// Copyright (c) 2012 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/upgrade_detector_impl.h"

#include <string>

#include "base/bind.h"
#include "base/command_line.h"
#include "base/file_path.h"
#include "base/memory/scoped_ptr.h"
#include "base/memory/singleton.h"
#include "base/path_service.h"
#include "base/string_number_conversions.h"
#include "base/string_util.h"
#include "base/time.h"
#include "base/utf_string_conversions.h"
#include "chrome/common/chrome_switches.h"
#include "chrome/common/chrome_version_info.h"
#include "chrome/installer/util/browser_distribution.h"
#include "content/public/browser/browser_thread.h"
#include "ui/base/resource/resource_bundle.h"

#if defined(OS_WIN)
#include "chrome/installer/util/install_util.h"
#elif defined(OS_MACOSX)
#include "chrome/browser/mac/keystone_glue.h"
#elif defined(OS_POSIX)
#include "base/process_util.h"
#include "base/version.h"
#endif

using content::BrowserThread;

namespace {

// How long (in milliseconds) to wait (each cycle) before checking whether
// Chrome's been upgraded behind our back.
const int kCheckForUpgradeMs = 2 * 60 * 60 * 1000;  // 2 hours.

// How long to wait (each cycle) before checking which severity level we should
// be at. Once we reach the highest severity, the timer will stop.
const int kNotifyCycleTimeMs = 20 * 60 * 1000;  // 20 minutes.

// Same as kNotifyCycleTimeMs but only used during testing.
const int kNotifyCycleTimeForTestingMs = 500;  // Half a second.

std::string CmdLineInterval() {
  const CommandLine& cmd_line = *CommandLine::ForCurrentProcess();
  return cmd_line.GetSwitchValueASCII(switches::kCheckForUpdateIntervalSec);
}

bool IsTesting() {
  const CommandLine& cmd_line = *CommandLine::ForCurrentProcess();
  return cmd_line.HasSwitch(switches::kSimulateUpgrade) ||
      cmd_line.HasSwitch(switches::kCheckForUpdateIntervalSec);
}

// How often to check for an upgrade.
int GetCheckForUpgradeEveryMs() {
  // Check for a value passed via the command line.
  int interval_ms;
  std::string interval = CmdLineInterval();
  if (!interval.empty() && base::StringToInt(interval, &interval_ms))
    return interval_ms * 1000;  // Command line value is in seconds.

  return kCheckForUpgradeMs;
}

// This task checks the currently running version of Chrome against the
// installed version. If the installed version is newer, it runs the passed
// callback task. Otherwise it just deletes the task.
void DetectUpgradeTask(const base::Closure& upgrade_detected_task,
                       bool* is_unstable_channel,
                       bool* is_critical_upgrade) {
  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));

  Version installed_version;
  Version critical_update;

#if defined(OS_WIN)
  // Get the version of the currently *installed* instance of Chrome,
  // which might be newer than the *running* instance if we have been
  // upgraded in the background.
  FilePath exe_path;
  if (!PathService::Get(base::DIR_EXE, &exe_path)) {
    NOTREACHED() << "Failed to find executable path";
    return;
  }

  bool system_install =
      !InstallUtil::IsPerUserInstall(exe_path.value().c_str());

  // TODO(tommi): Check if using the default distribution is always the right
  // thing to do.
  BrowserDistribution* dist = BrowserDistribution::GetDistribution();
  InstallUtil::GetChromeVersion(dist, system_install, &installed_version);

  if (installed_version.IsValid()) {
    InstallUtil::GetCriticalUpdateVersion(dist, system_install,
                                          &critical_update);
  }
#elif defined(OS_MACOSX)
  installed_version =
      Version(UTF16ToASCII(keystone_glue::CurrentlyInstalledVersion()));
#elif defined(OS_POSIX)
  // POSIX but not Mac OS X: Linux, etc.
  CommandLine command_line(*CommandLine::ForCurrentProcess());
  command_line.AppendSwitch(switches::kProductVersion);
  std::string reply;
  if (!base::GetAppOutput(command_line, &reply)) {
    DLOG(ERROR) << "Failed to get current file version";
    return;
  }

  installed_version = Version(reply);
#endif

  chrome::VersionInfo::Channel channel = chrome::VersionInfo::GetChannel();
  *is_unstable_channel = channel == chrome::VersionInfo::CHANNEL_DEV ||
                         channel == chrome::VersionInfo::CHANNEL_CANARY;

  // Get the version of the currently *running* instance of Chrome.
  chrome::VersionInfo version_info;
  if (!version_info.is_valid()) {
    NOTREACHED() << "Failed to get current file version";
    return;
  }
  Version running_version(version_info.Version());
  if (!running_version.IsValid()) {
    NOTREACHED();
    return;
  }

  // |installed_version| may be NULL when the user downgrades on Linux (by
  // switching from dev to beta channel, for example). The user needs a
  // restart in this case as well. See http://crbug.com/46547
  if (!installed_version.IsValid() ||
      (installed_version.CompareTo(running_version) > 0)) {
    // If a more recent version is available, it might be that we are lacking
    // a critical update, such as a zero-day fix.
    *is_critical_upgrade =
        critical_update.IsValid() &&
        (critical_update.CompareTo(running_version) > 0);

    // Fire off the upgrade detected task.
    BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
                            upgrade_detected_task);
  }
}

