// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using Microsoft.AspNetCore.Testing;

namespace Microsoft.AspNetCore.ConcurrencyLimiter.Tests.PolicyTests;

public class QueuePolicyTests
{
    [Fact]
    public void DoesNotWaitIfSpaceAvailable()
    {
        using var s = TestUtils.CreateQueuePolicy(2);

        var t1 = s.TryEnterAsync();
        Assert.True(t1.IsCompleted);

        var t2 = s.TryEnterAsync();
        Assert.True(t2.IsCompleted);

        var t3 = s.TryEnterAsync();
        Assert.False(t3.IsCompleted);
    }

    [Fact]
    public async Task WaitsIfNoSpaceAvailable()
    {
        using var s = TestUtils.CreateQueuePolicy(1);
        Assert.True(await s.TryEnterAsync().DefaultTimeout());

        var waitingTask = s.TryEnterAsync();
        Assert.False(waitingTask.IsCompleted);

        s.OnExit();
        Assert.True(await waitingTask.DefaultTimeout());
    }

    [Fact]
    public void DoesNotWaitIfQueueFull()
    {
        using var s = TestUtils.CreateQueuePolicy(2, 1);

        var t1 = s.TryEnterAsync();
        Assert.True(t1.IsCompleted);
        Assert.True(t1.Result);

        var t2 = s.TryEnterAsync();
        Assert.True(t2.IsCompleted);
        Assert.True(t2.Result);

        var t3 = s.TryEnterAsync();
        Assert.False(t3.IsCompleted);

        var t4 = s.TryEnterAsync();
        Assert.True(t4.IsCompleted);
        Assert.False(t4.Result);
    }

    [Fact]
    public async Task IsEncapsulated()
    {
        using var s1 = TestUtils.CreateQueuePolicy(1);
        using var s2 = TestUtils.CreateQueuePolicy(1);

        Assert.True(await s1.TryEnterAsync().DefaultTimeout());
        Assert.True(await s2.TryEnterAsync().DefaultTimeout());
    }
}
