Jifty::Plugin::Chart - A charting API for Jifty

  Plugins:
    - Chart: {}

  <% Jifty->web->chart(
      type   => 'Bar',
      width  => 400,
      height => 300,
      data   => [
          [ '2004', '2005', '2006', '2007' ], # labels
          [ 14,     15,     17,     22     ], # first data set
          [ 22,     25,     20,     21     ], # second data set
      ],
  ) %>

  Plugins:
    - Chart:
        DefaultRenderer: PlotKit
        PreloadRenderers:
         - XMLSWF
         - SimpleBars
         - App::Renderer::Custom

  my $renderer = $chart_plugin->init_renderer($renderer_class)

use strict;
use warnings;

package Jifty::Plugin::Chart;
use base qw/ Jifty::Plugin Class::Accessor::Fast /;

our $VERSION = '1.01';

use Jifty::Plugin::Chart::Web;
use Scalar::Util qw/ blessed /;

__PACKAGE__->mk_accessors(qw/ renderer renderers plugin_args _prereq_plugins/);

sub init {
    my $self = shift;
    my %args = (
        DefaultRenderer => 'Chart',
        @_,
    );

    # Save the arguments for use in init_renderer() later
    $self->plugin_args( \%args );
    $self->_prereq_plugins( [] );

    # Deprecating the old form
    if (defined $args{renderer}) {
        warn 'DEPRECATED: renderer argument to Chart plugin is deprecated.'
            .' Use DefaultRenderer instead.';
        $args{DefaultRenderer} = delete $args{renderer};
    }

    # Create the empty renderers list
    $self->renderers({});

    # Pre-load any renderers they plan to use
    if (defined $args{PreloadRenderers}) {
        $args{PreloadRenderers} = [ $args{PreloadRenderers} ]
            unless ref $args{PreloadRenderers};

        for my $renderer (@{ $args{PreloadRenderers} }) {
            $self->init_renderer( $renderer );
        }
    }

    # Load the default renderer
    $self->renderer( $self->init_renderer( $args{DefaultRenderer}, %args ) );

    push @Jifty::Web::ISA, 'Jifty::Plugin::Chart::Web';
}

sub init_renderer {
    my ( $self, $renderer_class ) = ( shift, shift );

    # If it's already an object, just return that
    if ( blessed($renderer_class)
            and $renderer_class->isa(__PACKAGE__.'::Renderer') ) {
        return $renderer_class;
    }

    # Prepend Jifty::Plugin::Chart::Renderer:: if we think we need to
    my @renderer_classes = (
        $renderer_class,
        __PACKAGE__ . '::Renderer::' . $renderer_class,
    );

    for my $renderer_class (@renderer_classes) {
        # Check to see if we already loaded this one
        my $renderer = $self->renderers->{ $renderer_class };
        return $renderer if defined $renderer;

        # Tell perl to load the class
        unless ($renderer_class->require) {
           warn $@ unless $@ =~ /^Can't locate /;
           next;
        }

        # Initialize the renderer
        $renderer = $renderer_class->new( %{ $self->plugin_args } );

        if( $renderer->can('prereq_plugins') ) {
          my @prereq_plugins =  $renderer->prereq_plugins ;
          push @{ $self->{_prereq_plugins} } , @prereq_plugins ;
        }

        # Remember it
        $self->renderers->{ $renderer_class } = $renderer;

        # Return it!
        return $renderer;
    }
}

sub prereq_plugins {
    my $self = shift;
    return @{ $self->_prereq_plugins };
}

1;