// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CHROME_VIEWS_TREE_VIEW_H__
#define CHROME_VIEWS_TREE_VIEW_H__

#include <map>

#include "base/basictypes.h"
#include "base/logging.h"
#include "chrome/views/native_control.h"

namespace ChromeViews {

class TreeModel;
class TreeModelNode;
class TreeView;

// Observer for the TreeModel. Notified of significant events to the model.
class TreeModelObserver {
 public:
  // Notification that nodes were added to the specified parent.
  virtual void TreeNodesAdded(TreeModel* model,
                              TreeModelNode* parent,
                              int start,
                              int count) = 0;

  // Notification that nodes were removed from the specified parent.
  virtual void TreeNodesRemoved(TreeModel* model,
                                TreeModelNode* parent,
                                int start,
                                int count) = 0;

  // Notification that the contents of a node has changed.
  virtual void TreeNodeChanged(TreeModel* model, TreeModelNode* node) = 0;
};

// TreeModelNode --------------------------------------------------------------

// Type of class returned from the model.
class TreeModelNode {
 public:
  // Returns the title for the node.
  virtual std::wstring GetTitle() = 0;
};

// TreeModel ------------------------------------------------------------------

// The model for TreeView.
class TreeModel {
 public:
  // Returns the root of the tree. This may or may not be shown in the tree,
  // see SetRootShown for details.
  virtual TreeModelNode* GetRoot() = 0;

  // Returns the number of children in the specified node.
  virtual int GetChildCount(TreeModelNode* parent) = 0;

  // Returns the child node at the specified index.
  virtual TreeModelNode* GetChild(TreeModelNode* parent, int index) = 0;

  // Returns the parent of a node, or NULL if node is the root.
  virtual TreeModelNode* GetParent(TreeModelNode* node) = 0;

  // Sets the observer of the model.
  virtual void SetObserver(TreeModelObserver* observer) = 0;

  // Sets the title of the specified node.
  // This is only invoked if the node is editable and the user edits a node.
  virtual void SetTitle(TreeModelNode* node,
                        const std::wstring& title) {
    NOTREACHED();
  }
};

// TreeViewController ---------------------------------------------------------

// Controller for the treeview.
class TreeViewController {
 public:
  // Notification that the selection of the tree view has changed. Use
  // GetSelectedNode to find the current selection.
  virtual void OnTreeViewSelectionChanged(TreeView* tree_view) = 0;

  // Returns true if the node can be edited. This is only used if the
  // TreeView is editable.
  virtual bool CanEdit(TreeView* tree_view, TreeModelNode* node) {
    return true;
  }
};

// TreeView -------------------------------------------------------------------

// TreeView displays hierarchical data as returned from a TreeModel. The user
// can expand, collapse and edit the items. A Controller may be attached to
// receive notification of selection changes and restrict editing.
class TreeView : public NativeControl, public TreeModelObserver {
 public:
  TreeView();
  virtual ~TreeView();

  // Sets the model. TreeView does not take ownership of the model.
  void SetModel(TreeModel* model);

  // Sets whether the user can edit the nodes. The default is true. If true,
  // the Controller is queried to determine if a particular node can be edited.
  void SetEditable(bool editable);

  // Edits the specified node. This cancels the current edit and expands
  // all parents of node.
  void StartEditing(TreeModelNode* node);

  // Cancels the current edit. Does nothing if not editing.
  void CancelEdit();

  // Commits the current edit. Does nothing if not editing.
  void CommitEdit();

  // If the user is editing a node, it is returned. If the user is not
  // editing a node, NULL is returned.
  TreeModelNode* GetEditingNode();

  // Selects the specified node. This expands all the parents of node.
  void SetSelectedNode(TreeModelNode* node);

  // Returns the selected node, or NULL if nothing is selected.
  TreeModelNode* GetSelectedNode();

  // Make sure node and all its parents are expanded.
  void Expand(TreeModelNode* node);

  // Convenience to expand ALL nodes in the tree.
  void ExpandAll();

  // Sets whether the root is shown. If true, the root node of the tree is
  // shown, if false only the children of the root are shown. The default is
  // true.
  void SetRootShown(bool root_visible);

  // TreeModelObserver methods. Don't call these directly, instead your model
  // should notify the observer TreeView adds to it.
  virtual void TreeNodesAdded(TreeModel* model,
                              TreeModelNode* parent,
                              int start,
                              int count);
  virtual void TreeNodesRemoved(TreeModel* model,
                                TreeModelNode* parent,
                                int start,
                                int count);
  virtual void TreeNodeChanged(TreeModel* model, TreeModelNode* node);

  // Sets the controller, which may be null. TreeView does not take ownership
  // of the controller.
  void SetController(TreeViewController* controller) {
    controller_ = controller;
  }

  // Sets whether enter is processed when not editing. If true, enter will
  // expand/collapse the node. If false, enter is passed to the focus manager
  // so that an enter accelerator can be enabled. The default is false.
  //
  // NOTE: Changing this has no effect after the hwnd has been created.
  void SetProcessesEnter(bool process_enter) {
    process_enter_ = process_enter;
  }
  bool GetProcessedEnter() { return process_enter_; }

