#!/bin/bash

# Minecraft Java serverdir builder

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

function perror() {
	echo $@
} >&2

# 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 -ni "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 $CMD in
		list) ;&
		create) ;&
		clone) ;&
		backup) ;&
		delete) ;&
		unassign) ;&
		assign)
			shift
			eval 'world_$CMD "$@"'
			;;
		*)
			fail "world: Unknown argument $CMD"
	esac

	exit $?
}

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

function world_list() {
	for WORLD in $WORLDS/*/; do
		WORLD=$(basename $WORLD)
		[ -e "$WORLDS/$WORLD.lock" ] && source "$WORLDS/$WORLD.lock"
		[ -z "$ASSIGNED_TO" ] || WORLD="$WORLD (-> $ASSIGNED_TO)"
		echo $WORLD
	done
}

# 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." )

	if [ -f "$WORLDS/$WORLD.lock" ]; then
		source "$WORLDS/$WORLD.lock"
		[ "$ASSIGNED_TO" = "$INSTANCE" ] \
			|| fail "$WORLD is already used by another instance."
	fi

	[ -L "$INSTANCES/$INSTANCE/$WORLD" ] \
		&& rm "$INSTANCES/$INSTANCE/$WORLD"
	[ -e "$INSTANCES/$INSTANCE/$WORLD" ] \
		&& fail "A file/folder named $WORLD already exists in the instance directory."

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

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

# 1: world
function world_unassign() {
	local WORLD="$1"
	world_exists "$WORLD" || fail "World $WORLD not found."

	[ -f "$WORLDS/$WORLD.lock" ] || fail "World is not in use."
	source "$WORLDS/$WORLD.lock"
	rm "$WORLDS/$WORLD.lock"

	[ -L "$INSTANCES/$ASSIGNED_TO/$WORLD" ] && rm "$INSTANCES/$ASSIGNED_TO/$WORLD"
	echo "$WORLD was assigned to $ASSIGNED_TO"

	#serverprop_set "$WORLDS/$WORLD/settings.sh" LOCK 1
}

function world_clone() {
	fail "TODO"
}

function world_backup() {
	fail "TODO"
}

function world_restore() {
	fail "TODO"
}

function world_delete() {
	fail "TODO"
}

# 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_list() {
	for INSTANCE in $INSTANCES/*/; do
		INSTANCE="$(basename "$INSTANCE")"
		instance_status "$INSTANCE" > /dev/null 2>&1 && INSTANCE+=" (RUNNING)"
		echo "$INSTANCE"
	done
	return 0
}

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

	local PWD="$(pwd)"

	cd "$INSTANCES/$1"

	$RUNNER status
	local RET=$?

	cd "$PWD"
	return $RET
}

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

# 1: name
function instance_create() {
	local NAME="$1"

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

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

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

	fail "TODO"
}

function instance_stop() {
	fail "TODO"
}

## version

function version() {
	local CMD="$1"
	case $CMD in
		list) ;&
		install) ;&
		uninstall)
			shift
			eval 'version_$CMD "$@"'
			;;
		*)
			fail "version: Unknown argument $CMD"
	esac

	exit $?
}

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

function version_list() {
	for VERSION in $VERSIONS/*.jar; do
		VERSION="$(basename "$VERSION")"

		echo "${VERSION%%.jar}"
	done
	return 0
}

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

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

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

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

	serverprop_set settings.sh MCJAR "$VERSION.jar"

	cd "$PWD"
}

function version_uninstall() {
	fail "TODO"
}

# NO_INTERACTIVE=1

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

RUNNER="$PREFIX/runner.sh"

[ -e ./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