/*
 *  rhctl
 *
 *  Copyright (C) 2009-2014 Christian Pointner <equinox@helsinki.at>
 *
 *  This file is part of rhctl.
 *
 *  rhctl 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.
 *
 *  rhctl 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 rhctl. If not, see <http://www.gnu.org/licenses/>.
 */

#include "datatypes.h"

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

#include "log.h"
#include "sig_handler.h"
#include "options.h"

#include "daemon.h"
#include "utils.h"

int process_serial(read_buffer_t* buffer, int serial_fd, int led_pipe_fd, bool *state)
{
  int ret = 0;
  struct timeval tv;
  fd_set fds;
  FD_ZERO(&fds);
  FD_SET(serial_fd, &fds);

  for(;;) {
    tv.tv_sec = 0;
    tv.tv_usec = 0;
    ret = select(serial_fd+1, &fds, NULL, NULL, &tv);
    if(!ret)
      return 0;
    else if(ret < 0)
      return ret;

    ret = read(serial_fd, &buffer->buf[buffer->offset], 1);
    if(!ret)
      return 2;
    if(ret == -1 && errno == EAGAIN)
      return 0;
    else if(ret < 0)
      break;

    if(buffer->buf[buffer->offset] == '\n') {
      buffer->buf[buffer->offset] = 0;

      if(buffer->offset > 0 && buffer->buf[buffer->offset-1] == '\r')
        buffer->buf[buffer->offset-1] = 0;

      if(strlen((char *)(buffer->buf))) {
        *state = TRUE;
        if(led_pipe_fd >= 0) {
          char buf = '1';
          ret = write(led_pipe_fd, &buf, 1);
          if(ret == -1 && errno != EAGAIN)
            log_printf(WARNING, "write to led process pipe returned with error: %s", strerror(errno));
        }
      }

      buffer->offset = 0;
      return 0;
    }

    buffer->offset++;
    if(buffer->offset >= sizeof(buffer->buf)) {
      log_printf(DEBUG, "string too long (fd=%d)", serial_fd);
      buffer->offset = 0;
      return 0;
    }
  }

  return ret;
}

int main_loop(int serial_fd, int cmd_fd, int led_pipe_fd, options_t* opt)
{
  log_printf(NOTICE, "entering main loop");

  fd_set readfds, tmpfds;
  FD_ZERO(&readfds);
  FD_SET(serial_fd, &readfds);
  FD_SET(cmd_fd, &readfds);
  int max_fd = serial_fd > cmd_fd ? serial_fd : cmd_fd;

  int sig_fd = signal_init();
  if(sig_fd < 0)
    return -1;
  FD_SET(sig_fd, &readfds);
  max_fd = (max_fd < sig_fd) ? sig_fd : max_fd;

  int return_value = 0;
  return_value = send_string(cmd_fd, "type heartbeat\n");
  if(return_value <= 0) {
    log_printf(ERROR, "error setting client type");
    return_value = -1;
  }
  else {
    log_printf(NOTICE, "connecting as type heartbeat");
    return_value = 0;
  }

  bool state = FALSE;
  send_string(cmd_fd, "heartbeat 0\n");

  read_buffer_t serial_buffer;
  serial_buffer.offset = 0;
  struct timeval timeout;
  u_int32_t time = 0;
  while(!return_value) {
    memcpy(&tmpfds, &readfds, sizeof(tmpfds));

    timeout.tv_sec = 0;
    timeout.tv_usec = 100000;
    int ret = select(max_fd+1, &tmpfds, NULL, NULL, &timeout);
    if(ret == -1 && errno != EINTR) {
      log_printf(ERROR, "select returned with error: %s", strerror(errno));
      return_value = -1;
      break;
    }
    if(ret == -1)
      continue;
    if(!ret) {
      time++;
      if(time >= opt->timeout_) {
        if(state == TRUE) {
          log_printf(WARNING, "heartbeat timeout");
          send_string(cmd_fd, "heartbeat 0\n");
          state = FALSE;
        }
        time = 0;
      }
      continue;
    }

    if(FD_ISSET(sig_fd, &tmpfds))
      if(signal_handle())
        return_value = 1;

    if(FD_ISSET(serial_fd, &tmpfds)) {
      bool old_state = state;
      return_value = process_serial(&serial_buffer, serial_fd, led_pipe_fd, &state);
      if(return_value)
        break;
      if(state) {
        if(!old_state) {
          log_printf(WARNING, "heartbeat returned");
          send_string(cmd_fd, "heartbeat 1\n");
        }
        time = 0;
      }
    }

