using AxCopilot.Services;
using FluentAssertions;
using Xunit;

namespace AxCopilot.Tests.Services;

public class DraftQueueProcessorServiceTests
{
    [Fact]
    public void TryStartNext_PicksPreferredDraftAndMarksItRunning()
    {
        var session = new ChatSessionStateService();
        var processor = new DraftQueueProcessorService();
        var first = session.EnqueueDraft("Chat", "first", "next");
        var second = session.EnqueueDraft("Chat", "second", "later");

        var started = processor.TryStartNext(session, "Chat", preferredDraftId: second!.Id);

        started.Should().NotBeNull();
        started!.Id.Should().Be(second.Id);
        session.GetDraftQueueItems("Chat").Single(x => x.Id == second.Id).State.Should().Be("running");
        session.GetDraftQueueItems("Chat").Single(x => x.Id == first!.Id).State.Should().Be("queued");
    }

    [Fact]
    public void HandleFailure_SchedulesRetryBeforeRetryLimit()
    {
        var session = new ChatSessionStateService();
        var processor = new DraftQueueProcessorService();
        var item = session.EnqueueDraft("Chat", "retry me", "next");
        processor.TryStartNext(session, "Chat", preferredDraftId: item!.Id);

        var handled = processor.HandleFailure(session, "Chat", item.Id, "boom", cancelled: false, maxAutoRetries: 3);

        handled.Should().BeTrue();
        var stored = session.GetDraftQueueItems("Chat").Single(x => x.Id == item.Id);
        stored.State.Should().Be("queued");
        stored.NextRetryAt.Should().NotBeNull();
    }

    [Fact]
    public void PromoteReadyBlockedItems_ClearsExpiredRetryWindow()
    {
        var session = new ChatSessionStateService();
        var processor = new DraftQueueProcessorService();
        var item = session.EnqueueDraft("Chat", "retry me", "next");
        processor.TryStartNext(session, "Chat", preferredDraftId: item!.Id);
        processor.HandleFailure(session, "Chat", item.Id, "boom", cancelled: false, maxAutoRetries: 3);
        session.CurrentConversation!.DraftQueueItems[0].NextRetryAt = DateTime.Now.AddSeconds(-1);

        var promoted = processor.PromoteReadyBlockedItems(session, "Chat");

        promoted.Should().Be(1);
        session.CurrentConversation!.DraftQueueItems[0].NextRetryAt.Should().BeNull();
    }

    [Fact]
    public void ClearCompleted_RemovesCompletedItems()
    {
        var session = new ChatSessionStateService();
        var processor = new DraftQueueProcessorService();
        var item = session.EnqueueDraft("Chat", "done item", "next");
        processor.TryStartNext(session, "Chat", preferredDraftId: item!.Id);
        processor.Complete(session, "Chat", item.Id);

        var removed = processor.ClearCompleted(session, "Chat");

        removed.Should().Be(1);
        session.GetDraftQueueItems("Chat").Should().BeEmpty();
    }

    [Fact]
    public void TryStartNext_AndHandleFailure_RecordQueueTasks()
    {
        var session = new ChatSessionStateService();
        var processor = new DraftQueueProcessorService();
        var taskRuns = new TaskRunService();
        var item = session.EnqueueDraft("Chat", "retry me", "next");

        processor.TryStartNext(session, "Chat", preferredDraftId: item!.Id, taskRuns: taskRuns);
        processor.HandleFailure(session, "Chat", item.Id, "boom", cancelled: false, maxAutoRetries: 3, taskRuns: taskRuns);

        taskRuns.ActiveTasks.Should().BeEmpty();
        taskRuns.RecentTasks.Should().ContainSingle(t => t.Kind == "queue" && t.Status == "blocked");
    }
}