  // Sets when the ContextMenuController is notified. If true, the
  // ContextMenuController is only notified when a node is selected and the
  // mouse is over a node. The default is true.
  void SetShowContextMenuOnlyWhenNodeSelected(bool value) {
    show_context_menu_only_when_node_selected_ = value;
  }
  bool GetShowContextMenuOnlyWhenNodeSelected() {
    return show_context_menu_only_when_node_selected_;
  }

  // If true, a right click selects the node under the mouse. The default
  // is true.
  void SetSelectOnRightMouseDown(bool value) {
    select_on_right_mouse_down_ = value;
  }
  bool GetSelectOnRightMouseDown() { return select_on_right_mouse_down_; }

 protected:

  // Creates and configures the tree_view.
  virtual HWND CreateNativeControl(HWND parent_container);

  // Invoked when the native control sends a WM_NOTIFY message to its parent.
  // Handles a variety of potential TreeView messages.
  virtual LRESULT OnNotify(int w_param, LPNMHDR l_param);

  // Yes, we want to be notified of key down for two reasons. To circumvent
  // VK_ENTER from toggling the expaned state when processes_enter_ is false,
  // and to have F2 start editting.
  virtual bool NotifyOnKeyDown() const { return true; }
  virtual bool OnKeyDown(int virtual_key_code);

  virtual void OnContextMenu(const CPoint& location);

 private:
  // See notes in TableView::TableViewWrapper for why this is needed.
  struct TreeViewWrapper {
    explicit TreeViewWrapper(TreeView* view) : tree_view(view) { }
    TreeView* tree_view;
  };

  // Internally used to track the state of nodes. NodeDetails are lazily created
  // as the user expands nodes.
  struct NodeDetails {
    NodeDetails(int id, TreeModelNode* node)
        : id(id), node(node), tree_item(NULL), loaded_children(false) {}

    // Unique identifier for the node. This corresponds to the lParam of
    // the tree item.
    const int id;

    // The node from the model.
    TreeModelNode* node;

    // From the native TreeView.
    //
    // This should be treated as const, but can't due to timing in creating the
    // entry.
    HTREEITEM tree_item;

    // Whether the children have been loaded.
    bool loaded_children;
  };

  // Invoked from ExpandAll(). Expands the supplied node and recursively
  // invokes itself with all children.
  void ExpandAll(TreeModelNode* node);

  // Deletes the root items from the treeview. This is used when the model
  // changes.
  void DeleteRootItems();

  // Creates the root items in the treeview from the model. This is used when
  // the model changes.
  void CreateRootItems();

  // Creates and adds an item to the treeview. parent_item identifies the
  // parent and is null for root items. after dictates where among the
  // children of parent_item the item is to be created. node is the node from
  // the model.
  void CreateItem(HTREEITEM parent_item, HTREEITEM after, TreeModelNode* node);

  // Removes entries from the map for item. This method will also
  // remove the items from the TreeView because the process of
  // deleting an item will send an TVN_GETDISPINFO message, consulting
  // our internal map data.
  void RecursivelyDelete(NodeDetails* node);

  // Returns the NodeDetails by node from the model.
  NodeDetails* GetNodeDetails(TreeModelNode* node) {
    DCHECK(node &&
           node_to_details_map_.find(node) != node_to_details_map_.end());
    return node_to_details_map_[node];
  }

  // Returns the NodeDetails by identifier (lparam of the HTREEITEM).
  NodeDetails* GetNodeDetailsByID(int id) {
    DCHECK(id_to_details_map_.find(id) != id_to_details_map_.end());
    return id_to_details_map_[id];
  }

  // Returns the NodeDetails by HTREEITEM.
  NodeDetails* GetNodeDetailsByTreeItem(HTREEITEM tree_item);

  // The window function installed on the treeview.
  static LRESULT CALLBACK TreeWndProc(HWND window,
                                      UINT message,
                                      WPARAM w_param,
                                      LPARAM l_param);

  // Handle to the tree window.
  HWND tree_view_;

  // The model, may be null.
  TreeModel* model_;

  // Maps from id to NodeDetails.
  std::map<int,NodeDetails*> id_to_details_map_;

  // Maps from model entry to NodeDetails.
  std::map<TreeModelNode*,NodeDetails*> node_to_details_map_;

  // Whether the user can edit the items.
  bool editable_;

  // Next id to create. Any time an item is added this is incremented by one.
  int next_id_;

  // The controller.
  TreeViewController* controller_;

  // Node being edited. If null, not editing.
  TreeModelNode* editing_node_;

  // Whether or not the root is shown in the tree.
  bool root_shown_;

  // Whether enter should be processed by the tree when not editing.
  bool process_enter_;

  // Whether we notify context menu controller only when mouse is over node
  // and node is selected.
  bool show_context_menu_only_when_node_selected_;

  // Whether the selection is changed on right mouse down.
  bool select_on_right_mouse_down_;

  // A wrapper around 'this', used for subclassing the TreeView control.
  TreeViewWrapper wrapper_;

  // Original handler installed on the TreeView.
  WNDPROC original_handler_;

  DISALLOW_EVIL_CONSTRUCTORS(TreeView);
};

}  // namespace ChromeViews

#endif  // CHROME_VIEWS_TREE_VIEW_H__