netcatchat

#!/usr/bin/env bash

# Set strict mode
#set -euo pipefail

# Main function wrapper
main() {
  # Check if common-functions exists
  if [[ ! -f "$(dirname "$0")/common-functions" ]]; then
    echo "Downloading common-functions from GitHub..."
    if ! curl -fsSL https://raw.githubusercontent.com/Flower7C3/bash-tools/master/common-functions -o "$(dirname "$0")/common-functions"; then
      echo "Failed to download common-functions"
      exit 1
    fi
  fi

  # Source common functions
  source "$(dirname "$0")/common-functions"

  # Call the actual main function
  netcatchat_main "$@"
}

netcatchat_main() {

  declare -A chat_users=()
  declare -r config_file_path="${HOME}/.config/netcatchat/config.sh"
  declare -r history_file_path="${HOME}/.config/netcatchat/history.txt"

  function show_usage() {
    log_usage_title '[-p <port>] [-n <@nickname>]'
    echo
    log_header 'Options'
    log_usage_options_line '-p <port>;--port <port>' \
      'sender port, default <b>%d</b>' "$sender_port"
    log_usage_options_line '-n <@nickname>;--nickname <@nickname>' \
      'sender @nickname, default <b>%s</b>' "$sender_nickname"
    log_usage_options_line '-u;--update' \
      'Update app'
    log_usage_options_line '-h;--help' \
      'Show this help message'
    exit 0
  }
  function show_commands() {
    log_header 'Commands'
    log_usage_options_line '@nickname message' \
      'write message to user, use <b>@all</b> to broadcast'
    log_usage_options_line '/p;/port' \
      'setup app port'
    log_usage_options_line '/n;/nick' \
      'setup Your @nickname'
    log_usage_options_line '/l [c|check];/list [c|check]' \
      'list saved recipients'
    log_usage_options_line '/c <@nickname> <ip/addr> <port>;/create <@nickname> <ip/addr> <port>' \
      'create new recipient'
    log_usage_options_line '/u <@nickname> <ip/addr> <port>;/update <@nickname> <ip/addr> <port>' \
      'update saved recipient data'
    log_usage_options_line '/r <@nickname_old> <@nickname_new>;/rename <@nickname_old> <@nickname_new>' \
      'change (rename) recipient <b>@nickname</b>'
    log_usage_options_line '/d <@nickname>;/delete <@nickname>' \
      'delete recipient'
    log_usage_options_line '/s;/scan' \
      'scan local network for hosts with open <u>%d</u> port' "$NETCAT_CHAT_APP_PORT"
    log_usage_options_line '/w;/welcome' \
      'send welcome message to all users from Your recipients list'
    log_usage_options_line '/x;/clear' \
      'clear history'
    log_usage_options_line '/h;/help' \
      'help screen'
    log_usage_options_line '/q;/exit;/quit;/bye' '<ctrl>+c' \
      'exit app'
  }

  ### VARIABLES ###
  readonly NETCAT_CHAT_SYSTEM_NICKNAME='@system'
  readonly NETCAT_CHAT_BROADCAST_NICKNAME='@all'
  readonly NETCAT_CHAT_APP_PORT='2812'
  readonly NICKNAME_CHECK_MODE_IGNORE='nickname_validate_mode_ignore'
  readonly NICKNAME_CHECK_MODE_ERR_IF_EXISTS='nickname_validate_mode_err_if_exists'
  readonly NICKNAME_CHECK_MODE_ERR_IF_NOT_EXISTS='nickname_validate_mode_err_if_not_exists'
  if uname | grep -iq Darwin; then
    # shellcheck disable=SC2155
    declare -r sender_hostname="$(ipconfig getifaddr en0)"
  else
    # shellcheck disable=SC2155
    declare -r sender_hostname="$(ip route get 1 | awk '{print $NF;exit}')"
  fi
  nc_pid=-1
  sender_port=''
  sender_nickname=''
  option=''

