<?php
/**
 * Disk space, OPcache and object cache.
 *
 * @package Keepwatch
 */

namespace Keepwatch\Checks;

defined( 'ABSPATH' ) || exit;

/**
 * Extends the environment group with hosting-level signals. Read-only; no remote calls.
 */
final class ServerCheck implements Check {

	/** Free disk ratio below this is recommended (0–1). */
	public const DISK_WARN = 0.15;

	/** Free disk ratio below this is critical. */
	public const DISK_CRIT = 0.05;

	/**
	 * {@inheritDoc}
	 */
	public function group(): string {
		return 'environment';
	}

	/**
	 * {@inheritDoc}
	 */
	public function run(): array {
		$free  = function_exists( 'disk_free_space' ) ? @disk_free_space( ABSPATH ) : false; // phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged -- host may disable disk_* .
		$total = function_exists( 'disk_total_space' ) ? @disk_total_space( ABSPATH ) : false; // phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged

		$opcache = false;
		if ( function_exists( 'opcache_get_status' ) ) {
			$status  = @opcache_get_status( false ); // phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged
			$opcache = is_array( $status ) && ! empty( $status['opcache_enabled'] );
		} elseif ( function_exists( 'opcache_get_configuration' ) ) {
			$opcache = true;
		}

		return self::evaluate(
			array(
				'disk_free'    => false === $free ? null : (int) $free,
				'disk_total'   => false === $total ? null : (int) $total,
				'opcache'      => $opcache,
				'object_cache' => function_exists( 'wp_using_ext_object_cache' ) && wp_using_ext_object_cache(),
			)
		);
	}

	/**
	 * Pure evaluation.
	 *
	 * @param array{disk_free: int|null, disk_total: int|null, opcache: bool, object_cache: bool} $facts Facts.
	 * @return Result[]
	 */
	public static function evaluate( array $facts ): array {
		$results = array();

		if ( null !== $facts['disk_free'] && null !== $facts['disk_total'] && $facts['disk_total'] > 0 ) {
			$ratio = $facts['disk_free'] / $facts['disk_total'];
			$label = sprintf(
				/* translators: 1: free space, 2: total space */
				__( 'Disk space: %1$s free of %2$s', 'keepwatch' ),
				size_format( $facts['disk_free'] ),
				size_format( $facts['disk_total'] )
			);
			if ( $ratio < self::DISK_CRIT ) {
				$results[] = new Result(
					'environment.disk',
					Result::CRITICAL,
					$label,
					__( 'The disk is nearly full. Sites stop updating, logging and uploading when space runs out.', 'keepwatch' )
				);
			} elseif ( $ratio < self::DISK_WARN ) {
				$results[] = new Result(
					'environment.disk',
					Result::RECOMMENDED,
					$label,
					__( 'Free up space or ask your host to expand the volume before updates fill the disk.', 'keepwatch' )
				);
			} else {
				$results[] = new Result( 'environment.disk', Result::GOOD, $label );
			}
		}

		$results[] = $facts['opcache']
			? new Result( 'environment.opcache', Result::GOOD, __( 'PHP OPcache is enabled', 'keepwatch' ) )
			: new Result(
				'environment.opcache',
				Result::RECOMMENDED,
				__( 'PHP OPcache is not enabled', 'keepwatch' ),
				__( 'OPcache caches compiled PHP and makes WordPress noticeably faster. Ask your host to enable it.', 'keepwatch' )
			);

		$results[] = $facts['object_cache']
			? new Result( 'environment.object_cache', Result::GOOD, __( 'A persistent object cache is in use', 'keepwatch' ) )
			: new Result(
				'environment.object_cache',
				Result::RECOMMENDED,
				__( 'No persistent object cache detected', 'keepwatch' ),
				__( 'Redis or Memcached (via a drop-in) reduces database load on busy sites. Optional on small sites.', 'keepwatch' )
			);

		return $results;
	}
}