PixiEditor/PixiEditor/Views/UserControls/Layers/LayersManager.xaml.cs

using PixiEditor.Models.Controllers;
using PixiEditor.Models.Controllers.Shortcuts;
using PixiEditor.Models.DataHolders;
using PixiEditor.Models.Layers;
using PixiEditor.Models.Undo;
using PixiEditor.ViewModels.SubViewModels.Main;
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;

namespace PixiEditor.Views.UserControls.Layers
{
    /// <summary>
    /// Interaction logic for LayersManager.xaml.
    /// </summary>
    public partial class LayersManager : UserControl
    {
        public object SelectedItem
        {
            get { return (object)GetValue(SelectedItemProperty); }
            set { SetValue(SelectedItemProperty, value); }
        }

        public static readonly DependencyProperty SelectedItemProperty =
            DependencyProperty.Register(nameof(SelectedItem), typeof(object), typeof(LayersManager), new PropertyMetadata(0));

        public ObservableCollection<IHasGuid> LayerTreeRoot
        {
            get { return (ObservableCollection<IHasGuid>)GetValue(LayerTreeRootProperty); }
            set { SetValue(LayerTreeRootProperty, value); }
        }

        public static readonly DependencyProperty LayerTreeRootProperty =
            DependencyProperty.Register(
                nameof(LayerTreeRoot),
                typeof(ObservableCollection<IHasGuid>),
                typeof(LayersManager),
                new PropertyMetadata(default(ObservableCollection<IHasGuid>), LayerTreeRootChanged));

        public ObservableCollection<IHasGuid> CachedLayerTreeRoot
        {
            get { return (ObservableCollection<IHasGuid>)GetValue(CachedLayerTreeRootProperty); }
            set { SetValue(CachedLayerTreeRootProperty, value); }
        }

        public static readonly DependencyProperty CachedLayerTreeRootProperty =
            DependencyProperty.Register(
                nameof(CachedLayerTreeRoot),
                typeof(ObservableCollection<IHasGuid>),
                typeof(LayersManager),
                new PropertyMetadata(default(ObservableCollection<IHasGuid>)));

        public LayersViewModel LayerCommandsViewModel
        {
            get { return (LayersViewModel)GetValue(LayerCommandsViewModelProperty); }
            set { SetValue(LayerCommandsViewModelProperty, value); }
        }

        public static readonly DependencyProperty LayerCommandsViewModelProperty =
            DependencyProperty.Register(nameof(LayerCommandsViewModel), typeof(LayersViewModel), typeof(LayersManager), new PropertyMetadata(default(LayersViewModel), ViewModelChanged));

        public bool OpacityInputEnabled
        {
            get { return (bool)GetValue(OpacityInputEnabledProperty); }
            set { SetValue(OpacityInputEnabledProperty, value); }
        }

        public static readonly DependencyProperty OpacityInputEnabledProperty =
            DependencyProperty.Register(nameof(OpacityInputEnabled), typeof(bool), typeof(LayersManager), new PropertyMetadata(false));

        public LayersManager()
        {
            InitializeComponent();
            numberInput.OnScrollAction = () => NumberInput_LostFocus(null, null);
        }

        private static void LayerTreeRootChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            var manager = (LayersManager)d;
            var newRoot = (ObservableCollection<IHasGuid>)e.NewValue;

            manager.CachedLayerTreeRoot = newRoot;
            return;
            //layer tree caching goes after than and disabled for now
            /*
            if (manager.CachedLayerTreeRoot == null || newRoot == null)
            {
                manager.CachedLayerTreeRoot = newRoot;
                return;
            }

            if (object.ReferenceEquals(manager.CachedLayerTreeRoot, newRoot))
                return;

