// Copyright 2015 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_PAGE_LOAD_METRICS_METRICS_WEB_CONTENTS_OBSERVER_H_
#define CHROME_BROWSER_PAGE_LOAD_METRICS_METRICS_WEB_CONTENTS_OBSERVER_H_

#include <map>
#include <memory>
#include <vector>

#include "base/macros.h"
#include "base/observer_list.h"
#include "base/time/time.h"
#include "chrome/browser/page_load_metrics/page_load_metrics_observer.h"
#include "chrome/common/page_load_metrics/page_load_metrics.mojom.h"
#include "chrome/common/page_load_metrics/page_load_timing.h"
#include "components/data_reduction_proxy/core/browser/data_reduction_proxy_data.h"
#include "content/public/browser/render_widget_host.h"
#include "content/public/browser/web_contents.h"
#include "content/public/browser/web_contents_binding_set.h"
#include "content/public/browser/web_contents_observer.h"
#include "content/public/browser/web_contents_user_data.h"
#include "content/public/common/resource_type.h"
#include "third_party/WebKit/public/platform/WebInputEvent.h"

namespace content {
class NavigationHandle;
class RenderFrameHost;
}  // namespace content

namespace page_load_metrics {

class PageLoadMetricsEmbedderInterface;
class PageLoadTracker;

// MetricsWebContentsObserver tracks page loads and loading metrics
// related data based on IPC messages received from a
// MetricsRenderFrameObserver.
class MetricsWebContentsObserver
    : public content::WebContentsObserver,
      public content::WebContentsUserData<MetricsWebContentsObserver>,
      public content::RenderWidgetHost::InputEventObserver,
      public mojom::PageLoadMetrics {
 public:
  // TestingObserver allows tests to observe MetricsWebContentsObserver state
  // changes. Tests may use TestingObserver to wait until certain state changes,
  // such as the arrivial of PageLoadTiming messages from the render process,
  // have been observed.
  class TestingObserver {
   public:
    explicit TestingObserver(content::WebContents* web_contents);
    virtual ~TestingObserver();

    void OnGoingAway();

    // Some PageLoadTiming messages will race with the navigation
    // commit. OnTrackerCreated() allows tests to manipulate the tracker very
    // early (eg, to add observers) to handle those cases.
    virtual void OnTrackerCreated(PageLoadTracker* tracker) {}

    // In cases where LoadTimingInfo is not needed, waiting until commit is
    // fine.
    virtual void OnCommit(PageLoadTracker* tracker) {}

   private:
    page_load_metrics::MetricsWebContentsObserver* observer_;

    DISALLOW_COPY_AND_ASSIGN(TestingObserver);
  };

  // Note that the returned metrics is owned by the web contents.
  static MetricsWebContentsObserver* CreateForWebContents(
      content::WebContents* web_contents,
      std::unique_ptr<PageLoadMetricsEmbedderInterface> embedder_interface);
  MetricsWebContentsObserver(
      content::WebContents* web_contents,
      std::unique_ptr<PageLoadMetricsEmbedderInterface> embedder_interface);
  ~MetricsWebContentsObserver() override;

  // content::WebContentsObserver implementation:
  void DidFinishNavigation(
      content::NavigationHandle* navigation_handle) override;
  void DidRedirectNavigation(
      content::NavigationHandle* navigation_handle) override;
  void NavigationStopped() override;
  void OnInputEvent(const blink::WebInputEvent& event) override;
  void WasShown() override;
  void WasHidden() override;
  void RenderProcessGone(base::TerminationStatus status) override;
  void RenderViewHostChanged(content::RenderViewHost* old_host,
                             content::RenderViewHost* new_host) override;
  void MediaStartedPlaying(
      const content::WebContentsObserver::MediaPlayerInfo& video_type,
      const content::WebContentsObserver::MediaPlayerId& id) override;
  void WebContentsDestroyed() override;

  // These methods are forwarded from the MetricsNavigationThrottle.
  void WillStartNavigationRequest(content::NavigationHandle* navigation_handle);
  void WillProcessNavigationResponse(
      content::NavigationHandle* navigation_handle);

  // A resource request completed on the IO thread. This method is invoked on
  // the UI thread. |render_frame_host_or_null will| be null for main or sub
  // frame requests when browser-side navigation is enabled.
  void OnRequestComplete(
      const GURL& url,
      const net::HostPortPair& host_port_pair,
      int frame_tree_node_id,
      const content::GlobalRequestID& request_id,
      content::RenderFrameHost* render_frame_host_or_null,
      content::ResourceType resource_type,
      bool was_cached,
      std::unique_ptr<data_reduction_proxy::DataReductionProxyData>
          data_reduction_proxy_data,
      int64_t raw_body_bytes,
      int64_t original_content_length,
      base::TimeTicks creation_time,
      int net_error,
      std::unique_ptr<net::LoadTimingInfo> load_timing_info);

  // Invoked on navigations where a navigation delay was added by the
  // DelayNavigationThrottle. This is a temporary method that will be removed
  // once the experiment is complete.
  void OnNavigationDelayComplete(content::NavigationHandle* navigation_handle,
                                 base::TimeDelta scheduled_delay,
                                 base::TimeDelta actual_delay);

