// Copyright (c) 2006-2013, Andrey N. Sabelnikov, www.sabelnikov.net
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
// * Neither the name of the Andrey N. Sabelnikov nor the
// names of its contributors may be used to endorse or promote products
// derived from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER  BE LIABLE FOR ANY
// DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
// ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//


#ifndef _MLOG_H_
#define _MLOG_H_

#ifdef _WIN32
#include <windows.h>
#ifndef ENABLE_VIRTUAL_TERMINAL_PROCESSING
#define ENABLE_VIRTUAL_TERMINAL_PROCESSING  0x0004
#endif
#endif

#include <ctime>
#include <atomic>
#include <boost/algorithm/string.hpp>
#include "epee/string_tools.h"
#include "epee/misc_os_dependent.h"
#include "epee/misc_log_ex.h"

#ifndef USE_GHC_FILESYSTEM
#include <filesystem>
namespace fs { using namespace std::filesystem; }
#else
#include <ghc/filesystem.hpp>
namespace fs = ghc::filesystem;
#endif

#undef OXEN_DEFAULT_LOG_CATEGORY
#define OXEN_DEFAULT_LOG_CATEGORY "logging"

#define MLOG_BASE_FORMAT "%datetime{%Y-%M-%d %H:%m:%s.%g}\t%thread\t%level\t%logger\t%loc\t%msg"

#define MLOG_LOG(x) CINFO(el::base::Writer,el::base::DispatchAction::FileOnlyLog,OXEN_DEFAULT_LOG_CATEGORY) << x

using namespace epee;

static std::string generate_log_filename(const char *base)
{
  std::string filename(base);
  static unsigned int fallback_counter = 0;
  char tmp[200];
  struct tm tm;
  time_t now = time(NULL);
  if (!epee::misc_utils::get_gmt_time(now, tm))
    snprintf(tmp, sizeof(tmp), "part-%u", ++fallback_counter);
  else
    strftime(tmp, sizeof(tmp), "%Y-%m-%d-%H-%M-%S", &tm);
  tmp[sizeof(tmp) - 1] = 0;
  filename += "-";
  filename += tmp;
  return filename;
}

std::string mlog_get_default_log_path(const char *default_filename)
{
  std::string process_name = epee::string_tools::get_current_module_name();
  std::string default_log_folder = epee::string_tools::get_current_module_folder();
  std::string default_log_file = process_name;
  std::string::size_type a = default_log_file.rfind('.');
  if ( a != std::string::npos )
    default_log_file.erase( a, default_log_file.size());
  if ( ! default_log_file.empty() )
    default_log_file += ".log";
  else
    default_log_file = default_filename;

  return (fs::u8path(default_log_folder) / fs::u8path(default_log_file)).u8string();
}

static void mlog_set_common_prefix()
{
  static const char * const expected_filename = "contrib/epee/src/mlog.cpp";
  const char *path = __FILE__, *expected_ptr = strstr(path, expected_filename);
  if (!expected_ptr)
    return;
  el::Loggers::setFilenameCommonPrefix(std::string(path, expected_ptr - path));
}

static const char *get_default_categories(int level)
{
  const char *categories = "";
  switch (level)
  {
    case 0:
      categories = "*:WARNING,net:FATAL,net.http:FATAL,net.p2p:FATAL,net.cn:FATAL,global:INFO,verify:FATAL,serialization:FATAL,logging:INFO,msgwriter:INFO";
      break;
    case 1:
      categories = "*:INFO,global:INFO,stacktrace:INFO,logging:INFO,msgwriter:INFO,perf.*:DEBUG";
      break;
    case 2:
      categories = "*:DEBUG";
      break;
    case 3:
      categories = "*:TRACE";
      break;
    case 4:
      categories = "*:TRACE";
      break;
    default:
      break;
  }
  return categories;
}

#ifdef WIN32
bool EnableVTMode()
{
  // Set output mode to handle virtual terminal sequences
  HANDLE hOut = GetStdHandle(STD_OUTPUT_HANDLE);
  if (hOut == INVALID_HANDLE_VALUE)
  {
    return false;
  }

  DWORD dwMode = 0;
  if (!GetConsoleMode(hOut, &dwMode))
  {
    return false;
  }

  dwMode |= ENABLE_VIRTUAL_TERMINAL_PROCESSING;
  if (!SetConsoleMode(hOut, dwMode))
  {
    return false;
  }
  return true;
}
#endif

void mlog_configure(const std::string &filename_base, bool console, const std::size_t max_log_file_size, const std::size_t max_log_files)
{
  el::Configurations c;
  c.setGlobally(el::ConfigurationType::Filename, filename_base);
  c.setGlobally(el::ConfigurationType::ToFile, "true");
  const char *log_format = getenv("OXEN_LOG_FORMAT");
  if (!log_format)
    log_format = MLOG_BASE_FORMAT;
  c.setGlobally(el::ConfigurationType::Format, log_format);
  c.setGlobally(el::ConfigurationType::ToStandardOutput, console ? "true" : "false");
  c.setGlobally(el::ConfigurationType::MaxLogFileSize, std::to_string(max_log_file_size));
  el::Loggers::setDefaultConfigurations(c, true);

