#!/bin/bash
# Copyright (C)  2016-2018 Iru Cai <mytbk920423@gmail.com>
# SPDX-License-Identifier: GPL-3.0-or-later

set -e

DISTROLIST=()
ISOLIST=()
BOOTPATH=
ROOTPATH=
DEVNAME=
KERNELDIR=
DATADIR=
INSTALL_GRUB=1
GRUBCFG_ONLY=0
DOWNLOAD_ONLY=0
UMOUNT_BOOT=0
UMOUNT_ROOT=0
CLEAN_USB=0

. functions.sh

msg() {
	echo -e "$1" >&2
}

fatalerror() {
	msg "\x1b[1;31m$1\x1b[0m"
	exit 1
}

usage() {
	>&2 cat << EOF
$0 [--root <path>] [options] [--distro=<metadist> <isofile>] [distro] ...
use $0 -L to list available distros
options:
  --root <path>
  --root=<path>: set the path to put the live USB data files
  --boot <path>
  --boot=<path>: set the path to put the kernel and loader files
  --clean: clean the old live USB files before installing
  --no-grub: do not install GRUB loader (still generate grub.cfg)
  --grubcfg: do not do real install, only generate grub.cfg file
  --downloadonly: only download the ISO files
  --dev=<diskdev>: write boot sector to <diskdev> (default <diskdev> is autodetected from <rootpath>)
EOF
}

try_mount() {
	local mnt
	if [[ "$1" =~ ^/dev ]]
	then
		if ! findmnt "$1" > /dev/null
		then
			udevil mount "$1" > /dev/null
			mnt=$(findmnt -n -o TARGET "$1")
		else
			mnt=$(findmnt -n -o TARGET "$1")
		fi
	else
		mnt="$1"
	fi
	echo "$mnt"
}

unset ISOPATH
CFGFILE="$HOME/.liveusb-builder"
test -f "$CFGFILE" && source "$CFGFILE" || true
ISOPATH=${ISOPATH:-"$HOME/isofiles"}

while [[ -n "$1" ]]
do
	case "$1" in
		-L)
			exec ./listisos.sh
			;;
		--boot=*)
			BOOTPATH="${1/--boot=}"
			;;
		--boot)
			shift
			BOOTPATH="$1"
			;;
		--root=*)
			ROOTPATH="${1/--root=}"
			;;
		--root)
			shift
			ROOTPATH="$1"
			;;
		--dev=*)
			DEVNAME=${1/--dev=}
			;;
		--no-grub)
			INSTALL_GRUB=0
			;;
		--grubcfg)
			GRUBCFG_ONLY=1
			;;
		--downloadonly)
			DOWNLOAD_ONLY=1
			;;
		--clean)
			CLEAN_USB=1
			;;
		--distro=*)
			metadist="${1/--distro=}"
			if [ ! -f "distro/$metadist/meta" ]
			then
				fatalerror "distro/$metadist/meta not found"
			fi
			shift
			isofn="$1"
			if [ ! -f "$isofn" ]
			then
				fatalerror "File $isofn not found"
			fi
			DISTROLIST=(${DISTROLIST[@]} "/meta@$metadist@$isofn")
			;;
		*=*|-*)
			usage
			exit 1
			;;
		*)
			if [ -f "distro/$1/isoinfo" ]
			then
				DISTROLIST=(${DISTROLIST[@]} "$1")
			else
				fatalerror "directory distro/$1/isoinfo not found"
			fi
			;;
	esac
	shift
done

if [[ -z "$ROOTPATH" && "$DOWNLOAD_ONLY" == 0 ]]; then
	usage
	exit 1
fi

_mnt="$(try_mount "$ROOTPATH")"
if [ "${_mnt}" != "$ROOTPATH" ]; then
	ROOTPATH="${_mnt}"
	UMOUNT_ROOT=1
fi

if [[ -z "$BOOTPATH" ]]; then
	BOOTPATH="$ROOTPATH"
else
	_mnt="$(try_mount "$BOOTPATH")"
	if [ "${_mnt}" != "$BOOTPATH" ]; then
		BOOTPATH="${_mnt}"
		UMOUNT_BOOT=1
	fi
fi

if [[ "$DOWNLOAD_ONLY" == 0 ]]; then
	UUID="$(findmnt -o UUID --raw --noheadings $ROOTPATH \
		|| fatalerror "UUID of $ROOTPATH not found, not a mountpoint?")"
	BOOTPART="$(findmnt -o SOURCE --raw --noheadings $BOOTPATH \
		|| fatalerror "$BOOTPATH seems not a mountpoint!")"
	# liveusb kernel and data should be placed on one disk
	# so get DEVNAME by the mountpoint of ROOTPATH is ok
	DEVNAME="/dev/$(getdiskbypart "/dev/disk/by-uuid/$UUID")"

