// Copyright (c) 2012 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 CHROME_BROWSER_CHROME_TO_MOBILE_SERVICE_H_
#define CHROME_BROWSER_CHROME_TO_MOBILE_SERVICE_H_

#include <map>
#include <queue>
#include <set>
#include <string>
#include <vector>

#include "base/compiler_specific.h"
#include "base/files/file_path.h"
#include "base/memory/scoped_vector.h"
#include "base/memory/weak_ptr.h"
#include "base/strings/string16.h"
#include "base/timer.h"
#include "base/values.h"
#include "chrome/browser/sessions/session_id.h"
#include "components/browser_context_keyed_service/browser_context_keyed_service.h"
#include "content/public/browser/notification_observer.h"
#include "content/public/browser/notification_registrar.h"
#include "google_apis/gaia/oauth2_access_token_consumer.h"
#include "googleurl/src/gurl.h"
#include "net/url_request/url_fetcher_delegate.h"
#include "sync/notifier/invalidation_handler.h"

class OAuth2AccessTokenFetcher;
class Browser;
class CloudPrintURL;
class MockChromeToMobileService;
class Profile;

namespace net {
class URLFetcher;
}

namespace user_prefs {
class PrefRegistrySyncable;
}

// ChromeToMobileService connects to the cloud print service to enumerate
// compatible mobiles owned by its profile and send URLs and MHTML snapshots.
class ChromeToMobileService : public BrowserContextKeyedService,
                              public net::URLFetcherDelegate,
                              public content::NotificationObserver,
                              public OAuth2AccessTokenConsumer,
                              public syncer::InvalidationHandler {
 public:
  class Observer {
   public:
    Observer();
    virtual ~Observer();

    // Called on generation of the page's MHTML snapshot.
    virtual void SnapshotGenerated(const base::FilePath& path, int64 bytes) = 0;

    // Called after URLFetcher responses from sending the URL (and snapshot).
    virtual void OnSendComplete(bool success) = 0;
  };

  // The supported mobile device operating systems.
  enum MobileOS {
    ANDROID = 0,
    IOS,
  };

  // The cloud print job types.
  enum JobType {
    URL = 0,
    DELAYED_SNAPSHOT,
    SNAPSHOT,
  };

  // The cloud print job submission data.
  struct JobData {
    JobData();
    ~JobData();

    MobileOS mobile_os;
    string16 mobile_id;
    GURL url;
    string16 title;
    base::FilePath snapshot;
    std::string snapshot_id;
    std::string snapshot_content;
    JobType type;

   private:
    DISALLOW_COPY_AND_ASSIGN(JobData);
  };

  // Returns whether Chrome To Mobile is enabled (gated on the Action Box UI).
  static bool IsChromeToMobileEnabled();

  // Update and return the IDC_CHROME_TO_MOBILE_PAGE command enabled state; the
  // state is derived from commandline, profile, and current page applicability.
  // NOTE: Call this instead of IsCommandEnabled(IDC_CHROME_TO_MOBILE_PAGE).
  static bool UpdateAndGetCommandState(Browser* browser);

  // Register the user prefs associated with this service.
  static void RegisterUserPrefs(user_prefs::PrefRegistrySyncable* registry);

  explicit ChromeToMobileService(Profile* profile);
  virtual ~ChromeToMobileService();

  // Returns true if the service has found any registered mobile devices.
  bool HasMobiles() const;

  // Get the non-NULL ListValue of mobile devices from the cloud print service.
  // The list is owned by PrefService, which outlives ChromeToMobileService.
  // Each device DictionaryValue contains strings "type", "name", and "id".
  // Virtual for unit test mocking.
  virtual const base::ListValue* GetMobiles() const;

  // Callback with an MHTML snapshot of the browser's selected WebContents.
  // Virtual for unit test mocking.
  virtual void GenerateSnapshot(Browser* browser,
                                base::WeakPtr<Observer> observer);

  // Send the browser's selected WebContents to the specified mobile device.
  // Virtual for unit test mocking.
  virtual void SendToMobile(const base::DictionaryValue* mobile,
                            const base::FilePath& snapshot,
                            Browser* browser,
                            base::WeakPtr<Observer> observer);

