// 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_CONTENT_BROWSER_CONTENT_TRANSLATE_DRIVER_H_
#define COMPONENTS_TRANSLATE_CONTENT_BROWSER_CONTENT_TRANSLATE_DRIVER_H_

#include <map>
#include <string>
#include <string_view>

#include "base/gtest_prod_util.h"
#include "base/memory/raw_ptr.h"
#include "base/memory/weak_ptr.h"
#include "base/observer_list.h"
#include "base/scoped_observation_traits.h"
#include "base/time/time.h"
#include "components/translate/content/common/translate.mojom.h"
#include "components/translate/core/browser/translate_driver.h"
#include "components/translate/core/common/translate_errors.h"
#include "content/public/browser/web_contents_observer.h"
#include "mojo/public/cpp/bindings/pending_receiver.h"
#include "mojo/public/cpp/bindings/pending_remote.h"
#include "mojo/public/cpp/bindings/receiver_set.h"
#include "mojo/public/cpp/bindings/remote.h"
#include "services/metrics/public/cpp/ukm_source_id.h"

namespace content {
class WebContents;
}  // namespace content

namespace language {
class UrlLanguageHistogram;
}  // namespace language

namespace translate {

struct LanguageDetectionDetails;
class TranslateManager;

// Content implementation of TranslateDriver.
class ContentTranslateDriver : public TranslateDriver,
                               public translate::mojom::ContentTranslateDriver,
                               public content::WebContentsObserver {
 public:
  class TranslationObserver : public base::CheckedObserver {
   public:
    // Handles when the value of IsPageTranslated is changed.
    virtual void OnIsPageTranslatedChanged(content::WebContents* source) {}

    // Handles when the value of translate_enabled is changed.
    virtual void OnTranslateEnabledChanged(content::WebContents* source) {}

    // Called when the page has been translated.
    virtual void OnPageTranslated(std::string_view source_lang,
                                  std::string_view translated_lang,
                                  translate::TranslateErrors error_type) {}
  };

  ContentTranslateDriver(
      content::WebContents& web_contents,
      language::UrlLanguageHistogram* url_language_histogram);

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

  ~ContentTranslateDriver() override;

  // Adds or removes observers.
  void AddTranslationObserver(TranslationObserver* observer);
  void RemoveTranslationObserver(TranslationObserver* observer);

  // Number of attempts before waiting for a page to be fully reloaded.
  void set_translate_max_reload_attempts(int attempts) {
    max_reload_check_attempts_ = attempts;
  }

  // Sets the TranslateManager associated with this driver.
  void set_translate_manager(TranslateManager* manager) {
    translate_manager_ = manager;
  }

  TranslateManager* translate_manager() { return translate_manager_; }

  static ContentTranslateDriver* FromWebContents(
      content::WebContents* web_contents);

  // Initiates translation once the page is finished loading.
  void InitiateTranslation(const std::string& page_lang, int attempt);



  // TranslateDriver methods.
  void OnIsPageTranslatedChanged() override;
  void OnTranslateEnabledChanged() override;
  bool IsLinkNavigation() override;
  void TranslatePage(int page_seq_no,
                     std::string_view translate_script,
                     std::string_view source_lang,
                     std::string_view target_lang) override;
  void RevertTranslation(int page_seq_no) override;
  bool IsIncognito() const override;
  const std::string& GetContentsMimeType() override;
  const GURL& GetLastCommittedURL() const override;
  const GURL& GetVisibleURL() override;
  ukm::SourceId GetUkmSourceId() override;
  bool HasCurrentPage() const override;

  // content::WebContentsObserver implementation.
  void DidFinishNavigation(
      content::NavigationHandle* navigation_handle) override;

  void OnPageTranslated(bool cancelled,
                        const std::string& source_lang,
                        const std::string& translated_lang,
                        TranslateErrors error_type);

  // Adds a receiver in |receivers_| for the passed |receiver|.
  void AddReceiver(
      mojo::PendingReceiver<translate::mojom::ContentTranslateDriver> receiver);

  // Called when a page has been loaded and can be potentially translated.
  void RegisterPage(
      mojo::PendingRemote<translate::mojom::TranslateAgent> translate_agent,
      const translate::LanguageDetectionDetails& details,
      bool page_level_translation_criteria_met) override;

 private:

  void OnPageAway(int page_seq_no);
  void OnSidePanelAway(int page_seq_no);

  int UpdatePageSequenceNumber();
  void BindTranslateAgent(
      int page_seq_no,
      mojo::PendingRemote<mojom::TranslateAgent> translate_agent,
      const GURL& url);

  void InitiateTranslationIfReload(
      content::NavigationHandle* navigation_handle);

  mojom::TranslateAgent* GetTranslateAgent(int page_seq_no);

  raw_ptr<TranslateManager> translate_manager_ = nullptr;

  base::ObserverList<TranslationObserver, true> translation_observers_;

  // Whether the associated browser context is off the record.
  bool is_otr_context_;

  // The last committed URL of the primary main frame of the contents.
  GURL last_committed_url_;

  // Max number of attempts before checking if a page has been reloaded.
  int max_reload_check_attempts_;

  ukm::SourceId last_registered_page_id_;
  int active_page_seq_no_;

  // Records mojo connections with all current alive pages.
  int next_page_seq_no_;
  // mojo::Remote<TranslateAgent> is the connection between this driver and a
  // TranslateAgent (which are per RenderFrame). Each TranslateAgent has a
  // |binding_| member, representing the other end of this pipe.
  struct PageAgents {
    mojo::Remote<mojom::TranslateAgent> main_agent;
    mojo::Remote<mojom::TranslateAgent> side_panel_agent;
  };
  std::map<int, PageAgents> translate_agents_;

  // Histogram to be notified about detected language of every page visited. Not
  // owned here.
  const raw_ptr<language::UrlLanguageHistogram> language_histogram_;

  // ContentTranslateDriver is a singleton per web contents but multiple render
  // frames may be contained in a single web contents. TranslateAgents get the
  // other end of this receiver in the form of a ContentTranslateDriver.
  mojo::ReceiverSet<translate::mojom::ContentTranslateDriver> receivers_;

  // Time when the navigation was finished (i.e., DidFinishNavigation
  // in the main frame). This is used to know a duration time to when the
  // page language is determined.
  base::TimeTicks finish_navigation_time_;

  base::WeakPtrFactory<ContentTranslateDriver> weak_pointer_factory_{this};
};

}  // namespace translate

namespace base {

template <>
struct ScopedObservationTraits<
    translate::ContentTranslateDriver,
    translate::ContentTranslateDriver::TranslationObserver> {
  static void AddObserver(
      translate::ContentTranslateDriver* source,
      translate::ContentTranslateDriver::TranslationObserver* observer) {
    source->AddTranslationObserver(observer);
  }
  static void RemoveObserver(
      translate::ContentTranslateDriver* source,
      translate::ContentTranslateDriver::TranslationObserver* observer) {
    source->RemoveTranslationObserver(observer);
  }
};

}  // namespace base

#endif  // COMPONENTS_TRANSLATE_CONTENT_BROWSER_CONTENT_TRANSLATE_DRIVER_H_