#!/usr/bin/env bash
# List out the pid for the process that is currently listening on the provided port
# Usage: wtfport find <port>
# Usage: wtfport kill <port>
# Example: wtfport find 3000
# Example: wtfport kill 3000

find_port() {
    local port=$1
    line="$(lsof -i -P -n | grep LISTEN | grep ":$port")"
    pid=$(echo "$line" | awk '{print $2}')
    pid_name=$(echo "$line" | awk '{print $1}')

    # If there's nothing running, exit
    if [[ -z "$pid" ]]; then
        echo >&2 -e "No process found listening on port $port"
        exit 0
    fi

    # output the process name to stderr so it won't be piped along
    echo >&2 -e "Process \"$pid_name\" is listening on port $port"

    # print the process id. It can be piped, for example to pbcopy
    echo -e "$pid"
}

kill_port() {
    local port=$1
    line="$(lsof -i -P -n | grep LISTEN | grep ":$port")"
    pid=$(echo "$line" | awk '{print $2}')
    pid_name=$(echo "$line" | awk '{print $1}')

    # If there's nothing running, exit
    if [[ -z "$pid" ]]; then
        echo >&2 -e "No process found listening on port $port"
        exit 0
    fi

    kill -9 "$pid"
    echo "Killed process \"$pid_name\" listening on port $port"
}

case "$1" in
find | f)
    if [ -z "$2" ]; then
        echo "Usage: wtfport find <port>"
        exit 1
    fi
    find_port "$2"
    ;;
kill | k)
    if [ -z "$2" ]; then
        echo "Usage: wtfport kill <port>"
        exit 1
    fi
    kill_port "$2"
    ;;
*)
    echo "Usage: wtfport <find|kill> <port>"
    exit 1
    ;;
esac