<?php
declare(strict_types=1);

use PHPUnit\Framework\TestCase;

/**
 * Architectural guard: core must never hard-depend on an AddOn's classes.
 *
 * The 11 AddOns are optional. A site can run this plugin alone, so every
 * reference core makes to an AddOn-owned class has to sit behind a
 * class_exists() check — otherwise that code path fatals.
 *
 * This caught a real defect: the admin Dashboard tab and two public REST
 * endpoints called TMDO_Listing_Stats (which ships in the HivePress AddOn)
 * unconditionally, so they died with "Class not found" on any plain install.
 *
 * Static analysis on purpose — the alternative, booting core once per AddOn
 * combination, is far more machinery for a weaker signal.
 */
class CoreBoundaryTest extends TestCase {

	/**
	 * Classes that are declared by an AddOn, never by core.
	 *
	 * Kept as prefixes so a newly added TMDO_HivePress_* adapter is covered
	 * without touching this list.
	 *
	 * @var string[]
	 */
	private const ADDON_CLASS_PREFIXES = array(
		'TMDO_HivePress',
		'TMDO_Hivepress',
		'TMDO_HP_',
		'TMDO_HPCT_',
		'TMDO_Listing_',
		'TMDO_Favorites_',
		'TMDO_Messages_',
		'TMDO_Memberships_',
		'TMDO_Requests_',
		'TMDO_Reviews_',
		'TMDO_Statistics_',
		'TMDO_WooCommerce',
		'TMDO_Woocommerce',
		'TMDO_WC_',
		'TMDO_LatePoint',
		'TMDO_Latepoint',
		'TMDO_Infocards',
		'TMDO_Bookings',
		'TMDO_Collab',
		'TMDO_Playlist',
		'TMDO_Quotation',
		'TMDO_Mobile_Bridge',
		'TMDO_Hub_',
		'TMDO_Spoke_',
		'TMDO_Admin_HivePress',
		'TMDO_Admin_WC',
		'TMDO_CLI_HivePress',
	);

	/**
	 * Every core production file, excluding vendor and the test suite itself.
	 *
	 * @return array<string, array{string}>
	 */
	public static function coreFileProvider(): array {
		$root  = dirname( __DIR__, 2 );
		$files = array();
		foreach ( array( 'includes', 'admin', 'cli', 'modules' ) as $dir ) {
			$iterator = new RecursiveIteratorIterator(
				new RecursiveDirectoryIterator( $root . '/' . $dir, FilesystemIterator::SKIP_DOTS )
			);
			foreach ( $iterator as $file ) {
				if ( 'php' === $file->getExtension() ) {
					$rel           = substr( $file->getPathname(), strlen( $root ) + 1 );
					$files[ $rel ] = array( $file->getPathname() );
				}
			}
		}
		ksort( $files );
		return $files;
	}

	/**
	 * @dataProvider coreFileProvider
	 *
	 * @param string $path Absolute path to a core production file.
	 */
	public function test_addon_classes_are_only_used_behind_a_guard( string $path ): void {
		$source = file_get_contents( $path );
		$this->assertIsString( $source, "Unreadable: {$path}" );

		$lines    = explode( "\n", $source );
		$offences = array();

		foreach ( $lines as $i => $line ) {
			$code = $this->strip_comments_and_strings( $line );
			foreach ( self::ADDON_CLASS_PREFIXES as $prefix ) {
				// Only static calls / constant reads bind at runtime; a bare
				// mention (e.g. inside an array of names to probe) does not.
				if ( ! preg_match( '/\b(' . preg_quote( $prefix, '/' ) . '\w*)::/', $code, $m ) ) {
					continue;
				}
				if ( $this->is_guarded( $lines, $i, $m[1] ) ) {
					continue;
				}
				$offences[] = sprintf( '%s:%d — %s', basename( $path ), $i + 1, trim( $line ) );
			}
		}

		$this->assertSame(
			array(),
			$offences,
			"Core calls an AddOn class without a class_exists() guard:\n" . implode( "\n", $offences )
		);
	}

	/**
	 * Remove line comments and string literals so mentions inside them are ignored.
	 */
	private function strip_comments_and_strings( string $line ): string {
		$line = preg_replace( '#(//|\*|\#).*$#', '', $line ) ?? $line;
		$line = preg_replace( "/'[^']*'/", "''", $line ) ?? $line;
		return preg_replace( '/"[^"]*"/', '""', $line ) ?? $line;
	}

	/**
	 * A guard counts if class_exists() for the same class appears earlier in
	 * the same function (or, for top-level code, earlier in the file).
	 *
	 * Function scope rather than a fixed line window: an early-return guard at
	 * the top of a 60-line CLI command legitimately protects every call below
	 * it, and a window tight enough to be meaningful would reject that.
	 *
	 * @param string[] $lines Whole file, split on newlines.
	 * @param int      $index Zero-based line index of the call site.
	 * @param string   $class Class name being called.
	 */
	private function is_guarded( array $lines, int $index, string $class ): bool {
		$from = 0;
		for ( $i = $index; $i >= 0; $i-- ) {
			if ( preg_match( '/^\t{1,2}(?:(?:public|private|protected|static|final|abstract)\s+)*function\s/', $lines[ $i ] ) ) {
				$from = $i;
				break;
			}
		}
		$slice = implode( "\n", array_slice( $lines, $from, $index - $from + 1 ) );
		return (bool) preg_match(
			'/class_exists\(\s*[\'"]' . preg_quote( $class, '/' ) . '[\'"]/',
			$slice
		);
	}
}