/*

 * This file is part of PowerDNS or dnsdist.

 * Copyright -- PowerDNS.COM B.V. and its contributors

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of version 2 of the GNU General Public License as

 * published by the Free Software Foundation.

 *

 * In addition, for the avoidance of any doubt, permission is granted to

 * link this program with OpenSSL and to (re)distribute the binaries

 * produced as the result of such linking.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

 */

#pragma once

#include <array>

#include <fstream>

#include <iomanip>

#include <iostream>

#include <optional>

#include <sstream>

#include "config.h"

#if !defined(RECURSOR)

#include <syslog.h>

#else

#include "logger.hh"

#endif // RECURSOR

/* This file is intended not to be metronome specific, and is simple example of C++2011

   variadic templates in action.

   The goal is rapid easy to use logging to console & syslog.

   Usage:

          string address="localhost";

          vinfolog("Got TCP connection from %s", remote);

          infolog("Bound to %s port %d", address, port);

          warnlog("Query took %d milliseconds", 1232.4); // yes, %d

          errlog("Unable to bind to %s: %s", ca.toStringWithPort(), strerr(errno));

   Will log to stdout. Will syslog in any case with LOG_INFO,

   LOG_WARNING, LOG_ERR respectively. If verbose=false, vinfolog is a noop.

   More generically, dolog(someiostream, "Hello %s", stream) will log to someiostream

   This will happily print a string to %d! Doesn't do further format processing.

*/

template <typename O>

inline void dolog(O& outputStream, const char* str)

{

  outputStream << str;

}

template <typename O, typename T, typename... Args>

void dolog(O& outputStream, const char* formatStr, T value, const Args&... args)

{

  while (*formatStr) {

    if (*formatStr == '%') {

      // NOLINTNEXTLINE(cppcoreguidelines-pro-bounds-pointer-arithmetic)

      if (*(formatStr + 1) == '%') {

        // NOLINTNEXTLINE(cppcoreguidelines-pro-bounds-pointer-arithmetic)

        ++formatStr;

      }

      else {

        outputStream << value;

        // NOLINTNEXTLINE(cppcoreguidelines-pro-bounds-pointer-arithmetic)

        formatStr += 2;

        dolog(outputStream, formatStr, args...);

        return;

      }

    }

    // NOLINTNEXTLINE(cppcoreguidelines-pro-bounds-pointer-arithmetic)

    outputStream << *formatStr++;

  }

}

#if !defined(RECURSOR)

#ifdef DNSDIST

namespace dnsdist::logging

{

class LoggingConfiguration

{

public:

  enum class TimeFormat

  {

    Numeric,

    ISO8601

  };

  static void setSyslog(bool value = true)

  {

    s_syslog = value;

  }

  static void setStructuredLogging(bool value = true, std::string levelPrefix = "")

  {

    s_structuredLogging = value;

    if (value) {

      s_structuredLevelPrefix = levelPrefix.empty() ? "prio" : std::move(levelPrefix);

    }

  }

  static void setLogTimestamps(bool value = true)

  {

    s_logTimestamps = value;

  }

  static void setStructuredTimeFormat(TimeFormat format)

  {

    s_structuredTimeFormat = format;

  }

  static void setVerboseStream(std::ofstream&& stream)

  {

    s_verboseStream = std::move(stream);

  }

  static bool getSyslog()

  {

    return s_syslog;

  }

  static bool getLogTimestamps()

  {

    return s_logTimestamps;

  }

  static std::optional<std::ofstream>& getVerboseStream()

  {

    return s_verboseStream;

  }

  static bool getStructuredLogging()

  {

    return s_structuredLogging;

  }

  static const std::string& getStructuredLoggingLevelPrefix()

  {

    return s_structuredLevelPrefix;

  }

  static TimeFormat getStructuredLoggingTimeFormat()

  {

    return s_structuredTimeFormat;

