using System;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;
using Junction.Domain;
using Junction.Domain.Models;
using Junction.Domain.Persistence;
using Moq;
using Xunit;

namespace Junction.Tests.Unit
{
    /// <summary>
    /// Shape/contract tests for <see cref="IMachineRepository"/> using a Moq mock.
    /// No real database: these assert the async signatures and Result shapes only.
    /// </summary>
    public class MachineRepositoryContractTests
    {
        private static readonly OperationError SampleError =
            new OperationError("repo.error", "repository", "boom");

        private static Machine SampleMachine(Guid id) =>
            new Machine(id, "Mill", "mtconnect", null, TimeSpan.FromSeconds(2));

        private static MachineSnapshot SampleSnapshot(Guid machineId) =>
            new MachineSnapshot(machineId, DateTimeOffset.UtcNow, ConnectionState.Connected, null);

        [Fact]
        public async Task GetAllAsync_Ok_WrapsReadOnlyListOfMachines()
        {
            var machines = new List<Machine> { SampleMachine(Guid.NewGuid()) };
            var mock = new Mock<IMachineRepository>();
            mock.Setup(r => r.GetAllAsync(It.IsAny<CancellationToken>()))
                .ReturnsAsync(Result<IReadOnlyList<Machine>>.Ok(machines));

            Result<IReadOnlyList<Machine>> result = await mock.Object.GetAllAsync(CancellationToken.None);

            Assert.True(result.IsSuccess);
            Assert.False(result.WasCancelled);
            Assert.Single(result.Value);
        }

        [Fact]
        public async Task GetAllAsync_Fail_HasErrorsNoValue()
        {
            var mock = new Mock<IMachineRepository>();
            mock.Setup(r => r.GetAllAsync(It.IsAny<CancellationToken>()))
                .ReturnsAsync(Result<IReadOnlyList<Machine>>.Fail(SampleError));

            var result = await mock.Object.GetAllAsync(CancellationToken.None);

            Assert.False(result.IsSuccess);
            Assert.Single(result.Errors);
            Assert.Equal("repo.error", result.Errors[0].Code);
        }

        [Fact]
        public async Task GetByIdAsync_Ok_WrapsMachine()
        {
            var id = Guid.NewGuid();
            var mock = new Mock<IMachineRepository>();
            mock.Setup(r => r.GetByIdAsync(id, It.IsAny<CancellationToken>()))
                .ReturnsAsync(Result<Machine>.Ok(SampleMachine(id)));

            var result = await mock.Object.GetByIdAsync(id, CancellationToken.None);

            Assert.True(result.IsSuccess);
            Assert.Equal(id, result.Value.Id);
        }

        [Fact]
        public async Task GetByIdAsync_Fail_NotFoundShape()
        {
            var mock = new Mock<IMachineRepository>();
            mock.Setup(r => r.GetByIdAsync(It.IsAny<Guid>(), It.IsAny<CancellationToken>()))
                .ReturnsAsync(Result<Machine>.Fail(SampleError));

            var result = await mock.Object.GetByIdAsync(Guid.NewGuid(), CancellationToken.None);

            Assert.False(result.IsSuccess);
            Assert.NotEmpty(result.Errors);
        }

        [Fact]
        public async Task GetByIdAsync_Cancelled_SetsWasCancelled()
        {
            var mock = new Mock<IMachineRepository>();
            mock.Setup(r => r.GetByIdAsync(It.IsAny<Guid>(), It.IsAny<CancellationToken>()))
                .ReturnsAsync(Result<Machine>.Cancelled());

            var result = await mock.Object.GetByIdAsync(Guid.NewGuid(), CancellationToken.None);

            Assert.False(result.IsSuccess);
            Assert.True(result.WasCancelled);
        }

        [Fact]
        public async Task UpsertAsync_ReturnsNonGenericResult_Ok()
        {
            var mock = new Mock<IMachineRepository>();
            mock.Setup(r => r.UpsertAsync(It.IsAny<Machine>(), It.IsAny<CancellationToken>()))
                .ReturnsAsync(Result.Ok());

            Result result = await mock.Object.UpsertAsync(SampleMachine(Guid.NewGuid()), CancellationToken.None);

            Assert.IsType<Result>(result);
            Assert.True(result.IsSuccess);
        }

        [Fact]
        public async Task UpsertAsync_Fail_CarriesErrors()
        {
            var mock = new Mock<IMachineRepository>();
            mock.Setup(r => r.UpsertAsync(It.IsAny<Machine>(), It.IsAny<CancellationToken>()))
                .ReturnsAsync(Result.Fail(SampleError));

            var result = await mock.Object.UpsertAsync(SampleMachine(Guid.NewGuid()), CancellationToken.None);

            Assert.False(result.IsSuccess);
            Assert.Single(result.Errors);
        }

        [Fact]
        public async Task DeleteAsync_ReturnsNonGenericResult_Ok()
        {
            var mock = new Mock<IMachineRepository>();
            mock.Setup(r => r.DeleteAsync(It.IsAny<Guid>(), It.IsAny<CancellationToken>()))
                .ReturnsAsync(Result.Ok());

            Result result = await mock.Object.DeleteAsync(Guid.NewGuid(), CancellationToken.None);

            Assert.IsType<Result>(result);
            Assert.True(result.IsSuccess);
        }