  // Flush any buffered metrics, as part of the metrics subsystem persisting
  // metrics as the application goes into the background. The application may be
  // killed at any time after this method is invoked without further
  // notification.
  void FlushMetricsOnAppEnterBackground();

  // This getter function is required for testing.
  const PageLoadExtraInfo GetPageLoadExtraInfoForCommittedLoad();

  // Register / unregister TestingObservers. Should only be called from tests.
  void AddTestingObserver(TestingObserver* observer);
  void RemoveTestingObserver(TestingObserver* observer);

  // public only for testing
  void OnTimingUpdated(content::RenderFrameHost* render_frame_host,
                       const mojom::PageLoadTiming& timing,
                       const mojom::PageLoadMetadata& metadata,
                       const mojom::PageLoadFeatures& new_features);

  // Informs the observers of the currently committed load that the event
  // corresponding to |event_key| has occurred. This should not be called within
  // WebContentsObserver::DidFinishNavigation methods.
  // This method is subject to change and may be removed in the future.
  void BroadcastEventToObservers(const void* const event_key);

 private:
  friend class content::WebContentsUserData<MetricsWebContentsObserver>;

  // page_load_metrics::mojom::PageLoadMetrics implementation.
  void UpdateTiming(mojom::PageLoadTimingPtr timing,
                    mojom::PageLoadMetadataPtr metadata,
                    mojom::PageLoadFeaturesPtr new_features) override;

  void HandleFailedNavigationForTrackedLoad(
      content::NavigationHandle* navigation_handle,
      std::unique_ptr<PageLoadTracker> tracker);

  void HandleCommittedNavigationForTrackedLoad(
      content::NavigationHandle* navigation_handle,
      std::unique_ptr<PageLoadTracker> tracker);

  // Return a PageLoadTracker (either provisional or committed) that matches the
  // given request attributes, or nullptr if there are no matching
  // PageLoadTrackers.
  PageLoadTracker* GetTrackerOrNullForRequest(
      const content::GlobalRequestID& request_id,
      content::RenderFrameHost* render_frame_host_or_null,
      content::ResourceType resource_type,
      base::TimeTicks creation_time);

  // Notify all loads, provisional and committed, that we performed an action
  // that might abort them.
  void NotifyPageEndAllLoads(PageEndReason page_end_reason,
                             UserInitiatedInfo user_initiated_info);
  void NotifyPageEndAllLoadsWithTimestamp(PageEndReason page_end_reason,
                                          UserInitiatedInfo user_initiated_info,
                                          base::TimeTicks timestamp,
                                          bool is_certainly_browser_timestamp);

  // Register / Unregister input event callback to given RenderViewHost
  void RegisterInputEventObserver(content::RenderViewHost* host);
  void UnregisterInputEventObserver(content::RenderViewHost* host);

  // Notify aborted provisional loads that a new navigation occurred. This is
  // used for more consistent attribution tracking for aborted provisional
  // loads. This method returns the provisional load that was likely aborted
  // by this navigation, to help instantiate the new PageLoadTracker.
  std::unique_ptr<PageLoadTracker> NotifyAbortedProvisionalLoadsNewNavigation(
      content::NavigationHandle* new_navigation,
      UserInitiatedInfo user_initiated_info);

  bool ShouldTrackNavigation(
      content::NavigationHandle* navigation_handle) const;

  // True if the web contents is currently in the foreground.
  bool in_foreground_;

  // The PageLoadTrackers must be deleted before the |embedder_interface_|,
  // because they hold a pointer to the |embedder_interface_|.
  std::unique_ptr<PageLoadMetricsEmbedderInterface> embedder_interface_;

  // This map tracks all of the navigations ongoing that are not committed
  // yet. Once a navigation is committed, it moves from the map to
  // committed_load_. Note that a PageLoadTrackers NavigationHandle is only
  // valid until commit time, when we remove it from the map.
  std::map<content::NavigationHandle*, std::unique_ptr<PageLoadTracker>>
      provisional_loads_;

  // Tracks aborted provisional loads for a little bit longer than usual (one
  // more navigation commit at the max), in order to better understand how the
  // navigation failed. This is because most provisional loads are destroyed
  // and vanish before we get signal about what caused the abort (new
  // navigation, stop button, etc.).
  std::vector<std::unique_ptr<PageLoadTracker>> aborted_provisional_loads_;

  std::unique_ptr<PageLoadTracker> committed_load_;

  // Has the MWCO observed at least one navigation?
  bool has_navigated_;

  base::ObserverList<TestingObserver> testing_observers_;
  content::WebContentsFrameBindingSet<mojom::PageLoadMetrics>
      page_load_metrics_binding_;

  DISALLOW_COPY_AND_ASSIGN(MetricsWebContentsObserver);
};

}  // namespace page_load_metrics

#endif  // CHROME_BROWSER_PAGE_LOAD_METRICS_METRICS_WEB_CONTENTS_OBSERVER_H_