#!/bin/rc
rfork ne
. /sys/lib/git/common.rc

patchname=/tmp/git.patchname.$pid
patchfile=/tmp/git.patchfile.$pid
fn sigexit{
	rm -f $patchname $patchfile
}

gitup

flagfmt='o:patchdir patchdir'; args='[query]'
eval `''{aux/getflags $*} || exec aux/usage

if(~ $#patchdir 1 && ! test -d $patchdir)
	mkdir -p $patchdir

q=$*
if(~ $#q 0)
	q=HEAD
commits=`{git/query $q || die $status}
n=1
m=$#commits


# sleazy hack: we want to run
# under rfork m for the web ui,
# so don't error if we can't mount
mntgen /mnt/scratch >[2]/dev/null || status=''
for(c in $commits){
	cp=`{git/query -p $c}
	pp=`{git/query -p $c'~'}
	fc=`$nl{git/query -c $c~ $c | sed 's/^..//'}

	@{
		rfork n
		cd /mnt/scratch
		if(test -d $pp/tree)
			bind $pp/tree a
		if(test -d $cp/tree)
			bind $cp/tree b
		
		echo From: `{cat $cp/author}
		echo Date: `{date -uf'WW, DD MMM YYYY hh:mm:ss Z' `{walk -em $cp/author}}
		<$cp/msg awk '
		NR == 1 {
			n = ENVIRON["n"]
			m = ENVIRON["m"]
			msg=$0
			if(m > 1)
				patch = sprintf("[PATCH %d/%d]", n, m)
			else
				patch = "[PATCH]"
			printf "Subject: %s %s\n\n", patch, msg
			
			gsub("^[ 	]|[ 	]$", "", msg)
			gsub("[^a-zA-Z0-9_]+", "-", msg)
			printf "%.4d-%s.patch", n, msg >ENVIRON["patchname"]
			next
		}
		{
			print
		}'
		echo '---'
		echo diff `{basename $pp} `{basename $cp}
		for(f in $fc){
			a=a/$f
			if(! test -e $a)
				a=/dev/null
			b=b/$f
			if(! test -e $b)
				b=/dev/null
			diff -ur $a $b
		}
	} >$patchfile
	if(~ $#patchdir 0){
		cat $patchfile
		! ~ $n $m && echo
	}
	if not{
		f=$patchdir/`{cat $patchname}
		mv $patchfile $f
		echo $f
	}
	n=`{echo $n + 1 | bc}
}
exit ''