// Copyright 2018 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 COMPONENTS_SEND_TAB_TO_SELF_SEND_TAB_TO_SELF_BRIDGE_H_
#define COMPONENTS_SEND_TAB_TO_SELF_SEND_TAB_TO_SELF_BRIDGE_H_

#include <map>
#include <memory>
#include <string>
#include <utility>
#include <vector>

#include "base/macros.h"
#include "base/memory/weak_ptr.h"
#include "base/time/time.h"
#include "components/history/core/browser/history_service_observer.h"
#include "components/send_tab_to_self/send_tab_to_self_entry.h"
#include "components/send_tab_to_self/send_tab_to_self_model.h"
#include "components/sync/base/model_type.h"
#include "components/sync/device_info/local_device_info_provider.h"
#include "components/sync/model/model_type_store.h"
#include "components/sync/model/model_type_sync_bridge.h"

namespace history {
class HistoryService;
}  // namespace history

namespace syncer {
class ModelTypeChangeProcessor;
}  // namespace syncer

namespace base {
class Clock;
}  // namespace base

namespace send_tab_to_self {

// Interface for a persistence layer for send tab to self.
// All interface methods have to be called on main thread.
class SendTabToSelfBridge : public syncer::ModelTypeSyncBridge,
                            public SendTabToSelfModel,
                            public history::HistoryServiceObserver {
 public:
  // |local_device_info_provider| must not be null and must outlive this object.
  // |clock| must not be null and must outlive this object.
  SendTabToSelfBridge(
      std::unique_ptr<syncer::ModelTypeChangeProcessor> change_processor,
      syncer::LocalDeviceInfoProvider* local_device_info_provider,
      base::Clock* clock,
      syncer::OnceModelTypeStoreFactory create_store_callback,
      history::HistoryService* history_service);
  ~SendTabToSelfBridge() override;

  // syncer::ModelTypeSyncBridge overrides.
  std::unique_ptr<syncer::MetadataChangeList> CreateMetadataChangeList()
      override;
  base::Optional<syncer::ModelError> MergeSyncData(
      std::unique_ptr<syncer::MetadataChangeList> metadata_change_list,
      syncer::EntityChangeList entity_data) override;
  base::Optional<syncer::ModelError> ApplySyncChanges(
      std::unique_ptr<syncer::MetadataChangeList> metadata_change_list,
      syncer::EntityChangeList entity_changes) override;
  void GetData(StorageKeyList storage_keys, DataCallback callback) override;
  void GetAllDataForDebugging(DataCallback callback) override;
  std::string GetClientTag(const syncer::EntityData& entity_data) override;
  std::string GetStorageKey(const syncer::EntityData& entity_data) override;

  // SendTabToSelfModel overrides.
  std::vector<std::string> GetAllGuids() const override;
  void DeleteAllEntries() override;
  const SendTabToSelfEntry* GetEntryByGUID(
      const std::string& guid) const override;
  const SendTabToSelfEntry* AddEntry(const GURL& url,
                                     const std::string& title,
                                     base::Time navigation_time) override;
  void DeleteEntry(const std::string& guid) override;
  void DismissEntry(const std::string& guid) override;

  // history::HistoryServiceObserver:
  void OnURLsDeleted(history::HistoryService* history_service,
                     const history::DeletionInfo& deletion_info) override;

  // For testing only.
  static std::unique_ptr<syncer::ModelTypeStore> DestroyAndStealStoreForTest(
      std::unique_ptr<SendTabToSelfBridge> bridge);

 private:
  using SendTabToSelfEntries =
      std::map<std::string, std::unique_ptr<SendTabToSelfEntry>>;

  // Notify all observers of any added |entries| when they are added the the
  // model via sync.
  void NotifyRemoteSendTabToSelfEntryAdded(
      const std::vector<const SendTabToSelfEntry*>& new_entries);

  // Notify all observers when the entries with |guids| have been removed from
  // the model via sync.
  void NotifyRemoteSendTabToSelfEntryDeleted(
      const std::vector<std::string>& guids);

  // Notify all observers that the model is loaded;
  void NotifySendTabToSelfModelLoaded();

  // Methods used as callbacks given to DataTypeStore.
  void OnStoreCreated(const base::Optional<syncer::ModelError>& error,
                      std::unique_ptr<syncer::ModelTypeStore> store);
  void OnReadAllData(
      const base::Optional<syncer::ModelError>& error,
      std::unique_ptr<syncer::ModelTypeStore::RecordList> record_list);

  // Used as callback given to LocalDeviceInfoProvider.
  void OnDeviceProviderInitialized();

  void OnReadAllMetadata(const base::Optional<syncer::ModelError>& error,
                         std::unique_ptr<syncer::MetadataBatch> metadata_batch);
  void OnCommit(const base::Optional<syncer::ModelError>& error);

  // Persists the changes in the given aggregators
  void Commit(std::unique_ptr<syncer::ModelTypeStore::WriteBatch> batch);

  // Returns a specific entry for editing. Returns null if the entry does not
  // exist.
  SendTabToSelfEntry* GetMutableEntryByGUID(const std::string& guid) const;

  // |entries_| is keyed by GUIDs.
  SendTabToSelfEntries entries_;

  // |clock_| isn't owned.
  const base::Clock* const clock_;

  // |local_device_info_provider_| isn't owned.
  syncer::LocalDeviceInfoProvider* const local_device_info_provider_;

  // |history_service_| isn't owned.
  history::HistoryService* const history_service_;

  std::string local_device_name_;

  // In charge of actually persisting changes to disk, or loading previous data.
  std::unique_ptr<syncer::ModelTypeStore> store_;

  // Used to listen for provider initialization. If the provider is already
  // initialized during our constructor then the subscription is never used.
  std::unique_ptr<syncer::LocalDeviceInfoProvider::Subscription>
      device_subscription_;

  base::WeakPtrFactory<SendTabToSelfBridge> weak_ptr_factory_;

  DISALLOW_COPY_AND_ASSIGN(SendTabToSelfBridge);
};

}  // namespace send_tab_to_self

#endif  // COMPONENTS_SEND_TAB_TO_SELF_SEND_TAB_TO_SELF_BRIDGE_H_