#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2013 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
 *
 * This file is part of HeuristicLab.
 *
 * HeuristicLab is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * HeuristicLab is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
 */
#endregion

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Windows.Forms;
using HeuristicLab.Collections;
using HeuristicLab.Common;
using HeuristicLab.MainForm;
using HeuristicLab.MainForm.WindowsForms;
using HeuristicLab.PluginInfrastructure;

namespace HeuristicLab.Core.Views {
  [View("ItemCollection View")]
  [Content(typeof(ItemCollection<>), true)]
  [Content(typeof(IItemCollection<>), false)]
  public partial class ItemCollectionView<T> : ItemView where T : class, IItem {
    protected Dictionary<T, List<ListViewItem>> itemListViewItemMapping;
    protected TypeSelectorDialog typeSelectorDialog;
    protected bool validDragOperation;

    public new IItemCollection<T> Content {
      get { return (IItemCollection<T>)base.Content; }
      set { base.Content = value; }
    }

    public ObservableCollection<T> ItemCollection {
      get { return Content as ObservableCollection<T>; }
    }

    public bool ShowDetails {
      get { return showDetailsCheckBox.Checked; }
      set { showDetailsCheckBox.Checked = value; }
    }

    public ListView ItemsListView {
      get { return itemsListView; }
    }

    public ItemCollectionView() {
      InitializeComponent();
      itemListViewItemMapping = new Dictionary<T, List<ListViewItem>>();
    }

    protected override void Dispose(bool disposing) {
      if (disposing) {
        if (typeSelectorDialog != null) typeSelectorDialog.Dispose();
        if (components != null) components.Dispose();
      }
      base.Dispose(disposing);
    }

    protected override void DeregisterContentEvents() {
      Content.ItemsAdded -= new CollectionItemsChangedEventHandler<T>(Content_ItemsAdded);
      Content.ItemsRemoved -= new CollectionItemsChangedEventHandler<T>(Content_ItemsRemoved);
      Content.CollectionReset -= new CollectionItemsChangedEventHandler<T>(Content_CollectionReset);
      foreach (T item in itemListViewItemMapping.Keys) {
        DeregisterItemEvents(item);
      }
      base.DeregisterContentEvents();
    }
    protected override void RegisterContentEvents() {
      base.RegisterContentEvents();
      Content.ItemsAdded += new CollectionItemsChangedEventHandler<T>(Content_ItemsAdded);
      Content.ItemsRemoved += new CollectionItemsChangedEventHandler<T>(Content_ItemsRemoved);
      Content.CollectionReset += new CollectionItemsChangedEventHandler<T>(Content_CollectionReset);
    }
    protected virtual void DeregisterItemEvents(T item) {
      item.ItemImageChanged -= new EventHandler(Item_ItemImageChanged);
      item.ToStringChanged -= new EventHandler(Item_ToStringChanged);
    }
    protected virtual void RegisterItemEvents(T item) {
      item.ItemImageChanged += new EventHandler(Item_ItemImageChanged);
      item.ToStringChanged += new EventHandler(Item_ToStringChanged);
    }

    protected override void OnContentChanged() {
      base.OnContentChanged();
      itemsListView.Items.Clear();
      itemListViewItemMapping.Clear();
      RebuildImageList();
      viewHost.Content = null;
      if (Content != null) {
        Caption += " (" + Content.GetType().Name + ")";
        foreach (T item in Content)
          AddListViewItem(CreateListViewItem(item));
        AdjustListViewColumnSizes();
        SortItemsListView(SortOrder.Ascending);
      }
    }

    protected override void SetEnabledStateOfControls() {
      base.SetEnabledStateOfControls();
      if (Content == null) {
        addButton.Enabled = false;
        sortAscendingButton.Enabled = false;
        sortDescendingButton.Enabled = false;
        removeButton.Enabled = false;
        itemsListView.Enabled = false;
        detailsGroupBox.Enabled = false;
      } else {
        addButton.Enabled = !Content.IsReadOnly && !ReadOnly;
        sortAscendingButton.Enabled = itemsListView.Items.Count > 1;
        sortDescendingButton.Enabled = itemsListView.Items.Count > 1;
        removeButton.Enabled = !Content.IsReadOnly && !ReadOnly && itemsListView.SelectedItems.Count > 0;
        itemsListView.Enabled = true;
        detailsGroupBox.Enabled = itemsListView.SelectedItems.Count == 1;
      }
    }

    protected virtual T CreateItem() {
      if (typeSelectorDialog == null) {
        typeSelectorDialog = new TypeSelectorDialog();
        typeSelectorDialog.Caption = "Select Item";
        typeSelectorDialog.TypeSelector.Caption = "Available Items";
        typeSelectorDialog.TypeSelector.Configure(typeof(T), false, true);
      }

