namespace Zcbot.WindowsNode.Tests;

public sealed class DataRootPageViewModelTests
{
    [Fact]
    public async Task ChangeMigratesConfirmedTargetAndReportsCompletion()
    {
        var service = new FakeDataRootManagementService();
        var viewModel = new DataRootPageViewModel(service);
        NodeDataMigrationResult? completed = null;
        viewModel.ChooseTargetRequested += _ => @"D:\zcbot-data";
        viewModel.ConfirmMigrationRequested += _ => true;
        viewModel.MigrationRequested += target => Task.FromResult(
            new NodeDataMigrationResult(@"C:\node-data", target, 3, 4096));
        viewModel.MigrationCompleted += result => completed = result;

        viewModel.ChangeCommand.Execute(null);
        await WaitUntilAsync(() => completed is not null);

        Assert.Equal(@"D:\zcbot-data", completed!.TargetDirectory);
        Assert.Contains("3 个文件", viewModel.Status);
        Assert.True(viewModel.IsMigrating);
    }

    [Fact]
    public async Task ChangeRefusesPendingJobsBeforeChoosingATarget()
    {
        var service = new FakeDataRootManagementService { PendingJobs = true };
        var viewModel = new DataRootPageViewModel(service);
        var chooseCount = 0;
        viewModel.ChooseTargetRequested += _ =>
        {
            chooseCount++;
            return @"D:\zcbot-data";
        };
        viewModel.MigrationRequested += _ => throw new InvalidOperationException();

        viewModel.ChangeCommand.Execute(null);
        await WaitUntilAsync(() => viewModel.Status.Contains("未完成任务"));

        Assert.Equal(0, chooseCount);
        Assert.False(viewModel.IsMigrating);
    }

    [Fact]
    public void EnvironmentManagedRootDisablesMigration()
    {
        var service = new FakeDataRootManagementService
        {
            Selection = new NodeDataRootSelection(
                @"D:\managed",
                IsEnvironmentManaged: true,
                "environment"),
        };
        var viewModel = new DataRootPageViewModel(service);

        Assert.False(viewModel.ChangeCommand.CanExecute(null));
        Assert.Contains(NodeDataRootSettings.EnvironmentVariableName, viewModel.Status);
    }

    private static async Task WaitUntilAsync(Func<bool> condition)
    {
        var deadline = DateTime.UtcNow.AddSeconds(2);
        while (!condition() && DateTime.UtcNow < deadline)
        {
            await Task.Delay(10);
        }
        Assert.True(condition());
    }

    private sealed class FakeDataRootManagementService : IDataRootManagementService
    {
        internal NodeDataRootSelection Selection { get; init; } = new(
            @"C:\node-data",
            IsEnvironmentManaged: false,
            "default");
        internal bool PendingJobs { get; init; }

        public NodeDataRootSelection ReadSelection() => Selection;

        public bool HasPendingJobs => PendingJobs;

        public string Normalize(string path) => Path.TrimEndingDirectorySeparator(path);
    }
}