Twitter Bootstrap Comment Form for Wordpress

twbs_comment_form_defaults.php

<?php

if ( ! function_exists( 'twbs_comment_form_defaults' ) ) {
	/**
	 * Customize default wp comment form.
	 *
	 * @link https://developer.wordpress.org/reference/hooks/comment_form_defaults/
	 * @link https://codex.wordpress.org/Function_Reference/comment_form
	 *
	 * @param array $defaults
	 * @return array
	 */
	function twbs_comment_form_defaults( $defaults ) {
		$commenter = wp_get_current_commenter();
		$req       = get_option( 'require_name_email' );
		
		$labels = [
			'author' => __( 'Name' ),
			'email' => __( 'Email' ),
			'url' => __( 'Website' ),
			'comment' => _x( 'Comment', 'noun' ),
			'required' => __( 'required' )
		];

		$req_html = sprintf( '(%s)', $labels['required'] );
		$req_attr = $req ? 'aria-required="true" required' : '';
		$req_mark = $req ? ' ' . $req_html : '';

		$defaults['submit_field'] = '<div class="form-group form-submit">%1$s %2$s</div>';
		$defaults['class_submit'] = 'btn btn-primary submit';

		$defaults['comment_field'] = implode( '', [
			'<div class="form-group comment-form-comment">',
			'<label for="comment" class="sr-only">' . $labels['comment'] . $req_html . '</label>',
			sprintf(
				'<textarea id="comment" name="comment" class="form-control" rows="8" placeholder="%1$s" aria-required="true" required="required"></textarea>',
				$labels['comment'] . ' *'
			),
			'</div>'
		] );

		$defaults['fields'] = [
			'author' => implode( '', [
				'<div class="form-group comment-form-author">',
				'<label for="author" class="sr-only">' . $labels['author'] . $req_mark . '</label> ',
				sprintf(
					'<input id="author" name="author" class="form-control" type="text" value="%1$s" placeholder="%2$s" maxlength="245" %3$s />',
					esc_attr( $commenter['comment_author'] ),
					$labels['author'] . ( $req ? ' *' : '' ),
					$req_attr
				),
				'</div>'
			] ),

			'email' => implode( '', [
				'<div class="form-group comment-form-email">',
				'<label for="email" class="sr-only">' . $labels['email'] . $req_mark . '</label> ',
				sprintf(
					'<input id="email" name="email" class="form-control" type="email" value="%1$s" placeholder="%2$s" maxlength="100" aria-describedby="email-notes" %3$s />',
					esc_attr(  $commenter['comment_author_email'] ),
					$labels['email'] . ( $req ? ' *' : '' ),
					$req_attr
				),
				'</div>'
			] ),

			'url' => implode( '', [
				'<div class="form-group comment-form-url">',
				'<label for="url" class="sr-only">' . $labels['url'] . '</label> ',
				sprintf(
					'<input id="url" name="url" class="form-control" type="url" value="%1$s" placeholder="%2$s" size="30" maxlength="200" />',
					esc_attr( $commenter['comment_author_url'] ),
					$labels['url']
				),
				'</div>'
			] ),
		];

		return $defaults;
	}
	add_filter( 'comment_form_defaults', 'twbs_comment_form_defaults' );
}