<?php

namespace Yoast\PHPUnitPolyfills\Helpers;

use Exception;
use TypeError;

/**
 * Helper functions for working with the resource type.
 *
 * ---------------------------------------------------------------------------------------------
 * This class is only intended for internal use by PHPUnit Polyfills and is not part of the public API.
 * This also means that it has no promise of backward compatibility.
 *
 * End-user should use the {@see \Yoast\PHPUnitPolyfills\Polyfills\AssertClosedResource()} trait instead.
 * ---------------------------------------------------------------------------------------------
 *
 * @internal
 *
 * @since 1.0.0
 */
final class ResourceHelper {

    /**
     * Determines whether a variable represents a resource, either open or closed.
     *
     * @param mixed $actual The variable to test.
     *
     * @return bool
     */
    public static function isResource( $actual ) {
        return ( $actual !== null
            && \is_scalar( $actual ) === false
            && \is_array( $actual ) === false
            && \is_object( $actual ) === false );
    }

    /**
     * Determines whether a variable represents a closed resource.
     *
     * @param mixed $actual The variable to test.
     *
     * @return bool
     */
    public static function isClosedResource( $actual ) {
        $type = \gettype( $actual );

        /*
         * PHP 7.2 introduced "resource (closed)".
         */
        if ( $type === 'resource (closed)' ) {
            return true;
        }

        /*
         * If gettype did not work, attempt to determine whether this is
         * a closed resource in another way.
         */
        $isResource       = \is_resource( $actual );
        $isNotNonResource = self::isResource( $actual );

        if ( $isResource === false && $isNotNonResource === true ) {
            return true;
        }

        if ( $isNotNonResource === true ) {
            try {
                $resourceType = @\get_resource_type( $actual );
                if ( $resourceType === 'Unknown' ) {
                    return true;
                }
            } catch ( TypeError $e ) {
                // Ignore. Not a resource.
            } catch ( Exception $e ) {
                // Ignore. Not a resource.
            }
        }

        return false;
    }

    /**
     * Helper function to determine whether the open/closed state of a resource is reliable.
     *
     * Due to some bugs in PHP itself, the "is closed resource" determination
     * cannot always be done reliably.
     *
     * This function can determine whether or not the current value in combination with
     * the current PHP version on which the test is being run is affected by this.
     *
     * @param mixed $actual The variable to test.
     *
     * @return bool
     */
    public static function isResourceStateReliable( $actual ) {
        try {
            $type = @\get_resource_type( $actual );

            if ( $type === 'xml' && self::isIncompatiblePHPForLibXMLResources() === true ) {
                return false;
            }
        } catch ( TypeError $e ) {
            // Ignore. Not a resource.
        } catch ( Exception $e ) {
            // Ignore. Not a resource.
        }

        return true;
    }

    /**
     * Check if the PHP version is one of a known set of PHP versions
     * containing a libxml version which does not report on closed resources
     * correctly.
     *
     * Version ranges based on {@link https://3v4l.org/tc4fE}.
     * 7.0.8 - 7.0.33, 7.1.0 - 7.1.33, 7.2.0 - 7.2.34, 7.3.0 - 7.3.21, 7.4.0 - 7.4.9
     *
     * @return bool
     */
    public static function isIncompatiblePHPForLibXMLResources() {
        if ( \PHP_VERSION_ID >= 70008 && \PHP_VERSION_ID < 70034 ) {
            return true;
        }

        if ( \PHP_VERSION_ID >= 70100 && \PHP_VERSION_ID < 70134 ) {
            return true;
        }

        if ( \PHP_VERSION_ID >= 70200 && \PHP_VERSION_ID < 70235 ) {
            return true;
        }

        if ( \PHP_VERSION_ID >= 70300 && \PHP_VERSION_ID < 70322 ) {
            return true;
        }

        if ( \PHP_VERSION_ID >= 70400 && \PHP_VERSION_ID < 70410 ) {
            return true;
        }

        return false;
    }
}