I would like to add next plugin to Ikiwiki. It's `progressbar` or simply `progress`.
I'm not sure what plugin name better is, probably that shorter ;) I know that
[DokuWiki](http://wiki.splitbrain.org/plugin:progressbar) has similar plugin,
so I think it can be useful also for Ikiwiki users.

Here is proposition of the plugin syntax:

    \[[!progress done=50]]

Of course, `done` argument is integer from 0 to 100. 

A here is its HTML result:

    <div class="progress">
      <div class="progress-done" style="width: 50%">50%</div>
    </div>

Note: I was trying with `<span>` tags too, but that tag is inline, so I can't
set `width` property for it.

Default CSS styles for the plugin can be like below:

    div.progress {
            border: 1px solid #ddd;
            /* border: 2px solid #ddd; */
            width: 200px;
            background: #fff;
            padding: 2px;
            /* padding: 0px; */
            border: 2px solid #aaa;
            background: #eee;
    }
    div.progress-done {
            height: 14px;
            background: #ff6600;
            font-size: 12px;
            text-align: center;
            vertical-align: middle;
    }

You can use alternative, commented CSS code for `div.progress` if you dislike
padding around done strip.

Any comments? --[[Paweł|ptecza]]

> This looks like a nice idea.  If I could add one further suggestion: Allow your
> ratio to be a pair of pagespecs.  Then you could have something like:

    \[[!progress totalpages="bugs/* and backlink(milestoneB)" donepages="bugs/* and backlink(milestoneB) and !link(bugs/done)"]]

> to have a progress bar marking how many bugs were compete for a
> particular milestone.  -- [[Will]]

>> Thanks a lot for your comment, Will! It seems very interesting for me.
>> I need to think more about improving that plugin. --[[Paweł|ptecza]]

>> Attached is a [[patch]] (well, source) for this.  You also need to add the proposed CSS above to `style.css`.
>> At the moment this plugin interacts poorly with the [[plugins/htmlscrubber]] plugin.
>> HTMLScrubber plugin removes the `style` attribute from the `progress-done` `div` tag, and so it defaults
>> to a width of 100%. -- [[Will]]

>>> Thank you for the code! I know how to fix that problem, because I had
>>> the same issue while writing [[todo/color_plugin]] :) --[[Paweł|ptecza]]

>>>> Ahh - good idea.  Patch updated to work with HTMLScrubber. --[[Will]]

    #!/usr/bin/perl
    package IkiWiki::Plugin::progress;
    
    use warnings;
    use strict;
    use IkiWiki 2.00;
    
    my $percentage_pattern = qr/[0-9]+\%/; # pattern to validate percentages
    
    sub import { #{{{
    	hook(type => "getsetup", id => "progress", call => \&getsetup);
    	hook(type => "preprocess", id => "progress", call => \&preprocess);
    	hook(type => "format",     id => "progress", call => \&format);
    } # }}}
    
    sub getsetup () { #{{{
    	return 
    		plugin => {
    			safe => 1,
    			rebuild => undef,
    		},
    } #}}}
    
    sub preprocess (@) { #{{{
    	my %params=@_;
    	
    	my $fill;
    	
    	if (defined $params{percent}) {
    		$fill = $params{percent};
    		($fill) = $fill =~ m/($percentage_pattern)/; # fill is untainted now
    	}
    	elsif (defined $params{totalpages} and defined $params{donepages}) {
    		add_depends($params{page}, $params{totalpages});
    		add_depends($params{page}, $params{donepages});
    
    		my @pages=keys %pagesources;
    		my $totalcount=0;
    		my $donecount=0;
    		foreach my $page (@pages) {
    			$totalcount++ if pagespec_match($page, $params{totalpages}, location => $params{page});
    			$donecount++ if pagespec_match($page, $params{donepages}, location => $params{page});
    		}
    		
    		if ($totalcount == 0) {
    			$fill = "100%";
    		} else {
    			my $number = $donecount/$totalcount*100;
    			$fill = sprintf("%u%%", $number);
    		}
    	}
    	else {
    		error("Missing parameters to progress plugin.  Need either `percent` or `totalpages` and `donepages` parameters.");
    	}
    
    	return <<EODIV
    <div class="progress">
      <div class="progress-done" style="width: $fill">$fill</div>
    </div>
    EODIV
    
    } # }}}
    
    sub format(@) { #{{{
    	my %params = @_;
    
    	# If HTMLScrubber has removed the style attribute, then bring it back
    
    	$params{content} =~ s!<div class="progress-done">($percentage_pattern)</div>!<div class="progress-done" style="width: $1">$1</div>!g;
    
    	return $params{content};    
    } #}}}
    
    1

Here is a potential documentation page:

-----

[[!template id=plugin name=progress author="[[Will]]"]]
[[!tag type/meta]]

Provides a \\[[!progress ]] [[ikiwiki/PreProcessorDirective]] that is
replaced with a progress bar.

There are two possible parameter sets.  The first is a single parameter
`percent` which holds a percentage figure for how complete the progress bar is.

The second possible set of parameters is a pair of [[ikiwiki/PageSpec]]s,
`totalpages` and `donepages`.  The progress plugin counts the number of
pages in each pagespec and shows the percentage of the total pages that are
done.

This plugin is included in ikiwiki, but is not enabled by default.

If it is turned on it can show what percentage of pages have discussion pages:

[[!progress totalpages="* and !*/Discussion" donepages="*/Discussion"]]