  }

private:

  static std::optional<std::ofstream> s_verboseStream;

  static std::string s_structuredLevelPrefix;

  static TimeFormat s_structuredTimeFormat;

  static bool s_structuredLogging;

  static bool s_logTimestamps;

  static bool s_syslog;

};

extern void logTime(std::ostream& stream);

}

#endif

inline void setSyslogFacility(int facility)

{

  /* we always call openlog() right away at startup */

  closelog();

  openlog("dnsdist", LOG_PID | LOG_NDELAY, facility);

}

namespace

{

inline const char* syslogLevelToStr(int level)

{

  static constexpr std::array levelStrs{

    "Emergency",

    "Alert",

    "Critical",

    "Error",

    "Warning",

    "Notice",

    "Info",

    "Debug"};

  return levelStrs.at(level);

}

Unexecuted instantiation: dnsdist-cache.cc:(anonymous namespace)::syslogLevelToStr(int)

Unexecuted instantiation: dnsdist-ecs.cc:(anonymous namespace)::syslogLevelToStr(int)

}

template <typename... Args>

void genlog(std::ostream& stream, [[maybe_unused]] int level, [[maybe_unused]] bool skipSyslog, const char* formatStr, const Args&... args)

{

  std::ostringstream str;

  dolog(str, formatStr, args...);

  auto output = str.str();

#ifdef DNSDIST

  if (!skipSyslog && dnsdist::logging::LoggingConfiguration::getSyslog()) {

    // NOLINTNEXTLINE(cppcoreguidelines-pro-type-vararg): syslog is what it is

    syslog(level, "%s", output.c_str());

  }

  if (dnsdist::logging::LoggingConfiguration::getLogTimestamps()) {

    dnsdist::logging::logTime(stream);

  }

  if (dnsdist::logging::LoggingConfiguration::getStructuredLogging()) {

    stream << dnsdist::logging::LoggingConfiguration::getStructuredLoggingLevelPrefix() << "=\"" << syslogLevelToStr(level) << "\" ";

    stream << "msg=" << std::quoted(output) << std::endl;

  }

  else {

    stream << output << std::endl;

  }

#else

  stream << output << std::endl;

#endif

}

template <typename... Args>

void verboselog(const char* formatStr, const Args&... args)

{

#ifdef DNSDIST

  if (auto& stream = dnsdist::logging::LoggingConfiguration::getVerboseStream()) {

    genlog(*stream, LOG_DEBUG, true, formatStr, args...);

  }

  else {

#endif /* DNSDIST */

    genlog(std::cout, LOG_DEBUG, false, formatStr, args...);

#ifdef DNSDIST

  }

#endif /* DNSDIST */

}

#ifdef DNSDIST

#include "dnsdist-configuration.hh"

#define vinfolog                                                          \

  if (dnsdist::configuration::getCurrentRuntimeConfiguration().d_verbose) \

  verboselog

#else

#define vinfolog \

  infolog

#endif

template <typename... Args>

void infolog(const char* formatStr, const Args&... args)

{

  genlog(std::cout, LOG_INFO, false, formatStr, args...);

}

template <typename... Args>

void warnlog(const char* formatStr, const Args&... args)

{

  genlog(std::cout, LOG_WARNING, false, formatStr, args...);

}

template <typename... Args>

void errlog(const char* formatStr, const Args&... args)

{

  genlog(std::cout, LOG_ERR, false, formatStr, args...);

}

#else // RECURSOR

#define vinfolog \

  if (false)     \

  infolog

template <typename... Args>

void infolog(const char* formatStr, const Args&... args)

{

  g_log << Logger::Info;

  dolog(g_log, formatStr, args...);

}

template <typename... Args>

void warnlog(const char* formatStr, const Args&... args)

{

  g_log << Logger::Warning;

  dolog(g_log, formatStr, args...);

}

template <typename... Args>

void errlog(const char* formatStr, const Args&... args)

{

  g_log << Logger::Error;

  dolog(g_log, formatStr, args...);

}

#endif