// Copyright (c) 2013 GitHub, Inc. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef ATOM_BROWSER_WINDOW_LIST_H_
#define ATOM_BROWSER_WINDOW_LIST_H_

#include <vector>

#include "base/basictypes.h"
#include "base/lazy_instance.h"
#include "base/observer_list.h"

namespace atom {

class NativeWindow;
class WindowListObserver;

class WindowList {
 public:
  typedef std::vector<NativeWindow*> WindowVector;
  typedef WindowVector::const_iterator const_iterator;
  typedef WindowVector::const_reverse_iterator const_reverse_iterator;

  // Windows are added to the list before they have constructed windows,
  // so the |window()| member function may return NULL.
  const_iterator begin() const { return windows_.begin(); }
  const_iterator end() const { return windows_.end(); }

  bool empty() const { return windows_.empty(); }
  size_t size() const { return windows_.size(); }

  NativeWindow* get(size_t index) const { return windows_[index]; }

  static WindowList* GetInstance();

  // Adds or removes |window| from the list it is associated with.
  static void AddWindow(NativeWindow* window);
  static void RemoveWindow(NativeWindow* window);

  // Adds and removes |observer| from the observer list.
  static void AddObserver(WindowListObserver* observer);
  static void RemoveObserver(WindowListObserver* observer);

  // Closes all windows.
  static void CloseAllWindows();

 private:
  WindowList();
  ~WindowList();

  // A vector of the windows in this list, in the order they were added.
  WindowVector windows_;

  // A list of observers which will be notified of every window addition and
  // removal across all WindowLists.
  static base::LazyInstance<ObserverList<WindowListObserver>>::Leaky observers_;

  static WindowList* instance_;

  DISALLOW_COPY_AND_ASSIGN(WindowList);
};

}  // namespace atom

#endif  // ATOM_BROWSER_WINDOW_LIST_H_