// Copyright (c) 2013 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.

#include "chrome/browser/ui/ash/session_state_delegate_chromeos.h"

#include "ash/multi_profile_uma.h"
#include "ash/session_state_observer.h"
#include "base/command_line.h"
#include "base/logging.h"
#include "base/prefs/pref_service.h"
#include "chrome/browser/chromeos/login/screen_locker.h"
#include "chrome/browser/chromeos/login/user.h"
#include "chrome/browser/chromeos/login/user_adding_screen.h"
#include "chrome/browser/chromeos/login/user_manager.h"
#include "chrome/browser/profiles/profile.h"
#include "chrome/browser/profiles/profile_manager.h"
#include "chrome/browser/ui/ash/multi_user/multi_user_window_manager.h"
#include "chrome/common/pref_names.h"
#include "chromeos/chromeos_switches.h"
#include "chromeos/dbus/dbus_thread_manager.h"
#include "chromeos/dbus/session_manager_client.h"
#include "google_apis/gaia/gaia_auth_util.h"

SessionStateDelegateChromeos::SessionStateDelegateChromeos() {
  chromeos::UserManager::Get()->AddSessionStateObserver(this);
}

SessionStateDelegateChromeos::~SessionStateDelegateChromeos() {
}

int SessionStateDelegateChromeos::GetMaximumNumberOfLoggedInUsers() const {
  // TODO(nkostylev): Show some UI messages why no more users could be added
  // to this session. http://crbug.com/230863
  // We limit list of logged in users to 10 due to memory constraints.
  // Note that 10 seems excessive, but we want to test how many users are
  // actually added to a session.
  // TODO(nkostylev): Adjust this limitation based on device capabilites.
  // http://crbug.com/230865
  return 10;
}

int SessionStateDelegateChromeos::NumberOfLoggedInUsers() const {
  return chromeos::UserManager::Get()->GetLoggedInUsers().size();
}

bool SessionStateDelegateChromeos::IsActiveUserSessionStarted() const {
  return chromeos::UserManager::Get()->IsSessionStarted();
}

bool SessionStateDelegateChromeos::CanLockScreen() const {
  const chromeos::UserList unlock_users =
      chromeos::UserManager::Get()->GetUnlockUsers();
  DCHECK_LE(unlock_users.size(), 1u);
  return !unlock_users.empty() && unlock_users[0]->can_lock();
}

bool SessionStateDelegateChromeos::IsScreenLocked() const {
  return chromeos::ScreenLocker::default_screen_locker() &&
         chromeos::ScreenLocker::default_screen_locker()->locked();
}

bool SessionStateDelegateChromeos::ShouldLockScreenBeforeSuspending() const {
  const chromeos::UserList unlock_users =
      chromeos::UserManager::Get()->GetUnlockUsers();
  DCHECK_LE(unlock_users.size(), 1u);
  Profile* profile =
      !unlock_users.empty()
          ? chromeos::UserManager::Get()->GetProfileByUser(unlock_users[0])
          : NULL;
  return profile && profile->GetPrefs()->GetBoolean(prefs::kEnableScreenLock);
}

void SessionStateDelegateChromeos::LockScreen() {
  if (!CanLockScreen())
    return;

  VLOG(1) << "Requesting screen lock from SessionStateDelegate";
  chromeos::DBusThreadManager::Get()->GetSessionManagerClient()->
      RequestLockScreen();
}

void SessionStateDelegateChromeos::UnlockScreen() {
  // This is used only for testing thus far.
  NOTIMPLEMENTED();
}

bool SessionStateDelegateChromeos::IsUserSessionBlocked() const {
  bool has_login_manager = CommandLine::ForCurrentProcess()->HasSwitch(
          chromeos::switches::kLoginManager);
  return (has_login_manager && !IsActiveUserSessionStarted()) ||
         IsScreenLocked() ||
         chromeos::UserAddingScreen::Get()->IsRunning();
}

const base::string16 SessionStateDelegateChromeos::GetUserDisplayName(
    ash::MultiProfileIndex index) const {
  DCHECK_LT(index, NumberOfLoggedInUsers());
  return chromeos::UserManager::Get()->
             GetLRULoggedInUsers()[index]->display_name();
}

const std::string SessionStateDelegateChromeos::GetUserEmail(
    ash::MultiProfileIndex index) const {
  DCHECK_LT(index, NumberOfLoggedInUsers());
  return chromeos::UserManager::Get()->
             GetLRULoggedInUsers()[index]->display_email();
}

