/// \file config.cpp
/// Contains generic functions for managing configuration.

#include "config.h"
#include "defines.h"
#include "stream.h"
#include "timing.h"
#include "tinythread.h"
#include <signal.h>
#include <string.h>

#ifdef __CYGWIN__
#include <windows.h>
#endif

#if defined(__FreeBSD__) || defined(__APPLE__) || defined(__MACH__)
#include <sys/wait.h>
#else
#include <wait.h>
#endif
#if defined(__APPLE__)
#include <mach-o/dyld.h>
#endif
#include "procs.h"
#include <dirent.h> //for getMyExec
#include <errno.h>
#include <fcntl.h>
#include <fstream>
#include <getopt.h>
#include <iostream>
#include <pwd.h>
#include <signal.h>
#include <stdlib.h>
#include <sys/types.h>
#include <unistd.h>
#include <stdarg.h> // for va_list

bool Util::Config::is_active = false;
bool Util::Config::is_restarting = false;
static Socket::Server *serv_sock_pointer = 0;
uint32_t Util::Config::printDebugLevel = DEBUG; //
std::string Util::Config::streamName;
char Util::exitReason[256] = {0};

void Util::logExitReason(const char *format, ...){
  if (exitReason[0]){return;}
  va_list args;
  va_start(args, format);
  vsnprintf(exitReason, 255, format, args);
  va_end(args);
}

std::string Util::listenInterface;
uint32_t Util::listenPort = 0;

Util::Config::Config(){
  // global options here
  vals["debug"]["long"] = "debug";
  vals["debug"]["short"] = "g";
  vals["debug"]["arg"] = "integer";
  vals["debug"]["help"] = "The debug level at which messages need to be printed.";
  vals["debug"]["value"].append((int64_t)DEBUG);
}

/// Creates a new configuration manager.
Util::Config::Config(std::string cmd){
  vals.null();
  long_count = 2;
  vals["cmd"]["value"].append(cmd);
  vals["version"]["long"] = "version";
  vals["version"]["short"] = "v";
  vals["version"]["help"] = "Display library and application version, then exit.";
  vals["help"]["long"] = "help";
  vals["help"]["short"] = "h";
  vals["help"]["help"] = "Display usage and version information, then exit.";
  vals["debug"]["long"] = "debug";
  vals["debug"]["short"] = "g";
  vals["debug"]["arg"] = "integer";
  vals["debug"]["help"] = "The debug level at which messages need to be printed.";
  vals["debug"]["value"].append((int64_t)DEBUG);
}

/// Adds an option to the configuration parser.
/// The option needs an unique name (doubles will overwrite the previous) and can contain the
/// following in the option itself:
///\code
///{
///   "short":"o",          //The short option letter
///   "long":"onName",      //The long option
///   "arg":"integer",      //The type of argument, if required.
///   "value":[],           //The default value(s) for this option if it is not given on the
///   commandline. "arg_num":1,          //The count this value has on the commandline, after all
///   the options have been processed. "help":"Blahblahblah" //The helptext for this option.
///}
///\endcode
void Util::Config::addOption(std::string optname, JSON::Value option){
  vals[optname] = option;
  if (!vals[optname].isMember("value") && vals[optname].isMember("default")){
    vals[optname]["value"].append(vals[optname]["default"]);
    vals[optname].removeMember("default");
  }
  long_count = 0;
  jsonForEach(vals, it){
    if (it->isMember("long")){long_count++;}
  }
}

