#!/bin/bash

# I keep Julia binaries in /opt/julia with the same directory structure
# as ~/.julia to store different versions, and use this script to switch
# between them. I also like to maintain a link of the ~/.julia folder to
# ~/julia, for easier package development.

JBIN=""
PDIR=""

if [[ ! "$1" ]]; then
	echo "Please specify a version, i.e."
	echo "$ jvm 0.4"
	exit 1
fi

# Look for the package directory
if [[ -d "$HOME/.julia/$1" ]]; then
	PDIR="$HOME/.julia/$1"
elif [[ -d "$HOME/.julia/v$1" ]]; then
	PDIR="$HOME/.julia/v$1"
else
	echo "No Julia packages for version $1 found."
	exit 1
fi

# Look for the executable
if [[ -d "/opt/julia/$1" ]]; then
	JBIN="/opt/julia/$1/bin/julia"
elif [[ -d "/opt/julia/v$1" ]]; then
	JBIN="/opt/julia/v$1/bin/julia"
else
	echo "Didn't find the executable in /opt/julia/<version>"
	exit 1
fi

echo "Linking executable for version $1..."
sudo rm /usr/bin/julia
sudo ln -s $JBIN /usr/bin/julia
echo "Linking packages shortcut for version $1..."
rm -r ~/julia; ln -s $PDIR ~/julia