components/translate/ios/browser/translate_controller.h

// Copyright 2014 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef COMPONENTS_TRANSLATE_IOS_BROWSER_TRANSLATE_CONTROLLER_H_
#define COMPONENTS_TRANSLATE_IOS_BROWSER_TRANSLATE_CONTROLLER_H_

#include <iterator>
#include <memory>
#include <set>
#include <string>

#include "base/gtest_prod_util.h"
#include "base/memory/weak_ptr.h"
#include "base/values.h"
#include "components/translate/core/common/translate_errors.h"
#import "ios/web/public/js_messaging/web_frames_manager.h"
#import "ios/web/public/web_state.h"
#include "ios/web/public/web_state_observer.h"
#import "ios/web/public/web_state_user_data.h"
#include "services/network/public/cpp/simple_url_loader.h"

class JSTranslateWebFrameManagerFactory;

namespace web {
class NavigationContext;
}  // namespace web

namespace translate {

// TranslateController controls the translation of the page, by injecting the
// translate scripts and monitoring the status.
class TranslateController : public web::WebFramesManager::Observer,
                            public web::WebStateObserver,
                            public web::WebStateUserData<TranslateController> {
 public:
  // Observer class to monitor the progress of the translation.
  class Observer {
   public:
    // Called when the translate script is ready.
    // |error_type| Indicates error code.
    virtual void OnTranslateScriptReady(TranslateErrors error_type,
                                        double load_time,
                                        double ready_time) = 0;

    // Called when the translation is complete.
    // |error_type| Indicates error code.
    virtual void OnTranslateComplete(TranslateErrors error_type,
                                     const std::string& source_language,
                                     double translation_time) = 0;
  };

  TranslateController(const TranslateController&) = delete;
  TranslateController& operator=(const TranslateController&) = delete;

  ~TranslateController() override;

  // Sets the observer.
  void set_observer(Observer* observer) { observer_ = observer; }

  // Injects the translate script.
  void InjectTranslateScript(const std::string& translate_script);

  // Reverts the translation.
  void RevertTranslation();

  // Starts the translation. Must be called when the translation script is
  // ready.
  void StartTranslation(const std::string& source_language,
                        const std::string& target_language);

  // Called when a JavaScript command is received.
  void OnJavascriptCommandReceived(const base::Value::Dict& payload);

  // Changes the JSTranslateWebFrameManagerFactory used by this
  // TranslateController. Only used for testing.
  void SetJsTranslateWebFrameManagerFactoryForTesting(
      JSTranslateWebFrameManagerFactory* manager);

 private:
  TranslateController(web::WebState* web_state,
                      JSTranslateWebFrameManagerFactory* js_manager_factory);
  friend class web::WebStateUserData<TranslateController>;
  WEB_STATE_USER_DATA_KEY_DECL();

  FRIEND_TEST_ALL_PREFIXES(TranslateControllerTest,
                           OnJavascriptCommandReceived);
  FRIEND_TEST_ALL_PREFIXES(TranslateControllerTest,
                           OnIFrameJavascriptCommandReceived);
  FRIEND_TEST_ALL_PREFIXES(TranslateControllerTest,
                           OnTranslateScriptReadyTimeoutCalled);
  FRIEND_TEST_ALL_PREFIXES(TranslateControllerTest,
                           OnTranslateScriptReadyCalled);
  FRIEND_TEST_ALL_PREFIXES(TranslateControllerTest, TranslationSuccess);
  FRIEND_TEST_ALL_PREFIXES(TranslateControllerTest, TranslationFailure);
  FRIEND_TEST_ALL_PREFIXES(TranslateControllerTest, OnTranslateLoadJavascript);
  FRIEND_TEST_ALL_PREFIXES(TranslateControllerTest,
                           OnTranslateSendRequestWithValidCommand);
  FRIEND_TEST_ALL_PREFIXES(TranslateControllerTest,
                           OnTranslateSendRequestWithBadURL);
  FRIEND_TEST_ALL_PREFIXES(TranslateControllerTest,
                           OnTranslateSendRequestWithBadMethod);

  // Methods to handle specific JavaScript commands.
  // The command is ignored if `payload` format is unexpected.
  void OnTranslateReady(const base::Value::Dict& payload);
  void OnTranslateComplete(const base::Value::Dict& payload);
  void OnTranslateLoadJavaScript(const base::Value::Dict& payload);
  void OnTranslateSendRequest(const base::Value::Dict& payload);

  // The callback when the script is fetched or a server error occurred.
  void OnScriptFetchComplete(std::unique_ptr<std::string> response_body);
  // The callback when translate requests have completed.
  void OnRequestFetchComplete(
      std::set<std::unique_ptr<network::SimpleURLLoader>>::iterator it,
      std::string url,
      int request_id,
      std::unique_ptr<std::string> response_body);

  // web::WebStateObserver implementation:
  void WebStateDestroyed(web::WebState* web_state) override;
  void DidStartNavigation(web::WebState* web_state,
                          web::NavigationContext* navigation_context) override;
  void WebStateRealized(web::WebState* web_state) override;

  // web::WebFramesManager implementation:
  void WebFrameBecameAvailable(web::WebFramesManager* web_frames_manager,
                               web::WebFrame* web_frame) override;
  void WebFrameBecameUnavailable(web::WebFramesManager* web_frames_manager,
                                 const std::string& frame_id) override;

  // The WebState this instance is observing. Will be null after
  // WebStateDestroyed has been called.
  web::WebState* web_state_ = nullptr;

  // The current main web frame of `web_state_`, if one exists.
  web::WebFrame* main_web_frame_ = nullptr;

  // Used to fetch translate requests. There may be multiple requests in flight.
  std::set<std::unique_ptr<network::SimpleURLLoader>> request_fetchers_;
  // Used to fetch additional scripts needed for translate.
  std::unique_ptr<network::SimpleURLLoader> script_fetcher_;

  Observer* observer_;
  JSTranslateWebFrameManagerFactory* js_manager_factory_;
  base::WeakPtrFactory<TranslateController> weak_method_factory_;
};

}  // namespace translate

#endif  // COMPONENTS_TRANSLATE_IOS_BROWSER_TRANSLATE_CONTROLLER_H_