#!/bin/bash
#
#  svnchache.sh - redirecting read-only svn to a (faster) cache repository
#  Copyright (C) 2007  Clifford Wolf <clifford@clifford.at>
#
#  This program is free software; you can redistribute it and/or modify
#  it under the terms of the GNU General Public License as published by
#  the Free Software Foundation; either version 2 of the License, or
#  (at your option) any later version.

if [ "$*" = "sync" ]; then
	while read from to; do
		echo "Syncing $to.."
		svnsync sync $to
	done < <( grep -h '^[^#]' /etc/svncache $HOME/.svncache 2> /dev/null; )
	exit 0
fi

declare -a newargs
found_url=0
error=0

sedscript=`mktemp`
greplist=`mktemp`

while read from to; do
	echo "s,^$from\(/\|$\),$to\1,;" >> "$sedscript"
	echo "^$to" >> "$greplist"
done < <( grep -h '^[^#]' /etc/svncache $HOME/.svncache 2> /dev/null; )

translate_arg() {
	translated_arg="$1"
	url="$( LC_ALL=C svn info "$1" 2> /dev/null | grep '^URL: ' | cut -f2- -d' '; )"
	if [ -n "$url" ]; then
		found_url=1
		newurl="$( echo "$url" | sed -f "$sedscript"; )"
		if echo "$newurl" | grep -qf "$greplist"; then
			translated_arg="$newurl"
		else
			echo "Can not translate: $url" >&2
			error=1
		fi
	fi
}

if [ $# != 0 -a "${1##-*}" != "" ]; then
	newargs=("$1")
	shift
	for arg in "$@"; do
		translate_arg "$arg"
		newargs=("${newargs[@]}" "$translated_arg")
	done
	if [ $found_url = 0 ]; then
		translate_arg "."
		newargs=("${newargs[@]}" "$translated_arg")
	fi
fi

rm -f "$sedscript"
rm -f "$greplist"

if [ $found_url = 0 -o $error = 1 ]; then
	{
		echo
		echo "Usage Example: $0 log -v -r300:600" 
		echo
		echo "Example /etc/svnchache or ~/.svncache entry:"
		echo "http://svn.clifford.at/tools file:///data/svncache/clifford-tools"
		echo
		echo "Caches can be created and kept in sync with 'svnsync'."
		echo
		echo "The command '$0 sync' calls 'svnsync sync' for all caches.";
		echo
	}>&2
	exit 1
fi

exec svn "${newargs[@]}"