#!/bin/bash
set -uo pipefail


################################################
# Initialize script environment

# Find the directory this script is stored in. (from: http://stackoverflow.com/questions/59895)
function get_source_dir() {
	local source="${BASH_SOURCE[0]}"
	while [[ -h $source ]]
	do
		local tmp="$(cd -P "$(dirname "${source}")" && pwd)"
		source="$(readlink "${source}")"
		[[ $source != /* ]] && source="${tmp}/${source}"
	done

	echo -n "$(realpath "$(dirname "${source}")")"
}

export ACTUAL_WORKING_DIRECTORY="$(realpath "$(pwd)")"
export GENTOO_INSTALL_REPO_DIR_ORIGINAL="$(get_source_dir)"
export GENTOO_INSTALL_REPO_DIR="$GENTOO_INSTALL_REPO_DIR_ORIGINAL"
export GENTOO_INSTALL_REPO_SCRIPT_ACTIVE=true
export GENTOO_INSTALL_REPO_SCRIPT_PID=$$

umask 0077

source "$GENTOO_INSTALL_REPO_DIR/scripts/utils.sh"
source "$GENTOO_INSTALL_REPO_DIR/scripts/config.sh"
source "$GENTOO_INSTALL_REPO_DIR/scripts/functions.sh"
source "$GENTOO_INSTALL_REPO_DIR/scripts/main.sh"


################################################
# Main dispatch

# Instantly kill when pressing ctrl-c
trap 'kill "$GENTOO_INSTALL_REPO_SCRIPT_PID"' INT

ACTION=""
CONFIG="$GENTOO_INSTALL_REPO_DIR/gentoo.conf"

while [[ $# -gt 0 ]]; do
	case "$1" in
		""|"help"|"--help"|"-help"|"-h")
			echo "Usage: $0 [opts]... <action>"
			echo "Performs a minimal gentoo installation. See https://github.com/oddlama/gentoo-install"
			echo "for more information. If the configuration file does not exist, the configurator will"
			echo "be started instead."
			echo ""
			echo "Options:"
			echo "  -c, --config <CONFIG>    Use the given configuration file instead of the default"
			echo "                           location (gentoo.conf). Applies to installation as well"
			echo "                           as initial configuration in case it doesn't exist."
			echo ""
			echo "Actions:"
			echo "  -i, --install            Installs gentoo as configured. (default if configuration exists)"
			echo "  -R, --chroot             Chroot into an existing system. The root filesystem"
			echo "                           is mounted automatically based on the partition"
			echo "                           UUIDs (generated when installing for the first time),"
			echo "                           and unmounted when the chroot exits"
			echo "  -u, --umount             Try to unmount all associated mountpoints. (Only needed"
			echo "                           if anything gets forcefully interrupted)"
			exit 0
			;;
		"-c"|"--config")
			[[ -f "$2" ]] \
				|| die "Config file not found: '$2'"
			CONFIG="$(cd "$ACTUAL_WORKING_DIRECTORY"; realpath --relative-to="$GENTOO_INSTALL_REPO_DIR" "$2" 2>/dev/null)"
			shift
			;;
		"-R"|"--chroot")
			[[ -z $ACTION ]] || die "Multiple actions given"
			ACTION="chroot"
			;;
		"-i"|"--install")
			[[ -z $ACTION ]] || die "Multiple actions given"
			ACTION="install"
			;;
		"-u"|"--umount"|"--unmount")
			[[ -z $ACTION ]] || die "Multiple actions given"
			ACTION="umount"
			;;
		"__install_gentoo_in_chroot")
			ACTION="__install_gentoo_in_chroot"
			;;
		*) die "Invalid option '$1'" ;;
	esac
	shift
done

# Check configuration location
[[ -z "${CONFIG%%$GENTOO_INSTALL_REPO_DIR*}" ]] \
	|| die "Configuration file must be inside the installation directory. This is needed so it is accessible from within the chroot environment."

if [[ -z "$ACTION" ]]; then
	if [[ -e "$CONFIG" ]]; then
		# Default if configuration exists: Run installer
		ACTION="install"
	else
		# Default if configuration does not exists: Run configurator, and exit afterwards.
		exec "$GENTOO_INSTALL_REPO_DIR/configure" "$CONFIG"
	fi
fi

# Load config
[[ -e "$CONFIG" ]] \
	|| die "Configuration file '$CONFIG' does not exist. To run the configurator, omit '-i' or "

source "$CONFIG"
[[ $I_HAVE_READ_AND_EDITED_THE_CONFIG_PROPERLY == "true" ]] \
	|| die "You have not properly read the config. Edit the config file and set I_HAVE_READ_AND_EDITED_THE_CONFIG_PROPERLY=true to continue."

preprocess_config
[[ $EUID == 0 ]] \
	|| die "Must be root"

mkdir_or_die 0755 "$TMP_DIR"

case "$ACTION" in
	"chroot")  main_chroot "$@" ;;
	"install") main_install "$@" ;;
	"umount")  main_umount "$@" ;;
	"__install_gentoo_in_chroot") main_install_gentoo_in_chroot "$@" ;;
	*) die "Invalid action '$ACTION'" ;;
esac