use document templates to override page templates

When a document has a template or layout set, the page will use that
instead of the template/layout set by the application.

This has revealed a bunch of technical debt around creating and giving
template _objects_ to the Page. Since the Page has the Site which has
the Theme, we don't need to give it objects. We can just give it
arrays/strings and it can figure it out.

Fixes #40

lib/Statocles/Document.pm

@@ -109,7 +109,9 @@ has date => (
 
 =attr template
 
-A template override for this document.
+A template override for this document. If set, the L<document
+page|Statocles::Page::Document> will use this instead of the template provided
+by the application.
 
 =cut
 
@@ -125,7 +127,9 @@ has template => (
 
 =attr layout
 
-A layout override for this document.
+A layout template override for this document. If set, the L<document
+page|Statocles::Page::Document> will use this instead of the layout provided
+by the application.
 
 =cut
 

lib/Statocles/Page/Document.pm

@@ -131,6 +131,38 @@ sub tags {
     return @{ $self->_tags };
 }
 
+=method template()
+
+The L<template|Statocles::Template> for this page. If the document has a template,
+it will be used. Otherwise, the L<template attribute|Statocles::Page/template> will
+be used.
+
+=cut
+
+around template => sub {
+    my ( $orig, $self, @args ) = @_;
+    if ( $self->document->has_template ) {
+        return $self->site->theme->template( @{ $self->document->template } );
+    }
+    return $self->$orig( @args );
+};
+
+=method layout()
+
+The L<layout template|Statocles::Template> for this page. If the document has a layout,
+it will be used. Otherwise, the L<layout attribute|Statocles::Page/layout> will
+be used.
+
+=cut
+
+around layout => sub {
+    my ( $orig, $self, @args ) = @_;
+    if ( $self->document->has_layout ) {
+        return $self->site->theme->template( @{ $self->document->layout } );
+    }
+    return $self->$orig( @args );
+};
+
 1;
 __END__
 

t/page/document.t

@@ -6,7 +6,10 @@ use Statocles::Document;
 use Statocles::Page::Document;
 use Text::Markdown;
 use Statocles::Site;
-my $site = Statocles::Site->new( deploy => tempdir );
+my $site = Statocles::Site->new(
+    deploy => tempdir,
+    theme => $SHARE_DIR->child(qw( theme )),
+);
 
 my $doc = Statocles::Document->new(
     path => '/path/to/document.markdown',
@@ -69,6 +72,28 @@ subtest 'page date overridden by published date' => sub {
     is $page->date->datetime, $tp->datetime;
 };
 
+subtest 'document template/layout override' => sub {
+    my $doc = Statocles::Document->new(
+        path => '/path/to/doc.markdown',
+        title => 'Page Title',
+        content => 'Page content',
+        template => '/document/recipe.html',
+        layout => '/layout/logo.html',
+    );
+
+    my $page = Statocles::Page::Document->new(
+        path => '/path/to/doc.html',
+        site => $site,
+        document => $doc,
+        template => '<%= $content %>', # will be overridden
+        layout => '<%= $content %>', # will be overridden
+    );
+
+    my $output = $page->render;
+    my $expect = "Logo layout\nRecipe template\nPage Title\n<p>Page content</p>\n\n\n";
+    eq_or_diff $output, $expect;
+};
+
 subtest 'template coercion' => sub {
 
     subtest 'template' => sub {

t/share/theme/document/recipe.html.ep

@@ -0,0 +1,3 @@
+Recipe template
+%= $self->title
+%= $content

t/share/theme/layout/logo.html.ep

@@ -0,0 +1,2 @@
+Logo layout
+<%= $content %>