using System;
using System.Collections.ObjectModel;
using System.IO;
using System.Linq;
using System.Reactive;
using System.Reactive.Linq;
using System.Threading.Tasks;
using Intromat.PersistentModel;
using Intromat.ViewModels.Nodes;
using Intromat.ViewModels.Previews;
using NodeNetwork.Toolkit.Group;
using NodeNetwork.Toolkit.NodeList;
using ReactiveUI;

namespace Intromat.ViewModels
{
    public class MainViewModel : ReactiveObject
    {
        private ProjectViewModel _project;
        private FileViewModel? _activeFile;
        private object? _propertiesContext;
        private DxTexturePreviewViewModel? _preview2dContext;
        private DxMeshPreviewViewModel? _preview3dContext;

        public MainViewModel()
        {
            AppState = ((AppStateViewModel)RxApp.SuspensionHost.AppState!)!;
            Explorer = new(this);

            var desktopPath = Environment.GetFolderPath(Environment.SpecialFolder.Desktop);
            var initialProjectPath = Path.Combine(desktopPath, "Project1", "Project1.iproj");
            if (File.Exists(initialProjectPath))
            {
                _project = Task.Run(() => ProjectSerializer.LoadProject(this, initialProjectPath)).GetAwaiter().GetResult()!;
            }
            else
            {
                _project = ProjectViewModel.CreateDefault(this, initialProjectPath, "Project1");
            }

            foreach (var nodeType in typeof(CodeGenNodeViewModel).Assembly.ExportedTypes.Where(t => typeof(CodeGenNodeViewModel).IsAssignableFrom(t) && !t.IsAbstract))
            {
                if (nodeType.Namespace == $"{nameof(Intromat)}.{nameof(Nodes)}")
                    continue;

                NodeList.AddNodeType(() => (CodeGenNodeViewModel)Activator.CreateInstance(nodeType)!);
            }

            Grouper = new NodeGrouper
            {
                GroupNodeFactory = subnet => new GroupNodeViewModel
                {
                    Name = "Group",
                    Subnet = (CodeGenNetworkViewModel)subnet
                },
                EntranceNodeFactory = () => new GroupSubnetIONodeViewModel
                {
                    IsEntranceNode = true
                },
                ExitNodeFactory = () => new GroupSubnetIONodeViewModel
                {
                    IsEntranceNode = false
                },
                SubNetworkFactory = parentNet =>
                {
                    var subNetwork = new CodeGenNetworkViewModel(((CodeGenNetworkViewModel)parentNet).Document, "Group") { ParentNetwork = (CodeGenNetworkViewModel)parentNet };
                    return subNetwork;
                },
                IOBindingFactory = (groupNode, entranceNode, exitNode) =>
                    new CodeNodeGroupIOBinding(groupNode, entranceNode, exitNode)
            };

            LoadProject = ReactiveCommand.CreateFromTask(async () =>
            {
                var file = await OpenProjectFile.Handle(true);
                if (file == null)
                    return null;

                var activeFile = ActiveFile;
                if (activeFile != null)
                    UndoRedo.Purge(activeFile);

                UndoRedo.Recording = false;
                try
                {
                    return await ProjectSerializer.LoadProject(this, file);
                }
                catch (Exception)
                {
                    // ignored, TODO
                }
                finally
                {
                    ActiveFile = null;
                    Files.Clear();
                    UndoRedo.Recording = true;
                }

                return null;
            });
            LoadProject.Where(n => n != null).Subscribe(project => Project = project!);

            SaveProject = ReactiveCommand.CreateFromTask(async () =>
            {
                await ProjectSerializer.SaveModel(Project);
            });

            SaveProjectAs = ReactiveCommand.CreateFromTask(() => throw new NotImplementedException());

            this.WhenAnyValue(vm => vm.Project).Subscribe(_ =>
            {
                if (Explorer.TreeRoot.Count == 0)
                    Explorer.TreeRoot.Add(Project);
                else
                {
                    Explorer.TreeRoot[0] = Project;
                }
            });

            this.WhenAnyValue(vm => vm.ActiveFile!.CurrentViewModel).Subscribe(n => PropertiesContext = n);

            UndoRedo.Recording = true;
        }

        public NodeListViewModel NodeList { get; } = new();
        public UndoRedoViewModel UndoRedo { get; } = new();
        public AppStateViewModel AppState { get; }
        public ExplorerViewModel Explorer { get; }

        public ReactiveCommand<Unit, ProjectViewModel?> LoadProject { get; }
        public ReactiveCommand<Unit, Unit> SaveProject { get; }
        public ReactiveCommand<Unit, Unit> SaveProjectAs { get; }
        public Interaction<bool, string?> OpenProjectFile { get; } = new();
        public Interaction<Unit, Func<FileViewModel>?> SelectTypeAndFileName { get; } = new();
        public Interaction<string?, string?> SelectName { get; } = new();

        public NodeGrouper Grouper { get; }

        public ProjectViewModel Project
        {
            get => _project;
            set => this.RaiseAndSetIfChanged(ref _project, value);
        }
        
        public ObservableCollection<FileViewModel> Files { get; } = new();

        public FileViewModel? ActiveFile
        {
            get => _activeFile; 
            set => this.RaiseAndSetIfChanged(ref _activeFile, value);
        }

        public object? PropertiesContext
        {
            get => _propertiesContext; 
            set => this.RaiseAndSetIfChanged(ref _propertiesContext, value);
        }

        public DxTexturePreviewViewModel? Preview2dContext
        {
            get => _preview2dContext; 
            set => this.RaiseAndSetIfChanged(ref _preview2dContext, value);
        }

        public DxMeshPreviewViewModel? Preview3dContext
        {
            get => _preview3dContext; 
            set => this.RaiseAndSetIfChanged(ref _preview3dContext, value);
        }
    }
}