/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim:set ts=2 sw=2 sts=2 et cindent: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "Telemetry.h"

#include <fstream>
#include <string>

#include <windows.h>

#include <knownfolders.h>
#include <shlobj_core.h>

#include "common.h"
#include "Cache.h"
#include "EventLog.h"
#include "Notification.h"
#include "Policy.h"
#include "UtfConvert.h"
#include "Registry.h"

#include "json/json.h"
#include "mozilla/ArrayUtils.h"
#include "mozilla/CmdLineAndEnvUtils.h"
#include "mozilla/HelperMacros.h"
#include "mozilla/UniquePtr.h"
#include "mozilla/Unused.h"
#include "mozilla/WinHeaderOnlyUtils.h"

#define TELEMETRY_BASE_URL "https://incoming.telemetry.mozilla.org/submit"
#define TELEMETRY_NAMESPACE "default-browser-agent"
#define TELEMETRY_PING_VERSION "1"
#define TELEMETRY_PING_DOCTYPE "default-browser"

// This is almost the complete URL, just needs a UUID appended.
#define TELEMETRY_PING_URL                                              \
  TELEMETRY_BASE_URL "/" TELEMETRY_NAMESPACE "/" TELEMETRY_PING_DOCTYPE \
                     "/" TELEMETRY_PING_VERSION "/"

// We only want to send one ping per day. However, this is slightly less than 24
// hours so that we have a little bit of wiggle room on our task, which is also
// supposed to run every 24 hours.
#define MINIMUM_PING_PERIOD_SEC ((23 * 60 * 60) + (45 * 60))

#define PREV_NOTIFICATION_ACTION_REG_NAME L"PrevNotificationAction"

#if !defined(RRF_SUBKEY_WOW6464KEY)
#  define RRF_SUBKEY_WOW6464KEY 0x00010000
#endif  // !defined(RRF_SUBKEY_WOW6464KEY)

using TelemetryFieldResult = mozilla::WindowsErrorResult<std::string>;
using BoolResult = mozilla::WindowsErrorResult<bool>;

// This function was copied from the implementation of
// nsITelemetry::isOfficialTelemetry, currently found in the file
// toolkit/components/telemetry/core/Telemetry.cpp.
static bool IsOfficialTelemetry() {
#if defined(MOZILLA_OFFICIAL) && defined(MOZ_TELEMETRY_REPORTING) && \
    !defined(DEBUG)
  return true;
#else
  return false;
#endif
}

static TelemetryFieldResult GetOSVersion() {
  OSVERSIONINFOEXW osv = {sizeof(osv)};
  if (::GetVersionExW(reinterpret_cast<OSVERSIONINFOW*>(&osv))) {
    std::ostringstream oss;
    oss << osv.dwMajorVersion << "." << osv.dwMinorVersion << "."
        << osv.dwBuildNumber;

    if (osv.dwMajorVersion == 10 && osv.dwMinorVersion == 0) {
      // Get the "Update Build Revision" (UBR) value
      DWORD ubrValue;
      DWORD ubrValueLen = sizeof(ubrValue);
      LSTATUS ubrOk =
          ::RegGetValueW(HKEY_LOCAL_MACHINE,
                         L"SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion",
                         L"UBR", RRF_RT_DWORD | RRF_SUBKEY_WOW6464KEY, nullptr,
                         &ubrValue, &ubrValueLen);
      if (ubrOk == ERROR_SUCCESS) {
        oss << "." << ubrValue;
      }
    }

    return oss.str();
  }

  HRESULT hr = HRESULT_FROM_WIN32(GetLastError());
  LOG_ERROR(hr);
  return TelemetryFieldResult(mozilla::WindowsError::FromHResult(hr));
}

static TelemetryFieldResult GetOSLocale() {
  wchar_t localeName[LOCALE_NAME_MAX_LENGTH] = L"";
  if (!GetUserDefaultLocaleName(localeName, LOCALE_NAME_MAX_LENGTH)) {
    HRESULT hr = HRESULT_FROM_WIN32(GetLastError());
    LOG_ERROR(hr);
    return TelemetryFieldResult(mozilla::WindowsError::FromHResult(hr));
  }

