// Copyright 2015 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/ssl/cert_report_helper.h"

#include <utility>

#include "base/logging.h"
#include "base/metrics/field_trial.h"
#include "base/rand_util.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/stringprintf.h"
#include "base/strings/utf_string_conversions.h"
#include "build/build_config.h"
#include "chrome/browser/browser_process.h"
#include "chrome/browser/profiles/profile.h"
#include "chrome/browser/ssl/ssl_cert_reporter.h"
#include "chrome/common/channel_info.h"
#include "chrome/common/pref_names.h"
#include "components/prefs/pref_service.h"
#include "components/safe_browsing/common/safe_browsing_prefs.h"
#include "components/security_interstitials/core/controller_client.h"
#include "components/security_interstitials/core/metrics_helper.h"
#include "components/strings/grit/components_strings.h"
#include "components/variations/variations_associated_data.h"
#include "content/public/browser/browser_context.h"
#include "content/public/browser/web_contents.h"
#include "ui/base/l10n/l10n_util.h"

#if defined(OS_WIN)
#include "base/enterprise_util.h"
#elif defined(OS_CHROMEOS)
#include "chrome/browser/chromeos/policy/browser_policy_connector_chromeos.h"
#endif

namespace {

// Certificate reports are only sent from official builds, but this flag can be
// set by tests.
static bool g_is_fake_official_build_for_cert_report_testing = false;

// Returns a pointer to the Profile associated with |web_contents|.
Profile* GetProfile(content::WebContents* web_contents) {
  return Profile::FromBrowserContext(web_contents->GetBrowserContext());
}

}  // namespace

// Constants for the HTTPSErrorReporter Finch experiment
const char CertReportHelper::kFinchExperimentName[] = "ReportCertificateErrors";
const char CertReportHelper::kFinchGroupShowPossiblySend[] =
    "ShowAndPossiblySend";
const char CertReportHelper::kFinchGroupDontShowDontSend[] =
    "DontShowAndDontSend";
const char CertReportHelper::kFinchParamName[] = "sendingThreshold";

CertReportHelper::CertReportHelper(
    std::unique_ptr<SSLCertReporter> ssl_cert_reporter,
    content::WebContents* web_contents,
    const GURL& request_url,
    const net::SSLInfo& ssl_info,
    CertificateErrorReport::InterstitialReason interstitial_reason,
    bool overridable,
    const base::Time& interstitial_time,
    security_interstitials::MetricsHelper* metrics_helper)
    : ssl_cert_reporter_(std::move(ssl_cert_reporter)),
      web_contents_(web_contents),
      request_url_(request_url),
      ssl_info_(ssl_info),
      interstitial_reason_(interstitial_reason),
      overridable_(overridable),
      interstitial_time_(interstitial_time),
      metrics_helper_(metrics_helper) {}

CertReportHelper::~CertReportHelper() {
}

// static
void CertReportHelper::SetFakeOfficialBuildForTesting() {
  g_is_fake_official_build_for_cert_report_testing = true;
}

void CertReportHelper::PopulateExtendedReportingOption(
    base::DictionaryValue* load_time_data) {
  // Only show the checkbox if not off-the-record and if this client is
  // part of the respective Finch group, and the feature is not disabled
  // by policy.
  const bool show = ShouldShowCertificateReporterCheckbox();

  load_time_data->SetBoolean(security_interstitials::kDisplayCheckBox, show);
  if (!show)
    return;

  load_time_data->SetBoolean(security_interstitials::kBoxChecked,
                             safe_browsing::IsExtendedReportingEnabled(
                                 *GetProfile(web_contents_)->GetPrefs()));

  const std::string privacy_link = base::StringPrintf(
      security_interstitials::kPrivacyLinkHtml,
      security_interstitials::CMD_OPEN_REPORTING_PRIVACY,
      l10n_util::GetStringUTF8(IDS_SAFE_BROWSING_PRIVACY_POLICY_PAGE).c_str());

  load_time_data->SetString(
      security_interstitials::kOptInLink,
      l10n_util::GetStringFUTF16(IDS_SAFE_BROWSING_SCOUT_REPORTING_AGREE,
                                 base::UTF8ToUTF16(privacy_link)));
}

void CertReportHelper::SetSSLCertReporterForTesting(
    std::unique_ptr<SSLCertReporter> ssl_cert_reporter) {
  ssl_cert_reporter_ = std::move(ssl_cert_reporter);
}

