<?php

declare(strict_types=1);

namespace Siteworxpro\App\Http\Middleware;

use League\Route\Dispatcher;
use League\Route\Route;
use Psr\Http\Server\MiddlewareInterface;
use Psr\Http\Server\RequestHandlerInterface;

/**
 * Base middleware helper for extracting route callables.
 *
 * This abstract middleware provides a utility method to inspect a League\Route
 * dispatcher and obtain the underlying route callable as a [class, method] tuple.
 *
 * @package Siteworxpro\App\Http\Middleware
 */
abstract class Middleware implements MiddlewareInterface
{
    /**
     * Extract the route callable [class, method] from a League\Route dispatcher.
     *
     * When the provided handler is a League\Route\Dispatcher, this inspects its
     * middleware stack, looks at the last segment (the resolved Route), and
     * attempts to normalize its callable into a [class, method] pair.
     *
     * Supported callable forms:
     * - array callable: [object|class-string, method-string]
     * - string callable: "ClassName::methodName"
     *
     * Returns null when the handler is not a Dispatcher, the stack is empty,
     * or the callable cannot be parsed.
     *
     * @param RequestHandlerInterface|Dispatcher $handler The downstream handler or dispatcher.
     *
     * @return array{0: class-string|object|null, 1: string|null}|null Tuple of [class|object, method] or null.
     */
    protected function extractRouteCallable(
        RequestHandlerInterface|Dispatcher $handler
    ): array|null {
        // Only proceed if this is a League\Route dispatcher.
        if (!$handler instanceof Dispatcher) {
            return null;
        }

        /** @var Route | null $lastSegment */
        // Retrieve the last middleware in the stack, which should be the Route.
        $lastSegment = array_last($handler->getMiddlewareStack());

        if ($lastSegment === null) {
            return null;
        }

        // Obtain the callable associated with the route.
        $callable = $lastSegment->getCallable();
        $class = null;
        $method = null;

        // Handle array callable: [object|class-string, 'method']
        if (is_array($callable) && count($callable) === 2) {
            [$class, $method] = $callable;
        } elseif (is_string($callable)) {
            // Handle string callable: 'ClassName::methodName'
            [$class, $method] = explode('::', $callable);
        }

        return [$class, $method];
    }
}