#!/bin/sh

WRITE=false
FILE="ChangeLog"
GITPATH="master..HEAD"

while [ "$1" != "" ]; do
	case $1 in
		-w )
			WRITE=true
			;;
		-f )
			shift
			FILE="$1"
			;;
		* )
			GITPATH="$1"
			;;
	esac
	shift
done

if `git branch --no-color | grep -q '^\*'`; then
	OUTPUT=""
	HEAD=""
	BRANCH=`git branch --no-color | grep '^\*' | grep -v 'no branch' | sed 's/^* //g' | sed 's/.*\///g' | grep '^[0-9][0-9.]'`
	if [ "$BRANCH" != "" ]; then
		DATE=`date -I`
		DIR=${PWD##*/}
		USER=`git config --get user.name`
		HEAD="$DATE         [RELEASE] Release of $DIR $BRANCH ($USER)"$'\n'
	fi

	LOG=`git log --pretty=format:"%ad %h %s (%an)" --date=short --no-merges $GITPATH`	
	if [ "$LOG" != "" ]; then
		OUTPUT=$HEAD$LOG$'\n'$'\n';
	fi

	if [ -f $FILE ]; then
		OUTPUT=$OUTPUT"`cat $FILE`"
	fi

	if $WRITE; then
		echo "$OUTPUT" > $FILE

		OUTPUT=$OUTPUT$'\n'$'\n'"File $FILE was written."
	fi

	echo "$OUTPUT"

fi

# USAGE
# git write-changelog [-w] [-f <filename>] [<path>]
# git write-changelog [-w] [-f ChangeLog] [master..HEAD]
# -w: Write log to file
# -f <filename>: Name of changelog file
# path: path for git log