#!/bin/sh

prog=makepkgbuild

die()
{
	rc=$1; shift
	echo "$prog: $*" 1>&2
	exit $rc
}

editpb()
{
	op=$1 func=$2

	case "$op" in
	append)
		regexp="^${func}[(][)]<?$"
		edin="/^ *$func() *{
/^}
i" ;;
	prepend)
		regexp=">${func}()"
		edin="/^ *$func() *{
/^[ \t]*cd/
a" ;;
	*)	die 1 "unknown editpb operation: $op"
	esac

	txt=$(awk -v r="$regexp" 'BEGIN { FS = "\n"; RS = "" }
	  $1 ~ r { for (i = 2; i <= NF; i++) print $i }' PKGMETA |\
	  sed 's/^/    /')
	[ "$txt" ] || return 0

	cat << END | ed -s PKGBUILD >/dev/null
$edin
$txt
.
wq
END
	return $?
}

[ -r PKGMETA ] || die 1 "PKGMETA could not be read."

[ "$TDIR" ] || die 1 "TDIR env. var is unset."
[ -d "$TDIR" ] || die 1 "template dir ($TDIR) not found."

tcmd=$(awk 'BEGIN { FS="\n"; RS="" } $1 == "template" { print $2 }' PKGMETA)
[ "$tcmd" ] || die 1 "PKGMETA is missing 'template' entry."

set -- $tcmd
cmd="$TDIR/$1"
[ -f "$cmd" -a -x "$cmd" ] \
  || die 2 "template command ($1) not in template dir ($TDIR)"

# Generate the PKGBUILD using basic pbfields script plus custom template.
"$TDIR/pbfields" < PKGMETA > PKGBUILD || die 1 "pbfields returned error ${?}."
"$TDIR"/$tcmd < PKGMETA >> PKGBUILD || die 1 "template pipeline ($tcmd) failed"

# Prepand/append text to the package, check, or build functions.
for func in package check build
do
	for op in append prepend
	do
		editpb $op $func \
		  || die 2 "error $? when trying to $op to ${func}()"
	done
done

exit 0