  el::Loggers::addFlag(el::LoggingFlag::HierarchicalLogging);
  el::Loggers::addFlag(el::LoggingFlag::CreateLoggerAutomatically);
  el::Loggers::addFlag(el::LoggingFlag::DisableApplicationAbortOnFatalLog);
  el::Loggers::addFlag(el::LoggingFlag::ColoredTerminalOutput);
  el::Loggers::addFlag(el::LoggingFlag::StrictLogFileSizeCheck);
  el::Helpers::installPreRollOutCallback([filename_base, max_log_files](const char *name, size_t){
    std::string rname = generate_log_filename(filename_base.c_str());
    int ret = rename(name, rname.c_str());
    if (ret < 0)
    {
      // can't log a failure, but don't do the file removal below
      return;
    }
    if (max_log_files != 0)
    {
      std::vector<fs::path> found_files;
      const auto filename_base_path = fs::u8path(filename_base);
      const auto parent_path = filename_base_path.has_parent_path() ? filename_base_path.parent_path() : fs::path(".");
      for (const auto& p : fs::directory_iterator{parent_path})
      {
        const std::string filename = p.path().u8string();
        if (filename.size() >= filename_base.size() && std::memcmp(filename.data(), filename_base.data(), filename_base.size()) == 0)
          found_files.push_back(p.path());
      }

      if (found_files.size() >= max_log_files)
      {
        std::sort(found_files.begin(), found_files.end(), [](auto& a, auto& b) {
          std::error_code ec;
          return fs::last_write_time(a, ec) < fs::last_write_time(b, ec);
        });
        for (size_t i = 0; i <= found_files.size() - max_log_files; ++i)
        {
          std::error_code ec;
          if (!fs::remove(found_files[i], ec))
            MERROR("Failed to remove " << found_files[i] << ": " << ec.message());
        }
      }
    }
  });
  mlog_set_common_prefix();
  const char *loki_log = getenv("OXEN_LOGS");
  if (!loki_log)
  {
    loki_log = get_default_categories(0);
  }
  mlog_set_log(loki_log);
#ifdef WIN32
  EnableVTMode();
#endif
}

void mlog_set_categories(const char *categories)
{
  std::string new_categories;
  if (*categories)
  {
    if (*categories == '+')
    {
      ++categories;
      new_categories = mlog_get_categories();
      if (*categories)
      {
        if (!new_categories.empty())
          new_categories += ",";
        new_categories += categories;
      }
    }
    else if (*categories == '-')
    {
      ++categories;
      new_categories = mlog_get_categories();
      std::vector<std::string> single_categories;
      boost::split(single_categories, categories, boost::is_any_of(","), boost::token_compress_on);
      for (const std::string &s: single_categories)
      {
        size_t pos = new_categories.find(s);
        if (pos != std::string::npos)
          new_categories = new_categories.erase(pos, s.size());
      }
    }
    else
    {
      new_categories = categories;
    }
  }
  el::Loggers::setCategories(new_categories.c_str(), true);
  MLOG_LOG("New log categories: " << el::Loggers::getCategories());
}

std::string mlog_get_categories()
{
  return el::Loggers::getCategories();
}

// maps epee style log level to new logging system
void mlog_set_log_level(int level)
{
  const char *categories = get_default_categories(level);
  mlog_set_categories(categories);
}

void mlog_set_log(const char *log)
{
  long level;
  char *ptr = NULL;

  if (!*log)
  {
    mlog_set_categories(log);
    return;
  }
  level = strtol(log, &ptr, 10);
  if (ptr && *ptr)
  {
    // we can have a default level, eg, 2,foo:ERROR
    if (*ptr == ',') {
      std::string new_categories = std::string(get_default_categories(level)) + ptr;
      mlog_set_categories(new_categories.c_str());
    }
    else {
      mlog_set_categories(log);
    }
  }
  else if (level >= 0 && level <= 4)
  {
    mlog_set_log_level(level);
  }
  else
  {
    MERROR("Invalid numerical log level: " << log);
  }
}

namespace epee
{

bool is_stdout_a_tty()
{
  static std::atomic<bool> initialized(false);
  static std::atomic<bool> is_a_tty(false);

  if (!initialized.load(std::memory_order_acquire))
  {
#if defined(WIN32)
    is_a_tty.store(0 != _isatty(_fileno(stdout)), std::memory_order_relaxed);
#else
    is_a_tty.store(0 != isatty(fileno(stdout)), std::memory_order_relaxed);
#endif
    initialized.store(true, std::memory_order_release);
  }

  return is_a_tty.load(std::memory_order_relaxed);
}

void set_console_color(int color, bool bright)
{
  if (!is_stdout_a_tty())
    return;

