rowbot/rowbot

#!/usr/bin/env bash

###
# logger
###

declare -A levels=(
  [debug]=1 [info]=2
  [warn]=3 [error]=4
)

log() {
  if [[ -v LEVEL ]] && (( levels[$level] <= levels[$LEVEL] )); then
    printf "%s: $1\n" "${LEVEL^^}" "${@:2}" >&"$log"
  fi
}

debug() {
  LEVEL=debug log "$@"
}

info() {
  LEVEL=info log "$@"
}

warn() {
  LEVEL=warn log "$@"
}

error() {
  LEVEL=error log "$@"
}

###
# argument parser for parsing arguments
##

declare -A opts

while (( $# )); do
  case $1 in
  --*=*)
    key=${1#--} key=${key%%=*}
    opts[$key]=${1#--*=}
    ;;
  --no-*)
    key=${1#--no-}
    opts[$key]=no
    ;;
  --)
    shift
    break
    ;;
  --*)
    key=${1#--}
    opts[$key]=yes
    ;;
  *)
    break
  esac

  shift
done

###
# default config
##

server=${opts[server]:-irc.libera.chat}
tls=${opts[tls]:-no}

if [[ $tls = yes ]]; then
  if ! hash socat 2>/dev/null; then
    printf 'please install socat to use tls with rowbot.\n' >&2
    exit 1
  fi

  port=${opts[port]:-6697}
else
  port=${opts[port]:-6667}
fi

level=${opts[log-level]:-info}

if [[ ${opts[log]} ]]; then
  exec {log}>"${opts[log]}"
else
  log=1
fi

nick=${opts[nick]:-rowbot-dev}
ident=${opts[ident]:-rowbot}
realname=${opts[realname]:-rowbot}
chan=${opts[chan]:-}

###
# net code
###

if [[ $tls = yes ]]; then
  coproc sock { socat OPENSSL:"$server":"$port" -; }
  exec {in_sock}<&"${sock[0]}" {out_sock}>&"${sock[1]}"
else
  exec {sock}<>/dev/tcp/"$server"/"$port"
  in_sock=$sock out_sock=$sock
fi

send() {
  local fmt
  printf -v fmt "$1" "${@:2}"
  printf '%s\r\n' "$fmt" >&"$out_sock"
  debug "sending line: %s" "$fmt"
}

recv() {
  declare -n sock_line=$1
  IFS= read -r "$1" <&"$in_sock"
  sock_line=${sock_line%$'\r'}
  debug "received line: %s" "$sock_line"
}

###
# irc recv code
###

on_ERROR() {
  error "${params[0]}"
  exit
}

on_MODE() {
  if (( ${#params[@]} == 2 )); then
    info "%s sets mode(s) %s on %s" "$from" "${params[1]}" "${params[0]}"
  else
    warn "mode line was not handled: %s" "$orig_line"
  fi
}

on_NOTICE() {
  info "[%s/%s] %s" "$from" "${params[0]}" "${params[1]}"
}

on_PING() {
  pong "${params[1]}"
  debug "received ping: %s" "${params[0]}"
}

on_PONG() {
  debug "received pong: %s" "${params[1]}"
}

on_QUIT() {
  info "%s has disconnected: %s" "$from" "${params[0]}"
}

on_001() {
  info %s "${params[1]}"

  if [[ $chan ]]; then
    join "$chan"
  fi

  while true; do
    ping "row your bot gently down the stream"
    sleep 10
  done &

  trap "kill $!" EXIT
}

on_002() {
  info %s "${params[1]}"
}

on_003() {
  info %s "${params[1]}"
}

on_004() {
  debug "%s " "${params[@]:1}"
}

declare -A isupport

on_005() {
  local param key value

  for param in "${params[@]:1:${#params[@]}-2}"; do
    IFS== read -r key value <<< "$param"
    isupport[$key]=$value
    debug "isupport: %s = %s" "$key" "$value"
  done
}

on_250() {
  info %s "${params[1]}"
}

on_251() {
  info %s "${params[1]}"
}

on_252() {
  info "There are %d operators online" "${params[1]}"
}

on_253() {
  info "There are %d unknown connections" "${params[1]}"
}

on_254() {
  info "There are %d channels formed" "${params[1]}"
}

on_255() {
  info %s "${params[1]}"
}

on_265() {
  info %s "${params[3]}"
}

on_266() {
  info %s "${params[3]}"
}

on_372() {
  info %s "${params[1]}"
}

on_375() {
  debug %s "${params[1]}"
}

on_376() {
  debug %s "${params[1]}"
}

###
# irc send code
###

join() {
  send "JOIN %s" "$1"
}

nick() {
  send "NICK %s" "$1"
  info "changing nickname to %s" "$1"
}

ping() {
  send "PING :%s" "$1"
}

pong() {
  send "PONG %s" "$1"
}

privmsg() {
  send "PRIVMSG %s :%s" "$1" "$2"
}

user() {
  send "USER %s * * :%s" "$ident" "$realname"
}

###
# utility hooks
##

hook_JOIN_greet() {
  privmsg "${params[0]}" "Hello, $from!"
}

###
# driver
###

nick "$nick"
user "$ident" "$realname"

while recv line; do
  params=( )
  has_words=no
  orig_line=$line

  if [[ ${line:0:1} = : ]]; then
    src=${line%% *} src=${src#:}
    line=${line#:"$src"} line=${line# }
    from=${src%@*} ident=${from#*!}
    from=${from%!*} host=${src#*@}
  fi

  cmd=${line%% *}
  line=${line#"$cmd"}
  line=${line# }

  while [[ $line ]]; do
    if [[ ${line:0:1} = : ]]; then
      params+=("${line:1}")
      line=""
      has_words=yes
    else
      param=${line%% *}
      params+=("$param")
      line=${line#"$param"} line=${line# }
    fi
  done

  if [[ $has_words = yes ]]; then
    read -ra words <<< "${params[@]:(-1)}"
  else
    words=( )
  fi

  while IFS= read -r hook; do
    "$hook"
  done < <(compgen -A function "hook_${cmd^^}_")

  if hash "on_${cmd^^}" 2>/dev/null; then
    "on_${cmd^^}"
  else
    warn "unhandled line: %s" "$orig_line"
  fi
done