// Copyright 2017 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "components/metrics/environment_recorder.h"

#include "base/base64.h"
#include "base/strings/string_number_conversions.h"
#include "components/metrics/metrics_pref_names.h"
#include "components/prefs/pref_registry_simple.h"
#include "components/prefs/pref_service.h"
#include "crypto/obsolete/sha1.h"
#include "third_party/metrics_proto/system_profile.pb.h"

namespace metrics {

// Computes a SHA-1 hash of |data| and returns it as a hex string. This
// function is intentionally declared in a separate header file
// "crypto/obsolete/sha1.h", so as to easily monitor current usage of SHA-1 in
// Chrome, since SHA-1 is now discouraged for new code.
std::string Sha1AsHexForSystemProfile(std::string_view data) {
  return base::HexEncode(
      crypto::obsolete::Sha1::Hash(base::as_byte_span(data)));
}

EnvironmentRecorder::EnvironmentRecorder(PrefService* local_state)
    : local_state_(local_state) {}

EnvironmentRecorder::~EnvironmentRecorder() = default;

std::string EnvironmentRecorder::SerializeAndRecordEnvironmentToPrefs(
    const SystemProfileProto& system_profile) {
  std::string serialized_system_profile;
  if (system_profile.SerializeToString(&serialized_system_profile)) {
    // Persist the system profile to disk. In the event of an unclean shutdown,
    // it will be used as part of the initial stability report.
    const std::string base64_system_profile =
        base::Base64Encode(serialized_system_profile);
    local_state_->SetString(prefs::kStabilitySavedSystemProfile,
                            base64_system_profile);
    local_state_->SetString(
        prefs::kStabilitySavedSystemProfileHash,
        Sha1AsHexForSystemProfile(serialized_system_profile));
  }

  return serialized_system_profile;
}

bool EnvironmentRecorder::LoadEnvironmentFromPrefs(
    SystemProfileProto* system_profile) {
  DCHECK(system_profile);

  const std::string base64_system_profile =
      local_state_->GetString(prefs::kStabilitySavedSystemProfile);
  if (base64_system_profile.empty()) {
    return false;
  }
  const std::string system_profile_hash =
      local_state_->GetString(prefs::kStabilitySavedSystemProfileHash);

  std::string serialized_system_profile;
  if (!base::Base64Decode(base64_system_profile, &serialized_system_profile)) {
    return false;
  }
  if (Sha1AsHexForSystemProfile(serialized_system_profile) !=
      system_profile_hash) {
    return false;
  }
  if (!system_profile->ParseFromString(serialized_system_profile)) {
    return false;
  }
  // Prevent initial stability logs from having the `fg_bg_id` field set, since
  // those logs contain metrics *about* a previous session, and are not emitted
  // during those sessions (and should certainly not be associated with any
  // particular background or foreground period).
  system_profile->clear_fg_bg_id();
  return true;
}

void EnvironmentRecorder::ClearEnvironmentFromPrefs() {
  local_state_->ClearPref(prefs::kStabilitySavedSystemProfile);
  local_state_->ClearPref(prefs::kStabilitySavedSystemProfileHash);
}

int64_t EnvironmentRecorder::GetLastBuildtime() {
  return local_state_->GetInt64(prefs::kStabilityStatsBuildTime);
}

std::string EnvironmentRecorder::GetLastVersion() {
  return local_state_->GetString(prefs::kStabilityStatsVersion);
}

void EnvironmentRecorder::SetBuildtimeAndVersion(int64_t buildtime,
                                                 const std::string& version) {
  local_state_->SetInt64(prefs::kStabilityStatsBuildTime, buildtime);
  local_state_->SetString(prefs::kStabilityStatsVersion, version);
}

// static
void EnvironmentRecorder::RegisterPrefs(PrefRegistrySimple* registry) {
  registry->RegisterStringPref(prefs::kStabilitySavedSystemProfile,
                               std::string());
  registry->RegisterStringPref(prefs::kStabilitySavedSystemProfileHash,
                               std::string());
  registry->RegisterStringPref(prefs::kStabilityStatsVersion, std::string());
  registry->RegisterInt64Pref(prefs::kStabilityStatsBuildTime, 0);
}

}  // namespace metrics