            UpdateCachedTree(manager.CachedLayerTreeRoot, newRoot);*/
        }

        private static void UpdateCachedTree(IList<IHasGuid> tree, IList<IHasGuid> newTree)
        {
            var (lcs1, lcs2) = LongestCommonSubsequence(tree, newTree);
            UpdateListUsingLCS(tree, newTree, lcs1);

            bool suc = AreCollectionsTheSame(tree, newTree);


            for (int i = 0; i < lcs1.Count; i++)
            {
                var entry = lcs1[i];
                if (entry is LayerGroup group)
                {
                    var corrGroup = (LayerGroup)lcs2[i];
                    UpdateCachedTree(group.Items, corrGroup.Items);
                    group.StructureData = corrGroup.StructureData;
                }
            }
        }

        private static void UpdateListUsingLCS(IList<IHasGuid> list, IList<IHasGuid> newList, IList<IHasGuid> lcs)
        {
            int oldI = 0;
            int newI = 0;
            for (int i = 0; i < lcs.Count; i++)
            {
                Guid curLcsEntry = lcs[i].GuidValue;

                while (true)
                {
                    if (curLcsEntry != list[oldI].GuidValue && curLcsEntry != newList[newI].GuidValue)
                    {
                        list[oldI] = newList[newI];
                        oldI++;
                        newI++;
                    }
                    else if (curLcsEntry == list[oldI].GuidValue && curLcsEntry != newList[newI].GuidValue)
                    {
                        list.Insert(oldI, newList[newI]);
                        oldI++;
                        newI++;
                    }
                    else if (curLcsEntry != list[oldI].GuidValue && curLcsEntry == newList[newI].GuidValue)
                    {
                        list.RemoveAt(oldI);
                    }
                    else
                    {
                        oldI++;
                        newI++;
                        break;
                    }
                }
            }
            while (list.Count > oldI)
                list.RemoveAt(list.Count - 1);
            for (; newI < newList.Count; newI++)
                list.Add(newList[newI]);
        }

        private static bool AreCollectionsTheSame(IList<IHasGuid> coll1, IList<IHasGuid> coll2)
        {
            if (coll1.Count != coll2.Count)
                return false;
            for (int i = 0; i < coll1.Count; i++)
            {
                if (coll1[i].GuidValue != coll2[i].GuidValue)
                    return false;
            }
            return true;
        }

        private static (IList<IHasGuid>, IList<IHasGuid>) LongestCommonSubsequence(IList<IHasGuid> coll1, IList<IHasGuid> coll2)
        {
            if (AreCollectionsTheSame(coll1, coll2))
                return (coll1, coll2);
            if (coll1.Count == 0 || coll2.Count == 0)
                return (new List<IHasGuid>(), new List<IHasGuid>());

            //calculate LCS matrix
            int w = coll1.Count;
            int h = coll2.Count;
            int[,] matrix = new int[w, h];
            for (int j = 0; j < h; j++)
            {
                for (int i = 0; i < w; i++)
                {
                    if (coll1[i].GuidValue == coll2[j].GuidValue)
                        matrix[i, j] = (i == 0 || j == 0) ? 1 : matrix[i - 1, j - 1] + 1;
                    else
                        matrix[i, j] = (i == 0 || j == 0) ? 0 : Math.Max(matrix[i - 1, j], matrix[i, j - 1]);
                }
            }

            //find the actual subsequence
            List<IHasGuid> subsequence1 = new();
            List<IHasGuid> subsequence2 = new();
            int x = w - 1;
            int y = h - 1;
            while (x >= 0 || y >= 0)
            {
                if (coll1[x].GuidValue == coll2[y].GuidValue)
                {
                    subsequence1.Add(coll1[x]);
                    subsequence2.Add(coll2[y]);
                    if (x == 0 & y == 0)
                        break;
                    if (x > 0)
                        x--;
                    if (y > 0)
                        y--;
                    continue;
                }
                if (x == 0 && y == 0)
                    break;
                if (x == 0)
                {
                    y--;
                    continue;
                }
                if (y == 0)
                {
                    x--;
                    continue;
                }

                if (matrix[x - 1, y] > matrix[x, y - 1])
                    x--;
                else
                    y--;
            }

