// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// Defines the Chrome Extensions WebNavigation API functions for observing and
// intercepting navigation events, as specified in the extension JSON API.

#ifndef CHROME_BROWSER_EXTENSIONS_API_WEB_NAVIGATION_WEB_NAVIGATION_API_H_
#define CHROME_BROWSER_EXTENSIONS_API_WEB_NAVIGATION_WEB_NAVIGATION_API_H_

#include <map>
#include <set>

#include "base/functional/callback.h"
#include "base/memory/raw_ptr.h"
#include "chrome/browser/extensions/api/web_navigation/frame_navigation_state.h"
#include "chrome/browser/profiles/profile.h"
#include "chrome/browser/ui/browser_tab_strip_tracker.h"
#include "chrome/browser/ui/browser_tab_strip_tracker_delegate.h"
#include "chrome/browser/ui/tabs/tab_strip_model.h"
#include "content/public/browser/web_contents_observer.h"
#include "content/public/browser/web_contents_user_data.h"
#include "extensions/browser/browser_context_keyed_api_factory.h"
#include "extensions/browser/event_router.h"
#include "extensions/browser/extension_function.h"
#include "url/gurl.h"

namespace extensions {

// Tab contents observer that forwards navigation events to the event router.
class WebNavigationTabObserver
    : public content::WebContentsObserver,
      public content::WebContentsUserData<WebNavigationTabObserver> {
 public:
  WebNavigationTabObserver(const WebNavigationTabObserver&) = delete;
  WebNavigationTabObserver& operator=(const WebNavigationTabObserver&) = delete;

  ~WebNavigationTabObserver() override;

  // Returns the object for the given |web_contents|.
  static WebNavigationTabObserver* Get(content::WebContents* web_contents);

  // content::WebContentsObserver implementation.
  void RenderFrameDeleted(content::RenderFrameHost* render_frame_host) override;
  void RenderFrameHostChanged(content::RenderFrameHost* old_host,
                              content::RenderFrameHost* new_host) override;
  void DidStartNavigation(
      content::NavigationHandle* navigation_handle) override;
  void DidFinishNavigation(
      content::NavigationHandle* navigation_handle) override;
  void DOMContentLoaded(content::RenderFrameHost* render_frame_host) override;
  void DidFinishLoad(content::RenderFrameHost* render_frame_host,
                     const GURL& validated_url) override;
  void DidFailLoad(content::RenderFrameHost* render_frame_host,
                   const GURL& validated_url,
                   int error_code) override;
  void DidOpenRequestedURL(content::WebContents* new_contents,
                           content::RenderFrameHost* source_render_frame_host,
                           const GURL& url,
                           const content::Referrer& referrer,
                           WindowOpenDisposition disposition,
                           ui::PageTransition transition,
                           bool started_from_context_menu,
                           bool renderer_initiated) override;

  // This method dispatches the already created onBeforeNavigate event.
  void DispatchCachedOnBeforeNavigate();

 private:
  explicit WebNavigationTabObserver(content::WebContents* web_contents);
  friend class content::WebContentsUserData<WebNavigationTabObserver>;

  void HandleCommit(content::NavigationHandle* navigation_handle);
  void HandleError(content::NavigationHandle* navigation_handle);

  // True if the transition and target url correspond to a reference fragment
  // navigation.
  bool IsReferenceFragmentNavigation(content::RenderFrameHost* frame_host,
                                     const GURL& url);

  // Called when a RenderFrameHost goes into pending deletion. Stop tracking it
  // and its children.
  void RenderFrameHostPendingDeletion(content::RenderFrameHost*);

  // The latest onBeforeNavigate event this frame has generated. It is stored
  // as it might not be sent immediately, but delayed until the tab is added to
  // the tab strip and is ready to dispatch events.
  std::unique_ptr<Event> pending_on_before_navigate_event_;

  WEB_CONTENTS_USER_DATA_KEY_DECL();
};

// Tracks new tab navigations and routes them as events to the extension system.
class WebNavigationEventRouter : public TabStripModelObserver,
                                 public BrowserTabStripTrackerDelegate {
 public:
  explicit WebNavigationEventRouter(Profile* profile);

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

  ~WebNavigationEventRouter() override;

