// Copyright 2013 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 CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_VERSION_H_
#define CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_VERSION_H_

#include <map>
#include <string>
#include <vector>

#include "base/basictypes.h"
#include "base/callback.h"
#include "base/gtest_prod_util.h"
#include "base/id_map.h"
#include "base/memory/ref_counted.h"
#include "base/memory/scoped_ptr.h"
#include "base/observer_list.h"
#include "base/timer/timer.h"
#include "content/browser/service_worker/embedded_worker_instance.h"
#include "content/browser/service_worker/service_worker_cache_listener.h"
#include "content/browser/service_worker/service_worker_script_cache_map.h"
#include "content/common/content_export.h"
#include "content/common/service_worker/service_worker_status_code.h"
#include "content/common/service_worker/service_worker_types.h"
#include "third_party/WebKit/public/platform/WebServiceWorkerEventResult.h"

class GURL;

namespace content {

class EmbeddedWorkerRegistry;
class ServiceWorkerContextCore;
class ServiceWorkerProviderHost;
class ServiceWorkerRegistration;
class ServiceWorkerVersionInfo;

// This class corresponds to a specific version of a ServiceWorker
// script for a given pattern. When a script is upgraded, there may be
// more than one ServiceWorkerVersion "running" at a time, but only
// one of them is activated. This class connects the actual script with a
// running worker.
class CONTENT_EXPORT ServiceWorkerVersion
    : NON_EXPORTED_BASE(public base::RefCounted<ServiceWorkerVersion>),
      public EmbeddedWorkerInstance::Listener {
 public:
  typedef base::Callback<void(ServiceWorkerStatusCode)> StatusCallback;
  typedef base::Callback<void(ServiceWorkerStatusCode,
                              const IPC::Message& message)> MessageCallback;
  typedef base::Callback<void(ServiceWorkerStatusCode,
                              ServiceWorkerFetchEventResult,
                              const ServiceWorkerResponse&)> FetchCallback;

  enum RunningStatus {
    STOPPED = EmbeddedWorkerInstance::STOPPED,
    STARTING = EmbeddedWorkerInstance::STARTING,
    RUNNING = EmbeddedWorkerInstance::RUNNING,
    STOPPING = EmbeddedWorkerInstance::STOPPING,
  };

  // Current version status; some of the status (e.g. INSTALLED and ACTIVATED)
  // should be persisted unlike running status.
  enum Status {
    NEW,         // The version is just created.
    INSTALLING,  // Install event is dispatched and being handled.
    INSTALLED,   // Install event is finished and is ready to be activated.
    ACTIVATING,  // Activate event is dispatched and being handled.
    ACTIVATED,   // Activation is finished and can run as activated.
    REDUNDANT,   // The version is no longer running as activated, due to
                 // unregistration or replace.
  };

  class Listener {
   public:
    virtual void OnWorkerStarted(ServiceWorkerVersion* version) {}
    virtual void OnWorkerStopped(ServiceWorkerVersion* version) {}
    virtual void OnVersionStateChanged(ServiceWorkerVersion* version) {}
    virtual void OnErrorReported(ServiceWorkerVersion* version,
                                 const base::string16& error_message,
                                 int line_number,
                                 int column_number,
                                 const GURL& source_url) {}
    virtual void OnReportConsoleMessage(ServiceWorkerVersion* version,
                                        int source_identifier,
                                        int message_level,
                                        const base::string16& message,
                                        int line_number,
                                        const GURL& source_url) {}
    // Fires when a version transitions from having a controllee to not.
    virtual void OnNoControllees(ServiceWorkerVersion* version) {}

   protected:
    virtual ~Listener() {}
  };

  ServiceWorkerVersion(
      ServiceWorkerRegistration* registration,
      const GURL& script_url,
      int64 version_id,
      base::WeakPtr<ServiceWorkerContextCore> context);

  int64 version_id() const { return version_id_; }
  int64 registration_id() const { return registration_id_; }
  const GURL& script_url() const { return script_url_; }
  const GURL& scope() const { return scope_; }
  RunningStatus running_status() const {
    return static_cast<RunningStatus>(embedded_worker_->status());
  }
  ServiceWorkerVersionInfo GetInfo();
  Status status() const { return status_; }

