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

###
# net code
###

if [[ $tls = yes ]]; then
  coproc sock { socat OPENSSL:"$server":"$port" -; }
  in_sock=${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"
}

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

###
# driver
###

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

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