      if (typeSelectorDialog.ShowDialog(this) == DialogResult.OK) {
        try {
          return (T)typeSelectorDialog.TypeSelector.CreateInstanceOfSelectedType();
        }
        catch (Exception ex) {
          ErrorHandling.ShowErrorDialog(this, ex);
        }
      }
      return null;
    }
    protected virtual ListViewItem CreateListViewItem(T item) {
      ListViewItem listViewItem = new ListViewItem();
      if (item == null) {
        listViewItem.Text = "null";
        itemsListView.SmallImageList.Images.Add(HeuristicLab.Common.Resources.VSImageLibrary.Nothing);
        listViewItem.ImageIndex = itemsListView.SmallImageList.Images.Count - 1;
      } else {
        listViewItem.Text = item.ToString();
        listViewItem.ToolTipText = item.ItemName + ": " + item.ItemDescription;
        itemsListView.SmallImageList.Images.Add(item.ItemImage);
        listViewItem.ImageIndex = itemsListView.SmallImageList.Images.Count - 1;
        listViewItem.Tag = item;
      }
      return listViewItem;
    }
    protected virtual void AddListViewItem(ListViewItem listViewItem) {
      if (listViewItem == null) throw new ArgumentNullException();
      T item = (listViewItem.Tag as T);
      itemsListView.Items.Add(listViewItem);
      if (item != null) {
        if (!itemListViewItemMapping.ContainsKey(item)) {
          RegisterItemEvents(item);
          itemListViewItemMapping.Add(item, new List<ListViewItem>());
        }
        itemListViewItemMapping[item].Add(listViewItem);
      }
      sortAscendingButton.Enabled = itemsListView.Items.Count > 1;
      sortDescendingButton.Enabled = itemsListView.Items.Count > 1;
    }
    protected virtual void RemoveListViewItem(ListViewItem listViewItem) {
      if (listViewItem == null) throw new ArgumentNullException();
      T item = (listViewItem.Tag as T);
      if (item != null) {
        itemListViewItemMapping[item].Remove(listViewItem);
        if (itemListViewItemMapping[item].Count == 0) {
          itemListViewItemMapping.Remove(item);
          DeregisterItemEvents(item);
        }
      }
      listViewItem.Remove();
      sortAscendingButton.Enabled = itemsListView.Items.Count > 1;
      sortDescendingButton.Enabled = itemsListView.Items.Count > 1;
    }
    protected virtual void UpdateListViewItemImage(ListViewItem listViewItem) {
      if (listViewItem == null) throw new ArgumentNullException();
      T item = listViewItem.Tag as T;
      int i = listViewItem.ImageIndex;
      itemsListView.SmallImageList.Images[i] = item == null ? HeuristicLab.Common.Resources.VSImageLibrary.Nothing : item.ItemImage;
      listViewItem.ImageIndex = -1;
      listViewItem.ImageIndex = i;
    }
    protected virtual void UpdateListViewItemText(ListViewItem listViewItem) {
      if (listViewItem == null) throw new ArgumentNullException();
      T item = listViewItem.Tag as T;
      listViewItem.Text = item == null ? "null" : item.ToString();
      listViewItem.ToolTipText = item == null ? string.Empty : item.ItemName + ": " + item.ItemDescription;
    }
    protected virtual IEnumerable<ListViewItem> GetListViewItemsForItem(T item) {
      if (item == null) {
        List<ListViewItem> listViewItems = new List<ListViewItem>();
        foreach (ListViewItem listViewItem in itemsListView.Items) {
          if (listViewItem.Tag == null) listViewItems.Add(listViewItem);
        }
        return listViewItems;
      } else {
        List<ListViewItem> listViewItems = null;
        itemListViewItemMapping.TryGetValue(item, out listViewItems);
        return listViewItems == null ? Enumerable.Empty<ListViewItem>() : listViewItems;
      }
    }