  switch(color)
  {
  case console_color_default:
    {
#ifdef WIN32
      HANDLE h_stdout = GetStdHandle(STD_OUTPUT_HANDLE);
      SetConsoleTextAttribute(h_stdout, FOREGROUND_RED | FOREGROUND_GREEN | FOREGROUND_BLUE| (bright ? FOREGROUND_INTENSITY:0));
#else
      if(bright)
        std::cout << "\033[1;37m";
      else
        std::cout << "\033[0m";
#endif
    }
    break;
  case console_color_white:
    {
#ifdef WIN32
      HANDLE h_stdout = GetStdHandle(STD_OUTPUT_HANDLE);
      SetConsoleTextAttribute(h_stdout, FOREGROUND_RED | FOREGROUND_GREEN | FOREGROUND_BLUE | (bright ? FOREGROUND_INTENSITY:0));
#else
      if(bright)
        std::cout << "\033[1;37m";
      else
        std::cout << "\033[0;37m";
#endif
    }
    break;
  case console_color_red:
    {
#ifdef WIN32
      HANDLE h_stdout = GetStdHandle(STD_OUTPUT_HANDLE);
      SetConsoleTextAttribute(h_stdout, FOREGROUND_RED | (bright ? FOREGROUND_INTENSITY:0));
#else
      if(bright)
        std::cout << "\033[1;31m";
      else
        std::cout << "\033[0;31m";
#endif
    }
    break;
  case console_color_green:
    {
#ifdef WIN32
      HANDLE h_stdout = GetStdHandle(STD_OUTPUT_HANDLE);
      SetConsoleTextAttribute(h_stdout, FOREGROUND_GREEN | (bright ? FOREGROUND_INTENSITY:0));
#else
      if(bright)
        std::cout << "\033[1;32m";
      else
        std::cout << "\033[0;32m";
#endif
    }
    break;

  case console_color_blue:
    {
#ifdef WIN32
      HANDLE h_stdout = GetStdHandle(STD_OUTPUT_HANDLE);
      SetConsoleTextAttribute(h_stdout, FOREGROUND_BLUE | FOREGROUND_INTENSITY);//(bright ? FOREGROUND_INTENSITY:0));
#else
      if(bright)
        std::cout << "\033[1;34m";
      else
        std::cout << "\033[0;34m";
#endif
    }
    break;

  case console_color_cyan:
    {
#ifdef WIN32
      HANDLE h_stdout = GetStdHandle(STD_OUTPUT_HANDLE);
      SetConsoleTextAttribute(h_stdout, FOREGROUND_GREEN | FOREGROUND_BLUE | (bright ? FOREGROUND_INTENSITY:0));
#else
      if(bright)
        std::cout << "\033[1;36m";
      else
        std::cout << "\033[0;36m";
#endif
    }
    break;

  case console_color_magenta:
    {
#ifdef WIN32
      HANDLE h_stdout = GetStdHandle(STD_OUTPUT_HANDLE);
      SetConsoleTextAttribute(h_stdout, FOREGROUND_BLUE | FOREGROUND_RED | (bright ? FOREGROUND_INTENSITY:0));
#else
      if(bright)
        std::cout << "\033[1;35m";
      else
        std::cout << "\033[0;35m";
#endif
    }
    break;

  case console_color_yellow:
    {
#ifdef WIN32
      HANDLE h_stdout = GetStdHandle(STD_OUTPUT_HANDLE);
      SetConsoleTextAttribute(h_stdout, FOREGROUND_RED | FOREGROUND_GREEN | (bright ? FOREGROUND_INTENSITY:0));
#else
      if(bright)
        std::cout << "\033[1;33m";
      else
        std::cout << "\033[0;33m";
#endif
    }
    break;

  }
}

void reset_console_color() {
  if (!is_stdout_a_tty())
    return;

#ifdef WIN32
  HANDLE h_stdout = GetStdHandle(STD_OUTPUT_HANDLE);
  SetConsoleTextAttribute(h_stdout, FOREGROUND_RED | FOREGROUND_GREEN | FOREGROUND_BLUE);
#else
  std::cout << "\033[0m";
  std::cout.flush();
#endif
}

}

static bool mlog(el::Level level, const char *category, const char *format, va_list ap) noexcept
{
  int size = 0;
  char *p = NULL;
  va_list apc;
  bool ret = true;

  /* Determine required size */
  va_copy(apc, ap);
  size = vsnprintf(p, size, format, apc);
  va_end(apc);
  if (size < 0)
    return false;

  size++;             /* For '\0' */
  p = (char*)malloc(size);
  if (p == NULL)
    return false;

  size = vsnprintf(p, size, format, ap);
  if (size < 0)
  {
    free(p);
    return false;
  }

  try
  {
    /* TODO(loki): when pulling upstream epee changes change this to:
    MCLOG(level, category, el::Color::Default, p);
    */
    MCLOG(level, category, p);
  }
  catch(...)
  {
    ret = false;
  }
  free(p);

  return ret;
}

#define DEFLOG(fun,lev) \
  bool m##fun(const char *category, const char *fmt, ...) { va_list ap; va_start(ap, fmt); bool ret = mlog(el::Level::lev, category, fmt, ap); va_end(ap); return ret; }

DEFLOG(error, Error)
DEFLOG(warning, Warning)
DEFLOG(info, Info)
DEFLOG(debug, Debug)
DEFLOG(trace, Trace)

#undef DEFLOG

#endif //_MLOG_H_