  ### CONFIG ###
  function config_load() {
    if [[ ! -f "$config_file_path" ]]; then
      log_info ---status "$config_file_path" 'Create config file'
      mkdir -p "$(dirname "$config_file_path")"
      touch "$config_file_path"
      chmod 400 "$config_file_path"
    else
      log_info ---status "$config_file_path" 'Read config file'
      # shellcheck disable=SC1090
      source "$config_file_path"
    fi
    history -r "$history_file_path"
    if [[ -z "$sender_port" ]]; then
      app_setup_port
    fi
    if [[ -z "$sender_nickname" ]]; then
      sender_nickname="@$(whoami)"
      app_setup_nickname
    fi
    if [[ "${#chat_users[*]}" -eq "0" ]]; then
      # shellcheck disable=SC2059
      log_info 'You have no recipients on contact list, type <b>/create</b> to add new person'
    fi
    while [[ $# -gt 0 ]]; do
      case "$1" in
      -p | --port)
        shift
        local _sender_port_error
        _sender_port_error=$(validate_port "$1")
        if [[ -n "$_sender_port_error" ]]; then
          log_error 'Invalid sender port from argv'
          exit 2
        else
          readonly sender_port=$1
        fi
        ;;
      -n | --nickname)
        shift
        local _sender_nickname_error
        _sender_nickname_error=$(validate_nickname "$1" "$NICKNAME_CHECK_MODE_IGNORE")
        if [[ -n "$_sender_nickname_error" ]]; then
          log_error 'Invalid sender nickname from argv'
          exit 2
        else
          readonly sender_nickname=$1
        fi
        ;;
      -h | --help)
        show_usage
        ;;
      -u | --update)
        update_application
        ;;
      -*)
        log_error 'Unknown option: <b>%s</b>' "$1"
        echo
        show_usage
        ;;
      *)
        log_error 'Unexpected argument: <b>%s</b>' "$1"
        echo
        show_usage
        ;;
      esac
      shift
    done
    local _has_previous_process
    # shellcheck disable=SC2009
    read -r -a _has_previous_process <<<"$(ps -a | grep "nc -l -k ${sender_port}" | grep -v 'grep' | awk '{print $1;}')"
    if [[ "${#_has_previous_process[*]}" -gt "0" ]]; then
      for _pid in "${_has_previous_process[@]}"; do
        kill "$_pid"
      done
    fi
  }
  function config_create() {
    local _variable_name="$1"
    local _variable_value="$2"
    local _variable_delete_error
    config_delete "$_variable_name"
    eval "${_variable_name}"'=${_variable_value}' 2>&1
    chmod 600 "$config_file_path"
    printf '%s="%s"'"\n" "$_variable_name" "$_variable_value" >>"$config_file_path"
    chmod 400 "$config_file_path"
  }
  function config_delete() {
    local _variable_name="$1"
    local _variable_name_escaped=$_variable_name
    _variable_name_escaped=${_variable_name_escaped/\[/\\\[}
    _variable_name_escaped=${_variable_name_escaped/\]/\\\]}
    eval "unset ${_variable_name}" 2>&1
    chmod 600 "$config_file_path"
    sed -i '' '/'"$_variable_name_escaped"'/d' "$config_file_path"
    chmod 400 "$config_file_path"
  }

  ### NETCAT ###
  function netcat_start() {
    if [[ -n "$sender_port" ]]; then
      log_success ---status "$BASHPID" "Started netcat chat"
      nc -l -k "$sender_port" 2>/dev/null &
      nc_pid=$!
      log_success ---status "$nc_pid" "Started netcat server on %d port" "$sender_port"
      message_from_system "<b>${sender_nickname}</b> in now connected to netcatchat from <u>${sender_hostname} ${sender_port}</u>"
    else
      log_error 'Sender port is not defined'
      app_setup_port
    fi
  }
  function netcat_kill() {
    if [[ "$nc_pid" -gt "0" ]]; then
      message_from_system "<b>${sender_nickname}</b> has left the building!"
      loading_animation_loop ---message 'Closing netcat server'
      kill ${nc_pid}
      loading_animation_loop ---message 'Closed netcat server' ---status "$nc_pid"
    fi
  }