    #region ListView Events
    protected virtual void itemsListView_SelectedIndexChanged(object sender, EventArgs e) {
      removeButton.Enabled = (Content != null) && !Content.IsReadOnly && !ReadOnly && itemsListView.SelectedItems.Count > 0;
      AdjustListViewColumnSizes();
      if (showDetailsCheckBox.Checked) {
        if (itemsListView.SelectedItems.Count == 1) {
          T item = (T)itemsListView.SelectedItems[0].Tag;
          detailsGroupBox.Enabled = true;
          viewHost.Content = item;
        } else {
          viewHost.Content = null;
          detailsGroupBox.Enabled = false;
        }
      }
    }
    protected virtual void itemsListView_KeyDown(object sender, KeyEventArgs e) {
      if (e.KeyCode == Keys.Delete) {
        if ((itemsListView.SelectedItems.Count > 0) && !Content.IsReadOnly && !ReadOnly) {
          if (ItemCollection != null) ItemCollection.RemoveRange(itemsListView.SelectedItems.Cast<ListViewItem>().Select(i => (T)i.Tag));
          else {
            foreach (ListViewItem item in itemsListView.SelectedItems)
              Content.Remove((T)item.Tag);
          }
        }
      }
    }
    protected virtual void itemsListView_DoubleClick(object sender, EventArgs e) {
      if (itemsListView.SelectedItems.Count == 1) {
        T item = itemsListView.SelectedItems[0].Tag as T;
        if (item != null) {
          IContentView view = MainFormManager.MainForm.ShowContent(item);
          if (view != null) {
            view.ReadOnly = ReadOnly;
            view.Locked = Locked;
          }
        }
      }
    }
    protected virtual void itemsListView_ItemDrag(object sender, ItemDragEventArgs e) {
      if (!Locked) {
        List<T> items = new List<T>();
        foreach (ListViewItem listViewItem in itemsListView.SelectedItems) {
          T item = listViewItem.Tag as T;
          if (item != null) items.Add(item);
        }

        if (items.Count > 0) {
          DataObject data = new DataObject();
          if (items.Count == 1) data.SetData(HeuristicLab.Common.Constants.DragDropDataFormat, items[0]);
          else data.SetData(HeuristicLab.Common.Constants.DragDropDataFormat, items);
          if (Content.IsReadOnly || ReadOnly) {
            DoDragDrop(data, DragDropEffects.Copy | DragDropEffects.Link);
          } else {
            DragDropEffects result = DoDragDrop(data, DragDropEffects.Copy | DragDropEffects.Link | DragDropEffects.Move);
            if ((result & DragDropEffects.Move) == DragDropEffects.Move) {
              foreach (T item in items) Content.Remove(item);
            }
          }
        }
      }
    }
    protected virtual void itemsListView_DragEnter(object sender, DragEventArgs e) {
      validDragOperation = false;
      if (!Content.IsReadOnly && !ReadOnly && (e.Data.GetData(HeuristicLab.Common.Constants.DragDropDataFormat) is T)) {
        validDragOperation = true;
      } else if (!Content.IsReadOnly && !ReadOnly && (e.Data.GetData(HeuristicLab.Common.Constants.DragDropDataFormat) is IEnumerable)) {
        validDragOperation = true;
        IEnumerable items = (IEnumerable)e.Data.GetData(HeuristicLab.Common.Constants.DragDropDataFormat);
        foreach (object item in items)
          validDragOperation = validDragOperation && (item is T);
      }
    }
    protected virtual void itemsListView_DragOver(object sender, DragEventArgs e) {
      e.Effect = DragDropEffects.None;
      if (validDragOperation) {
        if ((e.KeyState & 32) == 32) e.Effect = DragDropEffects.Link;  // ALT key
        else if ((e.KeyState & 4) == 4) e.Effect = DragDropEffects.Move;  // SHIFT key
        else if (e.AllowedEffect.HasFlag(DragDropEffects.Copy)) e.Effect = DragDropEffects.Copy;
        else if (e.AllowedEffect.HasFlag(DragDropEffects.Move)) e.Effect = DragDropEffects.Move;
        else if (e.AllowedEffect.HasFlag(DragDropEffects.Link)) e.Effect = DragDropEffects.Link;
      }
    }
    protected virtual void itemsListView_DragDrop(object sender, DragEventArgs e) {
      if (e.Effect != DragDropEffects.None) {
        if (e.Data.GetData(HeuristicLab.Common.Constants.DragDropDataFormat) is T) {
          T item = (T)e.Data.GetData(HeuristicLab.Common.Constants.DragDropDataFormat);
          Content.Add(e.Effect.HasFlag(DragDropEffects.Copy) ? (T)item.Clone() : item);
        } else if (e.Data.GetData(HeuristicLab.Common.Constants.DragDropDataFormat) is IEnumerable) {
          IEnumerable<T> items = ((IEnumerable)e.Data.GetData(HeuristicLab.Common.Constants.DragDropDataFormat)).Cast<T>();
          if (e.Effect.HasFlag(DragDropEffects.Copy)) {
            Cloner cloner = new Cloner();
            items = items.Select(x => cloner.Clone(x));
          }
          if (ItemCollection != null) ItemCollection.AddRange(items);
          else {
            foreach (T item in items)
              Content.Add(item);
          }
        }
      }
    }
    #endregion