            subsequence1.Reverse();
            subsequence2.Reverse();
            return (subsequence1, subsequence2);
        }

        private static void ViewModelChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            if (e.NewValue is LayersViewModel vm)
            {
                LayersManager manager = (LayersManager)d;
                vm.Owner.BitmapManager.AddPropertyChangedCallback(nameof(vm.Owner.BitmapManager.ActiveDocument), () =>
                {
                    var doc = vm.Owner.BitmapManager.ActiveDocument;
                    if (doc != null)
                    {
                        if (doc.ActiveLayer != null)
                        {
                            manager.SetActiveLayerAsSelectedItem(doc);
                        }
                        doc.AddPropertyChangedCallback(nameof(doc.ActiveLayer), () =>
                        {
                            manager.SetActiveLayerAsSelectedItem(doc);
                        });
                    }
                });
            }
        }

        private void SetActiveLayerAsSelectedItem(Document doc)
        {
            SelectedItem = doc.ActiveLayer;
            SetInputOpacity(SelectedItem);
        }

        private void SetInputOpacity(object item)
        {
            if (item is Layer layer)
            {
                numberInput.Value = layer.Opacity * 100f;
            }
            else if (item is LayerStructureItemContainer container)
            {
                numberInput.Value = container.Layer.Opacity * 100f;
            }
            else if (item is LayerGroup group)
            {
                numberInput.Value = group.StructureData.Opacity * 100f;
            }
            else if (item is LayerGroupControl groupControl)
            {
                numberInput.Value = groupControl.GroupData.Opacity * 100f;
            }
        }

        private void LayerStructureItemContainer_MouseMove(object sender, System.Windows.Input.MouseEventArgs e)
        {
            if (sender is LayerStructureItemContainer container
                && e.LeftButton == System.Windows.Input.MouseButtonState.Pressed && !container.Layer.IsRenaming)
            {
                Dispatcher.InvokeAsync(() => DragDrop.DoDragDrop(container, container, DragDropEffects.Move));
            }
        }

        private void HandleGroupOpacityChange(GuidStructureItem group, float value)
        {
            if (LayerCommandsViewModel.Owner?.BitmapManager?.ActiveDocument != null)
            {
                var doc = LayerCommandsViewModel.Owner.BitmapManager.ActiveDocument;

                if (group.Opacity == value)
                    return;

                var processArgs = new object[] { group.GroupGuid, value };
                var reverseProcessArgs = new object[] { group.GroupGuid, group.Opacity };

                ChangeGroupOpacityProcess(processArgs);

                LayerCommandsViewModel.Owner.BitmapManager.ActiveDocument.LayerStructure.ExpandParentGroups(group);

                doc.UndoManager.AddUndoChange(
                new Change(
                    ChangeGroupOpacityProcess,
                    reverseProcessArgs,
                    ChangeGroupOpacityProcess,
                    processArgs,
                    $"Change {group.Name} opacity"), false);
            }
        }

        private void ChangeGroupOpacityProcess(object[] processArgs)
        {
            if (processArgs.Length > 0 && processArgs[0] is Guid groupGuid && processArgs[1] is float opacity)
            {
                var structure = LayerCommandsViewModel.Owner.BitmapManager.ActiveDocument.LayerStructure;
                var group = structure.GetGroupByGuid(groupGuid);
                group.Opacity = opacity;
                var layers = structure.GetGroupLayers(group);
                layers.ForEach(x => x.Opacity = x.Opacity); // This might seems stupid, but it raises property changed, without setting any value. This is used to trigger converters that use group opacity
                numberInput.Value = opacity * 100;
            }
        }

        private void LayerGroup_MouseMove(object sender, System.Windows.Input.MouseEventArgs e)
        {
            if (sender is LayerGroupControl container && e.LeftButton == System.Windows.Input.MouseButtonState.Pressed
                && !container.GroupData.IsRenaming)
            {
                Dispatcher.InvokeAsync(() => DragDrop.DoDragDrop(container, container, DragDropEffects.Move));
            }
        }

        private void NumberInput_LostFocus(object sender, RoutedEventArgs e)
        {
            float val = numberInput.Value / 100f;

            object item = SelectedItem;

            if (item is Layer || item is LayerStructureItemContainer)
            {
                Layer layer = null;

                if (item is Layer lr)
                {
                    layer = lr;
                }
                else if (item is LayerStructureItemContainer container)
                {
                    layer = container.Layer;
                }

