#!/bin/bash

# Minecraft Java serverdir builder

function fail(){
	>&2 echo $@
	exit 1
}

# 1: file 2: attribute
function serverprop_get() {
	sed -n "s/$2=\(.*\)$/\1/p" "$1"
}

# 1: file 2: attribute 3: value
function serverprop_set() {
	if grep -s "^$2=.*$" "$1"; then
		sed -i "s/$2=.*$/$2=$3/g" "$1"
	else
		echo "$2=$3" >> "$1"
	fi
}

function confirm() {
	[ -z "$NO_INTERACTIVE" ] || return 1

	read -p "$@ [y/N] " choice
	case $choice in
		[yY]*)
			return 0;;
		*)
			return 1
	esac
}

# Sub Commands

## world

function world() {
	local CMD="$1"
	case $CMD in
		list) ;&
		create) ;&
		clone) ;&
		backup) ;&
		delete) ;&
		assign)
			shift
			eval 'world_$CMD "$@"'
			;;
		*)
			fail "world: Unknown argument $CMD"
	esac

	exit $?
}

function world_exists() {
	[ -d "$WORLDS/$1" ]
	return $?
}

# 1: world 2: instance
function world_assign() {
	local WORLD="$1"
	local INSTANCE="$2"

	world_exists "$WORLD" \
		||  ( confirm "World not found. Create?" \
		&& world_create "$WORLD" \
		|| fail "World $WORLD not found." )

	[ -f "$WORLDS/$WORLD.lock" ] && fail "$WORLD is already used by another instance."

	echo "ASSIGNED_TO=\"$INSTANCE\"" > "$WORLDS/$WORLD.lock"

	ln -s "$WORLDS/$WORLD" "$INSTANCES/$INSTANCE"
	serverprop_set "$INSTANCES/$INSTANCE/server.properties" level-name "$WORLD"
}


# 1: name
function world_create() {
	world_exists "$1" && fail "World already exists"
	mkdir "$WORLDS/$1"
}

## instance

function instance() {
	local CMD="$1"
	case $CMD in
		list) ;&
		create) ;&
		delete) ;&
		start) ;&
		stop) ;&
		status)
			shift
			eval 'instance_$CMD "$@"'
			;;
		*)
			fail "instance: Unknown argument $CMD"
	esac

	exit $?
}

function instance_exists() {
	[ -d "$INSTANCES/$1" ]
	return $?
}

# 1: name 2: world 3: version
function instance_create() {
	local NAME="$1"
	local WORLD="$2"
	local VERSION="$3"

	instance_exists "$NAME" && fail "$NAME already exists."
	mkdir "$INSTANCES/$NAME"

	version_install "$NAME" "$VERSION"
	confirm "Accept minecraft EULA?" && serverprop_set "$INSTANCES/$NAME/eula.txt" eula true

	world_assign "$WORLD" "$NAME"
}

function instance_start() {
	instance_exists "$1" || fail "instance $1 not found."


	# TODO
}

## version

function version() {
	fail "not implemented"
}

function version_exists() {
	[ -f "$VERSIONS/$1.jar" ]
	return $?
}

# 1: instance 2: version
function version_install() {
	instance_exists "$1" || fail "instance $1 not found."
	version_exists "$2" || fail "version $2 not found."

	local PWD=$(pwd)
	cd "$INSTANCES/$1"

	[ -e "$2.jar" ] && rm "$2.jar"

	ln -s "$VERSIONS/$2.jar" "$2.jar"

	serverprop_set settings.sh MCJAR "$2.jar"

	cd "$PWD"
}

# NO_INTERACTIVE=1

PREFIX=$(pwd)
VERSIONS="$PREFIX/versions"
WORLDS="$PREFIX/worlds"
INSTANCES="$PREFIX/instances"

RUNNER="$PREFIX/runner.sh"

[ -x ./settings.sh ] || fail "settings.sh not found."
source ./settings.sh

CMD="$1"
case $CMD in
	world) ;&
	instance) ;&
	version)
		shift
		eval '$CMD "$@"'
		;;
	*)
		fail "Unknown option $1"
esac