#!/bin/bash
GVM_VERSION="0.8"
PLATFORM=$(uname)

#
# function definitions
#

function help {
	CANDIDATES=$(curl -s "$GVM_SERVICE/candidates")
	echo ""
	echo "Usage: gvm <command> <candidate> [version]"
	echo ""
	echo "   command    :  install, uninstall, list, use, current, version, selfupdate or help"
	echo "   candidate  :  $CANDIDATES"
	echo "   version    :  optional, defaults to latest stable if not provided"
	echo ""
	echo "eg: gvm install grails 2.1.0"
}

function check_candidate_present {
	if [ -z "$1" ]; then
		echo -e "\nNo candidate provided."
		help
		exit 0
	fi
}

function check_version_present {
	if [ -z "$1" ]; then
		echo -e "\nNo candidate version provided."
		help
		exit 0
	fi
}

function determine_candidate_version {
	if [ -z "$1" ]; then
		VERSION=$(curl -s "$GVM_SERVICE/candidates/$CANDIDATE/default")
	else
		VERSION_VALID=$(curl -s "$GVM_SERVICE/candidates/$CANDIDATE/$1")
		if [ $VERSION_VALID == 'valid' ]; then
			VERSION="$1"
		else
			echo ""
			echo "Stop! $1 is not a valid $CANDIDATE version."
			exit 0
		fi
	fi
}

function check_installed {
	if [ -d "$GVM_DIR/$CANDIDATE/$VERSION" ]; then
		echo ""
		echo "Stop! $CANDIDATE $VERSION is already installed."
		exit 0
	fi
}

function check_not_installed {
	if [ ! -d "$GVM_DIR/$CANDIDATE/$VERSION" ]; then
		echo ""
		echo "Stop! $CANDIDATE $VERSION is not installed."
		exit 0
	fi
}

function build_version_csv {
	CANDIDATE="$1"
	CSV=""
	for version in $(ls -1 "$GVM_DIR/$CANDIDATE"); do
		if [ $version != 'current' ]; then
			CSV="$version,$CSV"
		fi
	done
	CSV=${CSV%?}
}

function determine_current_version {
	CANDIDATE="$1"
	CURRENT=$(readlink "$GVM_DIR/$CANDIDATE/current" | sed -e "s_$GVM_DIR/$CANDIDATE/__g")
}

function download {
	CANDIDATE="$1"
	VERSION="$2"
	mkdir -p "$GVM_DIR/archives"
	if [ ! -f "$GVM_DIR/archives/$CANDIDATE-$VERSION.zip" ]; then
		echo ""
		echo "Downloading: $CANDIDATE $VERSION" 
		echo ""
		DOWNLOAD_URL="$GVM_SERVICE/download/$CANDIDATE/$VERSION?platform=$PLATFORM"
		ZIP_ARCHIVE="$GVM_DIR/archives/$CANDIDATE-$VERSION.zip"
		curl -L "$DOWNLOAD_URL" > "$ZIP_ARCHIVE"
		validate_zip "$ZIP_ARCHIVE"
	else
		echo ""
		echo "Found a previously downloaded $CANDIDATE $VERSION archive. Not downloading it again..."
		validate_zip "$GVM_DIR/archives/$CANDIDATE-$VERSION.zip"
	fi
	echo ""
}

function validate_zip {
	ZIP_ARCHIVE="$1"
	ZIP_OK=$(zip -T "$ZIP_ARCHIVE" | grep 'OK')
	if [ -z "$ZIP_OK" ]; then
		rm "$ZIP_ARCHIVE"
		echo ""
		echo "Stop! The archive was corrupt and has been removed! Please try installing again."
		exit 0
	fi
}

function server_down {
	echo "------------------------------------------"
	echo "   This is serious! Service is down!      "
	echo " Please notify: @gvmtool immediately! "
	echo "------------------------------------------"
	exit 0
}

