#!/bin/sh
#
# git-changelog, Copyright © 2012 Matteo Cypriani
#
# This program is free software. It comes without any warranty, to
# the extent permitted by applicable law. You can redistribute it
# and/or modify it under the terms of the Do What The Fuck You Want
# To Public License, Version 2, as published by Sam Hocevar. See
# http://sam.zoy.org/wtfpl/COPYING for more details.
#
# This script generates a changelog list from the Git tag messages.
# Only the tags named after the format vX.Y[.Z[...]] are selected.
# The changelog content is displayed on the standard output, whereas the
# error output displays the included or skipped tag names.

set -e
#set -x

### User options

# Message to display at the top of the file (blank to display nothing)
HEADER="This file is automatically generated from the Git tag messages."

# Number of blank lines between two tag messages
NEWLINES=2

# Maximal number of lines to display for each tag message
NBLINES=1000

### End of user options

if [ $# -ne 0 ] ; then
	echo "Warning! $0 takes no arguments!" >&2
fi

# Indicates wether or not new lines should be printed
PRINTNL=0

# Print the header
if [ "$HEADER" != "" ] ; then
	echo "$HEADER"
	PRINTNL=1
fi

for TAG in $(git tag -l | sort -r) ; do
	if echo "$TAG" | grep -Eq '^v[0-9]+(\.[0-9]+)+$' ; then
		# Display current tag's name
		echo "$TAG" >&2

		# Print empty lines if needed
		if [ $PRINTNL -eq 1 ] ; then
			i=0
			while [ $i -lt $NEWLINES ] ; do
				echo
				i=$((i + 1))
			done
		fi

		# Print the tag message
		git tag -l "$TAG" -n$NBLINES | sed 's/ \+$//'

		PRINTNL=1
	else
		echo "Skipping $TAG" >&2
	fi
done