#!/bin/bash

set -eu

if [ "$#" -lt 1 ]; then
  echo 'Need at least 1 parameter'
  echo '-h for help'
  exit 1
fi

if [ "$1" = "-h" ]; then
    echo '<preseedFilePath> [dist] [arch] [mode] [boot]'
    echo ''
    echo 'Parameters:'
    echo 'seed  preseed file.'
    echo 'img   preferred image.'
    echo 'dist  preferred distribution.'
    echo 'arch  preferred architecture.'
    echo 'mode  whitch mode you want to automatically launch the installer.'
    echo 'boot  kernel boot options'
    echo ''
    echo 'List of supported values for each parameter and their defaults (*):'
    echo 'seed  must be a valid path of an existsing file.'
    echo 'img   netinst, netinst-mini*.'
    echo 'dist  sid, stable*, unstable, stretch, testing.'
    echo 'arch  amd64*, arm64, armhf, i386.'
    echo 'mode  none*, auto, expert.'
    echo 'boot  must be a set of valid kernel boot options'
    exit 0
fi

if [ -z "$1" ]; then
    echo 'Parameter 1 should not be empty or not set!'
    echo 'Issue a valid path of a preseed file. Aborting...'
    exit 1
else
    PRESEED_PATH=$1
fi

if [ -z "$2" ]; then
  IMAGE="netinst-mini"
fi

if [ -z "$3" ]; then
  DIST="stable"
fi

if [ -z "$4" ]; then
  ARCH="amd64"
fi

if [ -z "$5" ]; then
  MODE="none"
fi

if [ -f "$PRESEED_PATH" ]
then
	echo "Preseed file '${PRESEED_PATH}' found."
else
	echo "Preseed file '${PRESEED_PATH}' not found. Aborting..."
    exit 1
fi

SUPPORTED_IMAGES="netinst netinst-mini"
IMAGE=$2

if echo "${SUPPORTED_IMAGES}" | grep -w "${IMAGE}" > /dev/null; then
    echo "Image '${IMAGE}' supported"
else
    echo "Image '${IMAGE}' not supported! Aborting..."
    exit 1
fi

SUPPORTED_DIST="sid stable unstable stretch testing"
DIST=$3

if echo "${SUPPORTED_DIST}" | grep -w "${DIST}" > /dev/null; then
    echo "Dist '${DIST}' supported"
else
    echo "Dist '${DIST}' not supported! Aborting..."
    exit 1
fi

SUPPORTED_ARCH="amd64 armhf arm64"
ARCH=$4

if echo "${SUPPORTED_ARCH}" | grep -w "${ARCH}" > /dev/null; then
    echo "Architecture '${ARCH}' supported"
else
    echo "Architecture '${ARCH}' not supported! Aborting..."
    exit 1
fi

MIRROR="http://debian.mirror.garr.it"

if [ "$IMAGE" == "netinst-mini" ]; then
    IMG_URL="${MIRROR}/debian/dists/${DIST}/main/installer-${ARCH}/current/images/netboot/mini.iso"
else
    if [ "$IMAGE" == "netinst" ]; then
        IMG_URL="${MIRROR}/debian-cd/current/${ARCH}/iso-cd/debian-11.1.0-${ARCH}-${IMAGE}.iso"
    else
        echo "An error occurred in selecting the proper image. Aborting..."
        exit 1
    fi
fi

FILE_ISO="debian-${DIST}-${ARCH}-${IMAGE}.iso"
if [ -f "${FILE_ISO}" ]
then
	echo "${FILE_ISO} found."
else
	echo "${FILE_ISO} not found."
    echo "Downloading..."
    wget -O "${FILE_ISO}" "${IMG_URL}"
fi

SUPPORTED_MODE="none auto expert"
MODE=$5

if echo "${SUPPORTED_MODE}" | grep -w "${MODE}" > /dev/null; then
    echo "Mode '${MODE}' supported"
else
    echo "Mode '${MODE}' not supported! Aborting..."
    exit 1
fi

echo "Extracting..."
7z x -oisofiles "${FILE_ISO}"

# Adding a Preseed File to the Initrd:
# You now have the directory isofiles with all the ISO's files in it. Make
# initrd.gz writable by the user, uncompress it and append a preseed file to
# the initrd. Recompress the initrd and return initrd.gz to its original
# read-only state.

