<?php
/**
 * Page Templates.
 *
 * @package Frontend Dashboard.
 */

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * Class FED_Page_Template
 */
class FED_Page_Template {
	/**
	 * A reference to an instance of this class.
	 */
	private static $instance;
	/**
	 * The array of templates that this plugin tracks.
	 */
	protected $templates;

	/**
	 * Initializes the plugin by setting filters and administration functions.
	 */
	private function __construct() {
		$this->templates = array();
		// Add a filter to the attributes metabox to inject template into the cache.
		if ( version_compare( floatval( get_bloginfo( 'version' ) ), '4.7', '<' ) ) {
			// 4.6 and older
			add_filter(
				'page_attributes_dropdown_pages_args',
				array( $this, 'register_project_templates' )
			);
		} else {
			// Add a filter to the wp 4.7 version attributes metabox.
			add_filter(
				'theme_page_templates', array( $this, 'add_new_template' )
			);
		}
		// Add a filter to the save post to inject out template into the page cache.
		add_filter(
			'wp_insert_post_data',
			array( $this, 'register_project_templates' )
		);
		// Add a filter to the template include to determine if the page has our
		// template assigned and return it's path.
		add_filter(
			'template_include',
			array( $this, 'view_project_template' )
		);
		// Add your templates to this array.
		$this->templates = apply_filters( 'fed_add_new_page_template_url', array(
			'vendor/template-loaders/page-template/layouts/fed-login.php'     => 'FED Login',
			'vendor/template-loaders/page-template/layouts/fed-dashboard.php' => 'FED Dashboard',
			// 'vendor/template-loaders/page-template/layouts/fed_invoice.php'   => 'FED Invoice'.
		) );

	}

	/**
	 * Returns an instance of this class.
	 */
	public static function get_instance() {
		if ( null === self::$instance ) {
			self::$instance = new FED_Page_Template();
		}

		return self::$instance;
	}

	/**
	 * Adds our template to the page dropdown for v4.7+
	 *
	 * @param  array  $posts_templates  Template Name.
	 *
	 * @return array
	 */
	public function add_new_template( $posts_templates ) {
		$posts_templates = array_merge( $posts_templates, $this->templates );

		return $posts_templates;
	}

	/**
	 * Adds our template to the pages cache in order to trick WordPress
	 * into thinking the template file exists where it doens't really exist.
	 *
	 * @param $atts
	 *
	 * @return mixed
	 */
	public function register_project_templates( $atts ) {
		$theme = wp_get_theme();
		$cache_key = 'page_templates-' . md5( get_theme_root() . '/' . $theme->get_stylesheet() );

		// Get the existing templates from theme.
		$existing_templates = $theme->get_page_templates();

		// Merge only if it's an array
		if ( ! is_array( $existing_templates ) ) {
			$existing_templates = array();
		}

		// Add our templates, but keep existing intact
		$merged_templates = array_merge( $existing_templates, $this->templates );

		// Remove old cache and add updated one
		wp_cache_delete( $cache_key, 'themes' );
		wp_cache_add( $cache_key, $merged_templates, 'themes', 1800 );

		return $atts;
	}

	/**
	 * Checks if the template is assigned to the page
	 *
	 * @param $template
	 *
	 * @return string
	 */
	public function view_project_template( $template ) {

		// Get global post.
		global $post;
		// Return template if post is empty.
		if ( ! $post ) {
			return $template;
		}
		// Return default template if we don't have a custom one defined.
		if ( ! isset( $this->templates[ get_post_meta( $post->ID, '_wp_page_template', true ) ] ) ) {
			return $template;
		}
		$file = plugin_dir_path( BC_FED_PLUGIN ) . get_post_meta( $post->ID, '_wp_page_template', true );
		// Just to be safe, we check if the file exist first.
		if ( file_exists( $file ) ) {
			return $file;
		} else {
			error_log( '[FED] Missing page template file: ' . $file );
		}

		// Return template.
		return $template;
	}
}

add_action( 'plugins_loaded', array( 'FED_Page_Template', 'get_instance' ) );
