using System.Collections.Specialized;
using SpdUp.Core;
using SpdUp.ViewModels;

namespace SpdUp.Tests;

/// <summary>
/// Tests for DebugLogViewModel.
/// Uses a helper to run on STA thread for WPF Dispatcher compatibility.
/// </summary>
public class DebugLogViewModelTests
{
    private static void RunOnSta(Action action)
    {
        Exception? caught = null;
        var thread = new Thread(() =>
        {
            try { action(); }
            catch (Exception ex) { caught = ex; }
        });
        thread.SetApartmentState(ApartmentState.STA);
        thread.Start();
        thread.Join();
        if (caught is not null)
            throw new Xunit.Sdk.XunitException($"STA test failed: {caught.Message}", caught);
    }

    [Fact]
    public void Initial_LogLines_IsEmpty()
    {
        RunOnSta(() =>
        {
            var vm = new DebugLogViewModel();
            Assert.Empty(vm.LogLines);
        });
    }

    [Fact]
    public void AutoScroll_DefaultTrue()
    {
        RunOnSta(() =>
        {
            var vm = new DebugLogViewModel();
            Assert.True(vm.AutoScroll);
        });
    }

    [Fact]
    public void AutoScroll_Settable()
    {
        RunOnSta(() =>
        {
            var vm = new DebugLogViewModel();
            vm.AutoScroll = false;
            Assert.False(vm.AutoScroll);
        });
    }

    [Fact]
    public void FilterText_DefaultEmpty()
    {
        RunOnSta(() =>
        {
            var vm = new DebugLogViewModel();
            Assert.Equal(string.Empty, vm.FilterText);
        });
    }

    [Fact]
    public void FilterText_RaisesPropertyChanged()
    {
        RunOnSta(() =>
        {
            var vm = new DebugLogViewModel();
            var changed = new List<string>();
            vm.PropertyChanged += (_, e) => changed.Add(e.PropertyName!);

            vm.FilterText = "error";

            Assert.Contains("FilterText", changed);
            Assert.Contains("FilteredLogLines", changed);
        });
    }

    [Fact]
    public void ClearCommand_ClearsLogLines()
    {
        RunOnSta(() =>
        {
            var vm = new DebugLogViewModel();
            vm.LogLines.Add("test line 1");
            vm.LogLines.Add("test line 2");

            vm.ClearCommand.Execute(null);

            Assert.Empty(vm.LogLines);
        });
    }

    [Fact]
    public void FilteredLogLines_NoFilter_ReturnsAll()
    {
        RunOnSta(() =>
        {
            var vm = new DebugLogViewModel();
            vm.LogLines.Add("[INFO] started");
            vm.LogLines.Add("[ERROR] failed");
            vm.LogLines.Add("[WARN] low memory");

            var filtered = vm.FilteredLogLines.ToList();
            Assert.Equal(3, filtered.Count);
        });
    }

    [Fact]
    public void FilteredLogLines_WithFilter_ReturnsMatches()
    {
        RunOnSta(() =>
        {
            var vm = new DebugLogViewModel();
            vm.LogLines.Add("[INFO] started");
            vm.LogLines.Add("[ERROR] something failed");
            vm.LogLines.Add("[WARN] low memory");

            vm.FilterText = "error";

            var filtered = vm.FilteredLogLines.ToList();
            Assert.Single(filtered);
            Assert.Contains("ERROR", filtered[0]);
        });
    }

    [Fact]
    public void FilteredLogLines_CaseInsensitive()
    {
        RunOnSta(() =>
        {
            var vm = new DebugLogViewModel();
            vm.LogLines.Add("[INFO] Test Message");

            vm.FilterText = "test message";

            Assert.Single(vm.FilteredLogLines);
        });
    }

    [Fact]
    public void Commands_AreNotNull()
    {
        RunOnSta(() =>
        {
            var vm = new DebugLogViewModel();
            Assert.NotNull(vm.ClearCommand);
            Assert.NotNull(vm.CopyAllCommand);
        });
    }
}