  ### TRAP ###
  ctrl_c_trap_active='n'
  function ctrl_c_trap_init() {
    ctrl_c_trap_active='n'
    trap 'ctrl_c_trap_active="y";return;' SIGINT
  }
  function ctrl_c_trap_remove() {
    ctrl_c_trap_active='n'
    trap - SIGINT
  }
  function ctrl_c_trap_exec() {
    if [[ "$ctrl_c_trap_active" == "y" ]]; then
      echo
      return 0
    fi
    return 1
  }

  ### HISTORY ###
  function history_save() {
    history -s "$option"
    history -w "$history_file_path"
  }
  function history_clear() {
    log_success 'History removed'
    history -c
  }

  ### NAMES ###
  function name_to_nickname() {
    printf "@%s" "${1}"
  }
  function nickname_to_name() {
    printf "%s" "${1/@/}"
  }

  ### VALIDATION ###
  function validate_nickname() {
    local _nickname="$1"
    local _validate_exists_mode="$2"
    local _name
    _name=$(nickname_to_name "$_nickname")

    if [[ ! "$_nickname" == @* ]]; then
      log_error 'Nickname <b>%s</b> is invalid, all nicknames starts with <b>@</b> sign' "$_nickname"
      #    return 1
    elif [[ "$_nickname" == "$NETCAT_CHAT_SYSTEM_NICKNAME" ]] || [[ "$_nickname" == "$NETCAT_CHAT_BROADCAST_NICKNAME" ]]; then
      log_error 'Values <b>%s</b> and <b>%s</b> are reserved nicknames' "$NETCAT_CHAT_SYSTEM_NICKNAME" "$NETCAT_CHAT_BROADCAST_NICKNAME"
      #    return 2
      #    elif [[ "${#chat_users[@]}" -gt "0" ]] && [[ -z "${chat_users[$_name]}" ]] && [[ "$_validate_exists_mode" == "$NICKNAME_CHECK_MODE_ERR_IF_EXISTS" ]]; then
      #      log_error 'Recipient <b>%s</b> is already defined' "$_nickname"
      #    return 3
      #    elif [[ "${#chat_users[@]}" -gt "0" ]] && [[ -z "${chat_users[$_name]}" ]] && [[ "$_validate_exists_mode" == "$NICKNAME_CHECK_MODE_ERR_IF_NOT_EXISTS" ]]; then
      #      log_error 'Recipient <b>%s</b> is not defined' "$_nickname"
      #    return 4
      #  else
      #    return 0
    fi
  }

  function validate_hostname() {
    local _hostname=$1
    if [[ ! "$_hostname" =~ ^[A-Za-z0-9._%+-]+$ ]]; then
      log_error 'Hostname/IP address <b>%s</b> is invalid' "$_hostname"
      return 1
    else
      return 0
    fi
  }
  function validate_port() {
    local _port=$1
    if [[ ! "$_port" =~ ^[0-9]+$ ]]; then
      log_error 'Port <b>%s</b> number is invalid' "$_port"
      return 1
    elif [[ "$_port" -lt "1024" ]] || [[ "$_port" -gt "65536" ]]; then
      log_error 'Port number must be between <b>1024</b> and <b>65536</b>'
      return 2
    else
      return 0
    fi
  }
  ### SENDER ###
  function app_setup_port() {
    local _new_sender_port="${1:-}"
    local _new_sender_port_error
    while true; do
      prompt_input '_new_sender_port' 'Setup sender port number' "$_new_sender_port"
      if ctrl_c_trap_exec; then
        return
      fi
      _new_sender_port_error=$(validate_port "$_new_sender_port")
      if [[ -z "$_new_sender_port_error" ]]; then
        break
      else
        echo "$_new_sender_port_error"
        _new_sender_port=''
      fi
    done
    config_create 'sender_port' "$_new_sender_port"
    log_success 'Sender port saved' ---status "$_new_sender_port"
  }
  function app_setup_nickname() {
    local _new_sender_nickname="${1:-}"
    local _new_sender_nickname_error
    while true; do
      prompt_input '_new_sender_nickname' 'Setup sender nickname' "$_new_sender_nickname"
      if ctrl_c_trap_exec; then
        return
      fi
      _new_sender_nickname_error=$(validate_nickname "$_new_sender_nickname" "$NICKNAME_CHECK_MODE_IGNORE")
      if [[ -z "$_new_sender_nickname_error" ]]; then
        break
      else
        echo "$_new_sender_nickname_error"
        _new_sender_nickname=''
      fi
    done
    local _old_sender_nickname=$sender_nickname
    config_create 'sender_nickname' "$_new_sender_nickname"
    log_success 'Sender nickname saved' "$_new_sender_nickname"
    if [[ -n "$_old_sender_nickname" ]]; then
      message_from_system "$_old_sender_nickname is now known as $_new_sender_nickname"
    fi
  }