/// Prints a usage message to the given output.
void Util::Config::printHelp(std::ostream &output){
  unsigned int longest = 0;
  std::map<long long int, std::string> args;
  jsonForEach(vals, it){
    unsigned int current = 0;
    if (it->isMember("long")){current += (*it)["long"].asString().size() + 4;}
    if (it->isMember("short")){current += (*it)["short"].asString().size() + 3;}
    if (current > longest){longest = current;}
    current = 0;
    if (current > longest){longest = current;}
    if (it->isMember("arg_num")){
      current = it.key().size() + 3;
      if (current > longest){longest = current;}
      args[(*it)["arg_num"].asInt()] = it.key();
    }
  }
  output << "Usage: " << getString("cmd") << " [options]";
  for (std::map<long long int, std::string>::iterator i = args.begin(); i != args.end(); i++){
    if (vals[i->second].isMember("value") && vals[i->second]["value"].size()){
      output << " [" << i->second << "]";
    }else{
      output << " " << i->second;
    }
  }
  output << std::endl << std::endl;
  jsonForEach(vals, it){
    std::string f;
    if (it->isMember("long") || it->isMember("short")){
      if (it->isMember("long") && it->isMember("short")){
        f = "--" + (*it)["long"].asString() + ", -" + (*it)["short"].asString();
      }else{
        if (it->isMember("long")){f = "--" + (*it)["long"].asString();}
        if (it->isMember("short")){f = "-" + (*it)["short"].asString();}
      }
      while (f.size() < longest){f.append(" ");}
      if (it->isMember("arg")){
        output << f << "(" << (*it)["arg"].asString() << ") " << (*it)["help"].asString() << std::endl;
      }else{
        output << f << (*it)["help"].asString() << std::endl;
      }
    }
    if (it->isMember("arg_num")){
      f = it.key();
      while (f.size() < longest){f.append(" ");}
      output << f << "(" << (*it)["arg"].asString() << ") " << (*it)["help"].asString() << std::endl;
    }
  }
}

/// Parses commandline arguments.
/// Calls exit if an unknown option is encountered, printing a help message.
bool Util::Config::parseArgs(int &argc, char **&argv){
  int opt = 0;
  std::string shortopts;
  struct option *longOpts = (struct option *)calloc(long_count + 1, sizeof(struct option));
  int long_i = 0;
  int arg_count = 0;
  if (vals.size()){
    jsonForEach(vals, it){
      if (it->isMember("short")){
        shortopts += (*it)["short"].asString();
        if (it->isMember("arg")){shortopts += ":";}
      }
      if (it->isMember("long")){
        longOpts[long_i].name = (*it)["long"].asStringRef().c_str();
        longOpts[long_i].val = (*it)["short"].asString()[0];
        if (it->isMember("arg")){longOpts[long_i].has_arg = 1;}
        long_i++;
      }
      if (it->isMember("arg_num") && !(it->isMember("value") && (*it)["value"].size())){
        if ((*it)["arg_num"].asInt() > arg_count){arg_count = (*it)["arg_num"].asInt();}
      }
    }
  }

  while ((opt = getopt_long(argc, argv, shortopts.c_str(), longOpts, 0)) != -1){
    switch (opt){
    case 'h':
    case '?': printHelp(std::cout);
    case 'v': std::cout << "Version: " PACKAGE_VERSION ", release " RELEASE << std::endl;
#ifdef NOCRASHCHECK
      std::cout << "- Flag: No crash check. Will not attempt to detect and kill crashed processes."
                << std::endl;
#endif
#ifndef SHM_ENABLED
      std::cout << "- Flag: Shared memory disabled. Will use shared files in stead of shared "
                   "memory as IPC method."
                << std::endl;
#endif
#ifdef WITH_THREADNAMES
      std::cout << "- Flag: With threadnames. Debuggers will show sensible human-readable thread "
                   "names."
                << std::endl;
#endif
/*LTS-START*/
#ifndef UPDATER
      std::cout << "- Flag: Updater disabled. Server will not call back home and attempt to search "
                   "for updates at regular intervals."
                << std::endl;
#endif
#ifdef NOAUTH
      std::cout << "- Flag: No authentication. API calls do not require logging in with a valid "
                   "account first. Make sure access to API port isn't public!"
                << std::endl;
#endif
#ifdef KILLONEXIT
      std::cout << "- Flag: Kill on exit. All binaries will forcibly shut down all their children "
                   "on exit. This disabled rolling restart support."
                << std::endl;
#endif
#ifdef STATS_DELAY
      if (STATS_DELAY != 15){
        std::cout << "- Setting: Stats delay " << STATS_DELAY << ". Statistics of viewer counts are delayed by "
                  << STATS_DELAY << " seconds as opposed to the default of 15 seconds. ";
        if (STATS_DELAY > 15){
          std::cout << "This makes them more accurate." << std::endl;
        }else{
          std::cout << "This makes them less accurate." << std::endl;
        }
      }
#endif
      /*LTS-END*/
      std::cout << "Built on " __DATE__ ", " __TIME__ << std::endl;
      exit(0);
      break;
    default:
      jsonForEach(vals, it){
        if (it->isMember("short") && (*it)["short"].asString()[0] == opt){
          if (it->isMember("arg")){
            (*it)["value"].append(optarg);
          }else{
            (*it)["value"].append((int64_t)1);
          }
          break;
        }
      }
      break;
    }
  }// commandline options parser
  free(longOpts);         // free the long options array
  long_i = 1;             // re-use long_i as an argument counter
  while (optind < argc){// parse all remaining options, ignoring anything unexpected.
    jsonForEach(vals, it){
      if (it->isMember("arg_num") && (*it)["arg_num"].asInt() == long_i){
        (*it)["value"].append((std::string)argv[optind]);
        break;
      }
    }
    optind++;
    long_i++;
  }
  if (long_i <= arg_count){return false;}
  printDebugLevel = getInteger("debug");
  return true;
}

