#include <iostream>
#include <exception>
#include <stdexcept>
#include <string>

#include <locale.h>

#include <QDateTime>
#include <QApplication>
#include <QNetworkAccessManager>
#include <QRegularExpression>
#include <QObject>
#include <QSettings>
#include <QLibraryInfo>
#include <QSysInfo>
#include <QDir>
#include <QStandardPaths>
#include <QStringList>
#include <QMessageBox>
#include <QLockFile>

#if QT_VERSION >= 0x050200
#include <QCommandLineParser>
#include <QCommandLineOption>
#endif

#include "revision_utils.hpp"
#include "MetaDataRegistry.hpp"
#include "SettingsGroup.hpp"
#include "TraceFile.hpp"
#include "mainwindow.h"
#include "commons.h"
#include "lib/init_random_seed.h"

namespace
{
  struct RNGSetup
  {
    RNGSetup ()
    {
      // one time seed of pseudo RNGs from current time
      auto seed = QDateTime::currentMSecsSinceEpoch ();
      qsrand (seed);            // this is good for rand() as well
    }
  } seeding;
}

int main(int argc, char *argv[])
{
  init_random_seed ();

  register_types ();            // make the Qt magic happen

  // Multiple instances:
  QSharedMemory mem_jt9;

  QApplication a(argc, argv);
  try
    {
      setlocale (LC_NUMERIC, "C"); // ensure number forms are in
                                   // consistent format, do this after
                                   // instantiating QApplication so
                                   // that GUI has correct l18n

      // Override programs executable basename as application name.
      a.setApplicationName ("WSJT-X");
      a.setApplicationVersion (version ());
      bool multiple {false};

#if QT_VERSION >= 0x050200
      QCommandLineParser parser;
      parser.setApplicationDescription ("\nJT65A & JT9 Weak Signal Communications Program.");
      auto help_option = parser.addHelpOption ();
      auto version_option = parser.addVersionOption ();

      // support for multiple instances running from a single installation
      QCommandLineOption rig_option (QStringList {} << "r" << "rig-name"
                                     , a.translate ("main", "Where <rig-name> is for multi-instance support.")
                                     , a.translate ("main", "rig-name"));
      parser.addOption (rig_option);

      QCommandLineOption test_option (QStringList {} << "test-mode"
                                      , a.translate ("main", "Writable files in test location.  Use with caution, for testing only."));
      parser.addOption (test_option);

      if (!parser.parse (a.arguments ()))
        {
          QMessageBox::critical (nullptr, a.applicationName (), parser.errorText ());
          return -1;
        }
      else
        {
          if (parser.isSet (help_option))
            {
              QMessageBox::information (nullptr, a.applicationName (), parser.helpText ());
              return 0;
            }
          else if (parser.isSet (version_option))
            {
              QMessageBox::information (nullptr, a.applicationName (), a.applicationVersion ());
              return 0;
            }
        }

      QStandardPaths::setTestModeEnabled (parser.isSet (test_option));

      // support for multiple instances running from a single installation
      if (parser.isSet (rig_option) || parser.isSet (test_option))
        {
          auto temp_name = parser.value (rig_option);
          if (!temp_name.isEmpty ())
            {
              if (temp_name.contains (QRegularExpression {R"([\\/,])"}))
                {
                  std::cerr << QObject::tr ("Invalid rig name - \\ & / not allowed").toLocal8Bit ().data () << std::endl;
                  parser.showHelp (-1);
                }
                
              a.setApplicationName (a.applicationName () + " - " + temp_name);
            }

          if (parser.isSet (test_option))
            {
              a.setApplicationName (a.applicationName () + " - test");
            }

          multiple = true;
        }

      // disallow multiple instances with same instance key
      QLockFile instance_lock {QDir {QStandardPaths::writableLocation (QStandardPaths::TempLocation)}.absoluteFilePath (a.applicationName () + ".lock")};
      instance_lock.setStaleLockTime (0);
      auto ok = false;
      while (!(ok = instance_lock.tryLock ()))
        {
          if (QLockFile::LockFailedError == instance_lock.error ())
            {
              auto button = QMessageBox::question (nullptr
                                                   , QApplication::applicationName ()
                                                   , QObject::tr ("Another instance may be running, try to remove stale lock file?")
                                                   , QMessageBox::Yes | QMessageBox::Retry | QMessageBox::No
                                                   , QMessageBox::Yes);
              switch (button)
                {
                case QMessageBox::Yes:
                  instance_lock.removeStaleLockFile ();
                  break;

                case QMessageBox::Retry:
                  break;

                default:
                  throw std::runtime_error {"Multiple instances must have unique rig names"};
                }
            }
        }
#endif

      auto config_directory = QStandardPaths::writableLocation (QStandardPaths::ConfigLocation);
      QDir config_path {config_directory}; // will be "." if config_directory is empty
      if (!config_path.mkpath ("."))
        {
          throw std::runtime_error {"Cannot find a usable configuration path \"" + config_path.path ().toStdString () + '"'};
        }

      auto settings_file = config_path.absoluteFilePath (a.applicationName () + ".ini");
      QSettings settings(settings_file, QSettings::IniFormat);
      if (!settings.isWritable ())
        {
          throw std::runtime_error {QString {"Cannot access \"%1\" for writing"}.arg (settings_file).toStdString ()};
        }

#if WSJT_QDEBUG_TO_FILE
      // // open a trace file
      TraceFile trace_file {QDir {QStandardPaths::writableLocation (QStandardPaths::TempLocation)}.absoluteFilePath (a.applicationName () + "_trace.log")};

      // announce to trace file
      qDebug () << program_title (revision ()) + " - Program startup";
#endif

      // Create and initialize shared memory segment
      // Multiple instances: use rig_name as shared memory key
      mem_jt9.setKey(a.applicationName ());

      if(!mem_jt9.attach()) {
        if (!mem_jt9.create(sizeof(struct dec_data))) {
          QMessageBox::critical (nullptr, "Error", "Unable to create shared memory segment.");
          exit(1);
        }
      }
      memset(mem_jt9.data(),0,sizeof(struct dec_data)); //Zero all decoding params in shared memory

      unsigned downSampleFactor;
      {
        SettingsGroup {&settings, "Tune"};

        // deal with Windows Vista and earlier input audio rate
        // converter problems
        downSampleFactor = settings.value ("Audio/DisableInputResampling",
#if defined (Q_OS_WIN)
                                           // default to true for
                                           // Windows Vista and older
                                           QSysInfo::WV_VISTA >= QSysInfo::WindowsVersion ? true : false
#else
                                           false
#endif
                                           ).toBool () ? 1u : 4u;
      }

      MainWindow w(multiple, &settings, &mem_jt9, downSampleFactor, new QNetworkAccessManager {&a});
      w.show();

      QObject::connect (&a, SIGNAL (lastWindowClosed()), &a, SLOT (quit()));
      return a.exec();
    }
  catch (std::exception const& e)
    {
      QMessageBox::critical (nullptr, a.applicationName (), e.what ());
      std::cerr << "Error: " << e.what () << '\n';
    }
  catch (...)
    {
      QMessageBox::critical (nullptr, a.applicationName (), QObject::tr ("Unexpected error"));
      std::cerr << "Unexpected error\n";
      throw;			// hoping the runtime might tell us more about the exception
    }
  return -1;
}