  ### RECIPIENTS ###
  function recipients_list() {
    local _flag="${1:-}"
    if [[ "${#chat_users[*]}" -eq "0" ]]; then
      # shellcheck disable=SC2059
      log_error 'No recipients found, use <b>/create</b> to define new recipient'
    else
      for _recipient_name in "${!chat_users[@]}"; do
        # check status
        local _recipient_nickname
        _recipient_nickname=$(name_to_nickname "$_recipient_name")
        # shellcheck disable=SC2206
        local _recipient_address=(${chat_users[$_recipient_name]})
        case $_flag in
        c | check)
          log_info '%s %s' "$_recipient_nickname" "${_recipient_address[*]}"
          local _recipient_online_status=0
          recipient_online_status=$(ping "${_recipient_address[0]}" -c 1 -t 1 2>/dev/null | grep -e 'packets' | awk '{print $4;}')
          if [[ "$recipient_online_status" -gt "0" ]]; then
            local _recipient_connection_status
            recipient_connection_status=$(nmap "${_recipient_address[0]}" -p "${_recipient_address[1]}" | grep -e '/tcp' | awk '{print $2;}')
            if [[ "$recipient_connection_status" == "open" ]]; then
              log_success '<b>%s</b> %s is online' "$_recipient_nickname" "${_recipient_address[*]}"
            else
              log_error '<b>%s</b> %s is not connected to app' "$_recipient_nickname" "${_recipient_address[*]}"
            fi
          else
            log_error '<b>%s</b> %s is offline' "$_recipient_nickname" "${_recipient_address[*]}"
          fi
          ;;
        *)
          log_info '<b>%s</b> %s' "$_recipient_nickname" "${_recipient_address[*]}"
          ;;
        esac
      done
    fi
  }
  function hosts_scan_and_recipient_create() {
    local _nickname
    local _ip
    local _port_state
    local _ip_range
    _ip_range=$(echo "$sender_hostname" | awk -F. '{print $(1)"."$(2)"."$(3)".1-254"}')
    local _hosts_info
    read -r -a _hosts_info <<<"$(nmap "$_ip_range" -p ${NETCAT_CHAT_APP_PORT} | grep -e '/tcp\|report' | sed 's/Nmap scan report for //g')"
    local _sums_total
    _sums_total=${#_hosts_info[@]}
    for _index in $(seq 1 4 "$_sums_total"); do
      _ip="${_hosts_info[$((_index - 1))]}"
      _nickname=$(echo "@$_ip" | sed 's/\./_/g')
      _port_state="${_hosts_info[$((_index + 1))]}"
      if [[ "$_port_state" == "open" ]]; then
        recipient_update "${_nickname}" "${_ip}" "$NETCAT_CHAT_APP_PORT"
      elif [[ "$_port_state" == "closed" ]]; then
        log_error 'Host <b>%s</b> status is <b>%s</b>' "$_ip" "$_port_state"
      else
        log_info 'Host <b>%s</b> status is <b>%s</b>' "$_ip" "$_port_state"
      fi
    done
  }
  function recipient_create() {
    local _new_recipient_nickname="$1"
    local _new_recipient_nickname_error
    while true; do
      prompt_input '_new_recipient_nickname' "New recipient's nickname" "$_new_recipient_nickname"
      if ctrl_c_trap_exec; then
        return
      fi
      _new_recipient_nickname_error=$(validate_nickname "$_new_recipient_nickname" "$NICKNAME_CHECK_MODE_ERR_IF_EXISTS")
      if [[ -z "$_new_recipient_nickname_error" ]]; then
        break
      else
        echo "$_new_recipient_nickname_error"
        _new_recipient_nickname=''
      fi
    done
    local _new_recipient_name
    _new_recipient_name=$(nickname_to_name "$_new_recipient_nickname")
    local _new_recipient_hostname="$2"
    local _new_recipient_hostname_error
    while true; do
      prompt_input '_new_recipient_hostname' "New recipient's hostname/IP address" "$_new_recipient_hostname"
      if ctrl_c_trap_exec; then
        return
      fi
      _new_recipient_hostname_error=$(validate_hostname "$_new_recipient_hostname")
      if [[ -z "$_new_recipient_hostname_error" ]]; then
        break
      else
        echo "$_new_recipient_hostname_error"
        _new_recipient_hostname=''
      fi
    done
    local _new_recipient_port="$3"
    local _new_recipient_port_error
    while true; do
      prompt_input '_new_recipient_port' "New recipient's port number" "$_new_recipient_port"
      if ctrl_c_trap_exec; then
        return
      fi
      _new_recipient_port_error=$(validate_port "$_new_recipient_port")
      if [[ -z "$_new_recipient_port_error" ]]; then
        break
      else
        echo "$_new_recipient_port_error"
        _new_recipient_port=''
      fi
    done
    local _new_recipient_address
    _new_recipient_address=("$_new_recipient_hostname" "$_new_recipient_port")
    for _recipient_name in "${!chat_users[@]}"; do
      local _recipient_nickname
      _recipient_nickname=$(name_to_nickname "$_recipient_name")
      if [[ "${chat_users[$_recipient_name]}" == "${_new_recipient_address[*]}" ]]; then
        log_error 'Recipient data already defined and known as <b>%s</b>' "$_recipient_nickname"
        return 1
      fi
    done
    config_create "chat_users[${_new_recipient_name}]" "${_new_recipient_address[*]}"
    log_success 'Recipient <b>%s</b> created as <b>%s</b>' "$_new_recipient_nickname" "${_new_recipient_address[*]}"
  }
  function recipient_rename() {
    local _old_recipient_nickname="$1"
