/*
 *  gcsd
 *
 *  gcsd the generic command sequencer daemon can be used to serialize
 *  commands sent over various paralell communication channels to a
 *  single command output. It can be seen as a multiplexer for any
 *  kind of communication between a single resource and various clients
 *  which want to submit commands to it or query information from it.
 *  gcsd is written in C and Lua. The goal is to provide an easy to
 *  understand high level API based on Lua which can be used to
 *  implement the business logic of the so formed multiplexer daemon.
 *
 *
 *  Copyright (C) 2009-2010 Markus Grueneis <gimpf@spreadspace.org>
 *                          Christian Pointner <equinox@spreadspace.org>
 *
 *  This file is part of gcsd.
 *
 *  gcsd is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  any later version.
 *
 *  gcsd 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 gcsd. If not, see <http://www.gnu.org/licenses/>.
 */

#include <stdlib.h>
#include <stdio.h>
#include <errno.h>

#include <lua.h>
#include <lualib.h>
#include <lauxlib.h>

#include "datatypes.h"
#include "config.h"
#include "options.h"
#include "string_list.h"
#include "log.h"
#include "l_rawio.h"
#include "l_tcp.h"
#include "l_util.h"
#include "l_timer.h"
#include "l_log.h"
#include "l_sig_handler.h"

#ifndef WINVER
#include "daemon.h"
#endif

extern const char gcsd_lua_bytecode[];
extern const size_t gcsd_lua_bytecode_len;

#define LUA_MAIN_LOOP_FUNC "main_loop"

#if LUA_VERSION_NUM > 501
static const luaL_Reg gcsd_lualibs[] = {
  {"_G", luaopen_base},
  {LUA_LOADLIBNAME, luaopen_package},
  {LUA_TABLIBNAME, luaopen_table},
  {LUA_STRLIBNAME, luaopen_string},
  {LUA_MATHLIBNAME, luaopen_math},
  {LUA_RAWIOLIBNAME, luaopen_rawio},
  {LUA_TCPLIBNAME, luaopen_tcp},
  {LUA_UTILLIBNAME, luaopen_util},
  {LUA_TIMERLIBNAME, luaopen_timer},
  {LUA_LOGLIBNAME, luaopen_log},
  {LUA_SIGNALLIBNAME, luaopen_signal},
  {NULL, NULL}
};
#else
static const luaL_Reg gcsd_lualibs[] = {
  {"", luaopen_base},
  {LUA_LOADLIBNAME, luaopen_package},
  {LUA_TABLIBNAME, luaopen_table},
  {LUA_STRLIBNAME, luaopen_string},
  {LUA_MATHLIBNAME, luaopen_math},
  {LUA_RAWIOLIBNAME, luaopen_rawio},
  {LUA_TCPLIBNAME, luaopen_tcp},
  {LUA_UTILLIBNAME, luaopen_util},
  {LUA_TIMERLIBNAME, luaopen_timer},
  {LUA_LOGLIBNAME, luaopen_log},
  {LUA_SIGNALLIBNAME, luaopen_signal},
  {NULL, NULL}
};
#endif

int init_defines(lua_State *L)
{
  lua_newtable(L);

  lua_pushliteral(L, "OK");
  lua_pushinteger(L, 0);
  lua_settable(L, -3);
  lua_pushliteral(L, "KILL_CLIENT");
  lua_pushinteger(L, 1);
  lua_settable(L, -3);
  lua_pushliteral(L, "KILL_MODULE");
  lua_pushinteger(L, 2);
  lua_settable(L, -3);
  lua_pushliteral(L, "KILL_MODULE_CLASS");
  lua_pushinteger(L, 3);
  lua_settable(L, -3);
  lua_pushliteral(L, "KILL_DAEMON");
  lua_pushinteger(L, 4);
  lua_settable(L, -3);

  lua_pushliteral(L, "IN_MODULE");
  lua_pushinteger(L, 1);
  lua_settable(L, -3);
  lua_pushliteral(L, "OUT_MODULE");
  lua_pushinteger(L, 2);
  lua_settable(L, -3);
  lua_pushliteral(L, "INOUT_MODULE");
  lua_pushinteger(L, 3);
  lua_settable(L, -3);
  lua_pushliteral(L, "MISC_MODULE");
  lua_pushinteger(L, 4);
  lua_settable(L, -3);

  lua_pushliteral(L, "MODULES_PATH");
  lua_pushstring(L, MODULESDIR);
  lua_settable(L, -3);

  lua_setglobal(L, "defines");
  return 0;
}

int init_main_loop(lua_State *L)
{
  const luaL_Reg *lib = gcsd_lualibs;

