<?php
/**
 * Cached Vulnerability Provider.
 *
 * Decorator that wraps any AIPSC_Vulnerability_Provider with database
 * caching via AIPSC_Vulnerability_Cache.
 *
 * @package AipatchSecurityScanner
 */

if ( ! defined( 'ABSPATH' ) ) {
    exit;
}

/**
 * Class AIPSC_Cached_Vulnerability_Provider
 */
class AIPSC_Cached_Vulnerability_Provider implements AIPSC_Vulnerability_Provider {

    /**
     * @var AIPSC_Vulnerability_Provider
     */
    private $inner;

    /**
     * @var AIPSC_Vulnerability_Cache
     */
    private $cache;

    /**
     * @var int TTL in seconds.
     */
    private $ttl;

    /**
     * Constructor.
     *
     * @param AIPSC_Vulnerability_Provider $inner Inner provider.
     * @param AIPSC_Vulnerability_Cache    $cache Cache instance.
     * @param int                          $ttl   TTL in seconds.
     */
    public function __construct( AIPSC_Vulnerability_Provider $inner, AIPSC_Vulnerability_Cache $cache, $ttl = 43200 ) {
        $this->inner = $inner;
        $this->cache = $cache;
        $this->ttl   = $ttl;
    }

    /**
     * @inheritDoc
     */
    public function get_vulnerabilities( array $installed ): array {
        $all_vulns     = array();
        $uncached      = array();
        $provider_name = $this->inner->get_source_name();

        // Try cache first for each item.
        foreach ( $installed as $item ) {
            $cached = $this->cache->get( $item['slug'], $item['type'], $provider_name );

            if ( null !== $cached ) {
                // Filter by installed version.
                foreach ( $cached as $vuln ) {
                    if ( isset( $vuln['fix_version'] ) && version_compare( $item['version'], $vuln['fix_version'], '<' ) ) {
                        $vuln['installed_version'] = $item['version'];
                        $vuln['slug']              = $item['slug'];
                        $vuln['software_type']     = $item['type'];
                        $vuln['source']            = $provider_name . ' (cached)';
                        $all_vulns[]               = $vuln;
                    }
                }
            } else {
                $uncached[] = $item;
            }
        }

        // Fetch uncached items from the inner provider.
        if ( ! empty( $uncached ) ) {
            $fresh = $this->inner->get_vulnerabilities( $uncached );

            // Group results by slug for caching.
            $by_slug = array();
            foreach ( $fresh as $vuln ) {
                $slug = $vuln['slug'] ?? '';
                if ( ! isset( $by_slug[ $slug ] ) ) {
                    $by_slug[ $slug ] = array();
                }
                $by_slug[ $slug ][] = $vuln;
            }

            // Cache each slug's results.
            foreach ( $uncached as $item ) {
                $slug_data = isset( $by_slug[ $item['slug'] ] ) ? $by_slug[ $item['slug'] ] : array();
                $this->cache->set( $item['slug'], $item['type'], $provider_name, $slug_data, $this->ttl );
            }

            $all_vulns = array_merge( $all_vulns, $fresh );
        }

        return $all_vulns;
    }

    /**
     * @inheritDoc
     */
    public function get_source_name(): string {
        return $this->inner->get_source_name();
    }

    /**
     * @inheritDoc
     */
    public function is_available(): bool {
        return $this->inner->is_available();
    }
}