#!/bin/bash
# 
# Copyright 2013 Karljohan Lundin Palmerius
# 
# This script assist in the task of doing partial commit with
# subversion. It will copy the changed files, revert the changes and
# use the tool kompare to copy selected changes back to the code
# tree. Then it will make a commit after which the changed files will
# be copied back to the code tree, allowing the user to make a second
# partial commit.
# 
# Warning: since all changes are reverted in the process, there is a
# risk of data loss. Use this tool at your own risk, no guarantees are
# gives whatsoever. If you do find a bug, please report it back.
# 
# Usage: simply execute svn-ci-partial in you code tree. Do this from
# an interactive shell, since the subversion command-line tool may
# need to communicate with you.
# 
# Dependencies:
# Command-line tools bash, svn, kompare
# 
# 
# Revision history:
# 
# 2013-06-24  Moved creation of temporary folder to just before it is
#             first used.
# 
# 2013-06-24  Added debug output.
# 
# 2013-06-24  Added commit list so that only modified files are
#             committed.
# 
# 2013-06-11  Updated tool name and documentation.
# 
# 2013-06-10  Fix on IFS for correct handling of multiple files.
# 
# 2013-05-19  Initial version.
# 

KOMPARE=/usr/bin/kompare
#OUTPUT_LEVEL=0
OUTPUT_LEVEL=2

function error_and_exit {
    echo $1
    exit 1
}

function dbg_output {
    if [ "$OUTPUT_LEVEL" -ge "$2" ]
    then
        echo $1 >&2
    fi
}

dbg_output "(DD) Checking if current working directory is a Subversion copy." 2
svn info > /dev/null 2> /dev/null \
    || error_and_exit "No working copy!"

dbg_output "(DD) Checking modified files." 2
UP_TO_DATE=`svn status -uq 2> /dev/null \
    | grep "^M....... " \
    | sed -e "s/^M........//g" \
    | sed 's/\s\s*/ /g' \
    | cut -d ' ' -f 3-`
OUT_OF_DATE=`svn status -uq 2> /dev/null \
    | grep "^M.......\*" \
    | sed -e "s/^M........//g" \
    | sed 's/\s\s*/ /g' \
    | cut -d ' ' -f 3-`

onterm() {
    error_and_exit "Signal caught, there may be important files in backup in $TMP_FOLDER"
}

trap onterm INT TERM

if [ -n "$OUT_OF_DATE" ]
then
    error_and_exit "Out-of-date files exist ($OUT_OF_DATE_FILES)"
fi

if [ -z "$UP_TO_DATE" ]
then
    error_and_exit "No changed files exist"
fi

dbg_output "(DD) Creating temporary folder for backup and intermediate storing." 2
TMP_FOLDER=`mktemp -d`
dbg_output "(DD) Temporary folder: '$TMP_FOLDER'." 2

dbg_output "(DD) Copying modified files to temporary folder." 2
cp --parents $UP_TO_DATE $TMP_FOLDER \
    || error_and_exit "Couldn't copy changed files"

dbg_output "(DD) Reverting modified files in working copy." 2
svn revert $UP_TO_DATE > /dev/null 2> /dev/null

dbg_output "(DD) User intervention to copy changes back from temporary folder to working copy." 2
IFS=$'\n'
for path in $UP_TO_DATE
do
    kompare "$TMP_FOLDER/$path" "./$path"
done
unset IFS

dbg_output "(DD) Calling 'svn commit $UP_TO_DATE' to submit selected changes." 2
svn commit $UP_TO_DATE

dbg_output "(DD) Copying back the files from temporary folder to working copy." 2
cp -r $TMP_FOLDER/* . \
    || error_and_exit "Couldn't restore uncommited changes. Find backup in $TMP_FOLDER"

dbg_output "(DD) Removing temporary folder." 2
rm -r $TMP_FOLDER \
    || error_and_exit "Couldn't remove temporary files (in $TMP_FOLDER)"