  // This sets the new status and also run status change callbacks
  // if there're any (see RegisterStatusChangeCallback).
  void SetStatus(Status status);

  // Registers status change callback. (This is for one-off observation,
  // the consumer needs to re-register if it wants to continue observing
  // status changes)
  void RegisterStatusChangeCallback(const base::Closure& callback);

  // Starts an embedded worker for this version.
  // This returns OK (success) if the worker is already running.
  void StartWorker(const StatusCallback& callback);

  // Starts an embedded worker for this version.
  // |pause_after_download| notifies worker to pause after download finished
  // which could be resumed by EmbeddedWorkerInstance::ResumeAfterDownload.
  // This returns OK (success) if the worker is already running.
  void StartWorker(bool pause_after_download,
                   const StatusCallback& callback);

  // Stops an embedded worker for this version.
  // This returns OK (success) if the worker is already stopped.
  void StopWorker(const StatusCallback& callback);

  // Schedules an update to be run 'soon'.
  void ScheduleUpdate();

  // If an update is scheduled but not yet started, this resets the timer
  // delaying the start time by a 'small' amount.
  void DeferScheduledUpdate();

  // Starts an update now.
  void StartUpdate();

  // Sends an IPC message to the worker.
  // If the worker is not running this first tries to start it by
  // calling StartWorker internally.
  // |callback| can be null if the sender does not need to know if the
  // message is successfully sent or not.
  void SendMessage(const IPC::Message& message, const StatusCallback& callback);

  // Sends install event to the associated embedded worker and asynchronously
  // calls |callback| when it errors out or it gets response from the worker
  // to notify install completion.
  // |active_version_id| must be a valid positive ID
  // if there's an activated (previous) version running.
  //
  // This must be called when the status() is NEW. Calling this changes
  // the version's status to INSTALLING.
  // Upon completion, the version's status will be changed to INSTALLED
  // on success, or back to NEW on failure.
  void DispatchInstallEvent(int active_version_id,
                            const StatusCallback& callback);

  // Sends activate event to the associated embedded worker and asynchronously
  // calls |callback| when it errors out or it gets response from the worker
  // to notify activation completion.
  //
  // This must be called when the status() is INSTALLED. Calling this changes
  // the version's status to ACTIVATING.
  // Upon completion, the version's status will be changed to ACTIVATED
  // on success, or back to INSTALLED on failure.
  void DispatchActivateEvent(const StatusCallback& callback);

  // Sends fetch event to the associated embedded worker and calls
  // |callback| with the response from the worker.
  //
  // This must be called when the status() is ACTIVATED. Calling this in other
  // statuses will result in an error SERVICE_WORKER_ERROR_FAILED.
  void DispatchFetchEvent(const ServiceWorkerFetchRequest& request,
                          const base::Closure& prepare_callback,
                          const FetchCallback& fetch_callback);

  // Sends sync event to the associated embedded worker and asynchronously calls
  // |callback| when it errors out or it gets response from the worker to notify
  // completion.
  //
  // This must be called when the status() is ACTIVATED.
  void DispatchSyncEvent(const StatusCallback& callback);

  // Sends push event to the associated embedded worker and asynchronously calls
  // |callback| when it errors out or it gets response from the worker to notify
  // completion.
  //
  // This must be called when the status() is ACTIVATED.
  void DispatchPushEvent(const StatusCallback& callback,
                         const std::string& data);

  // Adds and removes |provider_host| as a controllee of this ServiceWorker.
  // A potential controllee is a host having the version as its .installing
  // or .waiting version.
  void AddControllee(ServiceWorkerProviderHost* provider_host);
  void RemoveControllee(ServiceWorkerProviderHost* provider_host);

  // Returns if it has controllee.
  bool HasControllee() const { return !controllee_map_.empty(); }

  // Adds and removes Listeners.
  void AddListener(Listener* listener);
  void RemoveListener(Listener* listener);