}  // namespace

UpgradeDetectorImpl::UpgradeDetectorImpl()
    : ALLOW_THIS_IN_INITIALIZER_LIST(weak_factory_(this)),
      is_unstable_channel_(false) {
  CommandLine command_line(*CommandLine::ForCurrentProcess());
  if (command_line.HasSwitch(switches::kDisableBackgroundNetworking))
    return;
  if (command_line.HasSwitch(switches::kSimulateUpgrade)) {
    UpgradeDetected();
    return;
  }
  // Windows: only enable upgrade notifications for official builds.
  // Mac: only enable them if the updater (Keystone) is present.
  // Linux (and other POSIX): always enable regardless of branding.
#if (defined(OS_WIN) && defined(GOOGLE_CHROME_BUILD)) || defined(OS_POSIX)
#if defined(OS_MACOSX)
  if (keystone_glue::KeystoneEnabled())
#endif
  {
    detect_upgrade_timer_.Start(FROM_HERE,
        base::TimeDelta::FromMilliseconds(GetCheckForUpgradeEveryMs()),
        this, &UpgradeDetectorImpl::CheckForUpgrade);
  }
#endif
}

UpgradeDetectorImpl::~UpgradeDetectorImpl() {
}

void UpgradeDetectorImpl::CheckForUpgrade() {
  weak_factory_.InvalidateWeakPtrs();
  base::Closure callback_task =
      base::Bind(&UpgradeDetectorImpl::UpgradeDetected,
                 weak_factory_.GetWeakPtr());
  // We use FILE as the thread to run the upgrade detection code on all
  // platforms. For Linux, this is because we don't want to block the UI thread
  // while launching a background process and reading its output; on the Mac and
  // on Windows checking for an upgrade requires reading a file.
  BrowserThread::PostTask(BrowserThread::FILE, FROM_HERE,
                          base::Bind(&DetectUpgradeTask,
                                     callback_task,
                                     &is_unstable_channel_,
                                     &is_critical_upgrade_));
}

void UpgradeDetectorImpl::UpgradeDetected() {
  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));

  // Stop the recurring timer (that is checking for changes).
  detect_upgrade_timer_.Stop();

  NotifyUpgradeDetected();

  // Start the repeating timer for notifying the user after a certain period.
  // The called function will eventually figure out that enough time has passed
  // and stop the timer.
  int cycle_time = IsTesting() ?
      kNotifyCycleTimeForTestingMs : kNotifyCycleTimeMs;
  upgrade_notification_timer_.Start(FROM_HERE,
      base::TimeDelta::FromMilliseconds(cycle_time),
      this, &UpgradeDetectorImpl::NotifyOnUpgrade);
}

void UpgradeDetectorImpl::NotifyOnUpgrade() {
  base::TimeDelta delta = base::Time::Now() - upgrade_detected_time();

  // We'll make testing more convenient by switching to seconds of waiting
  // instead of days between flipping severity.
  bool is_testing = IsTesting();
  int64 time_passed = is_testing ? delta.InSeconds() : delta.InHours();

  if (is_unstable_channel_) {
    // There's only one threat level for unstable channels like dev and
    // canary, and it hits after one hour. During testing, it hits after one
    // minute.
    const int kUnstableThreshold = 1;

    if (is_critical_upgrade_)
      set_upgrade_notification_stage(UPGRADE_ANNOYANCE_CRITICAL);
    else if (time_passed >= kUnstableThreshold) {
      set_upgrade_notification_stage(UPGRADE_ANNOYANCE_LOW);

      // That's as high as it goes.
      upgrade_notification_timer_.Stop();
    } else {
      return;  // Not ready to recommend upgrade.
    }
  } else {
    const int kMultiplier = is_testing ? 1 : 24;
    // 14 days when not testing, otherwise 14 seconds.
    const int kSevereThreshold = 14 * kMultiplier;
    const int kHighThreshold = 7 * kMultiplier;
    const int kElevatedThreshold = 4 * kMultiplier;
    const int kLowThreshold = 2 * kMultiplier;

    // These if statements must be sorted (highest interval first).
    if (time_passed >= kSevereThreshold || is_critical_upgrade_) {
      set_upgrade_notification_stage(
          is_critical_upgrade_ ? UPGRADE_ANNOYANCE_CRITICAL :
                                 UPGRADE_ANNOYANCE_SEVERE);

      // We can't get any higher, baby.
      upgrade_notification_timer_.Stop();
    } else if (time_passed >= kHighThreshold) {
      set_upgrade_notification_stage(UPGRADE_ANNOYANCE_HIGH);
    } else if (time_passed >= kElevatedThreshold) {
      set_upgrade_notification_stage(UPGRADE_ANNOYANCE_ELEVATED);
    } else if (time_passed >= kLowThreshold) {
      set_upgrade_notification_stage(UPGRADE_ANNOYANCE_LOW);
    } else {
      return;  // Not ready to recommend upgrade.
    }
  }

  NotifyUpgradeRecommended();
}

// static
UpgradeDetectorImpl* UpgradeDetectorImpl::GetInstance() {
  return Singleton<UpgradeDetectorImpl>::get();
}

// static
UpgradeDetector* UpgradeDetector::GetInstance() {
  return UpgradeDetectorImpl::GetInstance();
}