    #region Button Events
    protected virtual void addButton_Click(object sender, EventArgs e) {
      T item = CreateItem();
      if (item != null)
        Content.Add(item);
    }
    protected virtual void sortAscendingButton_Click(object sender, EventArgs e) {
      SortItemsListView(SortOrder.Ascending);
    }
    protected virtual void sortDescendingButton_Click(object sender, EventArgs e) {
      SortItemsListView(SortOrder.Descending);
    }
    protected virtual void removeButton_Click(object sender, EventArgs e) {
      if (itemsListView.SelectedItems.Count > 0) {
        if (ItemCollection != null) {
          ItemCollection.RemoveRange(itemsListView.SelectedItems.Cast<ListViewItem>().Select(i => (T)i.Tag));
        } else {
          foreach (ListViewItem item in itemsListView.SelectedItems)
            Content.Remove((T)item.Tag);
        }
        itemsListView.SelectedItems.Clear();
      }
    }
    #endregion

    #region CheckBox Events
    protected virtual void showDetailsCheckBox_CheckedChanged(object sender, EventArgs e) {
      if (showDetailsCheckBox.Checked) {
        splitContainer.Panel2Collapsed = false;
        detailsGroupBox.Enabled = itemsListView.SelectedItems.Count == 1;
        viewHost.Content = itemsListView.SelectedItems.Count == 1 ? (T)itemsListView.SelectedItems[0].Tag : null;
      } else {
        splitContainer.Panel2Collapsed = true;
        viewHost.Content = null;
      }
    }
    #endregion

    #region Content Events
    protected virtual void Content_ItemsAdded(object sender, CollectionItemsChangedEventArgs<T> e) {
      if (InvokeRequired)
        Invoke(new CollectionItemsChangedEventHandler<T>(Content_ItemsAdded), sender, e);
      else {
        foreach (T item in e.Items)
          AddListViewItem(CreateListViewItem(item));
        AdjustListViewColumnSizes();
      }

    }
    protected virtual void Content_ItemsRemoved(object sender, CollectionItemsChangedEventArgs<T> e) {
      if (InvokeRequired)
        Invoke(new CollectionItemsChangedEventHandler<T>(Content_ItemsRemoved), sender, e);
      else {
        foreach (T item in e.Items) {
          //remove only the first matching ListViewItem, because the IItem could be contained multiple times in the ItemCollection
          ListViewItem listviewItem = GetListViewItemsForItem(item).FirstOrDefault();
          if (listviewItem != null) RemoveListViewItem(listviewItem);
        }
        RebuildImageList();
      }
    }
    protected virtual void Content_CollectionReset(object sender, CollectionItemsChangedEventArgs<T> e) {
      if (InvokeRequired)
        Invoke(new CollectionItemsChangedEventHandler<T>(Content_CollectionReset), sender, e);
      else {
        foreach (T item in e.OldItems) {
          //remove only the first matching ListViewItem, because the IItem could be contained multiple times in the ItemCollection
          ListViewItem listviewItem = GetListViewItemsForItem(item).FirstOrDefault();
          if (listviewItem != null) RemoveListViewItem(listviewItem);
        }
        RebuildImageList();
        foreach (T item in e.Items)
          AddListViewItem(CreateListViewItem(item));
      }
    }
    #endregion

    #region Item Events
    protected virtual void Item_ItemImageChanged(object sender, EventArgs e) {
      if (InvokeRequired)
        Invoke(new EventHandler(Item_ItemImageChanged), sender, e);
      else {
        T item = (T)sender;
        foreach (ListViewItem listViewItem in GetListViewItemsForItem(item))
          UpdateListViewItemImage(listViewItem);
      }
    }
    protected virtual void Item_ToStringChanged(object sender, EventArgs e) {
      if (InvokeRequired)
        Invoke(new EventHandler(Item_ToStringChanged), sender, e);
      else {
        T item = (T)sender;
        foreach (ListViewItem listViewItem in GetListViewItemsForItem(item))
          UpdateListViewItemText(listViewItem);
        AdjustListViewColumnSizes();
      }
    }
    #endregion

    #region Helpers
    protected virtual void SortItemsListView(SortOrder sortOrder) {
      itemsListView.Sorting = SortOrder.None;
      itemsListView.Sorting = sortOrder;
      itemsListView.Sorting = SortOrder.None;
    }
    protected virtual void AdjustListViewColumnSizes() {
      if (itemsListView.Items.Count > 0) {
        for (int i = 0; i < itemsListView.Columns.Count; i++)
          itemsListView.Columns[i].AutoResize(ColumnHeaderAutoResizeStyle.ColumnContent);
      }
    }
    protected virtual void RebuildImageList() {
      itemsListView.SmallImageList.Images.Clear();
      foreach (ListViewItem listViewItem in itemsListView.Items) {
        T item = listViewItem.Tag as T;
        itemsListView.SmallImageList.Images.Add(item == null ? HeuristicLab.Common.Resources.VSImageLibrary.Nothing : item.ItemImage);
        listViewItem.ImageIndex = itemsListView.SmallImageList.Images.Count - 1;
      }
    }
    #endregion
  }
}