    local _old_recipient_nickname_error
    while true; do
      prompt_input 'old_recipient_nickname' "Recipient's old nickname" "$old_recipient_nickname"
      if ctrl_c_trap_exec; then
        return
      fi
      _old_recipient_nickname_error=$(validate_nickname "$old_recipient_nickname" "$NICKNAME_CHECK_MODE_ERR_IF_NOT_EXISTS")
      if [[ -z "$_old_recipient_nickname_error" ]]; then
        break
      else
        echo "$_old_recipient_nickname_error"
        old_recipient_nickname=''
      fi
    done
    local _old_recipient_name
    _old_recipient_name=$(nickname_to_name "$old_recipient_nickname")
    local _new_recipient_nickname="$2"
    local _new_recipient_nickname_error
    while true; do
      prompt_input '_new_recipient_nickname' "Recipient's new nickname" "$_new_recipient_nickname"
      if ctrl_c_trap_exec; then
        return
      fi
      _new_recipient_nickname_error=$(validate_nickname "$_new_recipient_nickname" "$NICKNAME_CHECK_MODE_ERR_IF_EXISTS")
      if [[ -z "$_new_recipient_nickname_error" ]]; then
        break
      else
        echo "$_new_recipient_nickname_error"
        _new_recipient_nickname=''
      fi
    done
    local _recipient_address
    _recipient_address=("${chat_users[${_old_recipient_name}]}")
    local _new_recipient_name
    _new_recipient_name=$(nickname_to_name "$_new_recipient_nickname")
    config_delete "chat_users[${_old_recipient_name}]" && config_create "chat_users[${_new_recipient_name}]" "${_recipient_address[*]}"
    log_success 'Recipient <b>%s</b> renamed to <b>%s</b>' "$old_recipient_nickname" "$_new_recipient_nickname"
  }
  function recipient_update() {
    local _new_recipient_nickname="$1"
    local _new_recipient_nickname_error
    while true; do
      prompt_input '_new_recipient_nickname' 'Recipient name' "$_new_recipient_nickname"
      if ctrl_c_trap_exec; then
        return
      fi
      _new_recipient_nickname_error=$(validate_nickname "$_new_recipient_nickname" "$NICKNAME_CHECK_MODE_IGNORE")
      if [[ -z "$_new_recipient_nickname_error" ]]; then
        break
      else
        echo "$_new_recipient_nickname_error"
        _new_recipient_nickname=''
      fi
    done
    local _new_recipient_name
    _new_recipient_name=$(nickname_to_name "$_new_recipient_nickname")
    local _old_recipient_address
    # shellcheck disable=SC2206
    _old_recipient_address=(${chat_users[$_new_recipient_name]})
    local _new_recipient_hostname="$2"
    local _new_recipient_hostname_error
    while true; do
      prompt_input '_new_recipient_hostname' "Recipient's updated hostname/IP address" "$_new_recipient_hostname"
      if ctrl_c_trap_exec; then
        return
      fi
      _new_recipient_hostname_error=$(validate_hostname "$_new_recipient_hostname")
      if [[ -z "$_new_recipient_hostname_error" ]]; then
        break
      else
        echo "$_new_recipient_hostname_error"
        _new_recipient_hostname=''
      fi
    done
    local _new_recipient_port="$3"
    local _new_recipient_port_error
    while true; do
      prompt_input '_new_recipient_port' "Recipient's updated port number" "$_new_recipient_port"
      if ctrl_c_trap_exec; then
        return
      fi
      _new_recipient_port_error=$(validate_port "$_new_recipient_port")
      if [[ -z "$_new_recipient_port_error" ]]; then
        break
      else
        echo "$_new_recipient_port_error"
        _new_recipient_port=''
      fi
    done
    local _new_recipient_address
    _new_recipient_address=("$_new_recipient_hostname" "$_new_recipient_port")
    for _recipient_name in "${!chat_users[@]}"; do
      if [[ "${chat_users[$_recipient_name]}" == "${_new_recipient_address[*]}" ]] && [[ "$_recipient_name" != "$_new_recipient_name" ]]; then
        local _recipient_nickname
        _recipient_nickname=$(name_to_nickname "$_recipient_name")
        log_error 'Recipient data <b>%s</b> already defined and known as <b>%s</b>' "${_new_recipient_address[*]}" "$_recipient_nickname"
        return 1
      fi
    done
    config_create "chat_users[${_new_recipient_name}]" "${_new_recipient_address[*]}"
    log_success 'Recipient <b>%s</b> updated as <b>%s</b>' "$_new_recipient_nickname" "${_new_recipient_address[*]}"
  }
  function recipient_delete() {
    local _recipient_nickname="$1"
    local _recipient_nickname_error
    while true; do
      prompt_input '_recipient_nickname' "Recipient's nickname to delete" "$_recipient_nickname"
      if ctrl_c_trap_exec; then
        return
      fi
      _recipient_nickname_error=$(validate_nickname "$_recipient_nickname" "$NICKNAME_CHECK_MODE_IGNORE")
      if [[ -z "$_recipient_nickname_error" ]]; then
        break
      else
        echo "$_recipient_nickname_error"
        _recipient_nickname=''
      fi
    done
    local _recipient_name
    _recipient_name=$(nickname_to_name "$_recipient_nickname")
    if [[ -z "${chat_users[$_recipient_name]}" ]]; then
      log_error 'Recipient %s not found' "$_recipient_nickname"
    else
      config_delete "chat_users[${_recipient_name}]"
      log_success 'Recipient %s deleted' "$_recipient_nickname"
    fi
  }

