<?php

/**
 * include those two lines at the top of the main plugin file
 *
 * include_once( plugin_dir_path(__FILE__) . '/php/utils/plugin_tools.php');
 * PLGNTLS_class::set_root_dir( plugin_dir_path(__FILE__), plugin_dir_url(__FILE__) );
 *
 * PLGNTLS means PLUGIN TOOLS
 */

class PLGNTLS_class
{
	private static $_root_path;
	private static $_root_url;

	private static $_ajax_already_there;
	private $_first_script;
	private $_prefix;
	private $_js_dependencies;
	private $_css_dependencies;

	/**
	 */
	public function __construct() {
		if (! isset( self::$_ajax_already_there ))
			self::$_ajax_already_there = false;
		$this->_prefix = "PLGNTLS";
		$this->_first_script = null;
		$this->_js_dependencies = array();
		$this->_css_dependencies = array();
	}

	/**
	 * can be used before class is instanciated :
	 * PLGNTLS_class::set_root_dir( plugin_dir_path(__FILE__), plugin_dir_url(__FILE__) );
	 */
	public static function set_root_dir($path, $url) {
		if (isset( self::$_root_path ))
			return ;
		if (isset( self::$_root_url ))
			return ;
		self::$_root_path = $path;
		self::$_root_url = $url;
	}
	public function get_path() {
		return(self::$_root_path);
	}
	public function get_url() {
		return(self::$_root_url);
	}


	public function add_to_front($files_arr = null, $vars = null) {
		$files = array();
		foreach($files_arr as $key => $file_name) {
			$files[] = $this->init_file($key, $file_name);
		}
		if (!is_null($files_arr))
			$this->add_files_to_front($files);
		$ajax = $this->get_ajax_script();
		$this->add_vars_to_front($vars, $ajax);
		return $this->create_html($files, $vars);
	}


/**
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * PRIVATES FUNCTIONS
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 */


	/**
	 * @param two arguments :
	 * 1. html files to include in front
	 * 	- can be a string of 1 filename
	 * 	- or an array of strings of filenames
	 * 	( https://stackoverflow.com/q/4747876/9497573 )
	 * 	- it's probably better to only add 1 file, and let it include other files
	 * 2. list of variables to make available to this files
	 * 	- in the form of key => val
	 * 	- recommanded to do it with compact()
	 * ex: create_html( "file.html", compact("var1","var2",) );
	 * ex: create_html( array("file1.html", "file2.html"), array("var1"=>"value") );
	 * @return a string of html code
	 *
	 * using ob_start() and ob_get_clean()
	 * allows to have php expansion inside the html loaded
	 * in opposition to the methode file_get_contents()
	 *
	 * https://stackoverflow.com/a/4402045/9497573
	 */
	private function create_html($files = null, $vars = null) {
		if (is_null($files))
			return null;
		$plgn_dir = $this->get_path();
		if (!is_null($vars))
			extract($vars);

		ob_start();
		foreach($files as $file) {
			if ($file->ext === 'html')
				include($file->path);
		}
		$html = ob_get_clean();

		return $html;
	}

	/**
	 * pass variables to js front as global variables
	 * @param array : list of key => value
	 * 	 with the key being name of the variable, like this :
	 * 		'my_var' => 'value',
	 * 	 simpler way to do it is to use compact when calling the function :
	 * 		add_var_to_front(compact("var1", "var2", "var3"));
	 * @param string (optionnal) : name of first embended script that need these variables
	 * 	 (it will be available to this script and all followings)
	 * 	 this name is the filename + "_" + extension :
	 * 	 init.js -> init_js
	 */
	private function add_vars_to_front($vars_arr, $ajax = null)
	{
		if (is_null($this->_first_script))
			return ;
		if (is_null($vars_arr) && is_null($ajax))
			return ;
		$handle = $this->_first_script;
		$object_name = $this->_prefix . "_data";

		$front = "";
		if (!is_null($vars_arr))
		{
			$vars_json = json_encode($vars_arr);
			$front .= "let $object_name = $vars_json;";
		}
		if (! is_null($ajax))
			$front .= "$ajax";
		wp_add_inline_script($handle, $front, 'before');
	}

	/**
	 * @param array : list of files :
	 * 	- with their path from root of their type of file (ex: from js/ to .js files)
	 * 	- and with their extension
	 * @param boolean
	 * 	- to add ajax script and variables
	 * 	- default to true
	 */
	private function add_files_to_front($files_arr) {
		//wp_enqueue_script(<give_it_a_name>, /url/to/file, [depends on], version, defer? );
		//wp_enqueue_style( <give_it_a_name>, /url/to/file, [depends on], version, media );

