smuuf/primi

<?php

declare(strict_types=1);

namespace Smuuf\Primi\Handlers;

use \Smuuf\StrictObject;
use \Smuuf\Primi\Context;
use \Smuuf\Primi\Ex\EngineInternalError;

/**
 * Static helper class for getting correct handler class for specific AST node.
 *
 * @internal
 */
abstract class HandlerFactory {

    use StrictObject;

    /** @var array<string, string|null> Dict of handler classes we know exist. */
    private static $handlersCache = [];

    private const PREFIX = '\Smuuf\Primi\Handlers\Kinds';

    /**
     * @return class-string|string
     */
    private static function buildHandlerClassName(string $name) {
        return self::PREFIX . "\\$name";
    }

    /**
     * NOTE: This is used only during parsing/compilation.
     *
     * @return class-string|string
     */
    public static function tryGetForName(string $name): ?string {

        $class = self::buildHandlerClassName($name);
        if (!\class_exists($class)) {
            return null;
        }

        return $class;

    }

    /**
     * Get handler class as string for a AST-node-type specific handler
     * identified by handler type.
     *
     * NOTE: Return type is omitted for performance reasons, as this method will
     * be called VERY often.
     *
     * @param string $name
     * @return ?class-string
     */
    public static function getFor($id) {

        // Using caching is of course faster than repeatedly building strings
        // and checking classes and stuff.
        if (\array_key_exists($id, self::$handlersCache)) {
            return self::$handlersCache[$id];
        }

        $class = self::buildHandlerClassName(KnownHandlers::fromId($id));
        if (!\class_exists($class)) {
            $msg = "Handler class '$class' for handler ID '$id' not found";
            throw new EngineInternalError($msg);
        }

        return self::$handlersCache[$id] = $class;

    }

    /**
     * Shorthand function for running a AST node passed as array.
     *
     * @param TypeDef_AstNode $node
     * @param Context $ctx
     * @return mixed
     */
    public static function runNode($node, $ctx) {
        return self::getFor($node['name'])::run($node, $ctx);
    }

}