#!/bin/rc

rfork n

fn usage {
	echo usage: sdiff [-c num] [-d date] [-r root]  file1 ... >[1=2]
	echo example: sdiff /sys/src/cmd/ls.c /sys/src/cmd/acme '>'ls.diff >[1=2]
	exit usage
}

b=/n/sources/plan9
nd=/tmp/newdir
nf=/tmp/newfile

cmd=ape/diff
arg=-Nru

if(~ $#* 0){
	usage
}

# choose context
if(~ $1 -c){
	if(~ $2 '')
		usage
	arg=(-NrU $2)
	shift
	shift
}

# diff against specific date
if(~ $1 -d){
	if(~ $2 '')
		usage
	yyyy=`{echo $2 | awk -F\- '{print $1}'}
	if(~ $yyyy '')
		usage
	mmdd=`{echo $2 | awk -F\- '{print $2$3}'}
	if(~ $mmdd '')
		usage
	b=/n/sourcesdump/$yyyy/$mmdd/plan9
	shift
	shift
}

# use another directory as root
if(~ $1 -r){
	if(~ $2 '')
		usage
	r=`{cleanname $2}
	shift
	shift
}

if(! test -d $b){
	9fs sourcesdump
	if(! ~ $status ''){
		echo $status
		exit
	}
}

rm -rf $nd $nf

for(i in $*){
	# i: local, s: sources
	s=`{cleanname $b/$i}
	if(! ~ $r '') # remove root
		s=`{echo $s | sed s,$r,,}
	if(test -d $i){
		if(test -d $s){
			if(~ $r '')
				$cmd $arg $s $i
			if not
				$cmd $arg $s $i | sed s,$r,,g
		}
		if not if(test -f $s){
			echo $s is a file, while $i is a directory >[1=2]
			exit
		}
		if not{
			# directory does not exist on server (new directory)
			mkdir $nd
			touch -t 0 $nd
			if(~ $r '')
				$cmd $arg $nd $i | sed s,$nd,$i,g
			if not
				$cmd $arg $nd $i | sed s,$nd,$i,g | sed s,$r,,g
			rm -rf $nd
		}
	}
	if not if(test -f $i){
		if(test -f $s){
			if(~ $r '')
				$cmd $arg $s $i
			if not
				$cmd $arg $s $i | sed s,$r,,g
		}
		if not if(test -d $s){
			echo $s is a directory, while $i is a file >[1=2]
			exit
		}
		if not{
			# file does not exist on server (new file)
			>$nf
			touch -t 0 $nf
			if(~ $r '')
				$cmd $arg $nf $i | sed s,$nf,$i,g
			if not
				$cmd $arg $nf $i | sed s,$nf,$i,g | sed s,$r,,g
			rm -f $nf
		}
	}
	if not{
		# file does not exist on client (we don't handle deletion)
		echo $i does not exist >[1=2]
		exit
	}
}