#!/bin/sh
#
# gentest @(#)gentest.sh	1.2 15/06/03 Copyright 2015 J. Schilling
#
# Usage: gentest	---> runs 1000 test loops
#	 gentest #	---> runs # test loops
#
# A random file test with 1..10 generations of patches in a single patch file.
# A file is generated, then modified 1..10 times and every time a diff is
# created and concatenated to a single patch file. Then the original file
# is patched and compared to the expected result.
#
# The diff type is random, this allows to check the quality of the automated
# diff type recognition.
#

trap cleanup EXIT INT HUP

cleanup() {
	rm -f generation saved_orig changed patch_file expected original original.rej failure xo xm xof xmf xef
}

rrand() {
	nawk '
	function random(low, range) {
		return int(range * rand()) + low
	}

	BEGIN {
		base = ARGV[1]
		max = ARGV[2]
		seed = ARGV[3]

		srand()		# Initialze with current time
		s = srand()	# get previous seed
		s = s + seed	# Current time + seed
		srand(s)	# Better new seed

		x = random(base, max)
		print x
	}
	' "$@"
}

makefile() {
	nawk '
	BEGIN {
		nflines = ARGV[1]
		for (i = 1; i <= nflines; i++) {
			printf("This is original line %d\n", i);
		}
	}
	' "$@"
}

changefile() {
	nawk '
	function random(n) {
		return int(n * rand())
	}

	BEGIN {
		nflines = ARGV[1]
		chlines = ARGV[2]
		seed = chlines

		ARGV[1] = ""	# Do not use as filename
		ARGV[2] = ""	# Do not use as filename

		srand()		# Initialze with current time
		s = srand()	# get previous seed
		s = s + seed	# Current time + seed
		srand(s)	# Better new seed

		for (i = 1; i <= nflines; i++) {
			change_line[i] = 0
		}

		while (chlines > 0) {
			i = random(nflines)
			if (change_line[i] == 0) {
				chlines--
				change_line[i] = 1
			}
		}
		i = 1;
	}

	{
		if (change_line[i] != 0) {
			what = random(3)
			if (what == 0) {
				print "Modified, was: " $0
			} else if (what == 1) {
				print $0
				print "New line, inserted after: " $0
			}
		} else {
			print $0
		}
		i++
		next
	}
	' "$@"
}


nlines=$$	# seed startup helper, awk would get seed based on time_t
maxlines=5000	# Longest file for our tests
maxch=4		# Max. 25% of all lines are changed

#
# Diff Program to use. Solaris diff -U0 has bugs, so use our fixed Solaris diff
# from the SCCS distribution.
#
diff=/opt/schily/ccs/bin/diff
type $diff > /dev/null 2> /dev/null
[ $? -ne 0 ] && diff=diff	# fallback to probably defective system diff
LC_ALL=C $diff -? 2>&1 | grep -i Option > /dev/null
if [ $? -ne 0 ]; then
	echo "No working diff program found"
	exit 1
fi
echo "Using diff programm: $diff"
#
# Reference patch program, note that gpatch has problems itself
# and fails with -diff -C0
#
rpatch=gpatch
#LC_ALL=C $rpatch -? 2>&1 | grep -i Option > /dev/null
#if [ $? -ne 0 ]; then
#	echo "Reference patch program \"$rpatch\" not working"
#	exit 1
#fi
#echo "Using reference patch programm: $rpatch"
#
# Test patch implementation:
# Add -W+ to permit POSIX + enhancements for "patch -s"
#
tpatch="eval ../../OBJ/"`../../../conf/oarch.sh`"/spatch -W+"
silent=-s
LC_ALL=C $tpatch -? 2>&1 | grep -i Option > /dev/null
if [ $? -ne 0 ]; then
	echo "Test patch program \"$tpatch\" not working"
	exit 1
fi
echo "Using test patch programm: $tpatch"

idx=0
total=0
maxidx=${1:-1000}
while [ $idx -le $maxidx ]
do
	nlines=`rrand 10 $maxlines $nlines`
	generations=`rrand 1 10 $nlines`

	max_changes=`expr $nlines / $maxch`
	changes=`rrand 1 $max_changes $nlines`

	makefile $nlines > original
	cp original saved_orig

	>patch_file				# avoid SVr4 :>file redirection bug
	>generation				# avoid SVr4 :>file redirection bug
	echo Test $idx: testing lines=$nlines changes=$changes generations=$generations
	echo Test $idx: testing lines=$nlines changes=$changes generations=$generations >> generation
	generation=1
	while [ $generation -le $generations ]; do

		seed=`expr $generation + $nlines`
		dtype=`rrand 0 93983 $seed`	# rrand 0 6 would be of bad quality, so
		dtype=`expr $dtype \% 6`	# use "rrand 0 bigprime % 6" instead

		if [ $dtype -eq 0 ]; then
			dtype="-c"
		elif [ $dtype -eq 1 ]; then
			dtype="-u"
		elif [ $dtype -eq 2 ]; then
			dtype="-C0"
		elif [ $dtype -eq 3 ]; then
			dtype="-U0"
		elif [ $dtype -eq 4 ]; then
			dtype="-e"
		else
			dtype="  "
		fi


		echo "Creating generation $generation of type ($dtype)..."
		echo "Creating generation $generation of type ($dtype)..." >> generation
		changefile $nlines $changes original > changed
		echo "Generation: $generation" >> patch_file
		echo "Index:original" >> patch_file
		$diff $dtype original changed >> patch_file
		mv changed original
		generation=`expr $generation + 1`
	done
	cp original expected
	cp saved_orig original

	echo Patching file...
	$tpatch original < patch_file
	ret=$?
	if [ $ret -ne 0 ]; then
		echo Test $idx: Patch returned $ret
		diff original expected > failure
		trap 0
		exit 1
	fi

	diff original expected > failure
		ret=$?
	if [ $ret -ne 0 ]; then
		echo Test $idx: diff returned $ret
		[ $ret -eq 1 ] && trap 0
		exit 1
	fi
	idx=`expr $idx + 1`
	total=`expr $total + $generations`
done
idx=`expr $idx - 1`
echo Test succeeded after $idx runs, total of $total patches...
