#! /usr/bin/perl
#
# Copyright (c) 2012 Red Hat.
# Copyright (c) 2008,2012 Aconex.  All Rights Reserved.
# Copyright (c) 2004 Silicon Graphics, Inc.  All Rights Reserved.
# 
# This program is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by the
# Free Software Foundation; either version 2 of the License, or (at your
# option) any later version.
# 
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
# or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
# for more details.
# 

use strict;
use warnings;
use PCP::PMDA;

use vars qw( $pmda $red $green $blue $user $system );
my ( $numfetch, $oldfetch ) = ( 0, -1 );
my ( $color_indom, $now_indom ) = ( 0, 1 );
my ( $red, $green, $blue ) = ( 0, 100, 200 );

# simple.now instance domain stuff...
my $simple_config = pmda_config('PCP_PMDAS_DIR') . '/simple/simple.conf';
my %timeslices;
my $file_error = 0;

sub simple_instance	# called once per ``instance request'' pdu
{
    &simple_timenow_check;
}

sub simple_fetch	# called once per ``fetch'' pdu, before callbacks
{
    $numfetch++;
    &simple_timenow_check;
}

sub simple_fetch_callback	# must return array of value,status
{
    my ($cluster, $item, $inst) = @_;

    return (PM_ERR_INST, 0) unless ( $inst == PM_IN_NULL
				    || ($cluster == 0 && $item == 1)
				    || ($cluster == 2 && $item == 4) );
    if ($cluster == 0) {
	if ($item == 0)	{ return ($numfetch, 1); }
	elsif ($item == 1) {
	    if ($inst == 0)	{ return ($red = ($red+1) % 255, 1); }
	    elsif ($inst == 1)	{ return ($green = ($green+1) % 255, 1); }
	    elsif ($inst == 2)	{ return ($blue = ($blue+1) % 255, 1); }
	    else		{ return (PM_ERR_INST, 0); }
	} else		{ return (PM_ERR_PMID, 0); }
    }
    elsif ($cluster == 1) {
	if ($oldfetch < $numfetch) {	# get current values, if needed
	    ($user, $system, undef, undef) = times;
	    $oldfetch = $numfetch;
	}
	if ($item == 2)		{ return ($user, 1); }
	elsif ($item == 3)	{ return ($system, 1); }
	else			{ return (PM_ERR_PMID, 0); }
    }
    elsif ($cluster == 2 && $item == 4) {
	my $value = pmda_inst_lookup($now_indom, $inst);
	return (PM_ERR_INST, 0) unless defined($value);
	return ($value, 1);
    }
    return (PM_ERR_PMID, 0);
}

sub simple_store_callback	# must return a single value (scalar context)
{
    my ($cluster, $item, $inst, $val) = @_;
    my $sts = 0;

    if ($cluster == 0) {
	if ($item == 0) {
	    if ($val < 0)	{ $val = 0; $sts = PM_ERR_BADSTORE; }
	    $numfetch = $val;
	}
	elsif ($item == 1) {
	    if ($val < 0)	{ $sts = PM_ERR_BADSTORE; $val = 0; }
	    elsif ($val > 255)	{ $sts = PM_ERR_BADSTORE; $val = 255; }

	    if ($inst == 0)	{ $red = $val; }
	    elsif ($inst == 1)	{ $green = $val; }
	    elsif ($inst == 2)	{ $blue = $val; }
	    else		{ $sts = PM_ERR_INST; }
	}
	else	{ $sts = PM_ERR_PMID; }
	return $sts;
    }
    elsif ( ($cluster == 1 && ($item == 2 || $item == 3))
	|| ($cluster == 2 && $item == 4) ) {
	return PM_ERR_PERMISSION;
    }
    return PM_ERR_PMID;
}

sub simple_timenow_check
{
    %timeslices = ();

    if (open(CONFIG, $simple_config)) {
	my %values;

	($values{'sec'}, $values{'min'}, $values{'hour'},
	    undef,undef,undef,undef,undef) = localtime;
	$_ = <CONFIG>;
	chomp;		# avoid possible \n on last field
	foreach my $spec (split(/,/)) {
	    $timeslices{$spec} = $values{$spec};
	}
	close CONFIG;
	$file_error = 0;
    }
    else {
	unless ($file_error == $!) {
	    $pmda->log("read failed on $simple_config: $!");
	    $file_error = $!;
	}
    }
    $pmda->replace_indom( $now_indom, \%timeslices);
}

$pmda = PCP::PMDA->new('simple', 253);
$pmda->connect_pmcd;

$pmda->add_metric(pmda_pmid(0,0), PM_TYPE_U32, PM_INDOM_NULL,
		  PM_SEM_INSTANT, pmda_units(0,0,0,0,0,0),
		  'simple.numfetch', '', '');
$pmda->add_metric(pmda_pmid(0,1), PM_TYPE_32, $color_indom,
		  PM_SEM_INSTANT, pmda_units(0,0,0,0,0,0),
		  'simple.color', '', '');
$pmda->add_metric(pmda_pmid(1,2), PM_TYPE_DOUBLE, PM_INDOM_NULL,
		  PM_SEM_COUNTER, pmda_units(0,1,0,0,PM_TIME_SEC,0),
		  'simple.time.user', '', '');
$pmda->add_metric(pmda_pmid(1,3), PM_TYPE_DOUBLE, PM_INDOM_NULL,
		  PM_SEM_COUNTER, pmda_units(0,1,0,0,PM_TIME_SEC,0),
		  'simple.time.sys', '', '');
$pmda->add_metric(pmda_pmid(2,4), PM_TYPE_U32, $now_indom,
		  PM_SEM_INSTANT, pmda_units(0,0,0,0,0,0),
		  'simple.now', '', '');

$pmda->add_indom($color_indom, [0 => 'red', 1 => 'green', 2 => 'blue'], '', '');
$now_indom = $pmda->add_indom($now_indom, {}, '', ''); # initialized on-the-fly
$pmda->set_fetch( \&simple_fetch );
$pmda->set_instance( \&simple_instance );
$pmda->set_fetch_callback( \&simple_fetch_callback );
$pmda->set_store_callback( \&simple_store_callback );

$pmda->set_user('pcp');
&simple_timenow_check;
$pmda->run;