hello-vdu.php

<?php
/**
 * Plugin Name: Hello VDU
 * Author: Arūnas Liuiza [KAYAK]
 * Version: 0.1.0
 * Text Domain: hello-vdu
*/

add_action( 'plugins_loaded', 'hello_vdu' );

function hello_vdu() {
	if ( false === Hello_VDU_Class::$instance ) {
		Hello_VDU_Class::$instance = new Hello_VDU_Class();
	}
	return Hello_VDU_Class::$instance;
}

class Hello_VDU_Class {
	public static $instance = false;
	public function __construct() {
		add_filter( 'the_content', array( $this, 'copyright' ), 100 );
		// add "updated" info to the title
		add_filter( 'the_title', array( $this, 'modified' ), 10, 2 );
		// add icons to post title
		add_filter( 'the_title', array( $this, 'icons' ), 100 );
		add_action( 'wp_enqueue_scripts', array( $this, 'assets') );
	}
	
	public function copyright( $content ) {
		if ( ! is_singular( 'post' ) ) {
			return $content;
		}
		$content .= '<hr />' . PHP_EOL;
		$content .= '<p><small>';
		$content .= sprintf( 
			__( 'The conents of this article cannot be republished in any form without a prior written consent of the owners of %s website.', 'hello-vdu' ),
			get_bloginfo( 'title' )
		);
		$content .= '</small></p>';
		return $content;
	}
	
	public function modified( $title, $post_id ) {
		if ( is_admin() ) {
			return $title;
		}
		if ( ! in_the_loop() ) {
			return $title;
		}
		$post = get_post( $post_id );
		if ( $post->post_date === $post->post_modified ) {
			return $title;
		}
		if ( 3 * HOUR_IN_SECONDS < current_time('timestamp') - strtotime( $post->post_modified ) ) {
			return $title;
		}
		$diff = sprintf( 
			__( '(updated %s ago)', 'hello-vdu' ),
			human_time_diff( strtotime( $post->post_modified ) )
		);
		$title .= " <small style='color:red;'>{$diff}</small>";
		return $title;
	}
	
	public function icons( $title ) {
		if ( is_admin() ) {
			return $title;
		}
		$patterns = array(
			'[foto]'  => '<span class="dashicons dashicons-camera"></span>',
			'[video]' => '<span class="dashicons dashicons-video-alt2"></span>',
			'[audio]' => '<span class="dashicons dashicons-format-audio"></span>',
		);
		$title = str_replace(
			array_keys( $patterns ),
			array_values( $patterns ),
			$title
		);
		return $title;
	}
	
	public function assets() {
		wp_enqueue_style( 'dashicons' );
	}
}