  // We'll need the locale string in UTF-8 to be able to submit it.
  Utf16ToUtf8Result narrowLocaleName = Utf16ToUtf8(localeName);

  return narrowLocaleName.unwrapOr("");
}

static FilePathResult GetPingFilePath(std::wstring& uuid) {
  wchar_t* rawAppDataPath;
  HRESULT hr = SHGetKnownFolderPath(FOLDERID_RoamingAppData, 0, nullptr,
                                    &rawAppDataPath);
  if (FAILED(hr)) {
    LOG_ERROR(hr);
    return FilePathResult(mozilla::WindowsError::FromHResult(hr));
  }
  mozilla::UniquePtr<wchar_t, mozilla::CoTaskMemFreeDeleter> appDataPath(
      rawAppDataPath);

  // The Path* functions don't set LastError, but this is the only thing that
  // can really cause them to fail, so if they ever do we assume this is why.
  hr = HRESULT_FROM_WIN32(ERROR_INSUFFICIENT_BUFFER);

  wchar_t pingFilePath[MAX_PATH] = L"";
  if (!PathCombineW(pingFilePath, appDataPath.get(), L"" MOZ_APP_VENDOR)) {
    LOG_ERROR(hr);
    return FilePathResult(mozilla::WindowsError::FromHResult(hr));
  }

  if (!PathAppendW(pingFilePath, L"" MOZ_APP_BASENAME)) {
    LOG_ERROR(hr);
    return FilePathResult(mozilla::WindowsError::FromHResult(hr));
  }

  if (!PathAppendW(pingFilePath, L"Pending Pings")) {
    LOG_ERROR(hr);
    return FilePathResult(mozilla::WindowsError::FromHResult(hr));
  }

  if (!PathAppendW(pingFilePath, uuid.c_str())) {
    LOG_ERROR(hr);
    return FilePathResult(mozilla::WindowsError::FromHResult(hr));
  }

  return std::wstring(pingFilePath);
}

static mozilla::WindowsError SendPing(
    const std::string defaultBrowser, const std::string previousDefaultBrowser,
    const std::string defaultPdf, const std::string osVersion,
    const std::string osLocale, const std::string notificationType,
    const std::string notificationShown, const std::string notificationAction,
    const std::string prevNotificationAction) {
  // Fill in the ping JSON object.
  Json::Value ping;
  ping["build_channel"] = MOZ_STRINGIFY(MOZ_UPDATE_CHANNEL);
  ping["build_version"] = MOZILLA_VERSION;
  ping["default_browser"] = defaultBrowser;
  ping["previous_default_browser"] = previousDefaultBrowser;
  ping["default_pdf_viewer_raw"] = defaultPdf;
  ping["os_version"] = osVersion;
  ping["os_locale"] = osLocale;
  ping["notification_type"] = notificationType;
  ping["notification_shown"] = notificationShown;
  ping["notification_action"] = notificationAction;
  ping["previous_notification_action"] = prevNotificationAction;

  // Stringify the JSON.
  Json::StreamWriterBuilder jsonStream;
  jsonStream["indentation"] = "";
  std::string pingStr = Json::writeString(jsonStream, ping);

  // Generate a UUID for the ping.
  FilePathResult uuidResult = GenerateUUIDStr();
  if (uuidResult.isErr()) {
    return uuidResult.unwrapErr();
  }
  std::wstring uuid = uuidResult.unwrap();

  // Write the JSON string to a file. Use the UUID in the file name so that if
  // multiple instances of this task are running they'll have their own files.
  FilePathResult pingFilePathResult = GetPingFilePath(uuid);
  if (pingFilePathResult.isErr()) {
    return pingFilePathResult.unwrapErr();
  }
  std::wstring pingFilePath = pingFilePathResult.unwrap();

  {
    std::ofstream outFile(pingFilePath);
    outFile << pingStr;
    if (outFile.fail()) {
      // We have no way to get a specific error code out of a file stream
      // other than to catch an exception, so substitute a generic error code.
      HRESULT hr = HRESULT_FROM_WIN32(ERROR_IO_DEVICE);
      LOG_ERROR(hr);
      return mozilla::WindowsError::FromHResult(hr);
    }
  }