bool Util::Config::hasOption(const std::string &optname){
  return vals.isMember(optname);
}

/// Returns a reference to the current value of an option or default if none was set.
/// If the option does not exist, this exits the application with a return code of 37.
JSON::Value &Util::Config::getOption(std::string optname, bool asArray){
  if (!vals.isMember(optname)){
    std::cout << "Fatal error: a non-existent option '" << optname << "' was accessed." << std::endl;
    exit(37);
  }
  if (!vals[optname].isMember("value") || !vals[optname]["value"].isArray()){
    vals[optname]["value"].append(JSON::Value());
    vals[optname]["value"].shrink(0);
  }
  if (asArray){return vals[optname]["value"];}
  int n = vals[optname]["value"].size();
  if (!n){
    static JSON::Value empty = "";
    return empty;
  }
  return vals[optname]["value"][n - 1];
}

/// Returns the current value of an option or default if none was set as a string.
/// Calls getOption internally.
std::string Util::Config::getString(std::string optname){
  return getOption(optname).asString();
}

/// Returns the current value of an option or default if none was set as a long long int.
/// Calls getOption internally.
int64_t Util::Config::getInteger(std::string optname){
  return getOption(optname).asInt();
}

/// Returns the current value of an option or default if none was set as a bool.
/// Calls getOption internally.
bool Util::Config::getBool(std::string optname){
  return getOption(optname).asBool();
}

struct callbackData{
  Socket::Connection *sock;
  int (*cb)(Socket::Connection &);
};

static void callThreadCallback(void *cDataArg){
  INSANE_MSG("Thread for %p started", cDataArg);
  callbackData *cData = (callbackData *)cDataArg;
  cData->cb(*(cData->sock));
  cData->sock->close();
  delete cData->sock;
  delete cData;
  INSANE_MSG("Thread for %p ended", cDataArg);
}

int Util::Config::threadServer(Socket::Server &server_socket, int (*callback)(Socket::Connection &)){
  Util::Procs::socketList.insert(server_socket.getSocket());
  while (is_active && server_socket.connected()){
    Socket::Connection S = server_socket.accept();
    if (S.connected()){// check if the new connection is valid
      callbackData *cData = new callbackData;
      cData->sock = new Socket::Connection(S);
      cData->cb = callback;
      // spawn a new thread for this connection
      tthread::thread T(callThreadCallback, (void *)cData);
      // detach it, no need to keep track of it anymore
      T.detach();
      HIGH_MSG("Spawned new thread for socket %i", S.getSocket());
    }else{
      Util::sleep(10); // sleep 10ms
    }
  }
  Util::Procs::socketList.erase(server_socket.getSocket());
  server_socket.close();
  return 0;
}