  ### MESSAGE ###
  function message_to_user() {
    local _sender_nickname=$1
    local _recipient_nickname=$2
    local _message_text=$3
    local _datetime
    _datetime=$(date +"%Y-%m-%d %H:%M:%S")
    local _message
    local _message_status
    if [[ "$_recipient_nickname" == "$NETCAT_CHAT_BROADCAST_NICKNAME" ]]; then
      # generate message
      if [[ "$_sender_nickname" == "$NETCAT_CHAT_SYSTEM_NICKNAME" ]]; then
        _message=$(printf "[%s] %s" "$_datetime" "$_message_text")
      else
        _message=$(printf "[%s] <b>%s</b> broadcast: %s" "$_datetime" "$_sender_nickname" "$_message_text")
      fi
      # display loopback
      log_info "$_message"
      # send message
      for _recipient_name in "${!chat_users[@]}"; do
        _message_status=$(message_unicast "$(name_to_nickname "$_recipient_name")" "$_message")
      done
    else
      # generate message
      if [[ "$_sender_nickname" == "$NETCAT_CHAT_SYSTEM_NICKNAME" ]]; then
        _message="$(printf "[%s] %s" "$_datetime" "$_message_text")"
      else
        _message="$(printf "[%s] <b>%s</b> » <b>%s</b>: %s" "$_datetime" "$_sender_nickname" "$_recipient_nickname" "$_message_text")"
      fi
      # display loopback
      printf "$%s\n" "$(message_unicast "$_recipient_nickname" "$_message")"
    fi
  }

