Wordpress - Custom fields in category (posts)

gistfile1.txt

<?php
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// CUSTOM FIELDS IN CATEGORY - BLOG
///////////////////////////////////
// retrieve values like this:
// -------------------------
// $category_extra_fields = get_option('category_extra_fields');
// $section_subtitle = $category_extra_fields[$category->term_id]['section_subtitle'][0];

define('MY_BLOG_CATEGORY_FIELDS', 'category_extra_fields');
add_action('category_add_form_fields','post_category_edit_form_fields');
add_action('category_edit_form_fields','post_category_edit_form_fields');

add_filter('edited_terms', 'update_my_post_category_fields');
function update_my_post_category_fields($term_id) {

	if($_POST['taxonomy'] == 'category'):
		$tag_id = intval($_POST['tag_ID']);
		$tag_extra_fields = get_option(MY_BLOG_CATEGORY_FIELDS);
		$tag_extra_fields[$tag_id]['section_color'][0] = $_POST['section_color'];
		$tag_extra_fields[$tag_id]['section_subtitle'][0] = $_POST['section_subtitle'];
		$tag_extra_fields_term = get_option(MY_BLOG_CATEGORY_FIELDS);
		$tag_extra_fields_term['term-' .$term_id]['section_color'] = $_POST['section_color'];
		$tag_extra_fields_term['term-' .$term_id]['section_subtitle'] = $_POST['section_subtitle'];

		update_option(MY_BLOG_CATEGORY_FIELDS, $tag_extra_fields_term);
		update_option(MY_BLOG_CATEGORY_FIELDS, $tag_extra_fields);
	endif;
}

function post_category_edit_form_fields () {

	$tag_id = intval($_GET['tag_ID']);
	$tag_extra_fields = get_option(MY_BLOG_CATEGORY_FIELDS);
	$section_color = $tag_extra_fields[$tag_id]['section_color'][0];
	$section_subtitle = $tag_extra_fields[$tag_id]['section_subtitle'][0];
	?>

	<tr class="form-field">
		<th valign="top" scope="row">
			<label>Subtitle</label>
		</th>
		<td>
			<input type="text" name="section_subtitle" value="<?php echo $section_subtitle; ?>" />
		</td>
	</tr>

	<tr class="form-field">
		<th valign="top" scope="row">
			<label>Section color:</label>
		</th>
		<td>
			<input type="color" name="section_color" value="<?php echo $section_color; ?>" />
		</td>
	</tr>

<?php
}
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////