int Util::Config::forkServer(Socket::Server &server_socket, int (*callback)(Socket::Connection &)){
  Util::Procs::socketList.insert(server_socket.getSocket());
  while (is_active && server_socket.connected()){
    Socket::Connection S = server_socket.accept();
    if (S.connected()){// check if the new connection is valid
      pid_t myid = fork();
      if (myid == 0){// if new child, start MAINHANDLER
        server_socket.drop();
        return callback(S);
      }else{// otherwise, do nothing or output debugging text
        HIGH_MSG("Forked new process %i for socket %i", (int)myid, S.getSocket());
        S.drop();
      }
    }else{
      Util::sleep(10); // sleep 10ms
    }
  }
  Util::Procs::socketList.erase(server_socket.getSocket());
  if (!is_restarting){server_socket.close();}
  return 0;
}

int Util::Config::serveThreadedSocket(int (*callback)(Socket::Connection &)){
  Socket::Server server_socket;
  if (Socket::checkTrueSocket(0)){
    server_socket = Socket::Server(0);
  }else if (vals.isMember("socket")){
    server_socket = Socket::Server(Util::getTmpFolder() + getString("socket"));
  }else if (vals.isMember("port") && vals.isMember("interface")){
    server_socket = Socket::Server(getInteger("port"), getString("interface"), false);
  }
  if (!server_socket.connected()){
    DEVEL_MSG("Failure to open socket");
    return 1;
  }
  Socket::getSocketName(server_socket.getSocket(), Util::listenInterface, Util::listenPort);
  serv_sock_pointer = &server_socket;
  activate();
  if (server_socket.getSocket()){
    int oldSock = server_socket.getSocket();
    if (!dup2(oldSock, 0)){
      server_socket = Socket::Server(0);
      close(oldSock);
    }
  }
  int r = threadServer(server_socket, callback);
  serv_sock_pointer = 0;
  return r;
}

int Util::Config::serveForkedSocket(int (*callback)(Socket::Connection &S)){
  Socket::Server server_socket;
  if (Socket::checkTrueSocket(0)){
    server_socket = Socket::Server(0);
  }else if (vals.isMember("socket")){
    server_socket = Socket::Server(Util::getTmpFolder() + getString("socket"));
  }else if (vals.isMember("port") && vals.isMember("interface")){
    server_socket = Socket::Server(getInteger("port"), getString("interface"), false);
  }
  if (!server_socket.connected()){
    DEVEL_MSG("Failure to open socket");
    return 1;
  }
  Socket::getSocketName(server_socket.getSocket(), Util::listenInterface, Util::listenPort);
  serv_sock_pointer = &server_socket;
  activate();
  if (server_socket.getSocket()){
    int oldSock = server_socket.getSocket();
    if (!dup2(oldSock, 0)){
      server_socket = Socket::Server(0);
      close(oldSock);
    }
  }
  int r = forkServer(server_socket, callback);
  serv_sock_pointer = 0;
  return r;
}

/// Activated the stored config. This will:
/// - Drop permissions to the stored "username", if any.
/// - Set is_active to true.
/// - Set up a signal handler to set is_active to false for the SIGINT, SIGHUP and SIGTERM signals.
void Util::Config::activate(){
  if (vals.isMember("username")){
    setUser(getString("username"));
    vals.removeMember("username");
  }
  struct sigaction new_action;
  struct sigaction cur_action;
  new_action.sa_sigaction = signal_handler;
  sigemptyset(&new_action.sa_mask);
  new_action.sa_flags = SA_SIGINFO;
  sigaction(SIGINT, &new_action, NULL);
  sigaction(SIGHUP, &new_action, NULL);
  sigaction(SIGTERM, &new_action, NULL);
  sigaction(SIGPIPE, &new_action, NULL);
  sigaction(SIGFPE, &new_action, NULL);
  // check if a child signal handler isn't set already, if so, set it.
  sigaction(SIGCHLD, 0, &cur_action);
  if (cur_action.sa_handler == SIG_DFL || cur_action.sa_handler == SIG_IGN){
    sigaction(SIGCHLD, &new_action, NULL);
  }
  is_active = true;
}

