#! /bin/sh

# Script uses rmadison to get versions of a source package in different suites
# and displays the changes between those versions.
# The script is intended to be called from within an SVN checkout.
# By default translation updates are suppressed.

# Usage: viewchanges <path-to-source>

# Copyright: Frans Pop <elendil@planet.nl>, 2007
# 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.

# TODO:
# - usage info display
# - parameter parsing
#   - take parameter to set combination of suites to check
#     (for example: -ut, -us, -uo, -ts, -to; default should be -ut)
#   - take parameter to show unreleased changes
#   - take parameter to do all packages under given directory
#   - take parameter for WITH_TRANSLATIONS
# - handle renaming of a source package between suites
#   This command could be used to get all source names:
#   'grep "^[^[:space:]]" $changelog | sed "s/ .*//" | uniq'
# - direct messages and errors to stderr; suppress informational messages;
#   verbose option?; vary exit code (e.g. if no changes)
# - optional features
#   - retrieve changelog from internet
#   - get versions using a different method than rmadison
#   - take parameter specifying version range

suite1=unstable
suite2=stable

changelog=$1/debian/changelog
package=$(basename $(echo $1 | sed "s:/*$::"))
rmadison_out=""

if [ -z "$package" ] || [ ! -f $changelog ]; then
	echo "You must privide a path to the source directory of a package"
	exit 1
elif ! type rmadison >/dev/null 2>&1; then
	echo "This script requires rmadison to be available"
	echo "Please install the package devscripts"
	exit 1
fi

get_rmadison () {
	if ! rmadison_out="$(rmadison $package | grep source)"; then
		echo "Error getting version information for $package"
		exit 1
	fi
}

get_version () {
	# Only fetch version info once
	if [ -z "$rmadison_out" ]; then
		get_rmadison 
	fi
	# Assumes highest version listed last; ignore stable updates
	echo "$rmadison_out" | grep " $1 " | awk '{print $3}' | \
		tail -n1 | sed -r "s/[a-z]+[0-9]$//"
}

checkversion () {
	grep -q "^$package ($1)" $changelog
	return $?
}

print_changelog () {
	local address_range
	if [ "$2" ]; then
		address_range="/^$package ($suite1_ver)/,/^$package ($suite2_ver)/"
	else
		address_range="/^$package ($suite1_ver)/,$"
	fi
	if [ "$WITH_TRANSLATIONS" ]; then
		sed -n "$address_range p" $changelog
	else
		sed -n "$address_range p" $changelog | \
			sed "/Updated translations/,/^$/ d"
	fi
}

suite1_ver=$(get_version $suite1)
suite2_ver=$(get_version $suite2)

if [ -z "$suite1_ver" ]; then
	echo "Package $package does exist in $suite1"
	exit 1
elif ! checkversion $suite1_ver; then
	echo "That's weird, version '$suite1_ver' does not appear in the changelog"
	exit 1
fi

# TODO: handle package renames?
if [ "$suite2_ver" ]; then
	if ! checkversion $suite2_ver; then
		if echo $suite2_ver | grep -q "[[:alpha:]]+[0-9]+$"; then
			echo "Removing point release suffix from '$suite2_ver'"
			suite2_altver=$(echo $suite2_ver | sed "s/[[:alpha:]]+[0-9]+$//")
		elif echo $suite2_ver | grep -q "\.[0-9]+$"; then
			echo "Removing possible point release suffix from '$suite2_ver'"
			suite2_altver=$(echo $suite2_ver | sed "s/\.[0-9]+$//")
		fi
		if checkversion $suite2_altver; then
			echo "Using version '$suite2_altver' instead of '$suite2_ver'"
			suite2_ver=$suite2_altver
		else
			echo "Unable to find entry for '$suite2_ver' in changelog"
			exit 1
		fi
	fi

	if [ "$suite1_ver" = "$suite2_ver" ]; then
		echo "There have been no changes in $package"
	else
		echo "Showing changes from version $suite2_ver to $suite1_ver"
		echo "----"
		print_changelog $suite1_ver $suite2_ver
	fi
else
	echo "Package does not exist in $suite2; displaying full changelog up to $suite1_ver"
	echo "----"
	print_changelog $suite1_ver
fi