// Copyright 2014 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 MOJO_SERVICES_VIEW_MANAGER_CONNECTION_MANAGER_H_
#define MOJO_SERVICES_VIEW_MANAGER_CONNECTION_MANAGER_H_

#include <map>
#include <set>

#include "base/basictypes.h"
#include "mojo/public/cpp/application/interface_factory.h"
#include "mojo/public/cpp/bindings/array.h"
#include "mojo/public/cpp/bindings/error_handler.h"
#include "mojo/services/public/interfaces/view_manager/view_manager.mojom.h"
#include "mojo/services/public/interfaces/window_manager/window_manager.mojom.h"
#include "mojo/services/view_manager/display_manager.h"
#include "mojo/services/view_manager/ids.h"
#include "mojo/services/view_manager/server_view.h"
#include "mojo/services/view_manager/server_view_delegate.h"
#include "mojo/services/view_manager/view_manager_export.h"

namespace mojo {

class ApplicationConnection;

namespace service {

class ViewManagerServiceImpl;

// ConnectionManager manages the set of connections to the ViewManager (all the
// ViewManagerServiceImpls) as well as providing the root of the hierarchy.
class MOJO_VIEW_MANAGER_EXPORT ConnectionManager
    : public ServerViewDelegate,
      public WindowManagerInternalClient,
      public InterfaceFactory<ViewManagerService>,
      public ErrorHandler {
 public:
  // Create when a ViewManagerServiceImpl is about to make a change. Ensures
  // clients are notified correctly.
  class ScopedChange {
   public:
    ScopedChange(ViewManagerServiceImpl* connection,
                 ConnectionManager* connection_manager,
                 bool is_delete_view);
    ~ScopedChange();

    ConnectionSpecificId connection_id() const { return connection_id_; }
    bool is_delete_view() const { return is_delete_view_; }

    // Marks the connection with the specified id as having seen a message.
    void MarkConnectionAsMessaged(ConnectionSpecificId connection_id) {
      message_ids_.insert(connection_id);
    }

    // Returns true if MarkConnectionAsMessaged(connection_id) was invoked.
    bool DidMessageConnection(ConnectionSpecificId connection_id) const {
      return message_ids_.count(connection_id) > 0;
    }

   private:
    ConnectionManager* connection_manager_;
    const ConnectionSpecificId connection_id_;
    const bool is_delete_view_;

    // See description of MarkConnectionAsMessaged/DidMessageConnection.
    std::set<ConnectionSpecificId> message_ids_;

    DISALLOW_COPY_AND_ASSIGN(ScopedChange);
  };

  ConnectionManager(ApplicationConnection* app_connection,
                    const Callback<void()>& native_viewport_closed_callback);
  ~ConnectionManager() override;

  // Returns the id for the next ViewManagerServiceImpl.
  ConnectionSpecificId GetAndAdvanceNextConnectionId();

  void AddConnection(ViewManagerServiceImpl* connection);
  void RemoveConnection(ViewManagerServiceImpl* connection);

  // See description of ViewManagerService::Embed() for details. This assumes
  // |transport_view_id| is valid.
  void EmbedAtView(ConnectionSpecificId creator_id,
                   const String& url,
                   Id transport_view_id,
                   InterfaceRequest<ServiceProvider> service_provider);

  // Returns the connection by id.
  ViewManagerServiceImpl* GetConnection(ConnectionSpecificId connection_id);

  // Returns the View identified by |id|.
  ServerView* GetView(const ViewId& id);

  ServerView* root() { return root_.get(); }

  bool IsProcessingChange() const { return current_change_ != NULL; }

  bool is_processing_delete_view() const {
    return current_change_ && current_change_->is_delete_view();
  }

  // Invoked when a connection messages a client about the change. This is used
  // to avoid sending ServerChangeIdAdvanced() unnecessarily.
  void OnConnectionMessagedClient(ConnectionSpecificId id);

  // Returns true if OnConnectionMessagedClient() was invoked for id.
  bool DidConnectionMessageClient(ConnectionSpecificId id) const;

