// Copyright 2020 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "chrome/browser/safe_browsing/generated_safe_browsing_pref.h"

#include <utility>

#include "chrome/browser/profiles/profile.h"
#include "chrome/common/extensions/api/settings_private.h"
#include "components/prefs/pref_service.h"
#include "components/safe_browsing/core/common/safe_browsing_prefs.h"

namespace settings_api = extensions::api::settings_private;

namespace safe_browsing {
const char kGeneratedSafeBrowsingPref[] = "generated.safe_browsing";

GeneratedSafeBrowsingPref::GeneratedSafeBrowsingPref(Profile* profile)
    : profile_(profile) {
  user_prefs_registrar_.Init(profile->GetPrefs());
  user_prefs_registrar_.AddMultiple(
      {prefs::kSafeBrowsingEnabled, prefs::kSafeBrowsingEnhanced,
       prefs::kSafeBrowsingScoutReportingEnabled},
      base::BindRepeating(
          &GeneratedSafeBrowsingPref::OnSafeBrowsingPreferencesChanged,
          base::Unretained(this)));
  user_prefs_registrar_.Add(
      prefs::kSecuritySettingsBundle,
      base::BindRepeating(&GeneratedSafeBrowsingPref::OnSettingsBundleChanged,
                          base::Unretained(this)));
}

extensions::settings_private::SetPrefResult GeneratedSafeBrowsingPref::SetPref(
    const base::Value* value) {
  if (!value->is_int()) {
    return extensions::settings_private::SetPrefResult::PREF_TYPE_MISMATCH;
  }

  auto selection = static_cast<SafeBrowsingState>(value->GetInt());

  if (selection != SafeBrowsingState::NO_SAFE_BROWSING &&
      selection != SafeBrowsingState::STANDARD_PROTECTION &&
      selection != SafeBrowsingState::ENHANCED_PROTECTION) {
    return extensions::settings_private::SetPrefResult::PREF_TYPE_MISMATCH;
  }

  // If SBER is forcefully disabled, Enhanced cannot be selected by the user.
  const PrefService::Preference* reporting_pref =
      profile_->GetPrefs()->FindPreference(
          prefs::kSafeBrowsingScoutReportingEnabled);
  const bool reporting_on = reporting_pref->GetValue()->GetBool();
  const bool reporting_enforced = !reporting_pref->IsUserModifiable();

  if (reporting_enforced && !reporting_on &&
      selection == SafeBrowsingState::ENHANCED_PROTECTION) {
    return extensions::settings_private::SetPrefResult::PREF_NOT_MODIFIABLE;
  }

  // kSafeBrowsingEnabled is considered the canonical source for Safe Browsing
  // management.
  const PrefService::Preference* enabled_pref =
      profile_->GetPrefs()->FindPreference(prefs::kSafeBrowsingEnabled);
  if (!enabled_pref->IsUserModifiable()) {
    return extensions::settings_private::SetPrefResult::PREF_NOT_MODIFIABLE;
  }

  // Update both Safe Browsing preferences to match selection.
  profile_->GetPrefs()->SetBoolean(
      prefs::kSafeBrowsingEnabled,
      selection != SafeBrowsingState::NO_SAFE_BROWSING);
  profile_->GetPrefs()->SetBoolean(
      prefs::kSafeBrowsingEnhanced,
      selection == SafeBrowsingState::ENHANCED_PROTECTION);

  // Set ESB not set in sync with Account ESB through TailoredSecurity.
  if (selection == SafeBrowsingState::ENHANCED_PROTECTION) {
    profile_->GetPrefs()->SetBoolean(
        prefs::kEnhancedProtectionEnabledViaTailoredSecurity, false);
  }

  return extensions::settings_private::SetPrefResult::SUCCESS;
}

extensions::api::settings_private::PrefObject
GeneratedSafeBrowsingPref::GetPrefObject() const {
  SafeBrowsingState safe_browsing_state =
      GetSafeBrowsingState(*profile_->GetPrefs());
  extensions::api::settings_private::PrefObject pref_object;
  pref_object.key = kGeneratedSafeBrowsingPref;
  pref_object.type = extensions::api::settings_private::PrefType::kNumber;
  pref_object.value = base::Value(static_cast<int>(safe_browsing_state));

