#!/bin/sh

# This script can launch a Debian Installer instance. It has multiple plugins
# that must provide the following methods:
#
#  - <plugin>_usage
#  - <plugin>_cleanup
#  - <plugin>_prepare
#  - <plugin>_run

set -e

call_for_plugin()
{
	plugin=$1
	method=$2
	shift 2

	args="$@"

	if ! ${plugin}_${method} $args; then
		return 1
	fi

	return 0
}

call_for_plugins()
{
	method=$1
	shift

	args="$@"

	for p in $PLUGINS; do
		call_for_plugin $p $method $args
	done
}

usage()
{
	cat <<EOF
Debian Installer Launcher

OPTIONS:

   -p, --plugin  Plugin to use

$(call_for_plugins "usage")



EOF
}

run_hook_scripts() {
	if [ -d /usr/share/debian-installer-launcher/hooks ]; then
		run-parts "$@" /usr/share/debian-installer-launcher/hooks
	fi
}

cleanup()
{
	call_for_plugins "cleanup"
	run_hook_scripts --reverse --arg=cleanup
}

PLUGINS_DIR="/usr/share/debian-installer-launcher/plugins"
PLUGINS=""
PLUGIN=""

# Setup cleanup function
trap 'cleanup' EXIT HUP INT QUIT TERM

# For easy development, override it in case we are in the source tree
[ -x debian-installer-launcher ] && PLUGINS_DIR="plugins"

# Load plugins
for p in $PLUGINS_DIR/*; do
	. $p
	PLUGINS="${p#$PLUGINS_DIR/} $PLUGINS"
done

# Default to live plugin on live systems
if [ -e /run/live/medium ]; then
	PLUGIN=live
else
	PLUGIN=kexec
fi

# Handle generic launcher arguments
for arg in $@; do
	case "$arg" in
		-h|--help)
			usage
			exit 0
			;;
		-p=*|--plugin=*)
			PLUGIN=${arg#*=}
			;;
	esac
done

# Check for plugin
if ! echo $PLUGINS | grep -q $PLUGIN; then
	echo "ERROR: '$PLUGIN' is not a valid plugin. Check and try again."
	exit 1
fi

run_hook_scripts --arg=startup

if call_for_plugin $PLUGIN "prepare" $@; then
	call_for_plugin $PLUGIN "run"
fi