  // Returns the ViewManagerServiceImpl that has |id| as a root.
  ViewManagerServiceImpl* GetConnectionWithRoot(const ViewId& id) {
    return const_cast<ViewManagerServiceImpl*>(
        const_cast<const ConnectionManager*>(this)->GetConnectionWithRoot(id));
  }
  const ViewManagerServiceImpl* GetConnectionWithRoot(const ViewId& id) const;

  void DispatchViewInputEventToDelegate(EventPtr event);

  // These functions trivially delegate to all ViewManagerServiceImpls, which in
  // term notify their clients.
  void ProcessViewDestroyed(ServerView* view);
  void ProcessViewBoundsChanged(const ServerView* view,
                                const gfx::Rect& old_bounds,
                                const gfx::Rect& new_bounds);
  void ProcessWillChangeViewHierarchy(const ServerView* view,
                                      const ServerView* new_parent,
                                      const ServerView* old_parent);
  void ProcessViewHierarchyChanged(const ServerView* view,
                                   const ServerView* new_parent,
                                   const ServerView* old_parent);
  void ProcessViewReorder(const ServerView* view,
                          const ServerView* relative_view,
                          const OrderDirection direction);
  void ProcessViewDeleted(const ViewId& view);

 private:
  typedef std::map<ConnectionSpecificId, ViewManagerServiceImpl*> ConnectionMap;

  // Invoked when a connection is about to make a change.  Subsequently followed
  // by FinishChange() once the change is done.
  //
  // Changes should never nest, meaning each PrepareForChange() must be
  // balanced with a call to FinishChange() with no PrepareForChange()
  // in between.
  void PrepareForChange(ScopedChange* change);

  // Balances a call to PrepareForChange().
  void FinishChange();

  // Returns true if the specified connection originated the current change.
  bool IsChangeSource(ConnectionSpecificId connection_id) const {
    return current_change_ && current_change_->connection_id() == connection_id;
  }

  // Implementation of the two embed variants.
  ViewManagerServiceImpl* EmbedImpl(
      ConnectionSpecificId creator_id,
      const String& url,
      const ViewId& root_id,
      InterfaceRequest<ServiceProvider> service_provider);

  // Overridden from ServerViewDelegate:
  void OnViewDestroyed(const ServerView* view) override;
  void OnWillChangeViewHierarchy(const ServerView* view,
                                 const ServerView* new_parent,
                                 const ServerView* old_parent) override;
  void OnViewHierarchyChanged(const ServerView* view,
                              const ServerView* new_parent,
                              const ServerView* old_parent) override;
  void OnViewBoundsChanged(const ServerView* view,
                           const gfx::Rect& old_bounds,
                           const gfx::Rect& new_bounds) override;
  void OnViewSurfaceIdChanged(const ServerView* view) override;
  void OnViewReordered(const ServerView* view,
                       const ServerView* relative,
                       OrderDirection direction) override;
  void OnWillChangeViewVisibility(const ServerView* view) override;
  void OnViewPropertyChanged(const ServerView* view,
                             const std::string& name,
                             const std::vector<uint8_t>* new_data) override;

  // WindowManagerInternalClient:
  virtual void DispatchInputEventToView(Id transport_view_id,
                                        EventPtr event) override;

  // InterfaceFactory<ViewManagerService>:
  virtual void Create(ApplicationConnection* connection,
                      InterfaceRequest<ViewManagerService> request) override;

  // ErrorHandler:
  void OnConnectionError() override;

  ApplicationConnection* app_connection_;

  WindowManagerInternalServicePtr window_manager_;

  // ID to use for next ViewManagerServiceImpl.
  ConnectionSpecificId next_connection_id_;

  // Set of ViewManagerServiceImpls.
  ConnectionMap connection_map_;

  DisplayManager display_manager_;

  scoped_ptr<ServerView> root_;

  // Set of ViewManagerServiceImpls created by way of Connect(). These have to
  // be explicitly destroyed.
  std::set<ViewManagerServiceImpl*> connections_created_by_connect_;

  // If non-null we're processing a change. The ScopedChange is not owned by us
  // (it's created on the stack by ViewManagerServiceImpl).
  ScopedChange* current_change_;

  DISALLOW_COPY_AND_ASSIGN(ConnectionManager);
};

}  // namespace service
}  // namespace mojo

#endif  // MOJO_SERVICES_VIEW_MANAGER_CONNECTION_MANAGER_H_