  function message_unicast() {
    local _recipient_nickname="$1"
    local _recipient_name
    _recipient_name=$(nickname_to_name "$_recipient_nickname")
    local _message="$2"
    local _recipient_address
    # shellcheck disable=SC2206
    _recipient_address=(${chat_users[$_recipient_name]})
    # shellcheck disable=SC2128
    if [[ -z "$_recipient_address" ]]; then
      log_error 'Recipient <b>%s</b> is not recognized, use <b>/create</b> to define new recipient or <b>/list</b> to list all recipients' "$_recipient_nickname"
      return 99
    else
      local _recipient_hostname=${_recipient_address[0]}
      # check status
      local _recipient_online_status=0
      _recipient_online_status=$(ping "$_recipient_hostname" -c 1 -t 1 | grep -e 'packets' | awk '{print $4;}')
      if [[ "$_recipient_online_status" -gt "0" ]]; then
        # send message
        local _formatted_message
        _formatted_message="$(log_message ---color "YELLOW" ---icon "$ICON_MESSAGE" ---bell "$_message")"
        _formatted_message+="$(log_message ---color "YELLOW" ---icon "$ICON_PROMPT" ---one-line "Chat: ")"
        # shellcheck disable=SC2086
        echo -n "${_formatted_message}" | nc -c "${_recipient_address[*]}"
        local _message_send_response=$?
        # check response
        if [[ "$_message_send_response" == "0" ]]; then
          log_info "$_message"
          return 0
        else
          log_error 'Recipient <b>%s</b> is not connected on %s' "$_recipient_nickname" "${_recipient_address[*]}"
          return $_message_send_response
        fi
      else
        log_error 'Recipient <b>%s</b> is offline' "$_recipient_nickname"
        return 99
      fi
    fi
  }
  function message_from_system() {
    local _message_text=$1
    message_to_user "$NETCAT_CHAT_SYSTEM_NICKNAME" "$NETCAT_CHAT_BROADCAST_NICKNAME" "$_message_text"
  }
  function option_get() {
    prompt_input 'option' 'Chat'
  }
  function option_reset() {
    option='/i'
  }

