// Copyright 2012-2026 The NATS Authors
// Licensed under the Apache License, Version 2.0

using Shouldly;
using ZB.MOM.NatsNet.Server;

namespace ZB.MOM.NatsNet.Server.Tests.JetStream;

public sealed class WaitQueueTests
{
    [Fact]
    public void Add_Peek_Pop_IsFull_ShouldBehaveAsFifo()
    {
        var q = new WaitQueue();

        q.Peek().ShouldBeNull();
        q.Pop().ShouldBeNull();

        q.Add(new WaitingRequest { Subject = "A", N = 1 });
        q.Add(new WaitingRequest { Subject = "B", N = 2 });

        q.Len.ShouldBe(2);
        q.IsFull(2).ShouldBeTrue();
        q.Peek()!.Subject.ShouldBe("A");

        q.Pop()!.Subject.ShouldBe("A");
        q.Pop()!.Subject.ShouldBe("B");
        q.Len.ShouldBe(1);

        q.Pop()!.Subject.ShouldBe("B");
        q.Len.ShouldBe(0);
        q.IsFull(1).ShouldBeFalse();
    }

    [Fact]
    public void AddPrioritized_AndCycle_ShouldPreserveStableOrder()
    {
        var q = new WaitQueue(max: 10);

        q.AddPrioritized(new WaitingRequest { Reply = "2a", N = 1, PriorityGroup = new PriorityGroup { Priority = 2 } })
            .ShouldBeTrue();
        q.AddPrioritized(new WaitingRequest { Reply = "1a", N = 1, PriorityGroup = new PriorityGroup { Priority = 1 } })
            .ShouldBeTrue();
        q.AddPrioritized(new WaitingRequest { Reply = "1b", N = 1, PriorityGroup = new PriorityGroup { Priority = 1 } })
            .ShouldBeTrue();

        q.Peek()!.Reply.ShouldBe("1a");
        q.Cycle();
        q.Peek()!.Reply.ShouldBe("1b");
    }
}