package Mojolicious::Plugin::EpRenderer;
use Mojo::Base 'Mojolicious::Plugin';

use Mojo::Template;
use Mojo::Util 'md5_sum';

# "What do you want?
#  I'm here to kick your ass!
#  Wishful thinking. We have long since evolved beyond the need for asses."
sub register {
  my ($self, $app, $conf) = @_;

  # Config
  $conf ||= {};
  my $name     = $conf->{name}     || 'ep';
  my $template = $conf->{template} || {};

  # Auto escape by default to prevent XSS attacks
  $template->{auto_escape} = 1 unless defined $template->{auto_escape};

  # Add "ep" handler
  $app->renderer->add_handler(
    $name => sub {
      my ($r, $c, $output, $options) = @_;

      # Generate name
      my $path = $r->template_path($options) || $options->{inline};
      return unless defined $path;
      my $list = join ', ', sort keys %{$c->stash};
      my $key = $options->{cache} = md5_sum "$path($list)";

      # Stash defaults
      $c->stash->{layout} ||= undef;

      # Cache
      my $cache = $r->cache;
      unless ($cache->get($key)) {

        # Initialize
        my $mt = Mojo::Template->new($template);

        # Self
        my $prepend = 'my $self = shift;';

        # Weaken
        $prepend .= q/use Scalar::Util 'weaken'; weaken $self;/;

        # Be a bit more relaxed for helpers
        $prepend .= q/no strict 'refs'; no warnings 'redefine';/;

        # Helpers
        $prepend .= 'my $_H = $self->app->renderer->helpers;';
        for my $name (sort keys %{$r->helpers}) {
          next unless $name =~ /^\w+$/;
          $prepend .= "sub $name; *$name = sub { ";
          $prepend .= "return \$_H->{'$name'}->(\$self, \@_) };";
        }

        # Be less relaxed for everything else
        $prepend .= 'use strict;';

        # Stash
        $prepend .= 'my $_S = $self->stash;';
        for my $var (keys %{$c->stash}) {
          next unless $var =~ /^\w+$/;
          $prepend .= " my \$$var = \$_S->{'$var'};";
        }

        # Prepend
        $mt->prepend($prepend);

        # Cache
        $cache->set($key => $mt);
      }

      # Render with epl
      return $r->handlers->{epl}->($r, $c, $output, $options);
    }
  );

  # Set default handler
  $app->renderer->default_handler('ep');
}

1;
__END__

=head1 NAME

Mojolicious::Plugin::EpRenderer - EP Renderer Plugin

=head1 SYNOPSIS

  # Mojolicious
  $self->plugin('ep_renderer');
  $self->plugin(ep_renderer => {name => 'foo'});
  $self->plugin(ep_renderer => {template => {line_start => '.'}});

  # Mojolicious::Lite
  plugin 'ep_renderer';
  plugin ep_renderer => {name => 'foo'};
  plugin ep_renderer => {template => {line_start => '.'}};

=head1 DESCRIPTION

L<Mojolicious::Plugin::EpRenderer> is a renderer for C<ep> templates.

=head1 TEMPLATES

C<ep> or C<Embedded Perl> is a simple template format where you embed perl
code into documents.
It is based on L<Mojo::Template>, but extends it with some convenient syntax
sugar designed specifically for L<Mojolicious>.
It supports L<Mojolicious> template helpers and exposes the stash directly as
perl variables.
This is a core plugin, that means it is always enabled and its code a good
example for learning to build new plugins.

=head1 OPTIONS

=head2 C<name>

  # Mojolicious::Lite
  plugin ep_renderer => {name => 'foo'};

Handler name.

=head2 C<template>

  # Mojolicious::Lite
  plugin ep_renderer => {template => {line_start => '.'}};

Template options.

=head1 METHODS

L<Mojolicious::Plugin::EpRenderer> inherits all methods from
L<Mojolicious::Plugin> and implements the following new ones.

=head2 C<register>

  $plugin->register;

Register renderer in L<Mojolicious> application.

=head1 SEE ALSO

L<Mojolicious>, L<Mojolicious::Guides>, L<http://mojolicio.us>.

=cut
