# -*-Perl-*-

# instances allowed: one 

# (single instance modules would be silly to use more than one of
# anyway, so we use package local storage.  This is faster and places
# less artificial load on the machine than doing everything through
# the object hash)


# todo: go back to using disk id numbers as reported rather than
# trying to make a contiguous numbering

package MGMmodule::diskstat;
use vars qw($xpath @rsectors @wsectors @prevr @prevw $widget $graph 
	    $numdisks $lastdisks $lastmod $kernel @disknames);
use IO::Seekable;

# class init
sub module_init{
    my$this=shift;
    my$toplevel=$this->{"toplevel"};
    my$xclass=$this->{"xclass"};

    # how many disks?  Call read once to init
    $numdisks=0;

    # 2.0 and 2.2
    if(defined($MGMmodule::helperST::proc{"disk_rblk"})){
	$kernel=0;$this->read_proc; 
    }

    # 2.4
    if(defined($MGMmodule::helperST::proc{"disk_io:"})){
	$kernel=4;$this->read_proc;
    } 

    # 2.6
    if(defined(%MGMmodule::helperST::disk26)){
	$kernel=6;$this->read_proc;
    } 

    if(!$numdisks){
	$toplevel->optionAdd("$xclass.active",'false',21);   
    } 
    $toplevel->optionAdd("$xclass.order",10,21);   
    $lastdisks=$numdisks;
    $this;
}

# instance init
sub module_instance{
    my$this=shift;
    my$toplevel=$this->{"toplevel"};
    return undef if(defined($xpath));
    $xpath=$this->{"xpath"};

    # modify defaults
    for(my$i=0;$i<$numdisks;$i++){
	$toplevel->optionAdd("$xpath.bar.".($i*2).".label", 
			     "$disknames[$i] read",21);
	$toplevel->optionAdd("$xpath.bar.".($i*2+1).".label", 
			     "$disknames[$i] write",21);
	$toplevel->optionAdd("$xpath.bar.".($i*2).".litbackground", 
			     '#e7ad74',21);
	$toplevel->optionAdd("$xpath.bar.".($i*2+1).".litbackground", 
			     '#ade774',21);
    }

    $toplevel->optionAdd("$xpath.scalewidadj", 160*$numdisks,21);  # narrower
    $toplevel->optionAdd("$xpath.scalereturn", 120,21);
    # this relies on the above defaults

    my($minx,$miny)=MGM::Graph::calcxysize($this,1024*1024*512,
					   ' sect/s',$numdisks*2);
    
    $toplevel->optionAdd("$xpath.minx",        $minx,21);      
    $toplevel->optionAdd("$xpath.miny",        $miny,21);      
    $this;
}

# instance widget build
sub module_run{
    my$this=shift;
    
    $graph=MGM::Graph->new($this,num=>$numdisks*2,
			   prompt=>' sect/s',
			   minscale=>128);

    $lastmod=-1;
    $widget=$graph->{"widget"};        # must return the widget
}

sub read_proc{
    if($kernel==6){ #2.6-ish
	undef @rsectors;
	undef @wsectors;
	$numdisks=0;
	foreach my $key (sort(keys %MGMmodule::helperST::disk26)){
	    
	    # if there are per-parition stats available, skip the whole-disk entries
	    if($key=~m/^[^0-9]+$/){
		if(defined($MGMmodule::helperST::disk26{"$key"."1"})){
		    next;
		}
	    }
	    
	    if($MGMmodule::helperST::disk26{$key}=~m/\d+\s+\d+\s+(\d+)\s+\d+\s+\d+\s+\d+\s+(\d+)/ ||
	       $MGMmodule::helperST::disk26{$key}=~m/\d+\s+(\d+)\s+\d+\s+(\d+)/){
	    
		# if this entry is as-yet unused, ignore it
		next if($1==0 && $2==0);
		
		$rsectors[$numdisks]=$1;
		$wsectors[$numdisks]=$2;
		$disknames[$numdisks]=$key;
		$numdisks++;
	    }
	}

    }else{
	# now uses the 00helper to save on opens
	if($kernel==4){ #2.4-ish
	    my $disk;
	    my@disks=split ' ',$MGMmodule::helperST::proc{"disk_io:"};
	    
	    $numdisks=0;
	    undef @rsectors;
	    undef @wsectors;
	    foreach $disk (@disks){
		$disk=~m/\(\d+,\d+\):\(\d+,\d+,(\d+),\d+,(\d+)\)/;
		if ($1 || $2){
		    $rsectors[$numdisks]=$1;
		    $wsectors[$numdisks]=$2;
		    $disknames[$numdisks]="disk$numdisks";
		    $numdisks++;
		}
	    }
	}else{ #2.0/2.2-ish
	    my@A=split ' ',$MGMmodule::helperST::proc{"disk_rblk"};
	    my@B=split ' ',$MGMmodule::helperST::proc{"disk_wblk"};
	    $numdisks=0;
	    map{if ($A[$_] || $B[$_]){$rsectors[$numdisks]=$A[$_];
				      $wsectors[$numdisks]=$B[$_];
				      $disknames[$numdisks]="disk$numdisks";
				  }}(0..$#A);
	}
    }
}

sub module_update{ 
    my$this=shift;

    # don't update unless the helper has
    if($lastmod!=$MGMmodule::helperST::lastmod){
	my$time=$MGMmodule::helperST::lastmod;
	$this->read_proc;

	return &reconfig if($numdisks != $lastdisks);
	$lastdisks=$numdisks;

	if(defined(@prevr)){
	    my @vals;
	    
	    for(my$i=0;$i<=$#rsectors;$i++){
		if ($rsectors[$i] or $wsectors[$i]){
		    my$r=($rsectors[$i]-$prevr[$i])/($time-$lastmod)*100;
		    my$w=($wsectors[$i]-$prevw[$i])/($time-$lastmod)*100;
		    push @vals, $r, $w;
		}
	    }
	    
	    # don't be clever and only call set if values change; set must
	    # be called each refresh period or the graph will get
	    # confused.
	    
	    $graph->set(@vals);
	}
	
	@prevr=@rsectors;
	@prevw=@wsectors;
	$lastmod=$time;
    }
}

sub reconfig{
    $lastdisks=$numdisks;
    @prevr=@rsectors;
    @prevw=@wsectors;
    &main::reinstance() if($widget->optionGet("reconfig","") eq 'true');
}

sub destroy{
    undef $xpath;
}

bless {};