#!/bin/bash
#
# Script de creation d'un media bootable Debian
# Pour l'ACAQB
#
# Dépend : syslinux,wget
#
OPTIND=1
DEBIAN_VERSION="8.6.0"
DEBIAN_ARCH="amd64"
BOOT_TYPE="efi64"
SYSLINUX_VERSION="6.03"
SYSLINUX_FILES="menu.c32 vesamenu.c32 libutil.c32 libcom32.c32"
SYSLINUX_BIOS_FILES=""
SYSLINUX_EFI_FILES="ldlinux.e64"
TMP_DIR="tmp"
MOUNT_DIR="/mnt/usbstick"

usage() {
    cat << EOF
USAGE: ${0} [-a architecture] [-b] 
    -a  amd64 | i386 CPU architecture
    -b bios boot type (default is efi64)
    -d device_block USB key to write
    
${0} initialize an usb key for Debian automatic install with preseed and a partman recipe.
EOF
}

download (){
    #Download function
    # $1 : filename
    # $2 : url
    # $3 : 1 if abort download if file exist
    echo -ne "Downloading $1 ... "
    if [[ -f $1 && $3 == "1" ]]
    then
        echo file already downloaded.
        return
    fi
    wget ‐‐no-clobber -4 $2/$1 &> /dev/null
    echo "done!"
}

create_dir(){
    # $1 directory to create
    if [ ! -d $1 ]; then mkdir -p $1; fi
}

# Arguments ...
while getopts "ha:bd:" opt; do
    case "$opt" in
        h)
            usage
            exit 0
            ;;
        a)
            if [[ $OPTARG == "amd64" || $OPTARG == "i386" ]]
            then
                DEBIAN_ARCH=$OPTARG
            else
                echo "CPU architecture must be amd64 of i386, bye."
                exit 1
            fi
            ;;
        b)
            BOOT_TYPE="bios"
            ;;
        d)
            if [ -b $OPTARG ]
            then
                dest=$OPTARG
            else
                echo "Destination is not a block device, bye."
                exit 1
            fi
            ;;
    esac
done

# Création du répertoire temporaire
if [ ! -d $TMP_DIR ]; then mkdir $TMP_DIR; fi

if [[ -z $dest ]]
then
    echo "No destination device specified, USB key will not be created."
fi

bootfiles_Debian="http://ftp.debian.org/debian/dists/jessie/main/installer-${DEBIAN_ARCH}/current/images/hd-media"
iso_url="http://cdimage.debian.org/debian-cd/${DEBIAN_VERSION}/${DEBIAN_ARCH}/iso-cd/"
iso_file="debian-${DEBIAN_VERSION}-${DEBIAN_ARCH}-netinst.iso "
syslinux_mod="/usr/lib/syslinux/"
current_dir=`pwd`

# Download Debian files (kernel, initrd and iso)
echo -e "\nPrepare Debian files\n---"
for file in "vmlinuz" "initrd.gz" 
do
    download $file $bootfiles_Debian 1
done
download $iso_file $iso_url 1

# Copy wanted syslinux file from archive
for file in $SYSLINUX_FILES
do
    echo "copie de $file"  
    cp ${syslinux_mod}/${BOOT_TYPE}/${file} ./syslinux/
done

case $BOOT_TYPE in
    efi64)
        for file in $SYSLINUX_EFI_FILES
        do
            echo "copying $file ..." 
            cp ${syslinux_mod}/${BOOT_TYPE}/${file} ./syslinux/
        done
        create_dir "EFI/boot"
        cp -T ${syslinux_mod}/${BOOT_TYPE}/efi/syslinux.efi EFI/boot/bootx64.efi
        ;;
    bios)
        for file in $SYSLINUX_BIOS_FILES
        do
            echo "copying $file ..." 
            cp ${syslinux_mod}/${BOOT_TYPE}/${file} ./syslinux/
        done
        ;;
esac

if [[ -n $dest ]]
then
    read -p "[WARNING] Disk $dest will be erased continue [Y/N]? " -n 1 -r
    if [[ ! $REPLY =~ ^[Yy]$ ]]
    then
       exit 1
    fi
    #dd if=/dev/zero of=${dest} bs=512 count=1 conv=notrunc &> /dev/null
    echo -e "\nCreating partition"
    parted -s ${dest} mklabel msdos mkpart primary fat32 1MiB 100% set 1 boot on
    mkfs.vfat ${dest}1 -n debian &> /dev/null
    
    # mount and copy
    create_dir $MOUNT_DIR
    mount ${dest}1 $MOUNT_DIR
    echo "copying all file to USB drive"
    cp * $MOUNT_DIR &> /dev/null
    cp -R syslinux  $MOUNT_DIR &> /dev/null
    if [[ $BOOT_TYPE == "efi64" ]];then cp -R EFI $MOUNT_DIR &> /dev/null; fi
    sync
    umount $MOUNT_DIR
    # Make key bootable if bios.
    if [[ $BOOT_TYPE == "bios" ]]
    then
        # In this mode, we need to write syslinux MBR.
        echo "Writing syslinux mbr.ini fo $dest"
        dd bs=440 count=1 conv=notrunc if=${syslinux_mod}/${BOOT_TYPE}/mbr.bin of=${dest}
        sleep 5
        #cd ${TMP_DIR}/syslinux-${SYSLINUX_VERSION}/bios/linux/
        syslinux --directory syslinux --install ${dest}1
        cd $current_dir
    fi 
    exit 0
fi