# ABSTRACT: Template toolkit engine for Dancer2

package Dancer2::Template::TemplateToolkit;
$Dancer2::Template::TemplateToolkit::VERSION = '0.166001';
use Moo;
use Carp qw/croak/;
use Dancer2::Core::Types;
use Dancer2::FileUtils qw'path';
use Scalar::Util qw();
use Template;

with 'Dancer2::Core::Role::Template';

has '+engine' => ( isa => InstanceOf ['Template'], );

sub _build_engine {
    my $self      = shift;
    my $charset   = $self->charset;
    my %tt_config = (
        ANYCASE  => 1,
        ABSOLUTE => 1,
        length($charset) ? ( ENCODING => $charset ) : (),
        %{ $self->config },
    );

    my $start_tag = $self->config->{'start_tag'};
    my $stop_tag = $self->config->{'stop_tag'} || $self->config->{end_tag};
    $tt_config{'START_TAG'} = $start_tag
      if defined $start_tag && $start_tag ne '[%';
    $tt_config{'END_TAG'} = $stop_tag
      if defined $stop_tag && $stop_tag ne '%]';

    Scalar::Util::weaken( my $ttt = $self );
    my $include_path = $self->config->{include_path};
    $tt_config{'INCLUDE_PATH'} ||= [
        ( defined $include_path ? $include_path : () ),
        sub { [ $ttt->views ] },
    ];

    return Template->new(%tt_config);
}

sub render {
    my ( $self, $template, $tokens ) = @_;

    my $content = '';
    my $charset = $self->charset;
    my @options = length($charset) ? ( binmode => ":encoding($charset)" ) : ();
    $self->engine->process( $template, $tokens, \$content, @options )
      or croak 'Failed to render template: ' . $self->engine->error;

    return $content;
}

# Override *_pathname methods from Dancer2::Core::Role::Template
# Let TT2 do the concatenation of paths to template names.
#
# TT2 will look in a its INCLUDE_PATH for templates.
# Typically $self->views is an absolute path, and we set ABSOLUTE=> 1 above.
# In that case TT2 does NOT itetare through what is set for INCLUDE_PATH
# However, if its not absolute, we want to allow TT2 iterate through the
# its INCLUDE_PATH, which we set to be $self->views.

sub view_pathname {
    my ( $self, $view ) = @_;
    return $self->_template_name($view);
}

sub layout_pathname {
    my ( $self, $layout ) = @_;
    return path(
        $self->layout_dir,
        $self->_template_name($layout),
    );
}

sub pathname_exists {
    my ( $self, $pathname ) = @_;
    return eval {
        # dies if pathname can not be found via TT2's INCLUDE_PATH search
        $self->engine->service->context->template( $pathname );
        1;
    };
}

1;

__END__

=pod

=encoding UTF-8

=head1 NAME

Dancer2::Template::TemplateToolkit - Template toolkit engine for Dancer2

=head1 VERSION

version 0.166001

=head1 SYNOPSIS

To use this engine, you may configure L<Dancer2> via C<config.yaml>:

    template:   "template_toolkit"

Or you may also change the rendering engine on a per-route basis by
setting it manually with C<set>:

    # code code code
    set template => 'template_toolkit';

=head1 DESCRIPTION

This template engine allows you to use L<Template::Toolkit> in L<Dancer2>.

=head1 METHODS

=head2 render($template, \%tokens)

Renders the template.  The first arg is a filename for the template file
or a reference to a string that contains the template.  The second arg
is a hashref for the tokens that you wish to pass to
L<Template::Toolkit> for rendering.

=head1 SEE ALSO

L<Dancer2>, L<Dancer2::Core::Role::Template>, L<Template::Toolkit>.

=head1 AUTHOR

Dancer Core Developers

=head1 COPYRIGHT AND LICENSE

This software is copyright (c) 2015 by Alexis Sukrieh.

This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.

=cut