#!/usr/bin/env bash

dir="$( cd "$( dirname "$0" )" && pwd )"

if [ -z "$1" ]; then
    echo "invalid args"
    exit
fi
if [ -z "$2" ]; then
    echo "invalid args"
    exit
fi

lang=$1
epoch=$(date +%s%3N)
basepath="/var/lib/lxc/piston/rootfs"
filepath="/tmp/$epoch/code.code"
argpath="/tmp/$epoch/args.args"
arg=$(basename $argpath)

# write arg file
mkdir -p $basepath/tmp/$epoch
chmod 777 $basepath/tmp/$epoch
cat $2 > $basepath$filepath
echo "${@:3}" > $basepath$argpath

# process incrementor
oldinc=$(cat $dir/i | awk '{$1=$1};1')
newinc=$(expr $oldinc + 1)

if (( newinc >= 151 )); then
    newinc=1
    echo 1 > $dir/i
else
    echo $newinc > $dir/i
fi

bin=
case "$lang" in
"python2")
    bin=python2
    ;;
"python" | "python3")
    bin=python3
    ;;
"ruby")
    bin=ruby
    ;;
"javascript" | "js" | "node")
    bin=node
    ;;
"c")
    bin=c
    ;;
"cpp" | "c++")
    bin=cpp
    ;;
"go")
    bin=go
    ;;
"c#" | "csharp" | "cs")
    bin=csharp
    ;;
"r")
    bin=r
    ;;
"php")
    bin=php
    ;;
"nasm" | "asm")
    bin=nasm
    ;;
"java")
    bin=java
    ;;
*)
    echo "invalid language"
    exit
esac

# runner
lxc-attach -n piston -- \
    /bin/bash -c "\
        PATH=/bin:/usr/bin:/usr/local/sbin:/usr/sbin:/sbin \
        bash /exec/$bin $newinc $epoch 2>&1 | head -c 65536"

# process janitor
lxc-attach -n piston -- \
    /bin/bash -c "for i in {1..2000}; do pkill -u runner$newinc --signal SIGKILL; done" > /dev/null 2>&1 &

rm -rf $basepath/tmp/$epoch