  // Hand the file off to pingsender to submit.
  FilePathResult pingsenderPathResult =
      GetRelativeBinaryPath(L"pingsender.exe");
  if (pingsenderPathResult.isErr()) {
    return pingsenderPathResult.unwrapErr();
  }
  std::wstring pingsenderPath = pingsenderPathResult.unwrap();

  std::wstring url(L"" TELEMETRY_PING_URL);
  url.append(uuid);

  const wchar_t* pingsenderArgs[] = {pingsenderPath.c_str(), url.c_str(),
                                     pingFilePath.c_str()};
  mozilla::UniquePtr<wchar_t[]> pingsenderCmdLine(
      mozilla::MakeCommandLine(mozilla::ArrayLength(pingsenderArgs),
                               const_cast<wchar_t**>(pingsenderArgs)));

  PROCESS_INFORMATION pi;
  STARTUPINFOW si = {sizeof(si)};
  si.dwFlags = STARTF_USESHOWWINDOW;
  si.wShowWindow = SW_HIDE;
  if (!::CreateProcessW(pingsenderPath.c_str(), pingsenderCmdLine.get(),
                        nullptr, nullptr, FALSE, 0, nullptr, nullptr, &si,
                        &pi)) {
    HRESULT hr = HRESULT_FROM_WIN32(GetLastError());
    LOG_ERROR(hr);
    return mozilla::WindowsError::FromHResult(hr);
  }

  CloseHandle(pi.hThread);
  CloseHandle(pi.hProcess);

  return mozilla::WindowsError::CreateSuccess();
}

// This function checks if a ping has already been sent today. If one has not,
// it assumes that we are about to send one and sets a registry entry that will
// cause this function to return true for the next day.
// This function uses unprefixed registry entries, so a RegistryMutex should be
// held before calling.
static BoolResult GetPingAlreadySentToday() {
  const wchar_t* valueName = L"LastPingSentAt";
  MaybeQwordResult readResult =
      RegistryGetValueQword(IsPrefixed::Unprefixed, valueName);
  if (readResult.isErr()) {
    HRESULT hr = readResult.unwrapErr().AsHResult();
    LOG_ERROR_MESSAGE(L"Unable to read registry: %#X", hr);
    return BoolResult(mozilla::WindowsError::FromHResult(hr));
  }
  mozilla::Maybe<ULONGLONG> maybeValue = readResult.unwrap();
  ULONGLONG now = GetCurrentTimestamp();
  if (maybeValue.isSome()) {
    ULONGLONG lastPingTime = maybeValue.value();
    if (SecondsPassedSince(lastPingTime, now) < MINIMUM_PING_PERIOD_SEC) {
      return true;
    }
  }

  mozilla::WindowsErrorResult<mozilla::Ok> writeResult =
      RegistrySetValueQword(IsPrefixed::Unprefixed, valueName, now);
  if (writeResult.isErr()) {
    HRESULT hr = readResult.unwrapErr().AsHResult();
    LOG_ERROR_MESSAGE(L"Unable to write registry: %#X", hr);
    return BoolResult(mozilla::WindowsError::FromHResult(hr));
  }
  return false;
}

// This both retrieves a value from the registry and writes new data
// (currentDefault) to the same value. If there is no value stored, the value
// passed for prevDefault will be converted to a string and returned instead.
//
// Although we already store and retrieve a cached previous default browser
// value elsewhere, it may be updated when we don't send a ping. The value we
// retrieve here will only be updated when we are sending a ping to ensure
// that pings don't miss a default browser transition.
static TelemetryFieldResult GetAndUpdatePreviousDefaultBrowser(
    const std::string& currentDefault, Browser prevDefault) {
  const wchar_t* registryValueName = L"PingCurrentDefault";

  MaybeStringResult readResult =
      RegistryGetValueString(IsPrefixed::Unprefixed, registryValueName);
  if (readResult.isErr()) {
    HRESULT hr = readResult.unwrapErr().AsHResult();
    LOG_ERROR_MESSAGE(L"Unable to read registry: %#X", hr);
    return TelemetryFieldResult(mozilla::WindowsError::FromHResult(hr));
  }
  mozilla::Maybe<std::string> maybeValue = readResult.unwrap();
  std::string oldCurrentDefault;
  if (maybeValue.isSome()) {
    oldCurrentDefault = maybeValue.value();
  } else {
    oldCurrentDefault = GetStringForBrowser(prevDefault);
  }

  mozilla::WindowsErrorResult<mozilla::Ok> writeResult = RegistrySetValueString(
      IsPrefixed::Unprefixed, registryValueName, currentDefault.c_str());
  if (writeResult.isErr()) {
    HRESULT hr = writeResult.unwrapErr().AsHResult();
    LOG_ERROR_MESSAGE(L"Unable to write registry: %#X", hr);
    return TelemetryFieldResult(mozilla::WindowsError::FromHResult(hr));
  }
  return oldCurrentDefault;
}

