#!/usr/bin/env zsh

# Utility to transform a raw patch into a patch to be put on the MPFR
# www server. Assume that update-version is in the same directory.
# MPFR_CURRENT_DIR should contain a path to a directory corresponding
# to /misc/www/mpfr-current in the MPFR repository; if not set, it is
# assumed to be "$HOME/mpfr-misc/www/mpfr-current".
#
# Typical use:
#   svn diff -c <REV> > $MPFR_CURRENT_DIR/mpfr.patch
#   cd $MPFR_CURRENT_DIR
#   patchlevel=$(($(ls patch?? | tail -n 1 | sed 's/patch//')+1))
#   .../build-patch mpfr.patch $patchlevel <patchname>
#   cat patch?? > allpatches
#
# But sometimes, autotools-generated files also need to be rebuilt
# for inclusion in the patch (e.g. if configure.ac is patched),
# with correction of timestamps.

set -e
prg=$0
upv=$prg:h/update-version

if [[ $# -gt 3 || $1 == -* ]] then
  echo "Usage: $prg [ <patch> [ <patchlevel> [ <patchname> ] ] ]" >&2
  exit 1
fi

mpfrdir=$(realpath ${MPFR_CURRENT_DIR:-$HOME/mpfr-misc/www/mpfr-current})
base=$mpfrdir:t
version=${base#mpfr-}

if [[ -z "$version" ]] then
  echo "${prg}: bad version" >&2
  exit 2
fi

if [[ $# -ge 2 ]] then
  newpatch=$(printf patch%02d $2)
else
  newpatch=$base-patch
fi

checkobj()
{
  if [[ -e $1 ]] then
    echo "${prg}: $1 is in the way" >&2
    exit 3
  fi
}
checkobj $base
checkobj $base-a
checkobj $base-b
checkobj $newpatch

atool -eqx -- $mpfrdir/$base.tar.xz
pushd $base
touch -a $mpfrdir/allpatches
patch -N -Z -p1 < $mpfrdir/allpatches
: > PATCHES
popd
mv -T $base $base-a
cp -aT $base-a $base-b

if [[ $# -ge 1 ]] then
  patchfile=$(realpath $1)
  pushd $base-b
  echo "Applying patch $1"
  if grep -q '^--- mpfr.*/' $patchfile; then
    p=1
  else
    p=0
  fi
  patch --no-backup-if-mismatch -p$p < $patchfile
  if [[ $# -ge 2 ]] then
    ~/wd/mpfr/tools/update-version ${(s:.:)version} p$2 -
    if [[ $# -ge 3 ]] then
      echo $3 >> PATCHES
    fi
  fi
  if ! cmp --quiet $mpfrdir/$base-{a,b}/doc/mpfr.texi; then
    ./configure
    make info
    make distclean
  fi
  popd
  set +e
  TZ=UTC0 diff -Naurd $base-a $base-b > $newpatch
  if [[ $? -ne 1 ]] then
    echo "${prg}: something has gone wrong with diff" >&2
    exit 4
  fi
  set -e
  rm -r $base-a $base-b
  echo "OK, patch in $newpatch"
fi