#!/bin/bash

mkdiskimg () {
    # Prepare image file
    cp /usr/lib/syslinux/bios/gptmbr.bin $1
    truncate -s 64M $1
    sgdisk -n 1:0:0 $1
    sgdisk -t 1:ef00 $1
    sgdisk -A 1:set:2 $1
    loopdev="$(losetup --show -f $1)"
    partprobe $loopdev
    mkfs.fat -n SEDUTILPBA "${loopdev}p1"
    syslinux -i "${loopdev}p1"
    
    # Mount image and copy files
    mount "${loopdev}p1" mnt
    mkdir -p mnt/EFI/BOOT
    cp /boot/$2 mnt/vmlinuz-linux
    cp /boot/$3 mnt/linuxpba.img
    cp /usr/lib/linuxpba/syslinux.cfg mnt/syslinux.cfg
    if [[ -e /boot/intel-ucode.img ]]
    then
        cp /boot/intel-ucode.img mnt/intel-ucode.img
    else
        sed -i 's/\/intel-ucode.img,//' mnt/syslinux.cfg
    fi
    cp mnt/syslinux.cfg mnt/EFI/BOOT/syslinux.cfg
    cp /usr/lib/syslinux/efi64/syslinux.efi mnt/EFI/BOOT/BOOTX64.EFI
    cp /usr/lib/syslinux/efi64/ldlinux.e64 mnt/EFI/BOOT
    
    # Unmount image
    umount mnt
    losetup -d "$loopdev"
}


if [[ ! -e /usr/bin/extlinux ]]
then
    echo "syslinux is not installed: nothing to do."
    exit 1
fi

if [[ ! -e /usr/bin/gdisk ]]
then
    echo "gptfdisk is not installed: nothing to do."
    exit 1
fi

if [[ ! -e /usr/bin/partprobe ]]
then
    echo "parted is not installed: nothing to do."
    exit 1
fi

mklinuxpba-initramfs

kernel_release="$(uname -r)"

case "${kernel_release##*-}" in
    "ARCH")
        kernel_image="vmlinuz-linux"
    ;;
    "lts")
        kernel_image="vmlinuz-linux-lts"
    ;;
    *)
        echo "The currenly running kernel is not supported."
        exit 1
    ;;
esac

mkdir -p "/tmp/linuxpbatemp/mnt"
pushd "/tmp/linuxpbatemp"

mkdiskimg linuxpba.diskimg $kernel_image linuxpba.img
mkdiskimg linuxpba-fallback.diskimg $kernel_image linuxpba-fallback.img

mv linuxpba.diskimg linuxpba-fallback.diskimg /boot
cd /tmp
rmdir -p linuxpbatemp/mnt
popd