/// Basic signal handler. Sets is_active to false if it receives
/// a SIGINT, SIGHUP or SIGTERM signal, reaps children for the SIGCHLD
/// signal, and ignores all other signals.
void Util::Config::signal_handler(int signum, siginfo_t *sigInfo, void *ignore){
  switch (signum){
  case SIGINT: // these three signals will set is_active to false.
  case SIGHUP:
  case SIGTERM:
    if (serv_sock_pointer){serv_sock_pointer->close();}
#if DEBUG >= DLVL_DEVEL
    static int ctr = 0;
    if (!is_active && ++ctr > 4){BACKTRACE;}
#endif
    switch (sigInfo->si_code){
    case SI_USER:
    case SI_QUEUE:
    case SI_TIMER:
    case SI_ASYNCIO:
    case SI_MESGQ:
      logExitReason("signal %s (%d) from process %d", strsignal(signum), signum, sigInfo->si_pid);
      break;
    default: logExitReason("signal %s (%d)", strsignal(signum), signum);
    }
    is_active = false;
  default:
    switch (sigInfo->si_code){
    case SI_USER:
    case SI_QUEUE:
    case SI_TIMER:
    case SI_ASYNCIO:
    case SI_MESGQ:
      INFO_MSG("Received signal %s (%d) from process %d", strsignal(signum), signum, sigInfo->si_pid);
      break;
    default: INFO_MSG("Received signal %s (%d)", strsignal(signum), signum); break;
    }
    break;
  case SIGCHLD:{// when a child dies, reap it.
    int status;
    pid_t ret = -1;
    while (ret != 0){
      ret = waitpid(-1, &status, WNOHANG);
      if (ret < 0 && errno != EINTR){break;}
    }
    HIGH_MSG("Received signal %s (%d) from process %d", strsignal(signum), signum, sigInfo->si_pid);
    break;
  }
  case SIGPIPE:
    // We ignore SIGPIPE to prevent messages triggering another SIGPIPE.
    // Loops are bad, m'kay?
    break;
  case SIGFPE: break;
  }
}// signal_handler

/// Adds the options from the given JSON capabilities structure.
/// Recurses into optional and required, added options as needed.
void Util::Config::addOptionsFromCapabilities(const JSON::Value &capa){
  // First add the required options.
  if (capa.isMember("required") && capa["required"].size()){
    jsonForEachConst(capa["required"], it){
      if (!it->isMember("short") || !it->isMember("option") || !it->isMember("type")){
        FAIL_MSG("Incomplete required option: %s", it.key().c_str());
        continue;
      }
      JSON::Value opt;
      opt["short"] = (*it)["short"];
      opt["long"] = (*it)["option"].asStringRef().substr(2);
      if (it->isMember("type")){
        // int, uint, debug, select, str
        if ((*it)["type"].asStringRef() == "int" || (*it)["type"].asStringRef() == "uint"){
          opt["arg"] = "integer";
        }else{
          opt["arg"] = "string";
        }
      }
      if (it->isMember("default")){opt["value"].append((*it)["default"]);}
      opt["help"] = (*it)["help"];
      addOption(it.key(), opt);
    }
  }
  // Then, the optionals.
  if (capa.isMember("optional") && capa["optional"].size()){
    jsonForEachConst(capa["optional"], it){
      if (it.key() == "debug"){continue;}
      if (!it->isMember("short") || !it->isMember("option") || !it->isMember("default")){
        FAIL_MSG("Incomplete optional option: %s", it.key().c_str());
        continue;
      }
      JSON::Value opt;
      opt["short"] = (*it)["short"];
      opt["long"] = (*it)["option"].asStringRef().substr(2);
      if (it->isMember("type")){
        // int, uint, debug, select, str
        if ((*it)["type"].asStringRef() == "int" || (*it)["type"].asStringRef() == "uint"){
          opt["arg"] = "integer";
        }else{
          opt["arg"] = "string";
        }
      }
      if (it->isMember("default")){opt["value"].append((*it)["default"]);}
      opt["help"] = (*it)["help"];
      addOption(it.key(), opt);
    }
  }
}