  // Router level handler for the creation of WebContents. Stores information
  // about the newly created WebContents. This information is later used when
  // the WebContents for the tab is added to the tabstrip and we receive the
  // TabStripModelChanged insertion.
  void RecordNewWebContents(content::WebContents* source_web_contents,
                            int source_render_process_id,
                            int source_render_frame_id,
                            GURL target_url,
                            content::WebContents* target_web_contents,
                            bool not_yet_in_tabstrip);

 private:
  // Used to cache the information about newly created WebContents objects.
  // Will run |on_destroy_| if/when the target WebContents is destroyed.
  class PendingWebContents : public content::WebContentsObserver {
   public:
    PendingWebContents();

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

    ~PendingWebContents() override;

    void Set(int source_tab_id,
             int source_render_process_id,
             int source_extension_frame_id,
             content::WebContents* target_web_contents,
             const GURL& target_url,
             base::OnceCallback<void(content::WebContents*)> on_destroy);

    // content::WebContentsObserver:
    void WebContentsDestroyed() override;

    int source_tab_id() const { return source_tab_id_; }
    int source_render_process_id() const { return source_render_process_id_; }
    int source_extension_frame_id() const { return source_extension_frame_id_; }
    content::WebContents* target_web_contents() const {
      return target_web_contents_;
    }
    GURL target_url() const { return target_url_; }

   private:
    // The Extensions API ID for the source tab.
    int source_tab_id_ = -1;
    // The source frame's RenderProcessHost ID.
    int source_render_process_id_ = -1;
    // The Extensions API ID for the source frame.
    int source_extension_frame_id_ = -1;
    raw_ptr<content::WebContents> target_web_contents_ = nullptr;
    GURL target_url_;
    base::OnceCallback<void(content::WebContents*)> on_destroy_;
  };

  // BrowserTabStripTrackerDelegate implementation.
  bool ShouldTrackBrowser(Browser* browser) override;

  // TabStripModelObserver implementation.
  void OnTabStripModelChanged(
      TabStripModel* tab_strip_model,
      const TabStripModelChange& change,
      const TabStripSelectionChange& selection) override;

  // The method takes the details of such an event and creates a JSON formatted
  // extension event from it.
  void TabAdded(content::WebContents* tab);

  // Removes |tab| from |pending_web_contents_| if it is there.
  void PendingWebContentsDestroyed(content::WebContents* tab);

  // Mapping pointers to WebContents objects to information about how they got
  // created.
  std::map<content::WebContents*, PendingWebContents> pending_web_contents_;

  // The profile that owns us via ExtensionService.
  raw_ptr<Profile> profile_;

  BrowserTabStripTracker browser_tab_strip_tracker_;
};

// API function that returns the state of a given frame.
class WebNavigationGetFrameFunction : public ExtensionFunction {
  ~WebNavigationGetFrameFunction() override = default;
  ResponseAction Run() override;
  DECLARE_EXTENSION_FUNCTION("webNavigation.getFrame", WEBNAVIGATION_GETFRAME)
};

// API function that returns the states of all frames in a given tab.
class WebNavigationGetAllFramesFunction : public ExtensionFunction {
  ~WebNavigationGetAllFramesFunction() override = default;
  ResponseAction Run() override;
  DECLARE_EXTENSION_FUNCTION("webNavigation.getAllFrames",
                             WEBNAVIGATION_GETALLFRAMES)
};

class WebNavigationAPI : public BrowserContextKeyedAPI,
                         public extensions::EventRouter::Observer {
 public:
  explicit WebNavigationAPI(content::BrowserContext* context);

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

  ~WebNavigationAPI() override;

  // KeyedService implementation.
  void Shutdown() override;

  // BrowserContextKeyedAPI implementation.
  static BrowserContextKeyedAPIFactory<WebNavigationAPI>* GetFactoryInstance();

  // EventRouter::Observer implementation.
  void OnListenerAdded(const extensions::EventListenerInfo& details) override;

 private:
  friend class BrowserContextKeyedAPIFactory<WebNavigationAPI>;
  friend class WebNavigationTabObserver;

  raw_ptr<content::BrowserContext> browser_context_;

  // BrowserContextKeyedAPI implementation.
  static const char* service_name() {
    return "WebNavigationAPI";
  }
  static const bool kServiceRedirectedInIncognito = true;
  static const bool kServiceIsNULLWhileTesting = true;

  // Created lazily upon OnListenerAdded.
  std::unique_ptr<WebNavigationEventRouter> web_navigation_event_router_;
};

}  // namespace extensions

#endif  // CHROME_BROWSER_EXTENSIONS_API_WEB_NAVIGATION_WEB_NAVIGATION_API_H_