// Copyright 2014 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 COMPONENTS_HISTORY_CORE_BROWSER_HISTORY_SERVICE_OBSERVER_H_
#define COMPONENTS_HISTORY_CORE_BROWSER_HISTORY_SERVICE_OBSERVER_H_

#include "base/macros.h"
#include "components/history/core/browser/history_types.h"
#include "components/history/core/browser/keyword_id.h"

namespace history {

class HistoryService;

class HistoryServiceObserver {
 public:
  HistoryServiceObserver() {}
  virtual ~HistoryServiceObserver() {}

  // Called when user visits an URL.
  //
  // The `row` ID will be set to the value that is currently in effect in the
  // main history database. `redirects` is the list of redirects leading up to
  // the URL. If we have a redirect chain A -> B -> C and user is visiting C,
  // then `redirects[0]=B` and `redirects[1]=A`. If there are no redirects,
  // `redirects` is an empty vector.
  virtual void OnURLVisited(HistoryService* history_service,
                            ui::PageTransition transition,
                            const URLRow& row,
                            const RedirectList& redirects,
                            base::Time visit_time) {}

  // Called when a URL has been added or modified.
  //
  // `changed_urls` lists the information for each of the URLs affected. The
  // rows will have the IDs that are currently in effect in the main history
  // database.
  virtual void OnURLsModified(HistoryService* history_service,
                              const URLRows& changed_urls) {}

  // TODO(https://crbug.com/1141501): this is for an experiment, and will be
  // removed once data is collected from experiment.
  virtual void OnURLsModified(HistoryService* history_service,
                              const URLRows& changed_urls,
                              UrlsModifiedReason reason);

  // Called when one or more URLs are deleted.
  //
  // `deletion_info` describes the urls that have been removed from history.
  virtual void OnURLsDeleted(HistoryService* history_service,
                             const DeletionInfo& deletion_info) {}

  // Is called to notify when `history_service` has finished loading.
  virtual void OnHistoryServiceLoaded(HistoryService* history_service) {}

  // Is called to notify when `history_service` is being deleted.
  virtual void HistoryServiceBeingDeleted(HistoryService* history_service) {}

  // Sent when a keyword search term is updated.
  //
  // `row` contains the URL information for search `term`.
  // `keyword_id` associated with a URL and search term.
  virtual void OnKeywordSearchTermUpdated(HistoryService* history_service,
                                          const URLRow& row,
                                          KeywordID keyword_id,
                                          const std::u16string& term) {}

  // Sent when a keyword search term is deleted.
  // `url_id` is the id of the url row.
  virtual void OnKeywordSearchTermDeleted(HistoryService* history_service,
                                          URLID url_id) {}

 private:
  DISALLOW_COPY_AND_ASSIGN(HistoryServiceObserver);
};

}  // namespace history

#endif  // COMPONENTS_HISTORY_CORE_BROWSER_HISTORY_SERVICE_OBSERVER_H_