#!/bin/sh

# We need to force Java 8 here since both Java 7 and 9 currently causes the game to crash
export PATH=/usr/lib/jvm/java-8-openjdk/jre/bin/:/usr/lib/jvm/java-8-jre/jre/bin/:$PATH

# Since launching the minecraft launch from the home directory bypass the update mechanism, I'm adding this
# small piece of code that will do a checksum of the versions.json file provided by mojang, if a new version
# of the game is out, I force a download of the launcher just to keep everyone up to date

# those 2 can be overrided if you want
MC_VERSION_URL=${MC_VERSION_URL:-"https://launchermeta.mojang.com/mc/game/version_manifest.json"}
MC_SUM_FILE=${MC_SUM_FILE:-"${HOME}/.minecraft/versions.sum"}

# compute sums
MC_VERSION_SUM=$( curl -s "${MC_VERSION_URL}" | sha256sum | cut -f 1 -d " " )
MC_CURRENT_SUM=$( cat "$MC_SUM_FILE" 2>/dev/null )

if [ "$MC_VERSION_SUM" != "$MC_CURRENT_SUM" ]; then
	export MC_FORCE_UPDATE=1
	echo "$MC_VERSION_SUM" > "$MC_SUM_FILE"
fi

if [ -e "${HOME}/.minecraft/launcher.jar" ] && [ -z "$MC_FORCE_UPDATE" ]; then
	exec java -jar "${HOME}/.minecraft/launcher.jar" $@
else
	exec java -jar /usr/share/minecraft/Minecraft.jar $@
fi

unset MC_FORCE_UPDATE