<?php
if (!defined('ABSPATH')) exit;

return new class extends WPH_Step {
    public function id(): string { return 'performance'; }
    public function title(): string { return 'Step 7 — Performance Check'; }
    public function sub_items(): array {
        return [
            'Run a quick PageSpeed Insights check on the homepage',
            'Note the scores (mobile and desktop) in the client record',
            'Flag if mobile score has dropped significantly since last check (more than 10 points)',
            'Check that caching is active — if using a caching plugin, confirm it is enabled and not throwing errors',
            'Check image sizes on the homepage — flag if uncompressed images over 500KB are being served',
        ];
    }

    public function autocheck(array $session_state): array {
        $f = [];
        $home = home_url('/');

        // PageSpeed Insights — no API key needed for low volume (25k/day per IP).
        // Skip on localhost: PSI can't reach a local URL.
        $host = parse_url($home, PHP_URL_HOST) ?: '';
        $is_local = preg_match('/(\.local|localhost|^127\.|^192\.168\.)/', $host);

        if ($is_local) {
            $f[] = $this->finding('psi_skipped', 'info', 'PageSpeed Insights', 'skipped (local host)', 'Run manually from a public URL: https://pagespeed.web.dev/');
        } else {
            foreach (['mobile', 'desktop'] as $strategy) {
                $psi = $this->psi($home, $strategy);
                if ($psi === null) {
                    $f[] = $this->finding('psi_' . $strategy, 'warn', 'PageSpeed (' . $strategy . ')', 'API error', 'Could not reach googleapis.com — retry or run manually.');
                    continue;
                }
                $score = (int) round((float) $psi['performance'] * 100);
                $level = $score >= 90 ? 'ok' : ($score >= 50 ? 'warn' : 'bad');
                $detail_bits = [];
                if (isset($psi['lcp']))   $detail_bits[] = 'LCP ' . $psi['lcp'];
                if (isset($psi['cls']))   $detail_bits[] = 'CLS ' . $psi['cls'];
                if (isset($psi['tbt']))   $detail_bits[] = 'TBT ' . $psi['tbt'];
                $f[] = $this->finding(
                    'psi_' . $strategy,
                    $level,
                    'PageSpeed (' . $strategy . ')',
                    $score . '/100',
                    implode(' · ', $detail_bits)
                );
            }
        }

        // Caching plugin detection
        $caching = [
            'wp-rocket/wp-rocket.php'           => 'WP Rocket',
            'wp-super-cache/wp-cache.php'       => 'WP Super Cache',
            'w3-total-cache/w3-total-cache.php' => 'W3 Total Cache',
            'litespeed-cache/litespeed-cache.php' => 'LiteSpeed Cache',
            'sg-cachepress/sg-cachepress.php'   => 'SG Optimizer',
            'wp-fastest-cache/wpFastestCache.php'=> 'WP Fastest Cache',
            'cache-enabler/cache-enabler.php'   => 'Cache Enabler',
        ];
        $found_caching = null;
        foreach ($caching as $file => $label) {
            if (is_plugin_active($file)) { $found_caching = $label; break; }
        }
        $f[] = $this->finding(
            'caching',
            $found_caching ? 'ok' : 'info',
            'Caching plugin',
            $found_caching ?: 'none detected',
            $found_caching ? '' : 'No common caching plugin active — host-level caching may still apply.'
        );

        // Heavy images on the homepage
        $resp = wp_remote_get($home, ['timeout' => 6]);
        if (!is_wp_error($resp)) {
            $body = (string) wp_remote_retrieve_body($resp);
            preg_match_all('/<img\b[^>]*src=["\']([^"\']+)["\']/i', $body, $m);
            $urls = isset($m[1]) ? array_slice(array_unique($m[1]), 0, 8) : [];
            $heavy = [];
            foreach ($urls as $u) {
                if (substr($u, 0, 2) === '//') $u = (parse_url($home, PHP_URL_SCHEME) ?: 'https') . ':' . $u;
                if (substr($u, 0, 1) === '/') $u = rtrim($home, '/') . $u;
                $head = wp_remote_head($u, ['timeout' => 3, 'redirection' => 2]);
                if (is_wp_error($head)) continue;
                $size = (int) wp_remote_retrieve_header($head, 'content-length');
                if ($size > 500 * 1024) {
                    $heavy[] = basename(parse_url($u, PHP_URL_PATH) ?: $u) . ' (' . size_format($size) . ')';
                }
            }
            $f[] = $this->finding(
                'heavy_images',
                $heavy ? 'warn' : 'ok',
                'Large homepage images',
                count($heavy) . ' over 500KB',
                $heavy ? implode(', ', $heavy) : ''
            );
        }

        return $f;
    }

    private function psi(string $url, string $strategy): ?array {
        $cache_key = 'wph_psi_' . md5($url . '|' . $strategy);
        $cached = get_transient($cache_key);
        if ($cached !== false) return $cached;
        $api = add_query_arg([
            'url'      => $url,
            'strategy' => $strategy,
            'category' => 'performance',
        ], 'https://www.googleapis.com/pagespeedonline/v5/runPagespeed');
        $resp = wp_remote_get($api, ['timeout' => 30]);
        if (is_wp_error($resp) || wp_remote_retrieve_response_code($resp) !== 200) {
            set_transient($cache_key, null, HOUR_IN_SECONDS);
            return null;
        }
        $data = json_decode((string) wp_remote_retrieve_body($resp), true);
        if (!is_array($data) || empty($data['lighthouseResult'])) {
            set_transient($cache_key, null, HOUR_IN_SECONDS);
            return null;
        }
        $lr = $data['lighthouseResult'];
        $out = [
            'performance' => $lr['categories']['performance']['score'] ?? null,
            'lcp'         => $lr['audits']['largest-contentful-paint']['displayValue'] ?? null,
            'cls'         => $lr['audits']['cumulative-layout-shift']['displayValue'] ?? null,
            'tbt'         => $lr['audits']['total-blocking-time']['displayValue'] ?? null,
        ];
        set_transient($cache_key, $out, 12 * HOUR_IN_SECONDS);
        return $out;
    }
};