                HandleLayerOpacityChange(val, layer);
            }
            else if (item is LayerGroup group)
            {
                HandleGroupOpacityChange(group.StructureData, val);
            }
            else if (item is LayerGroupControl groupControl)
            {
                HandleGroupOpacityChange(groupControl.GroupData, val);
            }

            ShortcutController.UnblockShortcutExecutionAll();
        }

        private void HandleLayerOpacityChange(float val, Layer layer)
        {
            float oldOpacity = layer.Opacity;
            if (oldOpacity == val)
                return;

            var doc = LayerCommandsViewModel.Owner.BitmapManager.ActiveDocument;

            doc.RaisePropertyChange(nameof(doc.LayerStructure));

            layer.OpacityUndoTriggerable = val;

            doc.LayerStructure.ExpandParentGroups(layer.GuidValue);

            doc.RaisePropertyChange(nameof(doc.LayerStructure));

            UndoManager undoManager = doc.UndoManager;


            undoManager.AddUndoChange(
                new Change(
                    UpdateNumberInputLayerOpacityProcess,
                    new object[] { oldOpacity },
                    UpdateNumberInputLayerOpacityProcess,
                    new object[] { val }));
            undoManager.SquashUndoChanges(2);
        }

        private void UpdateNumberInputLayerOpacityProcess(object[] args)
        {
            if (args.Length > 0 && args[0] is float opacity)
            {
                numberInput.Value = opacity * 100;
            }
        }

        private void TreeView_SelectedItemChanged(object sender, RoutedPropertyChangedEventArgs<object> e)
        {
            SetInputOpacity(SelectedItem);
        }

        private void Grid_Drop(object sender, DragEventArgs e)
        {
            dropBorder.BorderBrush = Brushes.Transparent;

            if (e.Data.GetDataPresent(LayerGroupControl.LayerContainerDataName))
            {
                HandleLayerDrop(e.Data);
            }

            if (e.Data.GetDataPresent(LayerGroupControl.LayerGroupControlDataName))
            {
                HandleGroupControlDrop(e.Data);
            }
        }

        private void HandleLayerDrop(IDataObject data)
        {
            var doc = LayerCommandsViewModel.Owner.BitmapManager.ActiveDocument;
            if (doc.Layers.Count == 0) return;

            var layerContainer = (LayerStructureItemContainer)data.GetData(LayerGroupControl.LayerContainerDataName);
            var refLayer = doc.Layers[0].GuidValue;
            doc.MoveLayerInStructure(layerContainer.Layer.GuidValue, refLayer);
            doc.LayerStructure.AssignParent(layerContainer.Layer.GuidValue, null);
        }

        private void HandleGroupControlDrop(IDataObject data)
        {
            var doc = LayerCommandsViewModel.Owner.BitmapManager.ActiveDocument;
            var groupContainer = (LayerGroupControl)data.GetData(LayerGroupControl.LayerGroupControlDataName);
            doc.LayerStructure.MoveGroup(groupContainer.GroupGuid, 0);
        }

        private void Grid_DragEnter(object sender, DragEventArgs e)
        {
            ((Border)sender).BorderBrush = LayerItem.HighlightColor;
        }

        private void Grid_DragLeave(object sender, DragEventArgs e)
        {
            ((Border)sender).BorderBrush = Brushes.Transparent;
        }

        private void SelectActiveItem(object sender, System.Windows.Input.MouseButtonEventArgs e)
        {
            SelectedItem = sender;
        }
    }
}