#!/usr/bin/awk -f
# Adds a "git describe" (nearest tag) output for `git log` (with support for
# color escapes and --graph markers). --oneline is not supported.
#
# Copyright (c) 2013 Peter Wu <lekensteyn@gmail.com>
# Licensed under GPLv3 or any latter version

function has_color(str) {
	if (str ~ /\033/) return 1;

	return 0;
}

{ print; }

{
	is_color = has_color($0);
	# strip color escapes for easier text matching
	gsub(/\033\[[0-9]*m/, "");

	text_len = length($0);
	# remove --graph markers
	sub(/^[*|][*|_/\\ ]*/, "");
	indent_len = length($0) - text_len;
}

# match only git's "commit" label, not something from the commit message.
$0 ~ /^commit/ &&
$1 == "commit" && $2 ~ /^[0-9a-f]{5,40}$/ {
	hash = $2;

	printf("%" indent_len "sDescribe: ", "");
	if (is_color) printf("\033[96m"); # light cyan
	system("git describe --first-parent " hash " | tr -d '\n'");
	if (is_color) printf("\033[m");
	printf("\n");
}