// If notifications actions occurred, we want to make sure a ping gets sent for
// them. If we aren't sending a ping right now, we want to cache the ping values
// for the next time the ping is sent.
// The values passed will only be cached if actions were actually taken
// (i.e. not when notificationShown == "not-shown")
HRESULT MaybeCache(Cache& cache, const std::string& notificationType,
                   const std::string& notificationShown,
                   const std::string& notificationAction,
                   const std::string& prevNotificationAction) {
  std::string notShown =
      GetStringForNotificationShown(NotificationShown::NotShown);
  if (notificationShown == notShown) {
    return S_OK;
  }

  Cache::Entry entry{
      .notificationType = notificationType,
      .notificationShown = notificationShown,
      .notificationAction = notificationAction,
      .prevNotificationAction = prevNotificationAction,
  };
  VoidResult result = cache.Enqueue(entry);
  if (result.isErr()) {
    return result.unwrapErr().AsHResult();
  }
  return S_OK;
}

// This function retrieves values cached by MaybeCache. If any values were
// loaded from the cache, the values passed in to this function are passed to
// MaybeCache so that they are not lost. If there are no values in the cache,
// the values passed will not be changed.
// Values retrieved from the cache will also be removed from it.
HRESULT MaybeSwapForCached(Cache& cache, std::string& notificationType,
                           std::string& notificationShown,
                           std::string& notificationAction,
                           std::string& prevNotificationAction) {
  Cache::MaybeEntryResult result = cache.Dequeue();
  if (result.isErr()) {
    HRESULT hr = result.unwrapErr().AsHResult();
    LOG_ERROR_MESSAGE(L"Failed to read cache: %#X", hr);
    return hr;
  }
  Cache::MaybeEntry maybeEntry = result.unwrap();
  if (maybeEntry.isNothing()) {
    return S_OK;
  }

  MaybeCache(cache, notificationType, notificationShown, notificationAction,
             prevNotificationAction);
  notificationType = maybeEntry.value().notificationType;
  notificationShown = maybeEntry.value().notificationShown;
  notificationAction = maybeEntry.value().notificationAction;
  if (maybeEntry.value().prevNotificationAction.isSome()) {
    prevNotificationAction = maybeEntry.value().prevNotificationAction.value();
  } else {
    prevNotificationAction =
        GetStringForNotificationAction(NotificationAction::NoAction);
  }
  return S_OK;
}

HRESULT ReadPreviousNotificationAction(std::string& prevAction) {
  MaybeStringResult maybePrevActionResult = RegistryGetValueString(
      IsPrefixed::Unprefixed, PREV_NOTIFICATION_ACTION_REG_NAME);
  if (maybePrevActionResult.isErr()) {
    HRESULT hr = maybePrevActionResult.unwrapErr().AsHResult();
    LOG_ERROR_MESSAGE(L"Unable to read prev action from registry: %#X", hr);
    return hr;
  }
  mozilla::Maybe<std::string> maybePrevAction = maybePrevActionResult.unwrap();
  if (maybePrevAction.isNothing()) {
    prevAction = GetStringForNotificationAction(NotificationAction::NoAction);
  } else {
    prevAction = maybePrevAction.value();
    // There's no good reason why there should be an invalid value stored here.
    // But it's also not worth aborting the whole ping over. This function will
    // silently change it to "no-action" if the value isn't valid to prevent us
    // from sending unexpected telemetry values.
    EnsureValidNotificationAction(prevAction);
  }
  return S_OK;
}