  // Delete the snapshot file (should be called on observer destruction).
  // Virtual for unit test mocking.
  virtual void DeleteSnapshot(const base::FilePath& snapshot);

  // Opens the "Learn More" help article link in the supplied |browser|.
  void LearnMore(Browser* browser) const;

  // BrowserContextKeyedService method.
  virtual void Shutdown() OVERRIDE;

  // net::URLFetcherDelegate method.
  virtual void OnURLFetchComplete(const net::URLFetcher* source) OVERRIDE;

  // content::NotificationObserver method.
  virtual void Observe(int type,
                       const content::NotificationSource& source,
                       const content::NotificationDetails& details) OVERRIDE;

  // OAuth2AccessTokenConsumer methods.
  virtual void OnGetTokenSuccess(const std::string& access_token,
                                 const base::Time& expiration_time) OVERRIDE;
  virtual void OnGetTokenFailure(const GoogleServiceAuthError& error) OVERRIDE;

  // syncer::InvalidationHandler implementation.
  virtual void OnInvalidatorStateChange(
      syncer::InvalidatorState state) OVERRIDE;
  virtual void OnIncomingInvalidation(
      const syncer::ObjectIdInvalidationMap& invalidation_map) OVERRIDE;

  // Expose access token accessors for test purposes.
  const std::string& GetAccessTokenForTest() const;
  void SetAccessTokenForTest(const std::string& access_token);

 private:
  friend class MockChromeToMobileService;

  // Handle the attempted creation of a temporary file for snapshot generation.
  void SnapshotFileCreated(base::WeakPtr<Observer> observer,
                           SessionID::id_type browser_id,
                           const base::FilePath& path);

  // Handle the attempted MHTML snapshot generation; alerts the observer.
  void SnapshotGenerated(base::WeakPtr<Observer> observer,
                         const base::FilePath& path,
                         int64 bytes);

  // Handle the attempted reading of the snapshot file for job submission.
  // Send valid snapshot contents if available, or log an error.
  void SnapshotFileRead(base::WeakPtr<Observer> observer,
                        scoped_ptr<JobData> data);

  // Initialize cloud print URLFetcher requests.
  void InitRequest(net::URLFetcher* request);

  // Submit a cloud print job request with the requisite data.
  void SendJobRequest(base::WeakPtr<Observer> observer, const JobData& data);

  // Clear the cached cloud print auth access token.
  void ClearAccessToken();

  // Send the OAuth2AccessTokenFetcher request.
  void RequestAccessToken();

  // Send the cloud print URLFetcher device search request.
  // Virtual for unit test mocking.
  virtual void RequestDeviceSearch();

  void HandleSearchResponse(const net::URLFetcher* source);
  void HandleSubmitResponse(const net::URLFetcher* source);

  base::WeakPtrFactory<ChromeToMobileService> weak_ptr_factory_;

  Profile* profile_;

  // Sync invalidation service state. Chrome To Mobile requires this service to
  // to keep the mobile device list up to date and prevent page send failures.
  bool sync_invalidation_enabled_;

  // Used to recieve TokenService notifications for GaiaOAuth2LoginRefreshToken.
  content::NotificationRegistrar registrar_;

  // The cloud print service URL and auth access token.
  GURL cloud_print_url_;
  std::string access_token_;

  // The set of snapshots currently available.
  std::set<base::FilePath> snapshots_;

  // The list of active URLFetcher requests owned by the service.
  ScopedVector<net::URLFetcher> url_fetchers_;

  // Map URLFetchers to observers for reporting OnSendComplete.
  typedef std::map<const net::URLFetcher*, base::WeakPtr<Observer> >
      RequestObserverMap;
  RequestObserverMap request_observer_map_;

  // The pending OAuth access token request and timers for retrying on failure.
  scoped_ptr<OAuth2AccessTokenFetcher> access_token_fetcher_;
  base::OneShotTimer<ChromeToMobileService> auth_retry_timer_;
  base::OneShotTimer<ChromeToMobileService> search_retry_timer_;

  // A queue of tasks to perform after an access token is lazily initialized.
  std::queue<base::Closure> task_queue_;

  DISALLOW_COPY_AND_ASSIGN(ChromeToMobileService);
};

#endif  // CHROME_BROWSER_CHROME_TO_MOBILE_SERVICE_H_