#!/bin/sh
#
# Build a Mercurial RPM in place.
#
# Bryan O'Sullivan <bos@serpentine.com>

root="`hg root 2>/dev/null`"
specfile=contrib/mercurial.spec

if [ -z "$root" ]; then
    echo 'You are not inside a Mercurial repository!' 1>&2
    exit 1
fi

rpmdir=/tmp/"`basename $root | sed 's/ /_/'`"-rpm

cd "$root"
rm -rf $rpmdir
mkdir -p $rpmdir/RPMS
hg clone "$root" $rpmdir/BUILD

if [ ! -f $specfile ]; then
    echo "Cannot find $specfile!" 1>&2
    exit 1
fi

tmpspec=/tmp/`basename "$specfile"`.$$
# Use the most recent tag as the version.
version=`hg tags | perl -e 'while(<STDIN>){if(/^(\d\S+)/){print$1;exit}}'`
# Compute the release number as the difference in revision numbers
# between the tip and the most recent tag.
release=`hg tags | perl -e 'while(<STDIN>){($tag,$id)=/^(\S+)\s+(\d+)/;if($tag eq "tip"){$tip = $id}elsif($tag=~/^\d/){print $tip-$id+1;exit}}'`
tip=`hg -q tip`

# Beat up the spec file
sed -e 's,^Source:.*,Source: /dev/null,' \
    -e "s,^Version:.*,Version: $version," \
    -e "s,^Release:.*,Release: $release," \
    -e "s,^%prep.*,Changeset: $tip\n\0," \
    -e 's,^%setup.*,,' \
    $specfile > $tmpspec

cat <<EOF >> $tmpspec
%changelog
* `date +'%a %b %d %Y'` `hg showconfig ui.username` $version-$release
- Automatically built via $0

EOF
hg log \
     --template '* {date|rfc822date} {author}\n- {desc|firstline}\n\n' \
     .hgtags \
  | sed -e 's/^\(\* [MTWFS][a-z][a-z]\), \([0-3][0-9]\) \([A-Z][a-z][a-z]\) /\1 \3 \2 /' \
        -e '/^\* [MTWFS][a-z][a-z] /{s/ [012][0-9]:[0-9][0-9]:[0-9][0-9] [+-][0-9]\{4\}//}' \
   >> $tmpspec

rpmbuild --define "_topdir $rpmdir" -bb $tmpspec
if [ $? = 0 ]; then
    rm -rf $tmpspec $rpmdir/BUILD
    mv $rpmdir/RPMS/*/* $rpmdir && rm -r $rpmdir/RPMS
    echo
    echo "Packages are in $rpmdir"
fi