  ApplySafeBrowsingManagementState(*profile_, pref_object);

  return pref_object;
}

void GeneratedSafeBrowsingPref::OnSafeBrowsingPreferencesChanged() {
  NotifyObservers(kGeneratedSafeBrowsingPref);
}

void GeneratedSafeBrowsingPref::OnSettingsBundleChanged() {
  auto bundle = GetSecurityBundleSetting(*profile_->GetPrefs());
  switch (bundle) {
    case SecuritySettingsBundleSetting::STANDARD:
      SetPref(std::make_unique<base::Value>(
                  static_cast<int>(SafeBrowsingState::STANDARD_PROTECTION))
                  .get());
      break;
    case SecuritySettingsBundleSetting::ENHANCED:
      SetPref(std::make_unique<base::Value>(
                  static_cast<int>(SafeBrowsingState::ENHANCED_PROTECTION))
                  .get());
      break;
    default:
      NOTREACHED();
  }
}

/* static */
void GeneratedSafeBrowsingPref::ApplySafeBrowsingManagementState(
    const Profile& profile,
    settings_api::PrefObject& pref_object) {
  // Computing the effective Safe Browsing managed state requires inspecting
  // three different preferences. It is possible that these may be in
  // temporarily conflicting managed states. The enabled preference is always
  // taken as the canonical source of management.
  const PrefService::Preference* enabled_pref =
      profile.GetPrefs()->FindPreference(prefs::kSafeBrowsingEnabled);
  const bool enabled_enforced = !enabled_pref->IsUserModifiable();
  const bool enabled_recommended =
      (enabled_pref && enabled_pref->GetRecommendedValue());
  const bool enabled_recommended_on =
      enabled_recommended && enabled_pref->GetRecommendedValue()->GetBool();

  // The enhanced preference may have a recommended setting. This only takes
  // effect if the enabled preference also has a recommended setting.
  const PrefService::Preference* enhanced_pref =
      profile.GetPrefs()->FindPreference(prefs::kSafeBrowsingEnhanced);
  const bool enhanced_recommended_on =
      enhanced_pref->GetRecommendedValue() &&
      enhanced_pref->GetRecommendedValue()->GetBool();

  // A forcefully disabled reporting preference will disallow enhanced from
  // being selected and thus it must also be considered.
  const PrefService::Preference* reporting_pref =
      profile.GetPrefs()->FindPreference(
          prefs::kSafeBrowsingScoutReportingEnabled);
  const bool reporting_on = reporting_pref->GetValue()->GetBool();
  const bool reporting_enforced = !reporting_pref->IsUserModifiable();

  if (!enabled_enforced && !enabled_recommended && !reporting_enforced) {
    // No relevant policies are applied.
    return;
  }

  if (enabled_enforced) {
    // Preference is fully controlled.
    pref_object.enforcement = settings_api::Enforcement::kEnforced;
    extensions::settings_private::GeneratedPref::ApplyControlledByFromPref(
        &pref_object, enabled_pref);
    return;
  }

  if (enabled_recommended) {
    // Set enforcement to recommended. This may be upgraded to enforced later
    // in this function.
    pref_object.enforcement = settings_api::Enforcement::kRecommended;
    if (enhanced_recommended_on) {
      pref_object.recommended_value =
          base::Value(static_cast<int>(SafeBrowsingState::ENHANCED_PROTECTION));
    } else if (enabled_recommended_on) {
      pref_object.recommended_value =
          base::Value(static_cast<int>(SafeBrowsingState::STANDARD_PROTECTION));
    } else {
      pref_object.recommended_value =
          base::Value(static_cast<int>(SafeBrowsingState::NO_SAFE_BROWSING));
    }
  }

  if (reporting_enforced && !reporting_on) {
    // Reporting has been forcefully disabled by policy. Enhanced protection is
    // thus also implicitly disabled by the same policy.
    pref_object.enforcement = settings_api::Enforcement::kEnforced;
    extensions::settings_private::GeneratedPref::ApplyControlledByFromPref(
        &pref_object, reporting_pref);

    pref_object.user_selectable_values.emplace();
    pref_object.user_selectable_values->Append(
        std::to_underlying(SafeBrowsingState::STANDARD_PROTECTION));
    pref_object.user_selectable_values->Append(
        std::to_underlying(SafeBrowsingState::NO_SAFE_BROWSING));
  }
}

}  // namespace safe_browsing