	KERNELDIR="$BOOTPATH/liveusb-kernel"
	DATADIR="$ROOTPATH/liveusb-data"
	GRUBCFG="$BOOTPATH/grub/grub.cfg"
	SYSLINUXCFG="$BOOTPATH/syslinux/syslinux.cfg"
	install -d "$BOOTPATH/grub" "$BOOTPATH/syslinux"
	install -d "$KERNELDIR" "$DATADIR"
	msg "Files will be copy to $ROOTPATH"
fi

if [[ "${#DISTROLIST[@]}" == 0 ]]; then
	usage
	exit 1
fi

if [ ! -z "$DEVNAME" ]; then
	msg "Boot sector will be written to $DEVNAME"
fi

if [[ "$CLEAN_USB" = 1 ]]; then
	msg "Cleaning old live USB files."
	rm -rf "$KERNELDIR"/* "$DATADIR"/*
fi

for i in ${DISTROLIST[@]}
do
	if [[ "$i" == /meta@* ]]
	then
		# FIXME: we assume the meta file path and the iso file name
		#	 does not have '@' character
		ISOFILE="$(echo "$i" | cut -d@ -f3)"
		ISOLIST=("${ISOLIST[@]}" "$ISOFILE")
		# TODO: we just use the file name as the ISO name
		# 	can we do it better?
		ISONAMELIST=("${ISONAMELIST[@]}" "$(basename "$ISOFILE")")
		continue
	fi
	process_isoinfo "$i"
	ISOLIST=("${ISOLIST[@]}" "$ISOFILE")
	ISONAMELIST=("${ISONAMELIST[@]}" "$ISONAME")

	if [ -f "$ISOPATH/$ISOFILE" ] && checksum_verify; then
		true
	else
		download_iso
	fi
done

if [[ "$DOWNLOAD_ONLY" == 1 ]]; then
	exit 0
fi

grubcfg_header > "$GRUBCFG"
syslinux_header > "$SYSLINUXCFG"

for i in `seq 1 ${#DISTROLIST[@]}`
do
	ISOFILE="${ISOLIST[$i-1]}"
	ISONAME="${ISONAMELIST[$i-1]}"
	DISTRO="${DISTROLIST[$i-1]}"
	ISO_FILEPATH="$ISOPATH/$ISOFILE"

	if [[ "$DISTRO" == /meta@* ]]
	then
		metadir="$(echo "$DISTRO" | cut -d@ -f2)"
		_meta=meta_
		ISO_FILEPATH="$ISOFILE"
		DISTRO="$metadir"
		set_distro "$metadir"
		KEYWORD="$ISONAME"
		source "distro/$metadir/meta"
	else
		_meta=
		ISO_FILEPATH="$ISOPATH/$ISOFILE"
		set_distro "$DISTRO"
		export DISTRONAME KEYWORD # for grub and syslinux generation
		process_distro "$DISTRO"
	fi

	if [ "$GRUBCFG_ONLY" == 0 ]; then
		install_live
	fi
	${_meta}gen_grubcfg "$DISTRO" >> "$GRUBCFG"
	${_meta}gen_syslinux "$DISTRO" >> "$SYSLINUXCFG"
done

if [ "$GRUBCFG_ONLY" == 1 ]; then
	msg 'Only generate grub.cfg and syslinux.cfg, will not install bootloader.'
elif [ "$INSTALL_GRUB" == 1 ]; then
	read -p 'Answer Y to install bootloader.[Y/n] '
	if [[ "$REPLY" =~ ^[Yy]|^$ ]]; then
		if ! as-root ./install_syslinux "$DEVNAME" "$BOOTPART" "$BOOTPATH"; then
			msg 'Failed to install syslinux, try to install GRUB as legacy BIOS bootloader.'
			as-root grub-install --force --boot-directory="$BOOTPATH" --target=i386-pc "$DEVNAME"
		fi
		as-root grub-install --boot-directory="$BOOTPATH" --efi-directory="$BOOTPATH" --bootloader-id=grub --target=x86_64-efi --removable --no-nvram "$DEVNAME"
	fi
fi

if [ "$UMOUNT_BOOT" == 1 ]; then
	msg 'Trying to umount the boot mountpoint, you may need to wait for sync() to complete.'
	udevil umount "$BOOTPATH"
fi
if [ "$UMOUNT_ROOT" == 1 -a "$ROOTPATH" != "$BOOTPATH" ]; then
	msg 'Trying to umount the root mountpoint, you may need to wait for sync() to complete.'
	udevil umount "$ROOTPATH"
fi