// Writes the previous notification action to the registry, but only if a
// notification was shown.
HRESULT MaybeWritePreviousNotificationAction(
    const NotificationActivities& activitiesPerformed) {
  if (activitiesPerformed.shown != NotificationShown::Shown) {
    return S_OK;
  }
  std::string notificationAction =
      GetStringForNotificationAction(activitiesPerformed.action);
  mozilla::WindowsErrorResult<mozilla::Ok> result = RegistrySetValueString(
      IsPrefixed::Unprefixed, PREV_NOTIFICATION_ACTION_REG_NAME,
      notificationAction.c_str());
  if (result.isErr()) {
    HRESULT hr = result.unwrapErr().AsHResult();
    LOG_ERROR_MESSAGE(L"Unable to write prev action to registry: %#X", hr);
    return hr;
  }
  return S_OK;
}

HRESULT SendDefaultBrowserPing(
    const DefaultBrowserInfo& browserInfo, const DefaultPdfInfo& pdfInfo,
    const NotificationActivities& activitiesPerformed) {
  std::string currentDefaultBrowser =
      GetStringForBrowser(browserInfo.currentDefaultBrowser);
  std::string currentDefaultPdf = pdfInfo.currentDefaultPdf;
  std::string notificationType =
      GetStringForNotificationType(activitiesPerformed.type);
  std::string notificationShown =
      GetStringForNotificationShown(activitiesPerformed.shown);
  std::string notificationAction =
      GetStringForNotificationAction(activitiesPerformed.action);

  TelemetryFieldResult osVersionResult = GetOSVersion();
  if (osVersionResult.isErr()) {
    return osVersionResult.unwrapErr().AsHResult();
  }
  std::string osVersion = osVersionResult.unwrap();

  TelemetryFieldResult osLocaleResult = GetOSLocale();
  if (osLocaleResult.isErr()) {
    return osLocaleResult.unwrapErr().AsHResult();
  }
  std::string osLocale = osLocaleResult.unwrap();

  std::string prevNotificationAction;
  HRESULT hr = ReadPreviousNotificationAction(prevNotificationAction);
  if (FAILED(hr)) {
    return hr;
  }
  // Intentionally discard the result of this write. There's no real reason
  // to abort sending the ping in the error case and it already wrote an error
  // message. So there isn't really anything to do at this point.
  MaybeWritePreviousNotificationAction(activitiesPerformed);

  Cache cache;

  // Do not send the ping if we are not an official telemetry-enabled build;
  // don't even generate the ping in fact, because if we write the file out
  // then some other build might find it later and decide to submit it.
  if (!IsOfficialTelemetry() || IsTelemetryDisabled()) {
    return MaybeCache(cache, notificationType, notificationShown,
                      notificationAction, prevNotificationAction);
  }

  // Pings are limited to one per day (across all installations), so check if we
  // already sent one today.
  // This will also set a registry entry indicating that the last ping was
  // just sent, to prevent another one from being sent today. We'll do this
  // now even though we haven't sent the ping yet. After this check, we send
  // a ping unconditionally. The only exception is for errors, and any error
  // that we get now will probably be hit every time.
  // Because unsent pings attempted with pingsender can get automatically
  // re-sent later, we don't even want to try again on transient network
  // failures.
  BoolResult pingAlreadySentResult = GetPingAlreadySentToday();
  if (pingAlreadySentResult.isErr()) {
    return pingAlreadySentResult.unwrapErr().AsHResult();
  }
  bool pingAlreadySent = pingAlreadySentResult.unwrap();
  if (pingAlreadySent) {
    return MaybeCache(cache, notificationType, notificationShown,
                      notificationAction, prevNotificationAction);
  }

  hr = MaybeSwapForCached(cache, notificationType, notificationShown,
                          notificationAction, prevNotificationAction);
  if (FAILED(hr)) {
    return hr;
  }

  // Don't update the registry's default browser data until we are sure we
  // want to send a ping. Otherwise it could be updated to reflect a ping we
  // never sent.
  TelemetryFieldResult previousDefaultBrowserResult =
      GetAndUpdatePreviousDefaultBrowser(currentDefaultBrowser,
                                         browserInfo.previousDefaultBrowser);
  if (previousDefaultBrowserResult.isErr()) {
    return previousDefaultBrowserResult.unwrapErr().AsHResult();
  }
  std::string previousDefaultBrowser = previousDefaultBrowserResult.unwrap();

  return SendPing(currentDefaultBrowser, previousDefaultBrowser,
                  currentDefaultPdf, osVersion, osLocale, notificationType,
                  notificationShown, notificationAction, prevNotificationAction)
      .AsHResult();
}