        [Fact]
        public async Task DeleteAsync_Cancelled_SetsWasCancelled()
        {
            var mock = new Mock<IMachineRepository>();
            mock.Setup(r => r.DeleteAsync(It.IsAny<Guid>(), It.IsAny<CancellationToken>()))
                .ReturnsAsync(Result.Cancelled());

            var result = await mock.Object.DeleteAsync(Guid.NewGuid(), CancellationToken.None);

            Assert.True(result.WasCancelled);
            Assert.False(result.IsSuccess);
        }

        [Fact]
        public async Task SaveSnapshotAsync_ReturnsNonGenericResult_Ok()
        {
            var machineId = Guid.NewGuid();
            var mock = new Mock<IMachineRepository>();
            mock.Setup(r => r.SaveSnapshotAsync(It.IsAny<MachineSnapshot>(), It.IsAny<CancellationToken>()))
                .ReturnsAsync(Result.Ok());

            Result result = await mock.Object.SaveSnapshotAsync(SampleSnapshot(machineId), CancellationToken.None);

            Assert.IsType<Result>(result);
            Assert.True(result.IsSuccess);
        }

        [Fact]
        public async Task SaveSnapshotAsync_Fail_CarriesErrors()
        {
            var mock = new Mock<IMachineRepository>();
            mock.Setup(r => r.SaveSnapshotAsync(It.IsAny<MachineSnapshot>(), It.IsAny<CancellationToken>()))
                .ReturnsAsync(Result.Fail(SampleError));

            var result = await mock.Object.SaveSnapshotAsync(SampleSnapshot(Guid.NewGuid()), CancellationToken.None);

            Assert.False(result.IsSuccess);
            Assert.NotEmpty(result.Errors);
        }

        [Fact]
        public async Task GetLatestSnapshotAsync_Ok_WrapsSnapshot()
        {
            var machineId = Guid.NewGuid();
            var mock = new Mock<IMachineRepository>();
            mock.Setup(r => r.GetLatestSnapshotAsync(machineId, It.IsAny<CancellationToken>()))
                .ReturnsAsync(Result<MachineSnapshot>.Ok(SampleSnapshot(machineId)));

            Result<MachineSnapshot> result = await mock.Object.GetLatestSnapshotAsync(machineId, CancellationToken.None);

            Assert.True(result.IsSuccess);
            Assert.Equal(machineId, result.Value.MachineId);
            Assert.Equal(ConnectionState.Connected, result.Value.ConnectionState);
        }

        [Fact]
        public async Task GetLatestSnapshotAsync_Fail_NoneStored()
        {
            var mock = new Mock<IMachineRepository>();
            mock.Setup(r => r.GetLatestSnapshotAsync(It.IsAny<Guid>(), It.IsAny<CancellationToken>()))
                .ReturnsAsync(Result<MachineSnapshot>.Fail(SampleError));

            var result = await mock.Object.GetLatestSnapshotAsync(Guid.NewGuid(), CancellationToken.None);

            Assert.False(result.IsSuccess);
            Assert.Single(result.Errors);
        }

        [Fact]
        public async Task AllMethods_HonorPassedCancellationToken()
        {
            using var cts = new CancellationTokenSource();
            var token = cts.Token;
            var mock = new Mock<IMachineRepository>();

            mock.Setup(r => r.GetAllAsync(token))
                .ReturnsAsync(Result<IReadOnlyList<Machine>>.Ok(new List<Machine>()));
            mock.Setup(r => r.GetByIdAsync(It.IsAny<Guid>(), token))
                .ReturnsAsync(Result<Machine>.Ok(SampleMachine(Guid.NewGuid())));
            mock.Setup(r => r.UpsertAsync(It.IsAny<Machine>(), token)).ReturnsAsync(Result.Ok());
            mock.Setup(r => r.DeleteAsync(It.IsAny<Guid>(), token)).ReturnsAsync(Result.Ok());
            mock.Setup(r => r.SaveSnapshotAsync(It.IsAny<MachineSnapshot>(), token)).ReturnsAsync(Result.Ok());
            mock.Setup(r => r.GetLatestSnapshotAsync(It.IsAny<Guid>(), token))
                .ReturnsAsync(Result<MachineSnapshot>.Ok(SampleSnapshot(Guid.NewGuid())));

            await mock.Object.GetAllAsync(token);
            await mock.Object.GetByIdAsync(Guid.NewGuid(), token);
            await mock.Object.UpsertAsync(SampleMachine(Guid.NewGuid()), token);
            await mock.Object.DeleteAsync(Guid.NewGuid(), token);
            await mock.Object.SaveSnapshotAsync(SampleSnapshot(Guid.NewGuid()), token);
            await mock.Object.GetLatestSnapshotAsync(Guid.NewGuid(), token);

            mock.Verify(r => r.GetAllAsync(token), Times.Once);
            mock.Verify(r => r.GetByIdAsync(It.IsAny<Guid>(), token), Times.Once);
            mock.Verify(r => r.UpsertAsync(It.IsAny<Machine>(), token), Times.Once);
            mock.Verify(r => r.DeleteAsync(It.IsAny<Guid>(), token), Times.Once);
            mock.Verify(r => r.SaveSnapshotAsync(It.IsAny<MachineSnapshot>(), token), Times.Once);
            mock.Verify(r => r.GetLatestSnapshotAsync(It.IsAny<Guid>(), token), Times.Once);
        }
    }
}