// Copyright 2019 The Cobalt Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#ifndef COBALT_UPDATER_UPDATER_MODULE_H_
#define COBALT_UPDATER_UPDATER_MODULE_H_

#include <map>
#include <memory>
#include <string>

#include "base/memory/scoped_refptr.h"
#include "base/message_loop/message_loop.h"
#include "base/threading/thread.h"
#include "cobalt/extension/updater_notification.h"
#include "cobalt/network/network_module.h"
#include "cobalt/updater/configurator.h"
#include "components/prefs/pref_service.h"
#include "components/update_client/crx_update_item.h"
#include "components/update_client/update_client.h"
#include "starboard/event.h"

namespace cobalt {
namespace updater {

using update_client::ComponentState;

enum class UpdaterStatus {
  kNewUpdate,
  kChecking,
  kUpdateAvailable,
  kDownloadingDiff,
  kDownloading,
  kSlotLocked,
  kDownloaded,
  kUpdatingDiff,
  kUpdating,
  kUpdated,
  kUpToDate,
  kUpdateError,
  kUninstalled,
  kRun
};

// Mapping a component state to an updater status.
const std::map<ComponentState, UpdaterStatus> component_to_updater_status_map =
    {
        {ComponentState::kNew, UpdaterStatus::kNewUpdate},
        {ComponentState::kChecking, UpdaterStatus::kChecking},
        {ComponentState::kCanUpdate, UpdaterStatus::kUpdateAvailable},
        {ComponentState::kDownloadingDiff, UpdaterStatus::kDownloadingDiff},
        {ComponentState::kDownloading, UpdaterStatus::kDownloading},
        {ComponentState::kDownloaded, UpdaterStatus::kDownloaded},
        {ComponentState::kUpdatingDiff, UpdaterStatus::kUpdatingDiff},
        {ComponentState::kUpdating, UpdaterStatus::kUpdating},
        {ComponentState::kUpdated, UpdaterStatus::kUpdated},
        {ComponentState::kUpToDate, UpdaterStatus::kUpToDate},
        {ComponentState::kUpdateError, UpdaterStatus::kUpdateError},
        {ComponentState::kUninstalled, UpdaterStatus::kUninstalled},
        {ComponentState::kRun, UpdaterStatus::kRun},
};

// Translating an updater status to a status string.
const std::map<UpdaterStatus, const char*> updater_status_string_map = {
    {UpdaterStatus::kNewUpdate, "Will check for update soon"},
    {UpdaterStatus::kChecking, "Checking for update"},
    {UpdaterStatus::kUpdateAvailable, "Update is available"},
    {UpdaterStatus::kDownloadingDiff, "Downloading delta update"},
    {UpdaterStatus::kDownloading, "Downloading update"},
    {UpdaterStatus::kSlotLocked, "Slot is locked"},
    {UpdaterStatus::kDownloaded, "Update is downloaded"},
    {UpdaterStatus::kUpdatingDiff, "Installing delta update"},
    {UpdaterStatus::kUpdating, "Installing update"},
    {UpdaterStatus::kUpdated, "Update installed, pending restart"},
    {UpdaterStatus::kUpToDate, "App is up to date"},
    {UpdaterStatus::kUpdateError, "Failed to update"},
    {UpdaterStatus::kUninstalled, "Update uninstalled"},
    {UpdaterStatus::kRun, "Transitioning..."},
};

// An interface that observes the updater. It provides notifications when the
// updater changes status.
class Observer : public update_client::UpdateClient::Observer {
 public:
  Observer(scoped_refptr<update_client::UpdateClient> update_client,
           scoped_refptr<Configurator> updater_configurator)
      : update_client_(update_client),
        updater_configurator_(updater_configurator) {
    const CobaltExtensionUpdaterNotificationApi* updater_notification_ext =
        static_cast<const CobaltExtensionUpdaterNotificationApi*>(
            SbSystemGetExtension(kCobaltExtensionUpdaterNotificationName));
    if (updater_notification_ext &&
        SbStringCompareAll(updater_notification_ext->name,
                           kCobaltExtensionUpdaterNotificationName) == 0 &&
        updater_notification_ext->version >= 1) {
      updater_notification_ext_ = updater_notification_ext;
    } else {
      updater_notification_ext_ = nullptr;
    }
  }


  // Overrides for update_client::UpdateClient::Observer.
  void OnEvent(Events event, const std::string& id) override;

 private:
  scoped_refptr<update_client::UpdateClient> update_client_;
  scoped_refptr<Configurator> updater_configurator_;
  update_client::CrxUpdateItem crx_update_item_;
  const CobaltExtensionUpdaterNotificationApi* updater_notification_ext_;
  DISALLOW_COPY_AND_ASSIGN(Observer);
};

// UpdaterModule checks for available Cobalt update and downloads the update
// that matches the underlying Starboard ABI (SABI) configuration. Then
// the update is unpacked to a dedicated location for installation. The update
// checks run according to a schedule defined by the Cobalt application.
class UpdaterModule {
 public:
  explicit UpdaterModule(network::NetworkModule* network_module);
  ~UpdaterModule();

  void Suspend();
  void Resume();

  std::string GetUpdaterChannel() const;
  void SetUpdaterChannel(const std::string& updater_channel);

  void CompareAndSwapChannelChanged(int old_value, int new_value);

  void RunUpdateCheck();

  std::string GetUpdaterStatus() const;

  void ResetInstallations();

  int GetInstallationIndex() const;

 private:
  base::Thread updater_thread_;
  scoped_refptr<update_client::UpdateClient> update_client_;
  std::unique_ptr<Observer> updater_observer_;
  network::NetworkModule* network_module_;
  scoped_refptr<Configurator> updater_configurator_;
  int update_check_count_ = 0;
  bool is_updater_running_;

  THREAD_CHECKER(thread_checker_);

  int GetUpdateCheckCount() { return update_check_count_; }
  void IncrementUpdateCheckCount() { update_check_count_++; }

  void Initialize();
  void Finalize();
  void MarkSuccessful();
  void Update();
};

}  // namespace updater
}  // namespace cobalt

#endif  // COBALT_UPDATER_UPDATER_MODULE_H_