/// Adds the default connector options. Also updates the capabilities structure with the default
/// options. Besides the options addBasicConnectorOptions adds, this function also adds port and
/// interface options.
void Util::Config::addConnectorOptions(int port, JSON::Value &capabilities){
  capabilities["optional"]["port"]["name"] = "TCP port";
  capabilities["optional"]["port"]["help"] = "TCP port to listen on";
  capabilities["optional"]["port"]["type"] = "uint";
  capabilities["optional"]["port"]["short"] = "p";
  capabilities["optional"]["port"]["option"] = "--port";
  capabilities["optional"]["port"]["default"] = (int64_t)port;

  capabilities["optional"]["interface"]["name"] = "Interface";
  capabilities["optional"]["interface"]["help"] = "Address of the interface to listen on";
  capabilities["optional"]["interface"]["default"] = "0.0.0.0";
  capabilities["optional"]["interface"]["option"] = "--interface";
  capabilities["optional"]["interface"]["short"] = "i";
  capabilities["optional"]["interface"]["type"] = "str";

  addBasicConnectorOptions(capabilities);
}// addConnectorOptions

/// Adds the default connector options. Also updates the capabilities structure with the default
/// options.
void Util::Config::addBasicConnectorOptions(JSON::Value &capabilities){
  capabilities["optional"]["username"]["name"] = "Username";
  capabilities["optional"]["username"]["help"] =
      "Username to drop privileges to - default if unprovided means do not drop privileges";
  capabilities["optional"]["username"]["option"] = "--username";
  capabilities["optional"]["username"]["short"] = "u";
  capabilities["optional"]["username"]["default"] = "root";
  capabilities["optional"]["username"]["type"] = "str";

  addOptionsFromCapabilities(capabilities);

  JSON::Value option;
  option["long"] = "json";
  option["short"] = "j";
  option["help"] = "Output connector info in JSON format, then exit.";
  option["value"].append((int64_t)0);
  addOption("json", option);
}

/// Gets directory the current executable is stored in.
std::string Util::getMyPath(){
  char mypath[500];
#ifdef __CYGWIN__
  GetModuleFileName(0, mypath, 500);
#else
#ifdef __APPLE__
  memset(mypath, 0, 500);
  unsigned int refSize = 500;
  int ret = _NSGetExecutablePath(mypath, &refSize);
#else
  int ret = readlink("/proc/self/exe", mypath, 500);
  if (ret != -1){
    mypath[ret] = 0;
  }else{
    mypath[0] = 0;
  }
#endif
#endif
  std::string tPath = mypath;
  size_t slash = tPath.rfind('/');
  if (slash == std::string::npos){
    slash = tPath.rfind('\\');
    if (slash == std::string::npos){return "";}
  }
  tPath.resize(slash + 1);
  return tPath;
}

/// Gets all executables in getMyPath that start with "Mist".
void Util::getMyExec(std::deque<std::string> &execs){
  std::string path = Util::getMyPath();
#ifdef __CYGWIN__
  path += "\\Mist*";
  WIN32_FIND_DATA FindFileData;
  HANDLE hdl = FindFirstFile(path.c_str(), &FindFileData);
  while (hdl != INVALID_HANDLE_VALUE){
    execs.push_back(FindFileData.cFileName);
    if (!FindNextFile(hdl, &FindFileData)){
      FindClose(hdl);
      hdl = INVALID_HANDLE_VALUE;
    }
  }
#else
  DIR *d = opendir(path.c_str());
  if (!d){return;}
  struct dirent *dp;
  do{
    errno = 0;
    if ((dp = readdir(d))){
      if (strncmp(dp->d_name, "Mist", 4) == 0){execs.push_back(dp->d_name);}
    }
  }while (dp != NULL);
  closedir(d);
#endif
}

/// Sets the current process' running user
void Util::setUser(std::string username){
  if (username != "root"){
    struct passwd *user_info = getpwnam(username.c_str());
    if (!user_info){
      ERROR_MSG("Error: could not setuid %s: could not get PID", username.c_str());
      return;
    }else{
      if (setuid(user_info->pw_uid) != 0){
        ERROR_MSG("Error: could not setuid %s: not allowed", username.c_str());
      }else{
        DEVEL_MSG("Change user to %s", username.c_str());
      }
    }
  }
}