#wget -O isofiles/linux https://d-i.debian.org/daily-images/amd64/daily/netboot/debian-installer/amd64/linux
#wget -O isofiles/initrd.gz https://d-i.debian.org/daily-images/amd64/daily/netboot/debian-installer/amd64/initrd.gz

cp "$PRESEED_PATH" preseed.cfg

if [ "$IMAGE" == "netinst-mini" ]; then
    ISOLINUX_PATH=""

    echo "Patching initrd.gz..."
    gunzip isofiles/initrd.gz
    echo preseed.cfg | cpio -H newc -o -A -F isofiles/initrd
    gzip isofiles/initrd

    # Boot Parameters
    echo "Patching boot parameters..."
    if [ "$MODE" != "none" ]; then
        sed -i "/default/c\default $5" isofiles/isolinux.cfg
        sed -i '/prompt/c\prompt 1' isofiles/isolinux.cfg
        sed -i '/timeout/c\timeout 50' isofiles/isolinux.cfg
    fi
    sed -i "/append priority=low/c\	append priority=low vga=788 initrd=initrd.gz $5 --- " isofiles/adtxt.cfg
    sed -i "/append auto=true/c\	append auto=true priority=critical vga=788 initrd=initrd.gz $5 --- quiet " isofiles/adtxt.cfg
else
    if [ "$IMAGE" == "netinst" ]; then
        ISOLINUX_PATH="isolinux"

        if [ "$ARCH" == "amd64" ]; then
            BUILD_ARCH="amd"
        else
            if [ "$ARCH" == "i386" ]; then
                BUILD_ARCH="386"
            else
                echo "Unsupported arch in the building process. Aborting..."
                exit 1
            fi
        fi

        echo "Patching initrd.gz..."
        gunzip isofiles/install.${BUILD_ARCH}/initrd.gz
        echo preseed.cfg | cpio -H newc -o -A -F isofiles/install.${BUILD_ARCH}/initrd
        gzip isofiles/install.${BUILD_ARCH}/initrd

        # Boot Parameters
        echo "Patching boot parameters..."
        if [ "$MODE" != "none" ]; then
            sed -i "/default/c\default $5" isofiles/isolinux/isolinux.cfg
            sed -i '/prompt/c\prompt 1' isofiles/isolinux/isolinux.cfg
            sed -i '/timeout/c\timeout 50' isofiles/isolinux/isolinux.cfg
        fi
        sed -i "/append priority=low/c\	append priority=low vga=788 initrd=/install.${BUILD_ARCH}/initrd.gz $5 --- " isofiles/isolinux/adtxt.cfg
        sed -i "/append auto=true/c\	append auto=true priority=critical vga=788 initrd=/install.${BUILD_ARCH}/initrd.gz $5 --- quiet " isofiles/isolinux/adtxt.cfg
    else
        echo "An error occurred in selecting the proper image for build process. Aborting..."
        exit 1
    fi
fi

# Import custom files into the ISO
cp -ar custom isofiles/custom || echo "[WARNING] Cannot import 'custom' folder."

# Creating a New Bootable ISO Image:
# The following instructions suffice for i386 and amd64 in legacy BIOS mode.


# The example names get mapped to their roles here
orig_iso="$FILE_ISO"
new_files=isofiles
new_iso="preseed-${FILE_ISO}"
mbr_template=isohdpfx.bin

# Extract MBR template file to disk
dd if="$orig_iso" bs=1 count=432 of="$mbr_template"

# Create the new ISO image
# https://wiki.debian.org/RepackBootableISO#What_is_a_bootable_ISO_9660_image_.3F
echo "Generating patched iso image..."
xorriso -as mkisofs \
   -r -V "Debian $ARCH n" \
   -o "$new_iso" \
   -J -J -joliet-long -cache-inodes \
   -isohybrid-mbr "$mbr_template" \
   -b "${ISOLINUX_PATH}/isolinux.bin" \
   -c boot.cat \
   -boot-load-size 4 -boot-info-table -no-emul-boot \
   -eltorito-alt-boot \
   -e boot/grub/efi.img \
   -no-emul-boot -isohybrid-gpt-basdat -isohybrid-apm-hfsplus \
   "$new_files"

#echo "Generating patched iso image..."
#genisoimage -r -J -b isolinux.bin -c boot.cat \
#            -no-emul-boot -boot-load-size 4 -boot-info-table \
#            -o "preseed-${FILE_ISO}" isofiles

echo "Cleaning temporary files..."
rm -rf isofiles/
rm preseed.cfg
rm isohdpfx.bin

echo "Done."
exit 0