using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.IO;
using System.Reactive.Linq;
using DynamicData;
using DynamicData.Binding;
using Intromat.Interfaces;
using ReactiveUI;

namespace Intromat.ViewModels
{
    public class FolderViewModel : ReactiveObject, ITreeItem
    {
        protected string _name;
        protected bool _isExpanded;
        protected bool _isSelected;
        protected ITreeItem _parent;
        protected readonly ObservableCollectionExtended<ITreeItem> _treeChildren = new();
        protected readonly ModuleViewModel _module;

        public FolderViewModel(ModuleViewModel? module, ITreeItem parent, string name)
        {
            _module = module ?? (ModuleViewModel)this;
            _parent = parent;
            _name = name;
            var folders = Folders.Connect();
            var files = Files.Connect();
            files
                .Cast(d => (ITreeItem)d)
                .Merge(folders.Cast(f => (ITreeItem)f))
                .Sort(TreeChildrenComparer)
                .Bind(_treeChildren) 
                .DisposeMany()
                .Subscribe();
        }

        public IComparer<ITreeItem> TreeChildrenComparer { get; } = Comparer<ITreeItem>.Create((i1, i2) =>
        {
            if (i1 is FolderViewModel && i2 is not FolderViewModel)
                return -1;
            if (i1 is not FolderViewModel && i2 is FolderViewModel)
                return 1;

            return String.Compare(i1.Name, i2.Name, StringComparison.Ordinal);
        });

        public string Name
        {
            get => _name;
            set
            {
                this.RaiseAndSetIfChanged(ref _name, value);
                // TODO: adjust path!
            }
        }

        public virtual string FullPath => Path.Combine(((FolderViewModel)_parent).FullPath, _name);

        public bool IsExpanded
        {
            get => _isExpanded;
            set => this.RaiseAndSetIfChanged(ref _isExpanded, value);
        }

        public bool IsSelected
        {
            get => _isSelected;
            set => this.RaiseAndSetIfChanged(ref _isSelected, value);
        }

        public ITreeItem Parent
        {
            get => _parent;
            set => this.RaiseAndSetIfChanged(ref _parent, value);
        }

        public ModuleViewModel Module => _module;
        public ISourceList<FolderViewModel> Folders { get; } = new SourceList<FolderViewModel>();
        public ISourceList<FileViewModel> Files { get; } = new SourceList<FileViewModel>();
        public ObservableCollection<ITreeItem> TreeChildren => _treeChildren;
    }
}