#if LUA_VERSION_NUM > 501
  for (; lib->func; lib++) {
    luaL_requiref(L, lib->name, lib->func, 1);
    lua_pop(L, 1);
  }
#else
  for (; lib->func; lib++) {
    lua_pushcfunction(L, lib->func);
    lua_pushstring(L, lib->name);
    lua_call(L, 1, 0);
  }
#endif

  int ret = luaL_loadbuffer(L, gcsd_lua_bytecode, gcsd_lua_bytecode_len, "gcsd");
  if(ret) {
    const char* err_str = luaL_checkstring(L, -1);
    switch(ret) {
    case LUA_ERRSYNTAX: log_printf(ERROR, "luaL_loadbuffer() syntax error: %s", err_str); break;
    case LUA_ERRMEM: log_printf(ERROR, "luaL_loadbuffer() malloc error: %s", err_str); break;
    default: log_printf(ERROR, "luaL_loadbuffer() unknown error: %s", err_str); break;
    }
    return -1;
  }

  ret = lua_pcall(L, 0, 0, 0);
  if(ret) {
    const char* err_str = luaL_checkstring(L, -1);
    switch(ret) {
    case LUA_ERRRUN: log_printf(ERROR, "lua_pcall() runtime error: %s", err_str); break;
    case LUA_ERRMEM: log_printf(ERROR, "lua_pcall() malloc error: %s", err_str); break;
    case LUA_ERRERR: log_printf(ERROR, "lua_pcall() error at error handler function: %s", err_str); break;
    }
    return -1;
  }

  return init_defines(L);
}

int call_main_loop(lua_State* L, options_t* opt)
{
  lua_getglobal(L, LUA_MAIN_LOOP_FUNC);
  if(!lua_isfunction(L, -1)) {
    log_printf(ERROR, "there is no function '%s' inside gcsd bytecode", LUA_MAIN_LOOP_FUNC);
    return -1;
  };

  options_lua_push(opt, L);

  int ret = lua_pcall(L, 1, LUA_MULTRET, 0);
  if(ret) {
    const char* err_str = luaL_checkstring(L, -1);
    switch(ret) {
    case LUA_ERRRUN: log_printf(ERROR, "lua_pcall(%s) runtime error: %s", LUA_MAIN_LOOP_FUNC, err_str); break;
    case LUA_ERRMEM: log_printf(ERROR, "lua_pcall(%s) malloc error: %s", LUA_MAIN_LOOP_FUNC, err_str); break;
    case LUA_ERRERR: log_printf(ERROR, "lua_pcall(%s) error at error handler function: %s", LUA_MAIN_LOOP_FUNC, err_str); break;
    }
    return -1;
  }

  int n = lua_gettop(L);
  log_printf(DEBUG, "%s returned %d values", LUA_MAIN_LOOP_FUNC, n);
  int i;
  for (i = 1; i <= n; i++)
    log_printf(DEBUG, "return value [%d] = '%s'", i, luaL_checkstring(L, i));

  ret = lua_tointeger(L, 1);
  return ret;
}

int main_loop(options_t* opt)
{
  lua_State *L;
  L = luaL_newstate();
  if(!L) {
    log_printf(ERROR, "error creating lua state");
    return -1;
  }

  int ret = init_main_loop(L);
  if(!ret)
    ret = call_main_loop(L, opt);

  lua_close(L);
  return ret;
}

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

  options_t opt;
  int ret = options_parse(&opt, argc, argv);
  if(ret) {
    if(ret > 0) {
      fprintf(stderr, "syntax error near: %s\n\n", argv[ret]);
    }
    if(ret == -2) {
      fprintf(stderr, "memory error on options_parse, exitting\n");
    }
    if(ret == -3) {
      options_print_version();
    }

    if(ret != -2 && ret != -3)
      options_print_usage();

    if(ret == -1 || ret == -3)
      ret = 0;

    options_clear(&opt);
    log_close();
    exit(ret);
  }
  string_list_element_t* tmp = opt.log_targets_.first_;
  while(tmp) {
    ret = log_add_target(tmp->string_);
    if(ret) {
      switch(ret) {
      case -2: fprintf(stderr, "memory error on log_add_target, exitting\n"); break;
      case -3: fprintf(stderr, "unknown log target: '%s', exitting\n", tmp->string_); break;
      case -4: fprintf(stderr, "this log target is only allowed once: '%s', exitting\n", tmp->string_); break;
      default: fprintf(stderr, "syntax error near: '%s', exitting\n", tmp->string_); break;
      }

      options_clear(&opt);
      log_close();
      exit(ret);
    }
    tmp = tmp->next_;
  }

  log_printf(NOTICE, "just started...");
  options_parse_post(&opt);

#ifndef WINVER
  priv_info_t priv;
  if(opt.username_)
    if(priv_init(&priv, opt.username_, opt.groupname_)) {
      options_clear(&opt);
      log_close();
      exit(-1);
    }
#endif

#ifndef WINVER
  FILE* pid_file = NULL;
  if(opt.pid_file_) {
    pid_file = fopen(opt.pid_file_, "w");
    if(!pid_file) {
      log_printf(WARNING, "unable to open pid file: %s", strerror(errno));
    }
  }

  if(opt.chroot_dir_)
    if(do_chroot(opt.chroot_dir_)) {
      options_clear(&opt);
      log_close();
      exit(-1);
    }
  if(opt.username_)
    if(priv_drop(&priv)) {
      options_clear(&opt);
      log_close();
      exit(-1);
    }

  if(opt.daemonize_) {
    pid_t oldpid = getpid();
    daemonize();
    log_printf(INFO, "running in background now (old pid: %d)", oldpid);
  }

  if(pid_file) {
    pid_t pid = getpid();
    fprintf(pid_file, "%d", pid);
    fclose(pid_file);
  }
#endif

  ret = main_loop(&opt);

  options_clear(&opt);

  if(!ret)
    log_printf(NOTICE, "normal shutdown");
  else if(ret < 0)
    log_printf(NOTICE, "shutdown after error");
  else
    log_printf(NOTICE, "shutdown after signal");

  log_close();

	return ret;
}