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

using FakeItEasy;
using Squidex.Infrastructure.EventSourcing;
using Squidex.Infrastructure.States;

namespace Squidex.Infrastructure.TestHelpers
{
    public sealed class TestState<T> where T : class, new()
    {
        private readonly List<Envelope<IEvent>> events = new List<Envelope<IEvent>>();
        private readonly ISnapshotStore<T> snapshotStore = A.Fake<ISnapshotStore<T>>();
        private HandleSnapshot<T>? handleSnapshot;
        private HandleEvent? handleEvent;

        public DomainId Id { get; }

        public IPersistenceFactory<T> PersistenceFactory { get; }

        public IPersistence<T> Persistence { get; } = A.Fake<IPersistence<T>>();

        public long Version { get; set; } = EtagVersion.Empty;

        public T Snapshot { get; set; } = new T();

        public TestState(string id, IPersistenceFactory<T>? persistenceFactory = null)
            : this(DomainId.Create(id), persistenceFactory)
        {
        }

        public TestState(DomainId id, IPersistenceFactory<T>? persistenceFactory = null)
        {
            Id = id;

            PersistenceFactory = persistenceFactory ?? A.Fake<IPersistenceFactory<T>>();

            A.CallTo(() => PersistenceFactory.Snapshots)
                .Returns(snapshotStore);

            A.CallTo(() => Persistence.Version)
                .ReturnsLazily(() => Version);

            A.CallTo(() => snapshotStore.ReadAllAsync(A<CancellationToken>._))
                .ReturnsLazily(() => new List<SnapshotResult<T>>
                {
                    new SnapshotResult<T>(id, Snapshot, Version, true)
                }.ToAsyncEnumerable());

            A.CallTo(() => PersistenceFactory.WithEventSourcing(A<Type>._, id, A<HandleEvent>._))
                .Invokes(x =>
                {
                    handleEvent = x.GetArgument<HandleEvent>(2);
                })
                .Returns(Persistence);

            A.CallTo(() => PersistenceFactory.WithSnapshots(A<Type>._, id, A<HandleSnapshot<T>>._))
                .Invokes(x =>
                {
                    handleSnapshot = x.GetArgument<HandleSnapshot<T>>(2);
                })
                .Returns(Persistence);

            A.CallTo(() => PersistenceFactory.WithSnapshotsAndEventSourcing(A<Type>._, id, A<HandleSnapshot<T>>._, A<HandleEvent>._))
                .Invokes(x =>
                {
                    handleSnapshot = x.GetArgument<HandleSnapshot<T>>(2);
                    handleEvent = x.GetArgument<HandleEvent>(3);
                })
                .Returns(Persistence);

            A.CallTo(() => Persistence.WriteEventsAsync(A<IReadOnlyList<Envelope<IEvent>>>._, A<CancellationToken>._))
                .Invokes(x =>
                {
                    events.AddRange(x.GetArgument<IReadOnlyList<Envelope<IEvent>>>(0)!);
                });

            A.CallTo(() => Persistence.WriteSnapshotAsync(A<T>._, A<CancellationToken>._))
                .Invokes(x =>
                {
                    Snapshot = x.GetArgument<T>(0)!;
                });

            A.CallTo(() => Persistence.ReadAsync(A<long>._, A<CancellationToken>._))
                .Invokes(x =>
                {
                    handleSnapshot?.Invoke(Snapshot, Version);

                    if (handleEvent != null)
                    {
                        foreach (var @event in events)
                        {
                            handleEvent(@event);
                        }
                    }
                });

            A.CallTo(() => Persistence.DeleteAsync(A<CancellationToken>._))
                .Invokes(x =>
                {
                    Snapshot = new T();
                });
        }

        public void AddEvent(Envelope<IEvent> @event)
        {
            events.Add(@event);
        }

        public void AddEvent(IEvent @event)
        {
            events.Add(Envelope.Create(@event));
        }
    }
}