using Opc.Ua;
using Shouldly;
using Xunit;
using ZB.MOM.WW.LmxOpcUa.Client.Shared.Models;
using ZB.MOM.WW.LmxOpcUa.Client.UI.Services;
using ZB.MOM.WW.LmxOpcUa.Client.UI.Tests.Fakes;
using ZB.MOM.WW.LmxOpcUa.Client.UI.ViewModels;

namespace ZB.MOM.WW.LmxOpcUa.Client.UI.Tests;

public class SubscriptionsViewModelTests
{
    private readonly FakeOpcUaClientService _service;
    private readonly SubscriptionsViewModel _vm;

    public SubscriptionsViewModelTests()
    {
        _service = new FakeOpcUaClientService();
        var dispatcher = new SynchronousUiDispatcher();
        _vm = new SubscriptionsViewModel(_service, dispatcher);
    }

    [Fact]
    public void AddSubscriptionCommand_CannotExecute_WhenDisconnected()
    {
        _vm.IsConnected = false;
        _vm.NewNodeIdText = "ns=2;s=SomeNode";
        _vm.AddSubscriptionCommand.CanExecute(null).ShouldBeFalse();
    }

    [Fact]
    public void AddSubscriptionCommand_CannotExecute_WhenNoNodeId()
    {
        _vm.IsConnected = true;
        _vm.NewNodeIdText = null;
        _vm.AddSubscriptionCommand.CanExecute(null).ShouldBeFalse();
    }

    [Fact]
    public async Task AddSubscriptionCommand_AddsItem()
    {
        _vm.IsConnected = true;
        _vm.NewNodeIdText = "ns=2;s=SomeNode";
        _vm.NewInterval = 500;

        await _vm.AddSubscriptionCommand.ExecuteAsync(null);

        _vm.ActiveSubscriptions.Count.ShouldBe(1);
        _vm.ActiveSubscriptions[0].NodeId.ShouldBe("ns=2;s=SomeNode");
        _vm.ActiveSubscriptions[0].IntervalMs.ShouldBe(500);
        _vm.SubscriptionCount.ShouldBe(1);
        _service.SubscribeCallCount.ShouldBe(1);
    }

    [Fact]
    public async Task RemoveSubscriptionCommand_RemovesItem()
    {
        _vm.IsConnected = true;
        _vm.NewNodeIdText = "ns=2;s=SomeNode";
        await _vm.AddSubscriptionCommand.ExecuteAsync(null);

        _vm.SelectedSubscription = _vm.ActiveSubscriptions[0];
        await _vm.RemoveSubscriptionCommand.ExecuteAsync(null);

        _vm.ActiveSubscriptions.ShouldBeEmpty();
        _vm.SubscriptionCount.ShouldBe(0);
        _service.UnsubscribeCallCount.ShouldBe(1);
    }

    [Fact]
    public void RemoveSubscriptionCommand_CannotExecute_WhenNoSelection()
    {
        _vm.IsConnected = true;
        _vm.SelectedSubscription = null;
        _vm.RemoveSubscriptionCommand.CanExecute(null).ShouldBeFalse();
    }

    [Fact]
    public async Task DataChanged_UpdatesMatchingRow()
    {
        _vm.IsConnected = true;
        _vm.NewNodeIdText = "ns=2;s=SomeNode";
        await _vm.AddSubscriptionCommand.ExecuteAsync(null);

        var dataValue = new DataValue(new Variant(42), StatusCodes.Good, DateTime.UtcNow);
        _service.RaiseDataChanged(new DataChangedEventArgs("ns=2;s=SomeNode", dataValue));

        _vm.ActiveSubscriptions[0].Value.ShouldBe("42");
        _vm.ActiveSubscriptions[0].Status.ShouldNotBeNull();
    }

    [Fact]
    public async Task DataChanged_DoesNotUpdateNonMatchingRow()
    {
        _vm.IsConnected = true;
        _vm.NewNodeIdText = "ns=2;s=SomeNode";
        await _vm.AddSubscriptionCommand.ExecuteAsync(null);

        var dataValue = new DataValue(new Variant(42), StatusCodes.Good, DateTime.UtcNow);
        _service.RaiseDataChanged(new DataChangedEventArgs("ns=2;s=OtherNode", dataValue));

        _vm.ActiveSubscriptions[0].Value.ShouldBeNull();
    }

    [Fact]
    public void Clear_RemovesAllSubscriptions()
    {
        _vm.ActiveSubscriptions.Add(new SubscriptionItemViewModel("ns=2;s=X", 1000));
        _vm.SubscriptionCount = 1;

        _vm.Clear();

        _vm.ActiveSubscriptions.ShouldBeEmpty();
        _vm.SubscriptionCount.ShouldBe(0);
    }

    [Fact]
    public void Teardown_UnhooksEventHandler()
    {
        _vm.Teardown();

        // After teardown, raising event should not update anything
        _vm.ActiveSubscriptions.Add(new SubscriptionItemViewModel("ns=2;s=X", 1000));
        var dataValue = new DataValue(new Variant(42), StatusCodes.Good, DateTime.UtcNow);
        _service.RaiseDataChanged(new DataChangedEventArgs("ns=2;s=X", dataValue));

        _vm.ActiveSubscriptions[0].Value.ShouldBeNull();
    }

    [Fact]
    public void DefaultInterval_Is1000()
    {
        _vm.NewInterval.ShouldBe(1000);
    }
}