  ### INIT ###
  log_title 'NetCat Chat'
  check_dependencies nc ping nmap grep
  #  trap "echo '';netcat_kill;" EXIT
  config_load "$@"
  netcat_start
  option_reset
  while true; do
    ctrl_c_trap_remove
    case $option in
    /p | /port | /p\ * | /port\ *)
      ctrl_c_trap_init
      history_save
      # shellcheck disable=SC2206
      option_array=($option)
      option_sender_port=${option_array[1]:-}
      unset option_array
      app_setup_port "$option_sender_port"
      netcat_kill
      netcat_start
      option_reset
      ;;
    /n | /nick | /n\ * | /nick\ *)
      ctrl_c_trap_init
      history_save
      # shellcheck disable=SC2206
      option_array=($option)
      option_sender_nickname=${option_array[1]:-}
      unset option_array
      app_setup_nickname "$option_sender_nickname"
      option_reset
      ;;
    /x | /clear)
      history_clear
      option_reset
      ;;
    /q | /exit | /quit | /bye)
      break
      ;;
    /h | /help | \?)
      show_commands
      history_save
      option_reset
      ;;
    /l | /list | /l\ * | /list\ *)
      history_save
      # shellcheck disable=SC2206
      option_array=($option)
      option_flag=${option_array[1]:-}
      unset option_array
      recipients_list "$option_flag"
      option_reset
      ;;
    /s | /scan)
      history_save
      hosts_scan_and_recipient_create
      option_reset
      ;;
    /c | /create | /c\ * | /create\ *)
      ctrl_c_trap_init
      history_save
      # shellcheck disable=SC2206
      option_array=($option)
      option_recipient_nickname=${option_array[1]:-}
      option_recipient_hostname=${option_array[2]:-}
      option_recipient_port=${option_array[3]:-}
      unset option_array
      recipient_create "$option_recipient_nickname" "$option_recipient_hostname" "$option_recipient_port"
      option_reset
      ;;
    /u | /update | /u\ * | /update\ *)
      ctrl_c_trap_init
      history_save
      # shellcheck disable=SC2206
      option_array=($option)
      option_recipient_nickname=${option_array[1]:-}
      option_recipient_hostname=${option_array[3]:-}
      option_recipient_port=${option_array[4]:-}
      unset option_array
      recipient_update "$option_recipient_nickname" "$option_recipient_hostname" "$option_recipient_port"
      option_reset
      ;;
    /r | /rename | /r\ * | /rename\ *)
      ctrl_c_trap_init
      history_save
      # shellcheck disable=SC2206
      option_array=($option)
      option_old_recipient_nickname=${option_array[1]:-}
      option_new_recipient_nickname=${option_array[2]:-}
      unset option_array
      recipient_rename "$option_old_recipient_nickname" "$option_new_recipient_nickname"
      option_reset
      ;;
    /d | /delete | /d\ * | /delete\ *)
      ctrl_c_trap_init
      history_save
      # shellcheck disable=SC2206
      option_array=($option)
      option_recipient_nickname=${option_array[1]:-}
      unset option_array
      recipient_delete "$option_recipient_nickname"
      option_reset
      ;;
    /w | /welcome)
      history_save
      message_to_user "$sender_nickname" "@all" "$(log_message 'Hi @all. My name is %s. You can add me to Your recipients list with <b>%s</b> command' "$sender_nickname" "/create $sender_nickname $sender_hostname $sender_port")"
      option_reset
      ;;
    \@*)
      history_save
      option_recipient_nickname=$(echo "$option" | awk '{print $1;}')
      option_message_text=$(echo "$option" | cut -d' ' -f2-)
      if [[ -n "$option_message_text" ]] && [[ "$option_message_text" != "@" ]] && [[ "$option_recipient_nickname" != "$option_message_text" ]]; then
        message_to_user "$sender_nickname" "$option_recipient_nickname" "$option_message_text"
      else
        log_error 'Empty message'
      fi
      option_reset
      ;;
    /i)
      option_get
      ;;
    *)
      # shellcheck disable=SC2059
      log_error 'Command not found. Use <code>/help</code> to see available commands.'
      option_reset
      ;;
    esac
  done
}

# Call main function
main "$@"