// Copyright (c) 2009 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_CHROMEOS_BOOT_TIMES_LOADER_H_
#define CHROME_BROWSER_CHROMEOS_BOOT_TIMES_LOADER_H_
#pragma once

#include <string>

#include "base/atomic_sequence_num.h"
#include "base/callback.h"
#include "base/time.h"
#include "chrome/browser/cancelable_request.h"
#include "chrome/common/notification_observer.h"
#include "chrome/common/notification_registrar.h"

namespace chromeos {

// BootTimesLoader loads the bootimes of Chrome OS from the file system.
// Loading is done asynchronously on the file thread. Once loaded,
// BootTimesLoader calls back to a method of your choice with the boot times.
// To use BootTimesLoader do the following:
//
// . In your class define a member field of type chromeos::BootTimesLoader and
//   CancelableRequestConsumerBase.
// . Define the callback method, something like:
//   void OnBootTimesLoader(chromeos::BootTimesLoader::Handle,
//                             BootTimesLoader::BootTimes boot_times);
// . When you want the version invoke: loader.GetBootTimes(&consumer, callback);
class BootTimesLoader
    : public CancelableRequestProvider,
      public NotificationObserver {
 public:
  BootTimesLoader();

  // All fields are 0.0 if they couldn't be found.
  typedef struct BootTimes {
    double firmware;           // Time from power button to kernel being loaded.
    double pre_startup;        // Time from kernel to system code being called.
    double x_started;          // Time X server is ready to be connected to.
    double chrome_exec;        // Time session manager executed Chrome.
    double chrome_main;        // Time chrome's main() was called.
    double login_prompt_ready; // Time login (or OOB) panel is displayed.
    double system;             // Time system took to start chrome.
    double chrome;             // Time chrome took to display login panel.
    double total;              // Time from power button to login panel.

    BootTimes() : firmware(0),
                  pre_startup(0),
                  x_started(0),
                  chrome_exec(0),
                  chrome_main(0),
                  login_prompt_ready(0),
                  system(0),
                  chrome(0),
                  total(0) {}
  } BootTimes;

  // Signature
  typedef Callback2<Handle, BootTimes>::Type GetBootTimesCallback;

  typedef CancelableRequest<GetBootTimesCallback> GetBootTimesRequest;

  static BootTimesLoader* Get();

  // Asynchronously requests the info.
  Handle GetBootTimes(
      CancelableRequestConsumerBase* consumer,
      GetBootTimesCallback* callback);

  // Records current uptime and disk usage for metrics use.
  // Posts task to file thread.
  // name will be used as part of file names in /tmp.
  // Existing stats files will not be overwritten.
  void RecordCurrentStats(const std::string& name);

  // Saves away the stats at main, so the can be recorded later. At main() time
  // the necessary threads don't exist yet for recording the data.
  void SaveChromeMainStats();

  // Records the data previously saved by SaveChromeMainStats(), using the
  // file thread. Existing stats files will not be overwritten.
  void RecordChromeMainStats();

  // Records the time that a login was attempted. This will overwrite any
  // previous login attempt times.
  void RecordLoginAttempted();

  // NotificationObserver implementation.
  virtual void Observe(NotificationType type,
                       const NotificationSource& source,
                       const NotificationDetails& details);

 private:
  // BootTimesLoader calls into the Backend on the file thread to load
  // the boot times.
  class Backend : public base::RefCountedThreadSafe<Backend> {
   public:
    Backend() {}

    void GetBootTimes(scoped_refptr<GetBootTimesRequest> request);

   private:
    friend class base::RefCountedThreadSafe<Backend>;

    ~Backend() {}

    DISALLOW_COPY_AND_ASSIGN(Backend);
  };

  struct Stats {
    std::string uptime;
    std::string disk;

    Stats() : uptime(std::string()), disk(std::string()) {}
  };

  static void RecordStats(
      const std::string& name, const Stats& stats);
  static Stats GetCurrentStats();

  // Used to hold the stats at main().
  Stats chrome_main_stats_;
  scoped_refptr<Backend> backend_;

  // Times for authentication and login metrics.
  base::Time login_attempt_;
  base::Time login_success_;
  base::Time chrome_first_render_;

  // Used to track notifications for login.
  NotificationRegistrar registrar_;
  base::AtomicSequenceNumber num_tabs_;
  bool have_registered_;

  DISALLOW_COPY_AND_ASSIGN(BootTimesLoader);
};

}  // namespace chromeos

#endif  // CHROME_BROWSER_CHROMEOS_BOOT_TIMES_LOADER_H_