#!/bin/bash

# git-make-dist -- Make a release tag in a git repository.  The tag
#                  will have the same content as the tarball produced
#                  by "make dist", plus the debian/ directory as it is
#                  tracked by git.

set -e

exportcwd () {
  for f in `find . -type f`; do
    ff=`echo $f | sed 's,^./,,'`
    if [ -x "$f" ]; then
      echo M 100755 inline $ff
    else
      echo M 100644 inline $ff
    fi
    echo data `wc -c <$f`
    cat $f
  done
}

exportcommit () {
  echo commit $1
  echo committer `git config user.name` '<'`git config user.email`'>' now
  echo 'data <<EOD'
  echo Prepare for distribution
  echo EOD
  echo from HEAD
  echo deleteall
  exportcwd
}

if [ $# != 1 ]; then
  echo >&2 "Usage: git-make-dist TAGNAME"
  exit 1
fi

tagname="$1"

if ! git diff --quiet ; then
  echo >&2 "Your working tree is not clean.  Aborting."
  exit 1
fi

if ! git diff --quiet --cached; then
  echo >&2 "Your index is not clean.  Aborting."
  exit 1
fi

if git rev-parse --verify $tagname >/dev/null >&/dev/null; then
  echo >&2 "Tag $tagname exists already.  Aborting."
  exit 1
fi

distdir=$(mktemp -d tmp.XXXXXX)
make distdir distdir=$distdir
for f in `git ls-files debian`; do
  if ! [ -a $distdir/$f ]; then
    mkdir -p $(dirname $distdir/$f)
    ln $f $distdir/$f
  fi
done

(cd $distdir && exportcommit refs/tags/$tagname) \
 | git fast-import --date-format=now --quiet --force

rm -rf $distdir