		$previous_css_basename = '';
		$previous_js_basename = '';
		foreach ($files_arr as $file) {
			if ($file->ext === "js") {
				if (is_null($this->_first_script))
					$this->_first_script = $file->handle;
				$depends_on = $this->check_dependencies($file, $previous_js_basename);
				if ($depends_on !== null)
					wp_enqueue_script( $file->handle, $file->url, $depends_on, $file->version, true);
				$previous_js_basename = $file->handle;
			}
			else if ($file->ext === "css") {
				$depends_on = $this->check_dependencies($file, $previous_css_basename);
				if ($depends_on !== null)
					wp_enqueue_style( $file->handle, $file->url, $depends_on, $file->version, '');
				$previous_css_basename = $file->handle;
			}
		}
	}
	private function check_dependencies(&$file, $previous_basename)
	{
		if ($file->ext === "js")
		{
			global $wp_scripts;
			$already_enqueued = array_search($file->handle, $wp_scripts->queue);
			if ($already_enqueued !== false)
				return null;
		}
		else if ($file->ext === "css")
		{
			global $wp_styles;
			$already_enqueued = array_search($file->handle, $wp_styles->queue);
			if ($already_enqueued !== false)
				return null;
		}

		$depends_on = array();
		if (isset($file->depends) && $file->depends !== '')
			$depends_on[] = $file->depends;
		if (isset($previous_basename) && $previous_basename !== '')
			$depends_on[] = $previous_basename;

		return $depends_on;
	}

	/**
	 * @param string : name of the file, with its path from its extension directory
	 * 	- from js/ root for .js files
	 * 	- from css/ root for .css files
	 * @return object / null :
	 * 	- null if file is not js or css
	 * 	- or an object with all the necessary infos :
	 * 	  - ext      : name.js -> "js"
	 * 	  - basename : name.js -> "name"
	 * 	  - handle   : name.js -> "name_js"
	 * 	  - url     : url to file in wordpress
	 * 	  - path    : path to file in server
	 * 	  - version : used to avoid browser caching
	 * 	  - depends : string if depends on a handle, or ''
	 */
	private function init_file($key, $file_name) {
		$file = (object)[];

		$file->ext = pathinfo($file_name, PATHINFO_EXTENSION);
		if (! in_array($file->ext, array("js", "css", "html")))
			return null;

		$file->basename = pathinfo($file_name, PATHINFO_BASENAME);
		$file->handle = "PLGNTLS_" . str_replace(".", "_", $file->basename);

		$file->url = $this->get_url().$file_name;
		$file->path = $this->get_path().$file_name;
		$file->version = date("ymd-Gis", filemtime($file->path));

		$file->depends = '';
		if (is_string($key))
			$file->depends = $key;

		return $file;
	}


	/**
	 * function that add the ajax script to front
	 * no real needs to check if already included :
	 * - $handle is uniq so it will not be re-enqueued
	 * 	the first enqueued version would be kept
	 * - if we used add_var_to_front() (which use wp_add_inline_script())
	 * 	the vars would be added twice
	 * 	leading to js syntaxe error (redeclaraiton of 'let' or 'const')
	 * - but we use wp_localize_script() so the object will be overwritten
	 * 	it's not a real pbm
	 * 	(what is more efficient, check for double or overwritte object ?)
	 */
	/**
	 * js function that creates an ajax post action
	 */
	private function get_ajax_script() {
		if (is_null($this->_first_script))
			return ;
		if (self::$_ajax_already_there)
			return ;
		self::$_ajax_already_there = true;

		ob_start();
			?>
			function <?php echo $this->_prefix ?>_ajax(ajax_data, action) {
				const _ajax_nonce = "<?php echo wp_create_nonce( 'wp-pageviews-nonce' ); ?>";
				const _ajax_url = "<?php echo admin_url( 'admin-ajax.php' ); ?>";
				const data = new FormData();
				data.append("action", action);
				data.append("_ajax_nonce", _ajax_nonce);
				data.append("data", ajax_data);

				return fetch(_ajax_url, {
					method: "POST",
					credentials: "same-origin",
					body: data
				});
			}
			<?php
		return ob_get_clean();
	}
}


?>