#!/bin/bash

# restarts program upon file changing, useful for writing code without having to restart it.
# also accepts a enter key to restart the program
# bugs, only works on scripts, kills everything with the name of the script except this script itself.

FULLCOMMAND="$@"
COMMAND=${FULLCOMMAND%% *}

# check if args set
if [ -z $1 ]; then
    echo "Usage $0 /full/path/to/myScript.xyz <arguments>"
    exit 1
fi
FILENAME=$(basename $COMMAND)

# Binary checking
#for i in inotifywait basename ps grep ;do
for i in basename ps grep ;do
    command -v $i >/dev/null 2>&1 || { echo >&2 "$0 - I require $i but it's not installed.  Aborting."; exit 1; }
done


# check if file actually exists
if [ ! -f "$COMMAND" ]; then
    echo "File $COMMAND not found!"
    exit 1
fi

function MonitorForChange() {
    # either waits for a file modification date change or a keypress
    origFilestamp=$(ls --time-style='+%d-%m-%Y %H:%M:%S' -l ${COMMAND})
    lastFilestamp=""
    while true; do
        lastFilestamp=$(ls --time-style='+%d-%m-%Y %H:%M:%S' -l ${COMMAND})
        if [ "$lastFilestamp" != "$origFilestamp" ] ; then
            return
        fi
        read -t 0.1 -n 1 foo
        if [ $? == 0 ]; then
            return
        fi
    done
}

# kill it
function Kill() {
    # dont kill this script but everything with the FILENAME var
    $(ps -ef | grep $FILENAME | awk '{print $2}' | grep -v ^$$\$ | xargs kill -15)
    # kill $PID 2>/dev/null | xargs
}

# start it
function Start() {
    # tweak to suit
    # $($FULLCOMMAND)
    source ${FULLCOMMAND} &
    # python ${FULLCOMMAND} &
    # bash -c "FULLCOMMAND"
}

while true; do
    Kill
    Start
    MonitorForChange
    echo "$0 - Program changed!"
done