// Copyright 2024 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_PAGE_LOAD_METRICS_BROWSER_NAVIGATION_HANDLE_USER_DATA_H_
#define COMPONENTS_PAGE_LOAD_METRICS_BROWSER_NAVIGATION_HANDLE_USER_DATA_H_

#include "content/public/browser/navigation_handle.h"
#include "content/public/browser/navigation_handle_user_data.h"

namespace page_load_metrics {

// Stores information about the location where a navigation was initiated from.
//
// Timing of availability:
// This user data is attached to a `content::NavigationHandle`. While some
// navigations attach it during the handle's creation (e.g., via a callback),
// other navigations (such as those initiated from the Omnibox) attach it
// immediately after the navigation is initiated. Consequently, this user data
// is NOT guaranteed to be present during `PageLoadMetricsObserver::OnStart()`.
//
// Instead, `PageLoadMetricsObserver::OnCommit()` (or
// `DidActivatePrerenderedPage()` for prerender activation) is a reliable time
// to retrieve this data, because:
// 1. By the time of commit, any post-initiation attachment code has already
//    run.
// 2. The `NavigationHandle` (and therefore this user data) is still alive.
// Note that once the navigation has finished committing, the
// `NavigationHandle` is destroyed, making the user data no longer accessible.
class NavigationHandleUserData
    : public content::NavigationHandleUserData<NavigationHandleUserData> {
 public:
  using InitiatorLocation = int16_t;
  static constexpr InitiatorLocation kInitiatorLocationOther = 0;

  ~NavigationHandleUserData() override;

  InitiatorLocation navigation_type() const { return navigation_type_; }

  const std::string& navigation_type_string() const {
    return navigation_type_string_;
  }

  bool is_served_by_legacy_search_prefetch() const {
    return is_served_by_legacy_search_prefetch_;
  }
  void set_is_served_by_legacy_search_prefetch(bool is_served) {
    is_served_by_legacy_search_prefetch_ = is_served;
  }

 private:
  NavigationHandleUserData(content::NavigationHandle& navigation,
                           InitiatorLocation navigation_type,
                           std::string navigation_type_string);

  // `navigation_type` is used to store where this navigation is initiated from.
  // This information is used to identify the source of the navigation, and this
  // kind of information is utilized by PageLoadMetricsObservers.
  const InitiatorLocation navigation_type_;

  // Stringified information of `navigation_type_`.
  const std::string navigation_type_string_;

  // Indicates whether this navigation was served by a legacy search prefetch
  // mechanism (i.e., DSEv1 search prefetch). Legacy search prefetch refers to
  // embedder-managed search prefetch mechanisms that operate outside and
  // predate the unified `content::PrefetchService` preloading pipeline.
  //
  // Because such prefetch requests are handled directly by the embedder rather
  // than the content layer, they do not automatically integrate with
  // `content::PreloadServingMetrics`. This variable allows the embedder to
  // signal that the navigation was served by the legacy search prefetch so that
  // `PreloadServingMetricsPageLoadMetricsObserver` can accurately record
  // preload serving metrics.
  bool is_served_by_legacy_search_prefetch_ = false;

  friend content::NavigationHandleUserData<NavigationHandleUserData>;
  NAVIGATION_HANDLE_USER_DATA_KEY_DECL();
};

}  // namespace page_load_metrics

#endif  // COMPONENTS_PAGE_LOAD_METRICS_BROWSER_NAVIGATION_HANDLE_USER_DATA_H_