<?php
/**
 * Control 2 — plugin files against their WordPress.org checksums (SPEC row 2).
 *
 * Silent on purpose (SPEC muette, reported): folders absent from get_plugins(),
 * files of the sums missing on disk, files whose sum cannot be compared
 * (no md5 on one side), any file of a plugin without sums (finalization lists
 * the plugin as not looked at).
 *
 * @package Timaub\AfterHackChecklist
 */

namespace Timaub\AfterHackChecklist\Domain\Rules;

use Timaub\AfterHackChecklist\Domain\Assumptions;
use Timaub\AfterHackChecklist\Domain\Context;
use Timaub\AfterHackChecklist\Domain\FileEntry;
use Timaub\AfterHackChecklist\Domain\Finding;
use Timaub\AfterHackChecklist\Domain\Text;

final class PluginRules {

	/** @return Finding[] */
	public static function inspect( FileEntry $f, Context $ctx ): array {
		$rel = substr( $f->path, strlen( $ctx->pluginsDir ) + 1 );
		$pos = strpos( $rel, '/' );
		if ( false === $pos ) {
			return self::singleFile( $f, $rel, $ctx );
		}
		$dir   = substr( $rel, 0, $pos );
		$inner = substr( $rel, $pos + 1 );
		$plug  = $ctx->pluginFor( $dir, true );
		if ( null === $plug || ! isset( $ctx->pluginChecksums[ $dir ] ) ) {
			return array();
		}
		$sums = $ctx->pluginChecksums[ $dir ];
		$args = array( $f->path, $dir, $sums->version );
		if ( $sums->has( $inner ) ) {
			list( $ok, $algo ) = $sums->compare( $inner, $f->md5, $f->sha256 );
			if ( false === $ok ) {
				$args[] = $algo;
				return array( Finding::make( 'plugin_modified', $f->path, $args ) );
			}
			return array();
		}
		if ( Text::isPhpFile( $inner ) ) {
			if ( self::isInertIndex( $f ) ) {
				return array( Finding::make( 'plugin_silence_index', $f->path, array( $f->path ) ) );
			}
			return array( Finding::make( 'plugin_unknown_php', $f->path, $args ) );
		}
		return array( Finding::make( 'plugin_extra_file', $f->path, $args ) );
	}

	/**
	 * index.php of at most 200 bytes that runs no code: the silence index of control 3
	 * (PHP opening tag and comments only), or a text without any "<?" (PHP prints it as
	 * is), like storage/index.php of All-in-One WP Migration 7.112, "Kangaroos cannot
	 * jump here" (test-fixtures/real/all-in-one-wp-migration-7.112/generated/). D-04.
	 */
	public static function isInertIndex( FileEntry $f ): bool {
		if ( 'index.php' !== strtolower( Text::basename( $f->path ) ) || $f->size > Assumptions::SILENCE_INDEX_MAX_BYTES ) {
			return false;
		}
		if ( UploadsRules::isSilenceIndex( $f ) ) {
			return true;
		}
		$s = null !== $f->content ? $f->content : $f->head;
		return null !== $s && strlen( $s ) === $f->size && false === strpos( $s, '<?' );
	}

	/** @return Finding[] */
	private static function singleFile( FileEntry $f, string $rel, Context $ctx ): array {
		if ( 'hello.php' === $rel ) {
			$core = $ctx->coreChecksums;
			if ( null === $core || ! isset( $core->sums[ Assumptions::CORE_HELLO_KEY ] ) || null === $f->md5 ) {
				return array();
			}
			if ( $f->md5 !== $core->sums[ Assumptions::CORE_HELLO_KEY ] ) {
				return array( Finding::make( 'plugin_hello_modified', $f->path, array( $f->path, $core->version, $core->locale ) ) );
			}
			return array();
		}
		if ( null === $ctx->pluginFor( $rel, false ) ) {
			return array();
		}
		$slug = Context::slugOf( $rel );
		if ( ! isset( $ctx->pluginChecksums[ $slug ] ) || ! $ctx->pluginChecksums[ $slug ]->has( $rel ) ) {
			return array();
		}
		$sums              = $ctx->pluginChecksums[ $slug ];
		list( $ok, $algo ) = $sums->compare( $rel, $f->md5, $f->sha256 );
		if ( false === $ok ) {
			return array( Finding::make( 'plugin_modified', $f->path, array( $f->path, $slug, $sums->version, $algo ) ) );
		}
		return array();
	}
}