#!/bin/bash

set -e

START_DIR=`pwd`
# required config items
XOR=""
DIR=""
IMG=""
# optional config items
ISOLINUX_BIN=""
BOOT_CAT=""
CONFFILE=$HOME/releng_build_isojigdo.conf
CLEAN=0

print_help() {
 cat << HLP
Usage:
 $0 -help
# using a config file ${CONFFILE}
 $0 -rc [-clean]
 config file content:
 XOR=/path/to/xorriso
 DIR=/path/to/input_dir
 IMG=/path/to/out_image
 ISOLINUX_BIN=/path/to/isolinux.bin
 BOOT_CAT=/path/to/boot.cat
# without using a config file
 $0 xorriso_cmd IN_dir OUT_image [IN_isolinux] [IN_bootcat] [-clean]
HLP
}

# help
if [ ! "${1}" -o "${1}" == "-help" ]; then print_help && exit 0; fi
# config file
if [ "${1}" == "-rc" ]; then
 if [ -e ${CONFFILE} ]; then
  . ${CONFFILE}
  printf "$0: Using config file %s\n" ${CONFFILE}
 else
  echo -e "\n$0: Config file ${CONFFILE} not found.\n" && exit 1
 fi
 if [ "${2}" == "-clean" ]; then CLEAN=1; fi
# command line args
elif [ "${3}" ]; then
 XOR="${1}"
 DIR="${2}"
 IMG="${3}"
 if [ "{4}" ]; then
  ISOLINUX_BIN="${4}"
  if [ "{5}" ]; then BOOT_CAT="${5}"; fi
  if [ "${4}" == "-clean" -o "${5}" == "-clean" -o "${6}" == "-clean" ]; then CLEAN=1; fi
 fi
# the rest
else
 print_help && exit 0
fi

if [ "${XOR}" == "" -o "${DIR}" == "" -o "${IMG}" == "" ]; then
 echo -e "\n$0: xorriso_cmd IN_dir and OUT_image are required\n"
 exit 1
fi

# all must be set at this point
printf "$0: Config items:"
printf "\n\txorriso_cmd=${XOR}\n\tIN_dir=${DIR}\n\tOUT_image=${IMG}.iso"
printf "\n\tIN_isolinux=${ISOLINUX_BIN}\n\tIN_bootcat=${BOOT_CAT}\n"
RES="${IMG}.iso ${IMG}.new ${IMG}.md5 ${IMG}.jigdo ${IMG}.template"
############################################################
main() {
# remove cruft from previous runs
# rm -f ${RES}

# grab an MBR
# dd if=some.iso bs=1K count=32 of=somembr.sysarea

# create FAT partition
# /sbin/mkfs.msdos -n Bla -C fatpart.fat 8192

# create MD5 list in base64 format
if which jigdo-gen-md5-list >/dev/null 2>&1; then
 printf "$0: Creating MD5 list in hex format..."
 jigdo-gen-md5-list ${DIR} > ${IMG}.md5
 printf "Done.\n"
else
 printf "\n$0: Not found: jigdo-gen-md5-list. Install jigit.\n"
 exit 1
fi

# build the command - general section
CMD="${XOR} \
 -as mkisofs \
 -quiet \
 -o ${IMG}.iso \
 -R \
 -V ISOJIGDO \
 -partition_offset 16 \
 -J -joliet-long \
"
# boot section TODO
#if [ "${5}" -a "${6}" ]; then
#CMD+=\
# -b boot/isolinux/isolinux.bin \                     # $5
# -c boot/boot.cat \                                  # $6
# -no-emul-boot -boot-load-size 4 -boot-info-table \
# -isohybrid-mbr somembr.sysarea \                    # TODO: figure out where to grab one
# -partition_offset 16 \
# -append_partition 2 0x01 fatpart.fat \
#fi

# jigdo section
CMD+="\
 -jigdo-template-compress gzip \
 -checksum_algorithm_iso md5,sha1,sha256,sha512 \
 -checksum_algorithm_template md5,sha1,sha256,sha512 \
 -jigdo-jigdo ${IMG}.jigdo \
 -jigdo-template ${IMG}.template \
 -jigdo-map Debian=${DIR} \
 -md5-list  ${IMG}.md5 \
 -jigdo-min-file-size 1024 \
"

CMD+="${DIR}"

# run it
echo -e "$0: Creating ISO and jigdo representations:\n$CMD\n"
${CMD}

# create another one from jigdo files
jigit-mkimage \
   -t ${IMG}.template \
   -j ${IMG}.jigdo \
   -m Debian=${DIR} \
   -o ${IMG}.new

# trap the exit code of diff and let the Universe explode
diff ${IMG}.iso ${IMG}.new
DIFF_RET="$?"
case ${DIFF_RET} in
     0)
      echo -e "$0: diff ${IMG}.iso ${IMG}.new matched.\n"
     ;;
     *)
      echo -e "$0: ATTN: diff returned code: $DIFF_RET\n"
     ;;
esac

# sort out the cruft
if [ ${CLEAN} -eq 1 ]; then
 # safety net, just in case -> we want to be in the starting
 # directory before removing whatever self-generated stuff
 cd "${START_DIR}" || exit 1
 rm -f ${RES}
 printf "$0: removed %s\n" ${RES}
else
 printf "$0: left %s\n" ${RES}
fi

# last hints
printf "\n$0: HINT: manual checks remained to be done:\n"
printf " * ${IMG}.img boots from USB stick and/or optical media.\n"
printf " * appended FAT partition is mountable.\n"
printf " * xorriso -indev ${IMG}.iso -pvd_info\n"
printf " * fdisk -lu ${IMG}.iso\n"

}

#
main