void CertReportHelper::HandleReportingCommands(
    security_interstitials::SecurityInterstitialCommand command,
    PrefService* pref_service) {
  switch (command) {
    case security_interstitials::CMD_DO_REPORT:
      safe_browsing::SetExtendedReportingPrefAndMetric(
          pref_service, true, /* value */
          safe_browsing::SBER_OPTIN_SITE_SECURITY_INTERSTITIAL);
      break;
    case security_interstitials::CMD_DONT_REPORT:
      safe_browsing::SetExtendedReportingPrefAndMetric(
          pref_service, false, /* value */
          safe_browsing::SBER_OPTIN_SITE_SECURITY_INTERSTITIAL);
      break;
    case security_interstitials::CMD_PROCEED:
      user_action_ = CertificateErrorReport::USER_PROCEEDED;
      break;
    case security_interstitials::CMD_DONT_PROCEED:
      user_action_ = CertificateErrorReport::USER_DID_NOT_PROCEED;
      break;
    default:
      // Other commands can be ignored.
      break;
  }
}

void CertReportHelper::FinishCertCollection() {
  if (!ShouldShowCertificateReporterCheckbox())
    return;

  if (!safe_browsing::IsExtendedReportingEnabled(
          *GetProfile(web_contents_)->GetPrefs()))
    return;

  if (metrics_helper_) {
    metrics_helper_->RecordUserInteraction(
        security_interstitials::MetricsHelper::EXTENDED_REPORTING_IS_ENABLED);
  }

  if (!ShouldReportCertificateError())
    return;

  std::string serialized_report;
  CertificateErrorReport report(request_url_.host(), ssl_info_);

  report.AddNetworkTimeInfo(g_browser_process->network_time_tracker());

  report.AddChromeChannel(chrome::GetChannel());

#if defined(OS_WIN)
  report.SetIsEnterpriseManaged(base::IsMachineExternallyManaged());
#elif defined(OS_CHROMEOS)
  report.SetIsEnterpriseManaged(g_browser_process->platform_part()
                                    ->browser_policy_connector_chromeos()
                                    ->IsEnterpriseManaged());
#endif

  report.SetInterstitialInfo(
      interstitial_reason_, user_action_,
      overridable_ ? CertificateErrorReport::INTERSTITIAL_OVERRIDABLE
                   : CertificateErrorReport::INTERSTITIAL_NOT_OVERRIDABLE,
      interstitial_time_);

  if (!report.Serialize(&serialized_report)) {
    LOG(ERROR) << "Failed to serialize certificate report.";
    return;
  }

  ssl_cert_reporter_->ReportInvalidCertificateChain(serialized_report);
}

bool CertReportHelper::ShouldShowCertificateReporterCheckbox() {
  // Only show the checkbox iff the user is part of the respective Finch group
  // and the window is not incognito and the feature is not disabled by policy.
  const bool in_incognito =
      web_contents_->GetBrowserContext()->IsOffTheRecord();
  const PrefService* pref_service = GetProfile(web_contents_)->GetPrefs();
  bool can_show_checkbox =
      safe_browsing::IsExtendedReportingOptInAllowed(*pref_service) &&
      !safe_browsing::IsExtendedReportingPolicyManaged(*pref_service);

  return base::FieldTrialList::FindFullName(kFinchExperimentName) ==
             kFinchGroupShowPossiblySend &&
         !in_incognito && can_show_checkbox;
}

bool CertReportHelper::ShouldReportCertificateError() {
  DCHECK(ShouldShowCertificateReporterCheckbox());

  bool is_official_build = g_is_fake_official_build_for_cert_report_testing;
#if defined(OFFICIAL_BUILD) && defined(GOOGLE_CHROME_BUILD)
  is_official_build = true;
#endif

  if (!is_official_build)
    return false;

  // Even in case the checkbox was shown, we don't send error reports
  // for all of these users. Check the Finch configuration for a sending
  // threshold and only send reports in case the threshold isn't exceeded.
  const std::string param =
      variations::GetVariationParamValue(kFinchExperimentName, kFinchParamName);
  if (!param.empty()) {
    double sendingThreshold;
    if (base::StringToDouble(param, &sendingThreshold)) {
      if (sendingThreshold >= 0.0 && sendingThreshold <= 1.0)
        return base::RandDouble() <= sendingThreshold;
    }
  }
  return false;
}