#!/usr/bin/perl
#
# a frontend to mysql and gnuplot, v0.01
#
# features that would be nice:
# 1) easy set up of plotting options
# 2) default from and default limit clauses automatically overriden if included on command line
# 3) readline history
#

use DBI;
use Data::Dumper;

$dbh = DBI->connect("dbi:mysql:db=primes",undef,undef) || die "Failed to connect to database";

$alive = 1;
while($alive) {

print "select>";

$select = <>;
#$select = "SELECT n & dPrevPrime FROM numbers LIMIT 500";

$default = "from numbers limit 100";

$slc = lc $select;

if($slc =~ /quit.*/) {
	exit(0);
} elsif (($set) = $slc =~ /set (.*)/) {
	($token, $value) = $set =~ /(.*?) (.*)/;
	print "Set $token: $value\n";

	if(!$token && ($value eq "default")) {
		$default = "";
	}

	if($token eq "default") {
		$default = $value;
		print "Default now $value\n";
	}

} elsif(($graph) = $select =~ /graph (.*)/) {

	$sth = $dbh->prepare($graph . " " . $default);

	if($sth->execute()) {
		graph($sth);
	} else {
		print "Error: " . $DBI::errstr . "\n";
	}
} else {
	open(FOO,"|mysql --table primes");
	if($slc =~ /.*select.*/) {
		print FOO "$select $default\n";
	} else {
		print FOO "$select\n";
	}
	close(FOO);
}
}


sub graph {
	my $sth = shift;

$file = "/tmp/graph.$$";
open(FOO,">$file");
$a = 0;
while($data = $sth->fetchrow_arrayref()) {
	$rows = @{$data};
	print FOO $a++;
	for($i=0;$i<$rows;$i++) {
		print FOO "\t";
		print FOO @{$data}[$i];
	}
	print FOO "\n";
}
close(FOO);

$rc = "";
$rcb = "";

for($i=0;$i<$rows;$i++) {
	$rc .= ":" if(length($rc));
	$rc .= $i;
	$rcb .= ",\\\n" if(length($rcb));
	$rcb .= "'" . $file . "' using 1:" . ($i+2) ." with lines";

	print "rcb: $rcb\n";
}

$ofile = "/tmp/script.$$";
$pfile = "output.png";

$script = "set terminal png\n";
$script .= "set out \"$pfile\"\n";
#print SCRIPT "set linestyle 1 linetype 1 linewidth 1 pointstyle 4 pointsize 1\n";
$script .= "set ls 1\n";
#print SCRIPT "plot '$file' using $rc with $rcb\n";
$script .= "plot $rcb\n";

open(SCRIPT,">$ofile");
print SCRIPT $script;
print $script;
close(SCRIPT);

system("gnuplot $ofile");

unlink($ofile);
unlink($file);
}