#!/bin/sh
set -e

if [ "$1" = "install" ] || [ "$1" = "upgrade" ]; then
  msg=
  for d in bin lib lib32 lib64 libo32 libx32 sbin; do
    if [ -L "$DPKG_ROOT/$d" ]; then
      target=$(readlink "$DPKG_ROOT/$d")
      if [ "$target" != "usr/$d" ]; then
        if [ "$d" = lib64 ] && [ "$target" = "usr/lib/aarch64-linux-gnu" ]; then
          # Work around https://github.com/systemd/systemd/issues/33919
          echo "Fixing bad /$d symbolic link created by systemd-nspawn."
          if [ -d "$DPKG_ROOT/usr/$d" ]; then
            ln -sf "usr/$d" "$DPKG_ROOT/$d"
          else
            rm "$DPKG_ROOT/$d"
          fi
        else
          msg="/$d is a symbolic link and not pointing at usr/$d exactly"
        fi
      elif [ ! -d "$DPKG_ROOT/usr/$d" ]; then
        msg="/$d is a dangling symbolic link"
      fi
      msg2="This is an unexpected situation. Cannot proceed with the upgrade"
    elif [ -d "$DPKG_ROOT/$d" ]; then
      msg="/$d is a directory, but should be a symbolic link"
      msg2="Please install the usrmerge package to convert this system to merged-/usr"
    fi
    if [ -n "$msg" ]; then
      cat <<EOF


******************************************************************************
*
* The base-files package cannot be installed because
* $msg.
*
* $msg2.
*
* For more information please read https://wiki.debian.org/UsrMerge.
*
******************************************************************************


EOF
      exit 1
    fi
  done
  for d in lib32 lib64 libo32 libx32; do
    # Install DEP17 M4 protective diversions
    dpkg-divert --quiet --package base-files --add --no-rename --divert "/.$d.usr-is-merged" "/$d"
  done
fi