<?php
namespace MailChannels;

require_once("PathEntry.php");

/*
 * PathRegistry allows the user to assign a combination of a url path, action, and method to certain "controller" and
 * function. PathEntries are assigned to controllers via the registerPath function. Calling resolvePath with an assigned
 * PathEntry results in the assign function being called on the assigned controller.
 */
final class PathRegistry {
    private static $entries = array();

    /*
     * registerPath assigns a controller and function to the given path, action, and method.
     */
    public static function registerPath($path, $action, $method, $controller, $function="index") {
        classExtends($controller, BaseController::class);

        if (self::entryExists($path, $action, $method)) {
            return false;
        }

        self::$entries[$path][$action][$method] = new PathEntry($controller, $function);

        return true;
    }

    /*
     * resolvePath looks for the corresponding controller and function to match the requests path, action, and method,
     * then calls the given function on that controller. The controller and function must have been registered to the path,
     * action, and method using the registerPath function.
     */
    public static function resolvePath($path, $action, $method) {
        $config = App::getConfig();

        if (!$config::CORS_ENABLED && $method === "OPTIONS") {
            header('Access-Control-Allow-Origin: *');
            header('Access-Control-Allow-Methods: *');
            header('Access-Control-Allow-Headers: *');
            return;
        }

        if (!$action) {
            $action = "index";
        }

        if (!self::entryExists($path, $action, $method)) {
            App::showPageNotFound();
        } else {
            $pathEntry = self::$entries[$path][$action][$method];

            $controllerName = $pathEntry->getController();
            $functionName = $pathEntry->getFunction();

            if (!class_exists($controllerName)) {
                App::showInternalError();
            }

            $controller = new $controllerName();

            if (!method_exists($controller, $functionName)) {
                App::showInternalError();
            }

            $controller->$functionName();
        }
    }

    /*
     * entryExists checks if there is an entry in the "entries" variable corresponding to the variables passed to this function.
     */
    private static function entryExists() {
        $args = func_get_args();

        $arr = self::$entries;
        foreach ($args as $arg) {
            if (!array_key_exists($arg, $arr)) {
                return false;
            }

            $arr = $arr[$arg];
        }

        return true;
    }
}