#!/bin/bash

SCRIPT_DIR="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)"

ask() {
    USER_ANSWER="?";
    while [ "$USER_ANSWER" != "n" ] && [ "$USER_ANSWER" != "y" ] ; do
        echo -n "$1 ? [y/n] "
        read -r -n 1 USER_ANSWER
        echo "";
    done
    if [ "$USER_ANSWER" == "y" ] ; then
        return 0
    else
        return 1
    fi
}

check_tools()
{
  package_list='xorriso isolinux python3-apt apt-utils python3-requests rsync wget'
  # shellcheck disable=SC2086
  if apt-get -s install ${package_list} |grep ^Inst
    then
      echo "Some tools are needed :"
      echo "apt install ${package_list}"
      exit 0
  fi
}

check_tools

usage() {
cat <<EOF

Upgrade an existant official debian iso to last revision.

options:
    -c|--configfile         Specify a config file 
    -h|--help               Show this message.
    -i|--isofile            Isofile to upgrade
    -o|--offline            Build a offline capable iso
    -v                      Show more output.

Configfile contents example:
ISOFILE=$HOME/debian-13.0.0-amd64-netinst.iso
PRESEED=$HOME/preseed.cfg
NEWFLAVOR=custom
MYFILES=$HOME/myfiles
WANTED=$HOME/wanted.txt
SUGGESTED=false
POPCON=false
EXTRA_SCRIPT=$HOME/mycustom.sh
OFFLINE=1
EOF
}

main() {

  cd "$SCRIPT_DIR" || exit 1

  ISOFILE=""
  VERBOSITY=0
  OFFLINE=0

  while [[ $# -gt 0 ]]; do
    case $1 in
      -c|--configfile)
          CONFIGFILE=$2
          [[ -z ${CONFIGFILE} ]] && echo "missing argument $1" && exit 1
          if [ -e "${CONFIGFILE}" ]
          then
              # shellcheck source=/dev/null
              source "${CONFIGFILE}"
          else
              echo "ERROR: specified configfile not found"*
              exit 1
          fi
          shift
          shift
      ;;
      -h|--help)
          usage
          exit 0
      ;;
      -i|--isofile)
          ISOFILE=$2
          [[ -z ${ISOFILE} ]] && echo "missing argument $1" && exit 1
          shift
          shift
      ;;
      -o|--offline)
          OFFLINE=1
          shift
      ;;
      *)
          echo "ERROR: unknown option: $1"
          usage
          exit 1
      ;;
    esac
  done

  # default initialisation of vars
  preseed=${PRESEED:-${SCRIPT_DIR}/preseed.cfg}
  newflavor=${NEWFLAVOR:-custom}
  myfiles=${MYFILES:-${HOME}/myfiles}
  wantedfile=${WANTED:-${HOME}/wanted.txt}
  excludedfile=${EXCLUDED:-${SCRIPT_DIR}/excluded.txt}
  extra_script=${EXTRA_SCRIPT:-${HOME}/mycustom.sh}

  # debian-13.0.0-amd64-netinst.iso
  bnfile=$(basename "${ISOFILE}")
  distribution=$( echo "${bnfile}" |cut --delimiter='-' --fields=1 )
  majorversion=$( echo "${bnfile}" |cut --delimiter='-' --fields=2 |cut --delimiter='.' --fields=1 )
  minorversion=$( echo "${bnfile}" |cut --delimiter='-' --fields=2 |cut --delimiter='.' --fields=2 )
  incrementalversion=$( echo "${bnfile}" |cut --delimiter='-' --fields=2 |cut --delimiter='.' --fields=3 )
  architecture=$( echo "${bnfile}" |cut --delimiter='-' --fields=3)
  # flavor=$( echo "${bnfile}" |cut --delimiter='-' --fields=4 |cut --delimiter='.' --fields=1 )
  # extension=$( echo "${bnfile}" |cut --delimiter='-' --fields=4 |cut --delimiter='.' --fields=2 )
  destination=${distribution}-${majorversion}.${minorversion}.${incrementalversion}-${architecture}-${newflavor}.iso

  if [ ! -e "${ISOFILE}" ]
  then
    echo "image not found : ${ISOFILE}"
    exit 1
  fi

  if [ ! -e "${wantedfile}" ]
  then
    cat > "${wantedfile}" <<EOF
local-apt-repository
rsync
EOF
  fi
  
  if [ ! -e "${excludedfile}" ]
  then
    cat > "${excludedfile}" <<EOF
gdm3
chromium
firefox
EOF
  fi

