// Copyright (c) 2011 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.
//
// This class is used by the RenderView to interact with a PhishingClassifier.

#ifndef CHROME_RENDERER_SAFE_BROWSING_PHISHING_CLASSIFIER_DELEGATE_H_
#define CHROME_RENDERER_SAFE_BROWSING_PHISHING_CLASSIFIER_DELEGATE_H_

#include "base/memory/scoped_ptr.h"
#include "base/strings/string16.h"
#include "content/public/common/page_transition_types.h"
#include "content/public/renderer/render_process_observer.h"
#include "content/public/renderer/render_view_observer.h"
#include "url/gurl.h"

namespace safe_browsing {
class ClientPhishingRequest;
class PhishingClassifier;
class Scorer;

class PhishingClassifierFilter : public content::RenderProcessObserver {
 public:
  static PhishingClassifierFilter* Create();
  virtual ~PhishingClassifierFilter();

  virtual bool OnControlMessageReceived(const IPC::Message& message) OVERRIDE;

 private:
  PhishingClassifierFilter();
  void OnSetPhishingModel(const std::string& model);

  DISALLOW_COPY_AND_ASSIGN(PhishingClassifierFilter);
};

class PhishingClassifierDelegate : public content::RenderViewObserver {
 public:
  // The RenderView owns us.  This object takes ownership of the classifier.
  // Note that if classifier is null, a default instance of PhishingClassifier
  // will be used.
  static PhishingClassifierDelegate* Create(content::RenderView* render_view,
                                            PhishingClassifier* classifier);
  virtual ~PhishingClassifierDelegate();

  // Called by the RenderView once there is a phishing scorer available.
  // The scorer is passed on to the classifier.
  void SetPhishingScorer(const safe_browsing::Scorer* scorer);

  // Called by the RenderView once a page has finished loading.  Updates the
  // last-loaded URL and page text, then starts classification if all other
  // conditions are met (see MaybeStartClassification for details).
  // We ignore preliminary captures, since these happen before the page has
  // finished loading.
  void PageCaptured(string16* page_text, bool preliminary_capture);

  // RenderViewObserver implementation, public for testing.

  // Called by the RenderView when a page has started loading in the given
  // WebFrame.  Typically, this will cause any pending classification to be
  // cancelled.  However, if the navigation is within the same page, we
  // continue running the current classification.
  virtual void DidCommitProvisionalLoad(WebKit::WebFrame* frame,
                                        bool is_new_navigation) OVERRIDE;

 private:
  friend class PhishingClassifierDelegateTest;

  PhishingClassifierDelegate(content::RenderView* render_view,
                             PhishingClassifier* classifier);

  enum CancelClassificationReason {
    NAVIGATE_AWAY,
    NAVIGATE_WITHIN_PAGE,
    PAGE_RECAPTURED,
    SHUTDOWN,
    NEW_PHISHING_SCORER,
    CANCEL_CLASSIFICATION_MAX  // Always add new values before this one.
  };

  // Cancels any pending classification and frees the page text.
  void CancelPendingClassification(CancelClassificationReason reason);

  // RenderViewObserver implementation.
  virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;

  // Called by the RenderView when it receives a StartPhishingDetection IPC
  // from the browser.  This signals that it is ok to begin classification
  // for the given toplevel URL.  If the URL has been fully loaded into the
  // RenderView and a Scorer has been set, this will begin classification,
  // otherwise classification will be deferred until these conditions are met.
  void OnStartPhishingDetection(const GURL& url);

  // Called when classification for the current page finishes.
  void ClassificationDone(const ClientPhishingRequest& verdict);

  // Returns the RenderView's toplevel URL.
  GURL GetToplevelUrl();

  // Shared code to begin classification if all conditions are met.
  void MaybeStartClassification();

  // The PhishingClassifier to use for the RenderView.  This is created once
  // a scorer is made available via SetPhishingScorer().
  scoped_ptr<PhishingClassifier> classifier_;

  // The last URL that the browser instructed us to classify,
  // with the ref stripped.
  GURL last_url_received_from_browser_;

  // The last top-level URL that has finished loading in the RenderView.
  // This corresponds to the text in classifier_page_text_.
  GURL last_finished_load_url_;

  // The transition type for the last load in the main frame.  We use this
  // to exclude back/forward loads from classification.  Note that this is
  // set in DidCommitProvisionalLoad(); the transition is reset after this
  // call in the RenderView, so we need to save off the value.
  content::PageTransition last_main_frame_transition_;

  // The URL of the last load that we actually started classification on.
  // This is used to suppress phishing classification on subframe navigation
  // and back and forward navigations in history.
  GURL last_url_sent_to_classifier_;

  // The page text that will be analyzed by the phishing classifier.  This is
  // set by OnNavigate and cleared when the classifier finishes.  Note that if
  // there is no Scorer yet when OnNavigate is called, or the browser has not
  // instructed us to classify the page, the page text will be cached until
  // these conditions are met.
  string16 classifier_page_text_;

  // Tracks whether we have stored anything in classifier_page_text_ for the
  // most recent load.  We use this to distinguish empty text from cases where
  // PageCaptured has not been called.
  bool have_page_text_;

  // Set to true if the classifier is currently running.
  bool is_classifying_;

  DISALLOW_COPY_AND_ASSIGN(PhishingClassifierDelegate);
};

}  // namespace safe_browsing

#endif  // CHROME_RENDERER_SAFE_BROWSING_PHISHING_CLASSIFIER_DELEGATE_H_