using w4c_workflows.Services;
using Xunit;

namespace w4c_workflows.Tests;

/// <summary>
/// P1-9: two overlapping syncs for the same <c>(tenant, repo)</c> must not run
/// concurrently, or they insert the same deterministic workflow/task ids and
/// collide on the primary key. The gate serializes that pair only — syncs for a
/// different repo/tenant stay parallel.
/// </summary>
public class SyncGateTests
{
    [Fact]
    public async Task Same_tenant_and_repo_waits_for_the_holder()
    {
        var gate = new SyncGate();
        var held = await gate.AcquireAsync("tenant-a", "repo", default);
        var waiter = gate.AcquireAsync("tenant-a", "repo", default);

        Assert.False(waiter.IsCompleted);

        held.Dispose();
        using var acquired = await waiter.WaitAsync(TimeSpan.FromSeconds(2));
        Assert.True(waiter.IsCompletedSuccessfully);
    }

    [Fact]
    public async Task Different_keys_do_not_block_each_other()
    {
        var gate = new SyncGate();
        using var first = await gate.AcquireAsync("tenant-a", "repo", default);

        // Another repo for the same tenant (and another tenant for the same repo)
        // must not wait behind the held gate.
        using var otherRepo = await gate.AcquireAsync("tenant-a", "other-repo", default).WaitAsync(TimeSpan.FromSeconds(2));
        using var otherTenant = await gate.AcquireAsync("tenant-b", "repo", default).WaitAsync(TimeSpan.FromSeconds(2));

        Assert.NotNull(otherRepo);
        Assert.NotNull(otherTenant);
    }

    [Fact]
    public async Task Dispose_is_idempotent_and_releases_once()
    {
        var gate = new SyncGate();
        var held = await gate.AcquireAsync("tenant-a", "repo", default);
        held.Dispose();
        held.Dispose();

        // A second acquisition after the (double) release must still succeed.
        using var next = await gate.AcquireAsync("tenant-a", "repo", default).WaitAsync(TimeSpan.FromSeconds(2));
        Assert.NotNull(next);
    }
}