// 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.
//
// A simple wrapper around invalidation::InvalidationClient that
// handles all the startup/shutdown details and hookups.

#ifndef COMPONENTS_INVALIDATION_SYNC_INVALIDATION_LISTENER_H_
#define COMPONENTS_INVALIDATION_SYNC_INVALIDATION_LISTENER_H_

#include <string>

#include "base/basictypes.h"
#include "base/callback_forward.h"
#include "base/compiler_specific.h"
#include "base/memory/scoped_ptr.h"
#include "base/memory/weak_ptr.h"
#include "base/threading/non_thread_safe.h"
#include "components/invalidation/invalidation_export.h"
#include "components/invalidation/state_writer.h"
#include "components/invalidation/sync_system_resources.h"
#include "google/cacheinvalidation/include/invalidation-listener.h"
#include "sync/internal_api/public/base/invalidator_state.h"
#include "sync/internal_api/public/util/weak_handle.h"
#include "sync/notifier/ack_handler.h"
#include "sync/notifier/invalidation_state_tracker.h"
#include "sync/notifier/unacked_invalidation_set.h"

namespace buzz {
class XmppTaskParentInterface;
}  // namespace buzz

namespace notifier {
class PushClient;
}  // namespace notifier

namespace syncer {

class ObjectIdInvalidationMap;
class RegistrationManager;

// SyncInvalidationListener is not thread-safe and lives on the sync
// thread.
class INVALIDATION_EXPORT_PRIVATE SyncInvalidationListener
    : public NON_EXPORTED_BASE(invalidation::InvalidationListener),
      public StateWriter,
      public SyncNetworkChannel::Observer,
      public AckHandler,
      public base::NonThreadSafe {
 public:
  typedef base::Callback<invalidation::InvalidationClient*(
      invalidation::SystemResources*,
      int,
      const invalidation::string&,
      const invalidation::string&,
      invalidation::InvalidationListener*)> CreateInvalidationClientCallback;

  class INVALIDATION_EXPORT_PRIVATE Delegate {
   public:
    virtual ~Delegate();

    virtual void OnInvalidate(
        const ObjectIdInvalidationMap& invalidations) = 0;

    virtual void OnInvalidatorStateChange(InvalidatorState state) = 0;
  };

  explicit SyncInvalidationListener(
      scoped_ptr<SyncNetworkChannel> network_channel);

  // Calls Stop().
  virtual ~SyncInvalidationListener();

  // Does not take ownership of |delegate| or |state_writer|.
  // |invalidation_state_tracker| must be initialized.
  void Start(
      const CreateInvalidationClientCallback&
          create_invalidation_client_callback,
      const std::string& client_id, const std::string& client_info,
      const std::string& invalidation_bootstrap_data,
      const UnackedInvalidationsMap& initial_object_states,
      const WeakHandle<InvalidationStateTracker>& invalidation_state_tracker,
      Delegate* delegate);

  void UpdateCredentials(const std::string& email, const std::string& token);

  // Update the set of object IDs that we're interested in getting
  // notifications for.  May be called at any time.
  void UpdateRegisteredIds(const ObjectIdSet& ids);

  // invalidation::InvalidationListener implementation.
  virtual void Ready(
      invalidation::InvalidationClient* client) OVERRIDE;
  virtual void Invalidate(
      invalidation::InvalidationClient* client,
      const invalidation::Invalidation& invalidation,
      const invalidation::AckHandle& ack_handle) OVERRIDE;
  virtual void InvalidateUnknownVersion(
      invalidation::InvalidationClient* client,
      const invalidation::ObjectId& object_id,
      const invalidation::AckHandle& ack_handle) OVERRIDE;
  virtual void InvalidateAll(
      invalidation::InvalidationClient* client,
      const invalidation::AckHandle& ack_handle) OVERRIDE;
  virtual void InformRegistrationStatus(
      invalidation::InvalidationClient* client,
      const invalidation::ObjectId& object_id,
      invalidation::InvalidationListener::RegistrationState reg_state) OVERRIDE;
  virtual void InformRegistrationFailure(
      invalidation::InvalidationClient* client,
      const invalidation::ObjectId& object_id,
      bool is_transient,
      const std::string& error_message) OVERRIDE;
  virtual void ReissueRegistrations(
      invalidation::InvalidationClient* client,
      const std::string& prefix,
      int prefix_length) OVERRIDE;
  virtual void InformError(
      invalidation::InvalidationClient* client,
      const invalidation::ErrorInfo& error_info) OVERRIDE;

  // AckHandler implementation.
  virtual void Acknowledge(
      const invalidation::ObjectId& id,
      const syncer::AckHandle& handle) OVERRIDE;
  virtual void Drop(
      const invalidation::ObjectId& id,
      const syncer::AckHandle& handle) OVERRIDE;

  // StateWriter implementation.
  virtual void WriteState(const std::string& state) OVERRIDE;

  // SyncNetworkChannel::Observer implementation.
  virtual void OnNetworkChannelStateChanged(
      InvalidatorState invalidator_state) OVERRIDE;

  void DoRegistrationUpdate();

  void RequestDetailedStatus(
      base::Callback<void(const base::DictionaryValue&)> callback) const;

  void StopForTest();

 private:
  void Stop();

  InvalidatorState GetState() const;

  void EmitStateChange();

  // Sends invalidations to their appropriate destination.
  //
  // If there are no observers registered for them, they will be saved for
  // later.
  //
  // If there are observers registered, they will be saved (to make sure we
  // don't drop them until they've been acted on) and emitted to the observers.
  void DispatchInvalidations(const ObjectIdInvalidationMap& invalidations);

  // Saves invalidations.
  //
  // This call isn't synchronous so we can't guarantee these invalidations will
  // be safely on disk by the end of the call, but it should ensure that the
  // data makes it to disk eventually.
  void SaveInvalidations(const ObjectIdInvalidationMap& to_save);

  // Emits previously saved invalidations to their registered observers.
  void EmitSavedInvalidations(const ObjectIdInvalidationMap& to_emit);

  // Generate a Dictionary with all the debugging information.
  scoped_ptr<base::DictionaryValue> CollectDebugData() const;

  WeakHandle<AckHandler> GetThisAsAckHandler();

  scoped_ptr<SyncNetworkChannel> sync_network_channel_;
  SyncSystemResources sync_system_resources_;
  UnackedInvalidationsMap unacked_invalidations_map_;
  WeakHandle<InvalidationStateTracker> invalidation_state_tracker_;
  Delegate* delegate_;
  scoped_ptr<invalidation::InvalidationClient> invalidation_client_;
  scoped_ptr<RegistrationManager> registration_manager_;
  // Stored to pass to |registration_manager_| on start.
  ObjectIdSet registered_ids_;

  // The states of the ticl and the push client.
  InvalidatorState ticl_state_;
  InvalidatorState push_client_state_;

  base::WeakPtrFactory<SyncInvalidationListener> weak_ptr_factory_;

  DISALLOW_COPY_AND_ASSIGN(SyncInvalidationListener);
};

}  // namespace syncer

#endif  // COMPONENTS_INVALIDATION_SYNC_INVALIDATION_LISTENER_H_