#!/usr/bin/env bash
SVN=svn

if [ $# -ne 2 ]; then
    echo "$0: merges changes done in a given revision of the current checkout"
    echo "usage: $0 <revision> <target directory>" 
    exit 1
fi

revision=$1
prev_revision=`expr $revision - 1`
srcdir=$PWD
dstdir="$2"

cd ${dstdir}

msg_file=`mktemp /tmp/ilc.XXXXXX || exit 1`
${SVN} log -r ${revision} ${srcdir} > ${msg_file}
message_lines=`cat ${msg_file} | wc -l`
log_message=`cat ${msg_file} | tail -n $((${message_lines}-2)) | head -n $((${message_lines}-4))`
rm -f ${msg_file}

changed_files=`${SVN} diff -c ${revision} --summarize ${srcdir} | sed -e "s,.*${srcdir}/,,"`

for f in ${changed_files}; do
    echo "Making sure that ${f} is up to date..."
    svn up -q ${f}
done

#echo "previous committed revision: ${prev_revision}"
#echo "last committed revision: ${revision}"
#echo "log message for that commit:"
#echo "${log_message}"
#echo "file affected by commit: ${changed_files}"
#exit 0

${SVN} merge -c ${revision} ${srcdir}
if [ $? -ne 0 ]; then
    echo "Oops, there was an error while merging. See whether you can fix it. :-)"
    cd ${srcdir}
    exit 1
fi

while true; do
    read -n 1 -p "c(o)mmit, (d)iff or (c)ancel ? " r
    echo
    if [ $r = "o" ]; then
	break
    elif [ $r = "c" ]; then
	exit 1
    elif [ $r = "d" ]; then
	${SVN} diff ${changed_files}
    fi
done

${SVN} -m "automatically merged revision ${revision}:${log_message}" ci ${changed_files}

cd ${srcdir}