application.Tests.TestSupport;
using Musify.Application.Users;
using Musify.Domain.Entities;
using Xunit;

namespace Musify.Application.Tests.Users;

public sealed class GetUserFollowingQueryHandlerTests : HandlerTestBase
{
    private GetUserFollowingQueryHandler CreateHandler() => new(Database);

    [Fact]
    public async Task Handle_Anonymous_ReturnsFollowedUsers()
    {
        var user = TestEntities.User(1, "user");
        var followedA = TestEntities.User(2, "followedA");
        var followedB = TestEntities.User(3, "followedB");
        await SeedAsync(
            user, followedA, followedB,
            new UserFollow { FollowerId = user.Id, FollowedId = followedA.Id },
            new UserFollow { FollowerId = user.Id, FollowedId = followedB.Id });

        var result = await CreateHandler().Handle(new GetUserFollowingQuery(null, user.Id, 1, 20), TestContext.Current.CancellationToken);

        Assert.False(result.IsError);
        Assert.Equal(2, result.Value.TotalItemCount);
        Assert.All(result.Value.Items, item => Assert.False(item.IsFollowedByViewer));
    }

    [Fact]
    public async Task Handle_Viewer_MarksUsersTheViewerFollows()
    {
        var viewer = TestEntities.User(1, "viewer");
        var user = TestEntities.User(2, "user");
        var followedA = TestEntities.User(3, "followedA");
        var followedB = TestEntities.User(4, "followedB");
        await SeedAsync(
            viewer, user, followedA, followedB,
            new UserFollow { FollowerId = user.Id, FollowedId = followedA.Id },
            new UserFollow { FollowerId = user.Id, FollowedId = followedB.Id },
            new UserFollow { FollowerId = viewer.Id, FollowedId = followedA.Id });

        var result = await CreateHandler().Handle(new GetUserFollowingQuery(viewer.Id, user.Id, 1, 20), TestContext.Current.CancellationToken);

        Assert.False(result.IsError);
        Assert.All(result.Value.Items, item => Assert.Equal(item.Id == followedA.Id, item.IsFollowedByViewer));
    }

    [Fact]
    public async Task Handle_Pagination_ReturnsRequestedPage()
    {
        await SeedAsync(
            TestEntities.User(1, "user"), TestEntities.User(2, "a"), TestEntities.User(3, "b"), TestEntities.User(4, "c"),
            new UserFollow { FollowerId = 1, FollowedId = 2 },
            new UserFollow { FollowerId = 1, FollowedId = 3 },
            new UserFollow { FollowerId = 1, FollowedId = 4 });

        var result = await CreateHandler().Handle(new GetUserFollowingQuery(null, 1, 2, 2), TestContext.Current.CancellationToken);

        Assert.False(result.IsError);
        Assert.Single(result.Value.Items);
        Assert.Equal(3, result.Value.TotalItemCount);
        Assert.False(result.Value.HasNextPage);
    }

    [Fact]
    public async Task Handle_UserMissing_ReturnsNotFound()
    {
        var result = await CreateHandler().Handle(new GetUserFollowingQuery(null, 404, 1, 20), TestContext.Current.CancellationToken);

        Assert.Equal(ErrorType.NotFound, result.FirstError.Type);
    }
}