#!/bin/bash
set -e

#
# warning this destroys target disk
#

function diskprep {
	[[ -z $disk ]] && echo disk not defined && exit 1

	total=`fdisk -l /dev/$disk | head -1 | awk '{print $7}'`

	# EFI type=ef
	#2048 * 512 = 1048576

	# swap type=82
	#2048 * 1024 = 2097152

	echo -n writing $disk.sfdisk...
	cat > $disk.sfdisk <<EOF && echo done
label: dos
label-id: 0x8ae$((RANDOM % 10))$((RANDOM % 10))3cc
device: $disk
unit: sectors

/dev/${disk}1 : start=2048, size=$((total-2097152-2048)), type=83, bootable
/dev/${disk}2 : start=$((total-2097152)), size=2097152, type=82
EOF

	echo -n applying $disk.sfdisk...
	sfdisk /dev/$disk < $disk.sfdisk

	echo -n partprobe...
	partprobe /dev/$disk && echo done

	fdisk -l /dev/$disk

	echo everything fine? \(y/n\)
	read -r input
	[[ $input != y ]] && exit 1
	unset input

}

function fsprep_mount {
        [[ -z $disk ]] && echo disk not defined && exit 1

        mkswap /dev/${disk}2

	# todo - enable fs_type
	# self-verbose
	mkfs.ext4 /dev/${disk}1

	mkdir -p lala/
	touch lala/NOT_MOUNTED
	mount /dev/${disk}1 lala/

	mkdir lala/proc/
	mount -o bind /proc lala/proc
}

[[ ! -x `which fdisk` ]]	&& echo fdisk executable not found && exit 1
[[ ! -x `which sfdisk` ]]	&& echo sfdisk executable not found && exit 1
[[ ! -x `which partprobe` ]]	&& echo partprobe executable not found && exit 1
[[ ! -x `which mkswap` ]]	&& echo mkswap executable not found && exit 1
[[ ! -x `which mkfs.ext4` ]]	&& echo mkfs.ext4 executable not found && exit 1

[[ -z $1 ]] && echo target disk?  e.g. sda or vda && exit 1
disk=$1

diskprep
fsprep_mount

ls -alhF lala/