## Funzioni di supporto

# Printa errore
echoerr(){
  echo -e "\n\e[0;31mError:\e[0m $1" 1>&2
  exit 1
}

# Printa la versione
print_version(){
  echo "$VERSION"

  return 0
}

# Printa il banner
print_banner(){
  echo "######################"
  echo "# LCM shiftctl v.$VERSION #"
  echo "######################"

  return 0
}

# Printa l'utilizzo
print_usage(){
  echo "shiftctl: record to and query LCM 150 shifts database file."
  echo ""
  echo "options:"
  echo "  -h  Print this help message"
  echo "  -v  Print current version"
  echo "  -t  Print the grand total of shifts durations"
  echo "  -r  Rotate shifts file"

  return 0
}

# Inizializza il file dei turni
initialize_dbfile(){
  echo "date;operator;host;comment" > $SHIFT_FILE 2>/dev/null ||\
  echoerr "Failed to create shifts file $SHIFT_FILE."
  chgrp "$OPGROUP" "$SHIFT_FILE" &>/dev/null ||\
  echoerr "Failed to change group ownership of shifts file $SHIFT_FILE to $OPGROUP."
  chmod g=wr,o= "$SHIFT_FILE" &>/dev/null ||\
  echoerr "Failed to change mode of shifts file $SHIFT_FILE."

  return 0
}

## Funzioni di check

# Check dell'utente che esegue il programma
# può essere solo uno dei tre associato agli
# ID sopra.
check_user(){
  if [ "$RUNNER" = "$ID_0_150" ] || [ "$RUNNER" = "$ID_1_150" ] || [ "$RUNNER" = "$ID_2_150" ]
  then
    echo -e "\nHi, $RUNNER!"
  else
    echoerr "$RUNNER, you are not an LCM operator. Go sweep sea."
  fi

  return 0
}

# Controlla che l'utente che esegue il
# programma sia root
check_root(){
  if [ "$(id -u)" -ne 0 ]
  then
    echoerr "Only root can do this. You are not root, you are pathetic."
  fi

  return 0
}

# Controlla se il file dei turni esiste e ha la mode
# corretta
check_dbfile(){
  case $1 in
    exist)
      [ -f "$SHIFT_FILE" ]
      ;;
    mode)
      [ -w "$SHIFT_FILE" ] && [ -r "$SHIFT_FILE" ]
      ;;
    *)
      echoerr "$0: $1 is an invalid argument."
  esac

    return $?
}

# Controlla e inizializza in modo intelligente il file
# dei turni
smartinit_dbfile(){
  check_dbfile exist || initialize_dbfile
  check_dbfile mode ||\
  echoerr "Shifts file "$SHIFT_FILE" is not readable and/or writable by you."

  return 0
}