using System.Collections.ObjectModel;
using System.Collections.Specialized;
using System.ComponentModel;
using System.Text;
using CommunityToolkit.Mvvm.ComponentModel;
using CommunityToolkit.Mvvm.Input;

namespace ClaudeDo.Ui.ViewModels.Islands.Detail;

public partial class SubtaskRowSampleViewModel : ObservableObject
{
    [ObservableProperty] string _title = "";
    [ObservableProperty] bool _done;
    [ObservableProperty] bool _isEditing;

    [RelayCommand] void ToggleDone() => Done = !Done;
    [RelayCommand] void BeginEdit() => IsEditing = true;
    [RelayCommand] void CommitEdit() => IsEditing = false;
}

public partial class DescriptionStepsCardViewModel : ClaudeDo.Ui.ViewModels.ViewModelBase
{
    [ObservableProperty]
    [NotifyPropertyChangedFor(nameof(IsDescriptionView))]
    bool _isStepsView;

    public bool IsDescriptionView => !IsStepsView;

    [ObservableProperty]
    [NotifyPropertyChangedFor(nameof(ComposedPreview))]
    string _title = "";

    [ObservableProperty]
    [NotifyPropertyChangedFor(nameof(ComposedPreview))]
    string _editableDescription = "";

    [ObservableProperty] bool _isEditingDescription;
    [ObservableProperty] string _newSubtaskTitle = "";

    public ObservableCollection<SubtaskRowSampleViewModel> Subtasks { get; } = new();

    public string ComposedPreview => BuildComposedPreview();

    [RelayCommand] void ToggleCardView() => IsStepsView = !IsStepsView;
    [RelayCommand] void ToggleEditDescription() => IsEditingDescription = !IsEditingDescription;

    [RelayCommand]
    void AddSubtask()
    {
        if (string.IsNullOrWhiteSpace(NewSubtaskTitle)) return;
        var row = new SubtaskRowSampleViewModel { Title = NewSubtaskTitle.Trim() };
        row.PropertyChanged += OnRowPropertyChanged;
        Subtasks.Add(row);
        NewSubtaskTitle = "";
        OnPropertyChanged(nameof(ComposedPreview));
    }

    [RelayCommand]
    void ToggleSubtaskDone(SubtaskRowSampleViewModel row)
    {
        row.Done = !row.Done;
    }

    [RelayCommand]
    void CommitSubtaskEdit(SubtaskRowSampleViewModel row)
    {
        row.IsEditing = false;
    }

    private void OnRowPropertyChanged(object? sender, PropertyChangedEventArgs e)
    {
        if (e.PropertyName is nameof(SubtaskRowSampleViewModel.Done)
                           or nameof(SubtaskRowSampleViewModel.Title))
            OnPropertyChanged(nameof(ComposedPreview));
    }

    private void OnSubtasksChanged(object? sender, NotifyCollectionChangedEventArgs e)
    {
        if (e.NewItems is not null)
            foreach (SubtaskRowSampleViewModel row in e.NewItems)
                row.PropertyChanged += OnRowPropertyChanged;
        if (e.OldItems is not null)
            foreach (SubtaskRowSampleViewModel row in e.OldItems)
                row.PropertyChanged -= OnRowPropertyChanged;
        OnPropertyChanged(nameof(ComposedPreview));
    }

    private string BuildComposedPreview()
    {
        var sb = new StringBuilder();
        sb.AppendLine(Title);

        if (!string.IsNullOrWhiteSpace(EditableDescription))
        {
            sb.AppendLine();
            sb.AppendLine(EditableDescription.TrimEnd());
        }

        var openSteps = Subtasks.Where(s => !s.Done).ToList();
        if (openSteps.Count > 0)
        {
            sb.AppendLine();
            sb.AppendLine("## Sub-Tasks");
            foreach (var step in openSteps)
                sb.AppendLine($"- [ ] {step.Title}");
        }

        return sb.ToString().TrimEnd();
    }

    public DescriptionStepsCardViewModel()
    {
        Subtasks.CollectionChanged += OnSubtasksChanged;

        _title = "Refactor diff viewer";
        _editableDescription =
            "Split the current monolithic diff renderer into smaller, testable components.\n\n" +
            "The goal is to improve readability and allow unit testing of each parsing stage independently.";

        var samples = new[]
        {
            new SubtaskRowSampleViewModel { Title = "Extract DiffParser into its own class", Done = true },
            new SubtaskRowSampleViewModel { Title = "Add unit tests for DiffParser",          Done = true },
            new SubtaskRowSampleViewModel { Title = "Wire new parser into DiffViewerViewModel" },
            new SubtaskRowSampleViewModel { Title = "Update snapshot tests" },
        };
        foreach (var row in samples)
        {
            row.PropertyChanged += OnRowPropertyChanged;
            Subtasks.Add(row);
        }
    }
}