  ServiceWorkerScriptCacheMap* script_cache_map() { return &script_cache_map_; }
  EmbeddedWorkerInstance* embedded_worker() { return embedded_worker_.get(); }

  // Dooms this version to have REDUNDANT status and its resources deleted.  If
  // the version is controlling a page, these changes will happen when the
  // version no longer controls any pages.
  void Doom();
  bool is_doomed() const { return is_doomed_; }

 private:
  friend class base::RefCounted<ServiceWorkerVersion>;
  FRIEND_TEST_ALL_PREFIXES(ServiceWorkerControlleeRequestHandlerTest,
                           ActivateWaitingVersion);
  FRIEND_TEST_ALL_PREFIXES(ServiceWorkerVersionTest, ScheduleStopWorker);
  FRIEND_TEST_ALL_PREFIXES(ServiceWorkerVersionTest, ListenerAvailability);
  typedef ServiceWorkerVersion self;
  typedef std::map<ServiceWorkerProviderHost*, int> ControlleeMap;
  typedef IDMap<ServiceWorkerProviderHost> ControlleeByIDMap;

  ~ServiceWorkerVersion() override;

  // EmbeddedWorkerInstance::Listener overrides:
  void OnStarted() override;
  void OnStopped() override;
  void OnReportException(const base::string16& error_message,
                         int line_number,
                         int column_number,
                         const GURL& source_url) override;
  void OnReportConsoleMessage(int source_identifier,
                              int message_level,
                              const base::string16& message,
                              int line_number,
                              const GURL& source_url) override;
  bool OnMessageReceived(const IPC::Message& message) override;

  void OnStartMessageSent(ServiceWorkerStatusCode status);

  void DispatchInstallEventAfterStartWorker(int active_version_id,
                                            const StatusCallback& callback);
  void DispatchActivateEventAfterStartWorker(const StatusCallback& callback);

  // Message handlers.
  void OnGetClientDocuments(int request_id);
  void OnActivateEventFinished(int request_id,
                               blink::WebServiceWorkerEventResult result);
  void OnInstallEventFinished(int request_id,
                              blink::WebServiceWorkerEventResult result);
  void OnFetchEventFinished(int request_id,
                            ServiceWorkerFetchEventResult result,
                            const ServiceWorkerResponse& response);
  void OnSyncEventFinished(int request_id);
  void OnPushEventFinished(int request_id);
  void OnPostMessageToDocument(int client_id,
                               const base::string16& message,
                               const std::vector<int>& sent_message_port_ids);

  void ScheduleStopWorker();
  void DoomInternal();

  const int64 version_id_;
  int64 registration_id_;
  GURL script_url_;
  GURL scope_;
  Status status_;
  scoped_ptr<EmbeddedWorkerInstance> embedded_worker_;
  scoped_ptr<ServiceWorkerCacheListener> cache_listener_;
  std::vector<StatusCallback> start_callbacks_;
  std::vector<StatusCallback> stop_callbacks_;
  std::vector<base::Closure> status_change_callbacks_;

  // Message callbacks.
  IDMap<StatusCallback, IDMapOwnPointer> activate_callbacks_;
  IDMap<StatusCallback, IDMapOwnPointer> install_callbacks_;
  IDMap<FetchCallback, IDMapOwnPointer> fetch_callbacks_;
  IDMap<StatusCallback, IDMapOwnPointer> sync_callbacks_;
  IDMap<StatusCallback, IDMapOwnPointer> push_callbacks_;

  ControlleeMap controllee_map_;
  ControlleeByIDMap controllee_by_id_;
  base::WeakPtr<ServiceWorkerContextCore> context_;
  ObserverList<Listener> listeners_;
  ServiceWorkerScriptCacheMap script_cache_map_;
  base::OneShotTimer<ServiceWorkerVersion> stop_worker_timer_;
  base::OneShotTimer<ServiceWorkerVersion> update_timer_;
  bool is_doomed_;

  base::WeakPtrFactory<ServiceWorkerVersion> weak_factory_;

  DISALLOW_COPY_AND_ASSIGN(ServiceWorkerVersion);
};

}  // namespace content

#endif  // CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_VERSION_H_