  # create working dir (iso loop in /tmp)
  temp_file=/tmp/tmp_iso_directory.txt
  if [ -e ${temp_file} ]
  then
    temp_dir=$(cat ${temp_file})
  else
    temp_dir=$(mktemp -d)
    echo "${temp_dir}" > ${temp_file}
  fi

  echo "##### extracting iso"
  if [ ! -e "${temp_dir}"/md5sum.txt ]
  then
    echo "extracting iso to ${temp_dir}"
    xorriso -osirrox on -indev "${ISOFILE}" -extract / "${temp_dir}"
    chmod -R +w "${temp_dir}"
  fi

  if [ ! -d "${myfiles}" ]
  then
    mkdir -p "${myfiles}"
  fi

  echo "### download wanted packages"
  if [ -e "${wantedfile}" ] && [ -e "${excludedfile}" ]
  then
    if python3 download_myfiles.py --isodir "${temp_dir}"     \
          --wanted "${wantedfile}" --excluded "${excludedfile}" \
          --files "${myfiles}" --quiet 
    then
      echo "### myfiles generation ok"
    else
      echo "### myfiles generation failure !!!"
      exit 1
    fi
  else
    echo "download_myfiles.py disabled"
  fi

  echo "### add extra script content"
  if [ -e "${extra_script}" ]
  then
    eval "$(cat "${extra_script}")"
  fi

  if [[ ${OFFLINE} -gt 0 ]]
  then
    if ! grep local-apt-repository "${wantedfile}"
    then
      echo "ERROR: local-apt-repository is required in wanted file for offline mode"
      exit 1
    else
      cat > "${myfiles}"/local-apt-repository.sh <<"EOEF"
#!/usr/bin/env bash
echo "### Activate apt cdrom"
sed --expression "s/^[#]*deb cdrom:/deb [trusted=yes] cdrom:/" /etc/apt/sources.list
sed --expression="s/^[#]*deb cdrom:/deb [trusted=yes] cdrom:/" --in-place /etc/apt/sources.list
echo "### Prepare for local-apt-repository usage"
local_apt_repository=/srv/local-apt-repository
source_directory=/media/cdrom0
original_list=/tmp/original_list.txt
cat > ${original_list} <<EOF
EOF
mkdir -p "${local_apt_repository}"
find ${source_directory} -name Packages.gz
while IFS= read -r -d '' gzlist
do
  echo "### Scan ${gzlist}"
  zgrep pool "${gzlist}" | cut --delimiter=' ' --fields=2 >> ${original_list}
done <    <(find ${source_directory} -name Packages.gz -print0)
pushd ${source_directory} || return 1
    while IFS= read -r -d '' packagepath
    do
        if ! grep "^${packagepath}$" ${original_list}
        then
            echo "### Package $(basename "${packagepath}") not in original cd. Copy in /local-apt-repository."
            mkdir --parents --verbose ${local_apt_repository}/"$(dirname "${packagepath}")"
            cp --verbose "${packagepath}" ${local_apt_repository}"/$(dirname "${packagepath}")"/"$(basename "${packagepath}")"
        fi
    done <    <(find pool -name "*.deb" -print0)
popd || return 1
apt --yes install "$(find ${local_apt_repository} -name "local-apt-repository*.deb")"
apt clean
apt update
apt upgrade
EOEF
    fi
  fi

cat > "${myfiles}"/README.custom <<"EOF"
===
In offline mode, 
Mount cdrom ( mount /dev/sr0 )
And execute local-apt-repository.sh
===

EOF

  chmod -R +w "${temp_dir}"

  echo "### customize initrd with preseed"
  if [ -e "${preseed}" ]
  then
    # cpio on "out mode" don't allow to rename/basename file on the fly
    # so we need to put the file somewhere with the target name
    # and go (pushd) to the directoy considered as root (/) of the initrd
    cp --verbose "${preseed}" /tmp/preseed.cfg
    pushd /tmp || return 1
      case $(uname -m) in
        i686)
          echo "### Detected install.386"
          gunzip --verbose "${temp_dir}/install.386/initrd.gz"
          echo preseed.cfg | cpio --format=newc --create --append --verbose --file="${temp_dir}"/install.386/initrd
          gzip --verbose "${temp_dir}"/install.386/initrd
          ls -l "${temp_dir}"/install.386/initrd.gz
        ;;
        x86_64)
          echo "### Detected install.amd"
          gunzip --verbose "${temp_dir}/install.amd/initrd.gz"
          echo preseed.cfg | cpio --format=newc --create --append --verbose --file="${temp_dir}"/install.amd/initrd
          gzip --verbose "${temp_dir}"/install.amd/initrd
          ls -l "${temp_dir}"/install.amd/initrd.gz
        ;;
        *)
          echo "Platform not implemented"
          exit 1
        ;;
      esac
    popd || return 1
  fi

  echo "### Add content of myfiles"
  rsync --verbose --recursive "${myfiles}"/ "${temp_dir}"

  echo "### Calculate md5sum.txt"
  chmod +w "${temp_dir}"/md5sum.txt
  pushd "${temp_dir}" || return 1
    find . -follow -type f ! -name "md5sum.txt" -print0 | xargs -0 md5sum > md5sum.txt
  popd || return 1
  chmod -R -w "${temp_dir}"

  echo "### Create iso"
  xorriso -as mkisofs -o "${destination}"           \
    -isohybrid-mbr /usr/lib/ISOLINUX/isohdpfx.bin   \
    -c isolinux/boot.cat -b isolinux/isolinux.bin   \
    -no-emul-boot -boot-load-size 4                 \
    -boot-info-table "${temp_dir}"

}

if [[ "${BASH_SOURCE[0]}" == "$0" ]]; then
    main "$@"
fi