const std::string SessionStateDelegateChromeos::GetUserID(
    ash::MultiProfileIndex index) const {
  DCHECK_LT(index, NumberOfLoggedInUsers());
  return gaia::CanonicalizeEmail(gaia::SanitizeEmail(
      chromeos::UserManager::Get()->
             GetLRULoggedInUsers()[index]->email()));
}

const gfx::ImageSkia& SessionStateDelegateChromeos::GetUserImage(
    ash::MultiProfileIndex index) const {
  DCHECK_LT(index, NumberOfLoggedInUsers());
  return chromeos::UserManager::Get()->GetLRULoggedInUsers()[index]->image();
}

void SessionStateDelegateChromeos::GetLoggedInUsers(ash::UserIdList* users) {
  const chromeos::UserList& logged_in_users =
      chromeos::UserManager::Get()->GetLoggedInUsers();
  for (chromeos::UserList::const_iterator it = logged_in_users.begin();
       it != logged_in_users.end(); ++it) {
    const chromeos::User* user = (*it);
    users->push_back(user->email());
  }
}

void SessionStateDelegateChromeos::SwitchActiveUser(
    const std::string& user_id) {
  // Disallow switching to an already active user since that might crash.
  // Also check that we got a user id and not an email address.
  DCHECK_EQ(user_id,
            gaia::CanonicalizeEmail(gaia::SanitizeEmail(user_id)));
  if (user_id == chromeos::UserManager::Get()->GetActiveUser()->email())
    return;
  chromeos::UserManager::Get()->SwitchActiveUser(user_id);
}

void SessionStateDelegateChromeos::CycleActiveUser(CycleUser cycle_user) {
  // Make sure there is a user to switch to.
  if (NumberOfLoggedInUsers() <= 1)
    return;

  const chromeos::UserList& logged_in_users =
      chromeos::UserManager::Get()->GetLoggedInUsers();

  std::string user_id = chromeos::UserManager::Get()->GetActiveUser()->email();

  // Get an iterator positioned at the active user.
  chromeos::UserList::const_iterator it;
  for (it = logged_in_users.begin();
       it != logged_in_users.end(); ++it) {
    if ((*it)->email() == user_id)
      break;
  }

  // Active user not found.
  if (it == logged_in_users.end())
    return;

  // Get the user's email to select, wrapping to the start/end of the list if
  // necessary.
  switch (cycle_user) {
    case CYCLE_TO_NEXT_USER:
      if (++it == logged_in_users.end())
        user_id = (*logged_in_users.begin())->email();
      else
        user_id = (*it)->email();
      break;
    case CYCLE_TO_PREVIOUS_USER:
      if (it == logged_in_users.begin())
        it = logged_in_users.end();
      user_id = (*(--it))->email();
      break;
  }

  // Switch using the transformed |user_id|.
  chromeos::UserManager::Get()->SwitchActiveUser(user_id);
}

void SessionStateDelegateChromeos::AddSessionStateObserver(
    ash::SessionStateObserver* observer) {
  session_state_observer_list_.AddObserver(observer);
}

void SessionStateDelegateChromeos::RemoveSessionStateObserver(
    ash::SessionStateObserver* observer) {
  session_state_observer_list_.RemoveObserver(observer);
}

bool SessionStateDelegateChromeos::TransferWindowToDesktopOfUser(
    aura::Window* window,
    ash::MultiProfileIndex index) {
  if (chrome::MultiUserWindowManager::GetMultiProfileMode() !=
          chrome::MultiUserWindowManager::MULTI_PROFILE_MODE_SEPARATED)
    return false;
  chrome::MultiUserWindowManager* window_manager =
      chrome::MultiUserWindowManager::GetInstance();
  if (window_manager->GetWindowOwner(window).empty())
    return false;

  ash::MultiProfileUMA::RecordTeleportAction(
      ash::MultiProfileUMA::TELEPORT_WINDOW_DRAG_AND_DROP);

  DCHECK_LT(index, NumberOfLoggedInUsers());
  window_manager->ShowWindowForUser(window,
      chromeos::UserManager::Get()->GetLRULoggedInUsers()[index]->email());
  return true;
}

void SessionStateDelegateChromeos::ActiveUserChanged(
    const chromeos::User* active_user) {
  FOR_EACH_OBSERVER(ash::SessionStateObserver,
                    session_state_observer_list_,
                    ActiveUserChanged(active_user->email()));
}

void SessionStateDelegateChromeos::UserAddedToSession(
    const chromeos::User* added_user) {
  FOR_EACH_OBSERVER(ash::SessionStateObserver,
                    session_state_observer_list_,
                    UserAddedToSession(added_user->email()));
}