    if(FD_ISSET(cmd_fd, &tmpfds)) {
      u_int8_t buf[100];
      int ret = recv(cmd_fd, buf, 100, 0);
      if(!ret)
        return_value = 3;
      if(ret == -1 && errno == EAGAIN)
        return_value = 0;
      else if(ret < 0)
        return_value = ret;
    }
  }

  signal_stop();
  return return_value;
}

int led_process(int pipe_fd, int led_fd)
{
  struct timeval timeout;
  char buf;
  int ret;

  log_printf(INFO, "led_process: starting up");
  for(;;) {
    ret = read(pipe_fd, &buf, 1);
    if(ret == -1 && errno == EAGAIN)
      continue;
    else if(!ret || ret < 0) {
      log_printf(ERROR, "led_process: read returned with error: %s", strerror(errno));
      break;
    }

    buf = '1';
    ret = write(led_fd, &buf, 1);
    if(ret == -1 && errno != EAGAIN) {
      log_printf(ERROR, "led_process: write returned with error: %s", strerror(errno));
      break;
    }

    timeout.tv_sec = 0;
    timeout.tv_usec = 100000;
    ret = select(0, NULL, NULL, NULL, &timeout);
    if(ret == -1 && errno != EINTR) {
      log_printf(ERROR, "led_process: select returned with error: %s", strerror(errno));
      break;
    }

    buf = '0';
    ret = write(led_fd, &buf, 1);
    if(ret == -1 && errno != EAGAIN) {
      log_printf(ERROR, "led_process: write returned with error: %s", strerror(errno));
      break;
    }
  }
  log_printf(INFO, "led_process: stopped");
  return -1;
}

int start_led_process(options_t* opt)
{
  int pipefd[2];
  int led_fd;
  pid_t cpid;

  led_fd = open(opt->led_filename_, O_WRONLY);
  if(led_fd < 0) {
    log_printf(ERROR, "led_process: open() failed: %s", strerror(errno));
    return -2;
  }

  if (pipe(pipefd) == -1) {
    log_printf(ERROR, "led_process: pipe() failed: %s", strerror(errno));
    close(led_fd);
    return -2;
  }

  cpid = fork();
  if (cpid == -1) {
    log_printf(ERROR, "led_process: fork() failed: %s", strerror(errno));
    close(pipefd[0]);
    close(pipefd[1]);
    close(led_fd);
    return -2;
  }

  if (cpid == 0) {
    close(pipefd[1]);
    return led_process(pipefd[0], led_fd);
  }

  close(pipefd[0]);
  close(led_fd);
  return pipefd[1];
}

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, exiting\n");
    }
    if(ret == -5) {
      fprintf(stderr, "syntax error: invalid baudrate\n");
    }

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

    options_clear(&opt);
    log_close();
    exit(ret);
  }
  string_list_element_t* tmp = opt.log_targets_.first_;
  if(!tmp) {
    log_add_target("syslog:3,heartbeatclient,daemon");
  }
  else {
    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...");
  if(options_parse_post(&opt)) {
    options_clear(&opt);
    log_close();
    exit(-1);
  }

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

  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);
  }

  int led_pipe_fd = -1;
  if(opt.led_filename_) {
    log_printf(NOTICE, "starting led blink process");
    led_pipe_fd = start_led_process(&opt);
    if(led_pipe_fd == -1) {
      options_clear(&opt);
      log_close();
      exit(0);
    }
    if(led_pipe_fd < -1) {
      options_clear(&opt);
      log_close();
      exit(-1);
    }
  }

  int cmd_fd = 0;
  int serial_fd = 0;
  for(;;) {
    cmd_fd = connect_command_socket(opt.command_sock_);
    if(cmd_fd < 0)
      ret = 3;
    else {
      serial_fd = open(opt.serial_dev_, O_RDWR | O_NOCTTY);
      if(serial_fd < 0)
        ret = 2;
      else {
        ret = setup_tty(serial_fd, opt.baudrate_);
        if(ret)
          ret = 2;
        else
          ret = main_loop(serial_fd, cmd_fd, led_pipe_fd, &opt);
      }
    }

    if(ret == 2 || ret == 3) {
      if(ret == 2)
        log_printf(ERROR, "%s error, trying to reopen in 5 seconds..", opt.serial_dev_);
      if(ret == 3)
        log_printf(ERROR, "socket error, trying to reconnect in 5 seconds..");

      if(cmd_fd > 0)
        close(cmd_fd);
      if(serial_fd > 0)
        close(serial_fd);
      sleep(5);
    }
    else
      break;
  }

  if(cmd_fd > 0)
    close(cmd_fd);
  if(serial_fd > 0)
    close(serial_fd);

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

  options_clear(&opt);
  log_close();

  return ret;
}