#!/usr/bin/perl

our $VI = $ENV{VERSION};
our $V;
our $opt_v = 0; # verbose

sub errlog { print STDERR "pssqlpp:$_[0]\n"; }

if($VI=~m!(\d+)(\.(\d+))?!) {
	my ($maj,$min)=($1+0,$3+0);
	if($maj>=10) { $min=0; }
	$V = $maj+$min/10.0;
	errlog "Preprocessing for Postgres version $V";
} else {
	errlog "No Postgres version specified in VERSION environment variable";
}

print "-- preprocessed by pgsqlpp for PG=$V\n";
my $i=0;  # line number
my $sv=0; # selected version
my $rv=0; # required version
my $unless=0;
while($l=<>) {
	$i++;
	if($l=~m!^#(\S+)\s*(\S*)!) {
		my ($c,$v2)=($1,$2);
		if($opt_v) { errlog "Directive line $i \#$c $v2"; }
		if($c eq 'if') { $sv=$v2; $unless=0; }
		elsif($c eq 'unless') { $sv=$v2; $unless=1; }
		elsif($c eq 'else') { $unless=!$unless; }
		elsif($c eq 'end') { $sv=0; }
		elsif($c eq 'require') { $rv=$v2; }
		elsif($c eq 'required') { $rv=0; }
		else {
			errlog "Unknown Directive line $i \#$c $v2";
		}
	} else {
		if(($sv==0 || ($unless?($V<$sv):($V>=$sv)))
		   && ($rv==0 || $V>=$rv)) {
			print $l;
		}
	}
}