#
# Various sanity checks and default settings
#

if [ ! $(which curl) ]; then
	echo "Please install curl through your package manager before using this tool."
	exit 0
fi

if [ ! "$GVM_SERVICE" ]; then
	GVM_SERVICE="http://localhost:8080"
fi

if [ ! "$GVM_DIR" ]; then
	GVM_DIR="$HOME/.gvm"
fi

if [ ! -d "$GVM_DIR" ]; then
	mkdir "$GVM_DIR"
fi

BROADCAST=$(curl -s "$GVM_SERVICE/app/alive/$GVM_VERSION")
if [ "$BROADCAST" ]; then
	echo "$BROADCAST"
else
	server_down
fi

if [ "$1" == "help" -o -z "$1" ]; then
	help
	exit 0
fi

#
# Command functions
#

function gvm-install {
	CANDIDATE="$1"
	check_candidate_present "$CANDIDATE"
	determine_candidate_version "$2"
	check_installed

	download "$CANDIDATE" "$VERSION"
	echo "Installing: $CANDIDATE $VERSION"

	mkdir -p "$GVM_DIR/$CANDIDATE"

	unzip -oq "$GVM_DIR/archives/$CANDIDATE-$VERSION.zip" -d "/tmp/"
	mv "/tmp/$CANDIDATE-$VERSION" "$GVM_DIR/$CANDIDATE/$VERSION"
	echo "Done installing!"
	echo ""
	echo "Start using $CANDIDATE $VERSION by issuing the following command:"
	echo "   gvm use $CANDIDATE $VERSION"
}

function gvm-use {
	CANDIDATE="$1"
	check_candidate_present "$CANDIDATE"

	determine_candidate_version "$2"
	check_not_installed

	if [ -L "$GVM_DIR/$CANDIDATE/current" ]; then
		unlink "$GVM_DIR/$CANDIDATE/current"
	fi
	ln -s "$GVM_DIR/$CANDIDATE/$VERSION" "$GVM_DIR/$CANDIDATE/current"
	echo ""
	echo Using "$CANDIDATE" version "$VERSION"
}

function gvm-current {
	CANDIDATE="$1"
	check_candidate_present "$CANDIDATE"
	determine_current_version "$CANDIDATE"
	if [ -n "$CURRENT" ]; then
		echo Using "$CANDIDATE" version "$CURRENT"
	else
		echo Not using any version of "$CANDIDATE"
	fi
}

function gvm-list {
	CANDIDATE="$1"
	check_candidate_present "$CANDIDATE"
	build_version_csv "$CANDIDATE"
	determine_current_version "$CANDIDATE"
	FRAGMENT=$(curl -s "$GVM_SERVICE/candidates/$CANDIDATE/list?platform=$PLATFORM&current=$CURRENT&installed=$CSV")
	echo "$FRAGMENT"
}

function gvm-uninstall {
	CANDIDATE="$1"
	VERSION="$2"
	check_candidate_present "$CANDIDATE"
	check_version_present "$VERSION"
	CURRENT=$(readlink "$GVM_DIR/$CANDIDATE/current" | sed -e "s_$GVM_DIR/$CANDIDATE/__g")
	if [ -h "$GVM_DIR/$CANDIDATE/current" -a "$VERSION" == "$CURRENT" ]; then
		echo ""
		echo "Unselecting $CANDIDATE $VERSION..."
		unlink "$GVM_DIR/$CANDIDATE/current"
	fi
	echo ""
	if [ -d "$GVM_DIR/$CANDIDATE/$VERSION" ]; then
		echo "Uninstalling $CANDIDATE $VERSION..."
		rm -rf "$GVM_DIR/$CANDIDATE/$VERSION"
	else
		echo "$CANDIDATE $VERSION is not installed."
	fi
}

function gvm-version {
	echo "Groovy enVironment Manager $GVM_VERSION"
}

function gvm-selfupdate {
	mkdir -p "$GVM_DIR/bin"

	curl -s "$GVM_SERVICE/res/init?platform=$PLATFORM" > "$GVM_DIR/bin/gvm-init.sh"
	curl -s "$GVM_SERVICE/res/gvm" > "$GVM_DIR/bin/gvm"

	chmod +x "$GVM_DIR/bin/gvm-init.sh"
	chmod +x "$GVM_DIR/bin/gvm"

	echo ""
	echo "Successfully upgraded GVM."
	echo ""
}

# INSERT NEW COMMANDS BEFORE HERE

# Check whether the command exists

CMD_TYPE=`type -t gvm-"$1"`

if [ -z $CMD_TYPE ]; then
	echo -e "\nInvalid command: $1"
	help
	exit 0
fi

# Check whether the candidate exists

CANDIDATE_VALID=$(curl -s "$GVM_SERVICE/candidates/$2")
if [ "$CANDIDATE_VALID" == 'invalid' ]; then
	echo -e "\nStop! $2 is not a valid candidate."
	exit 0
fi

# Main command

gvm-"$1" "$2" "$3"