// ==========================================================================
//  Squidex Headless CMS
// ==========================================================================
//  Copyright (c) Squidex UG (haftungsbeschraenkt)
//  All rights reserved. Licensed under the MIT license.
// ==========================================================================

using FakeItEasy;
using NodaTime;
using Squidex.Infrastructure;
using Squidex.Infrastructure.TestHelpers;
using Xunit;

namespace Squidex.Domain.Apps.Entities.Comments
{
    public class WatchingServiceTests
    {
        private readonly CancellationTokenSource cts = new CancellationTokenSource();
        private readonly CancellationToken ct;
        private readonly TestState<WatchingService.State> state1;
        private readonly TestState<WatchingService.State> state2;
        private readonly IClock clock = A.Fake<IClock>();
        private readonly DomainId appId = DomainId.NewGuid();
        private readonly string resource1 = "resource1";
        private readonly string resource2 = "resource2";
        private readonly WatchingService sut;
        private Instant now = SystemClock.Instance.GetCurrentInstant();

        public WatchingServiceTests()
        {
            ct = cts.Token;

            A.CallTo(() => clock.GetCurrentInstant())
                .ReturnsLazily(() => now);

            state1 = new TestState<WatchingService.State>($"{appId}_{resource1}");
            state2 = new TestState<WatchingService.State>($"{appId}_{resource2}", state1.PersistenceFactory);

            sut = new WatchingService(state1.PersistenceFactory)
            {
                Clock = clock
            };
        }

        [Fact]
        public async Task Should_only_return_self_if_no_one_watching()
        {
            var watching = await sut.GetWatchingUsersAsync(appId, resource1, "user1", ct);

            Assert.Equal(new[] { "user1" }, watching);
        }

        [Fact]
        public async Task Should_return_users_watching_on_same_resource()
        {
            await sut.GetWatchingUsersAsync(appId, resource1, "user1", ct);
            await sut.GetWatchingUsersAsync(appId, resource2, "user2", ct);

            var watching1 = await sut.GetWatchingUsersAsync(appId, resource1, "user3", ct);
            var watching2 = await sut.GetWatchingUsersAsync(appId, resource2, "user4", ct);

            Assert.Equal(new[] { "user1", "user3" }, watching1);
            Assert.Equal(new[] { "user2", "user4" }, watching2);
        }

        [Fact]
        public async Task Should_cleanup_old_users()
        {
            await sut.GetWatchingUsersAsync(appId, resource1, "user1", ct);
            await sut.GetWatchingUsersAsync(appId, resource2, "user2", ct);

            now = now.Plus(Duration.FromMinutes(2));

            await sut.GetWatchingUsersAsync(appId, resource1, "user3", ct);
            await sut.GetWatchingUsersAsync(appId, resource2, "user4", ct);

            var watching1 = await sut.GetWatchingUsersAsync(appId, resource1, "user5", ct);
            var watching2 = await sut.GetWatchingUsersAsync(appId, resource2, "user6", ct);

            Assert.Equal(new[] { "user3", "user5" }, watching1);
            Assert.Equal(new[] { "user4", "user6" }, watching2);

            A.CallTo(() => state1.Persistence.WriteSnapshotAsync(A<WatchingService.State>._, ct))
                .MustHaveHappened();

            A.CallTo(() => state2.Persistence.WriteSnapshotAsync(A<WatchingService.State>._, ct))
                .MustHaveHappened();
        }
    }
}