<?php
/**
 * Autoloader bootstrap.
 *
 * Uses the Composer autoloader when the dependencies have been installed and
 * falls back to a minimal PSR-4 autoloader otherwise, so the plugin remains
 * installable from a plain ZIP archive.
 *
 * @package FormPilot
 * @since   1.0.0
 */

declare( strict_types = 1 );

namespace FormPilot;

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

/*
 * The version guard comes first, before Composer's autoloader is touched.
 *
 * `vendor/autoload.php` runs `platform_check.php`, which throws a
 * `RuntimeException` on PHP below the version `composer.json` requires — and it
 * does that at *include* time, long before `formpilot_requirements_met()` gets to
 * show the admin notice the bootstrap promises. On a site running PHP 8.1 the
 * result was a white screen for the whole site, not a notice on the plugins
 * page. Answering the same question ourselves first keeps that promise.
 *
 * `vendor/` is a development convenience and is excluded from the distribution
 * ZIP; the fallback below is what a normal install uses.
 *
 * `uninstall.php` loads this file without the main plugin file, so the version
 * constant is absent there. Reading it unguarded was an `Undefined constant`
 * fatal on every delete from the Plugins screen: the delete aborted and nothing
 * was removed. Without the constant, the fallback is used.
 */
if ( defined( 'FORMPILOT_MIN_PHP_VERSION' ) && version_compare( PHP_VERSION, FORMPILOT_MIN_PHP_VERSION, '>=' ) && is_readable( FORMPILOT_PLUGIN_DIR . 'vendor/autoload.php' ) ) {
	require_once FORMPILOT_PLUGIN_DIR . 'vendor/autoload.php';

	return;
}

spl_autoload_register(
	/**
	 * Minimal PSR-4 autoloader for the FormPilot namespace.
	 *
	 * @param string $class_name Fully qualified class name.
	 *
	 * @return void
	 */
	static function ( string $class_name ): void {
		$prefix   = 'FormPilot\\';
		$base_dir = FORMPILOT_PLUGIN_DIR . 'src/';
		$length   = strlen( $prefix );

		if ( 0 !== strncmp( $prefix, $class_name, $length ) ) {
			return;
		}

		$relative = substr( $class_name, $length );
		$file     = $base_dir . str_replace( '\\', '/', $relative ) . '.php';

		if ( is_readable( $file ) ) {
			require_once $file;
		}
	}
);