namespace ItWorx.KnowledgeHub.Domain.Tests;

using ItWorx.KnowledgeHub.Domain.Knowledge;

public sealed class PageCreationSessionTests
{
    private static readonly DateTimeOffset Now = new(2026, 8, 3, 12, 0, 0, TimeSpan.Zero);

    [Fact]
    public void Open_starts_in_the_Open_status_with_an_expiry_derived_from_the_lifespan()
    {
        var session = PageCreationSession.Open(Guid.NewGuid(), null, Guid.NewGuid(), Now, TimeSpan.FromHours(24));

        Assert.True(session.IsOpen);
        Assert.Equal(PageCreationSessionStatus.Open, session.Status);
        Assert.Equal(Now.AddHours(24), session.ExpiresAt);
        Assert.Null(session.CommittedPageId);
        Assert.Null(session.ClosedAt);
        Assert.False(session.IsExpired(Now));
        Assert.True(session.IsExpired(Now.AddHours(25)));
    }

    [Fact]
    public void MarkCommitted_transitions_to_Committed_and_records_the_page_id()
    {
        var session = PageCreationSession.Open(Guid.NewGuid(), null, Guid.NewGuid(), Now, TimeSpan.FromHours(24));
        var pageId = Guid.NewGuid();

        session.MarkCommitted(pageId, Now.AddMinutes(5));

        Assert.False(session.IsOpen);
        Assert.Equal(PageCreationSessionStatus.Committed, session.Status);
        Assert.Equal(pageId, session.CommittedPageId);
        Assert.Equal(Now.AddMinutes(5), session.ClosedAt);
    }

    [Fact]
    public void MarkCommitted_a_second_time_throws_never_silently_double_commits()
    {
        var session = PageCreationSession.Open(Guid.NewGuid(), null, Guid.NewGuid(), Now, TimeSpan.FromHours(24));
        session.MarkCommitted(Guid.NewGuid(), Now);

        Assert.Throws<InvalidOperationException>(() => session.MarkCommitted(Guid.NewGuid(), Now));
    }

    [Fact]
    public void MarkDiscarded_transitions_to_Discarded()
    {
        var session = PageCreationSession.Open(Guid.NewGuid(), null, Guid.NewGuid(), Now, TimeSpan.FromHours(24));

        session.MarkDiscarded(Now.AddMinutes(1));

        Assert.Equal(PageCreationSessionStatus.Discarded, session.Status);
        Assert.Equal(Now.AddMinutes(1), session.ClosedAt);
    }

    [Fact]
    public void MarkDiscarded_is_idempotent_when_already_discarded()
    {
        var session = PageCreationSession.Open(Guid.NewGuid(), null, Guid.NewGuid(), Now, TimeSpan.FromHours(24));
        session.MarkDiscarded(Now);

        var exception = Record.Exception(() => session.MarkDiscarded(Now.AddMinutes(1)));

        Assert.Null(exception);
        Assert.Equal(PageCreationSessionStatus.Discarded, session.Status);
    }

    [Fact]
    public void MarkDiscarded_after_MarkCommitted_throws_a_committed_page_can_never_be_discarded()
    {
        var session = PageCreationSession.Open(Guid.NewGuid(), null, Guid.NewGuid(), Now, TimeSpan.FromHours(24));
        session.MarkCommitted(Guid.NewGuid(), Now);

        Assert.Throws<InvalidOperationException>(() => session.MarkDiscarded(Now));
    }
}