get-irc-bans.sh

#!/usr/bin/env bash
# shellcheck disable=SC2039

HOST=$1
PORT=$2
NAME=$3

NICK="imabot"
USER="$NICK :$NICK"

exec 3<>/dev/tcp/$HOST/$PORT

echo -e "NICK $NICK\r\nUSER $NICK $NICK $NICK :$NICK\r\n" >&3

# shellcheck disable=SC2039

# PARSE an irc message into a $PREFIX and array of $PARAMS and a $TAIL
# the $TAIL is also the last element of the $PARAMS array
parse_irc_msg() {
    __MSG=$1

    clean_irc_msg
    for (( __i=0; __i<${#__MSG}; __i++ )); do
        __CHAR="${__MSG:$__i:1}"

        # IF the first char is a : there is a prefix
        if [ $__i = 0 ] && [ "$__CHAR" = ":" ]; then
            PREFIX="${__MSG:$((__i + 1))}"
            PREFIX="${PREFIX%% *}"
            __i=$((__i + ${#PREFIX} + 1))
        # IF there is any other : in the message
        # it is the tail and after that end of message
        elif [ "$__CHAR" = ":" ]; then
            TAIL="${__MSG:$((__i + 1))}"
            PARAMS+=("$TAIL")
            break
        # Anything else is a normal parameter
        # and gets parsed without any spaces
        else
            __PARAM="${__MSG:$__i}"
            __PARAM="${__PARAM%% *}"
            __PARAM="${__PARAM##*( )}"

            # IF this is the first string after a space
            # it is the command
            if [ -z "$CMD" ]; then
                CMD="$__PARAM"
            else
                PARAMS+=("$__PARAM")
            fi

            __i=$((__i + ${#__PARAM}))
        fi

        unset __PARAM
        unset __CHAR
    done

    unset __i
    unset __MSG
}

clean_irc_msg() {
    unset PREFIX
    unset CMD
    unset PARAMS
    unset TAIL
}

while IFS="\r\n" read -r msg; do
    [ -n "$DEBUG" ] && echo "$msg"
    parse_irc_msg "$msg"
    if [ "$CMD" = "PING" ]; then
        echo -e "PONG $TAIL" >&3 &
    elif [ "$CMD" = "001" ]; then
        ( sleep 60; echo -e "LIST" >&3 ) &
#        echo -e "MODE #gnulag +b" >&3
    elif [ "$CMD" = "322" ]; then
        CHANNELS+=("${PARAMS[1]}")
    elif [ "$CMD" = "323" ]; then
        ( for channel in "${CHANNELS[@]}"; do
            if [ "${channel:0:1}" = "#" ]; then
                sleep 1
                echo -e "MODE $channel +b" >&3
            fi
          done ) &
    elif [ "$CMD" = "367" ]; then
        BAN="${PARAMS[2]}"
        if [[ "$BAN" == *"$NAME"* ]]; then
            echo "${PARAMS[1]}"
            BANNED_CHANNELS+=("${PARAMS[2]}")
        fi
    fi
done <&3