<?php

namespace FluentCartBreakdance\Admin;

use FluentCartBreakdance\Breakdance\EditorSupport;
use FluentCartBreakdance\Breakdance\TemplateRegistry;
use FluentCartBreakdance\Compatibility\Contracts;
use FluentCartBreakdance\Compatibility\VersionProfiles;

defined('ABSPATH') || exit;

/**
 * WP12A (Golf 4, ELITE-PLAN.md par. 303-314): a light, buildchain-free WordPress
 * admin page under Instellingen ("Settings") that surfaces the Health/Contract
 * Sentinel: live contract status, active version profile, environment/flag
 * status, cache-plugin advice and a copyable, PII-free diagnostic report.
 *
 * Read-only consumer of Contracts.php/VersionProfiles.php (this fork does not
 * own those files) and of the `fcbd_takeover` (TemplateRegistry) and
 * `fcbd_preview_product_id` (EditorSupport) options already registered by
 * earlier forks. This class registers no new option that any other fork reads.
 *
 * `fcbd_atomized_checkout` (self::ATOMIZED_CHECKOUT_OPTION) is a reserved flag
 * name for the checkout-atomization family (WP9), which IS built (CheckoutRenderer-
 * backed FC_Checkout* elements, see src/Compatibility/Contracts.php
 * wp9CheckoutRendererContracts()/wp9CheckoutSchemaAndFormContracts()): no writer
 * in this codebase turns the flag on yet, because it is intentionally held off
 * until the real purchase-flow gate (Golf 3) ships, not because the feature is
 * unfinished. This page therefore reports it as "uit" by design, not as an
 * unbuilt-feature placeholder. This is documented, not a bug: see the restrisico
 * list in this fork's report.
 *
 * Every dynamic value is escaped at the point of output (esc_html/esc_attr/
 * esc_textarea); no raw variable is ever echoed. No email address, order
 * record, API key, or other secret is ever read or displayed on this page or
 * in its diagnostic report: gatherEnvironment()/detectCachePlugins()/
 * buildReportText() only ever touch plugin/theme version strings, boolean
 * feature flags, and Contracts::verify()'s own PHP-side capability detail
 * (class/method/shortcode names and file:line evidence, never row data).
 */
final class HealthPage
{
    /**
     * Reserved option name for the checkout-atomization feature flag (WP9);
     * the checkout family is built, but no writer flips this flag on yet
     * pending the real purchase-flow gate (Golf 3). See class docblock.
     */
    public const ATOMIZED_CHECKOUT_OPTION = 'fcbd_atomized_checkout';

    public const PAGE_SLUG = 'fcbd-health';

    private static string $hookSuffix = '';

    /**
     * Whether the current admin screen is one of $screenIds or this plugin's
     * own Health page. Admin notices use it to stay limited in scope
     * (Plugin Directory guideline 11).
     *
     * @param array<int, string> $screenIds
     */
    public static function isNoticeScreen(array $screenIds): bool
    {
        if (!function_exists('get_current_screen')) {
            return false;
        }

        $screen = get_current_screen();
        if (!$screen || !isset($screen->id)) {
            return false;
        }

        $id = (string) $screen->id;
        if (self::$hookSuffix !== '' && $id === self::$hookSuffix) {
            return true;
        }

        // Network admin screens carry a "-network" suffix (plugins-network).
        $baseId = substr($id, -8) === '-network' ? substr($id, 0, -8) : $id;

        return in_array($baseId, $screenIds, true);
    }

    public static function hook(): void
    {
        add_action('admin_menu', [self::class, 'registerMenu']);
        add_action('admin_enqueue_scripts', [self::class, 'maybeEnqueueAssets']);
    }

    public static function registerMenu(): void
    {
        if (!function_exists('add_submenu_page')) {
            return;
        }

        $hook = add_submenu_page(
            'options-general.php',
            __('FluentCart Health', 'sparkcore-commerce'),
            __('FluentCart Health', 'sparkcore-commerce'),
            'manage_options',
            self::PAGE_SLUG,
            [self::class, 'render']
        );

        if (is_string($hook)) {
            self::$hookSuffix = $hook;
        }
    }

    public static function maybeEnqueueAssets(string $hookSuffix): void
    {
        if ($hookSuffix === '' || $hookSuffix !== self::$hookSuffix) {
            return;
        }

        if (!function_exists('wp_enqueue_style')) {
            return;
        }

        wp_enqueue_style(
            'fcbd-admin-health',
            defined('FCBD_URL') ? FCBD_URL . 'assets/admin-health.css' : '',
            [],
            defined('FCBD_VERSION') ? FCBD_VERSION : null
        );
    }

    public static function render(): void
    {
        if (!function_exists('current_user_can') || !current_user_can('manage_options')) {
            if (function_exists('wp_die')) {
                wp_die(esc_html__('You do not have permission to view this page.', 'sparkcore-commerce'));
            }

            return;
        }

        $contractResults = Contracts::verify();
        $versionProfile = VersionProfiles::evaluate();
        $environment = self::gatherEnvironment();
        $cacheAdvice = self::detectCachePlugins();
        $reportText = self::buildReportText($contractResults, $versionProfile, $environment, $cacheAdvice);

        echo '<div class="wrap fcbd-health-wrap">';
        echo '<h1>' . esc_html__('FluentCart Health', 'sparkcore-commerce') . '</h1>';

        self::renderVersionProfileSection($versionProfile);
        self::renderContractSection($contractResults);
        self::renderEnvironmentSection($environment);
        self::renderCacheAdviceSection($cacheAdvice);
        self::renderReportSection($reportText);

        echo '</div>';
    }

    // =====================================================================
    // (a) contract-status + version-profile section
    // =====================================================================

    /**
     * @param array{version: string|null, status: string, message: string} $versionProfile
     */
    private static function renderVersionProfileSection(array $versionProfile): void
    {
        echo '<h2>' . esc_html__('Version profile', 'sparkcore-commerce') . '</h2>';
        echo '<table class="widefat fcbd-health-table">';
        echo '<tbody>';

        echo '<tr><th scope="row">' . esc_html__('Audited FluentCart profiles', 'sparkcore-commerce') . '</th>';
        echo '<td>' . esc_html(self::auditedFluentCartProfilesLabel()) . '</td></tr>';

        echo '<tr><th scope="row">' . esc_html__('Verified Breakdance baseline', 'sparkcore-commerce') . '</th>';
        echo '<td>' . esc_html(Contracts::VERIFIED_BREAKDANCE_VERSION) . '</td></tr>';

        echo '<tr><th scope="row">' . esc_html__('Active FluentCart version', 'sparkcore-commerce') . '</th>';
        echo '<td>' . esc_html($versionProfile['version'] ?? __('unknown', 'sparkcore-commerce')) . '</td></tr>';

        echo '<tr><th scope="row">' . esc_html__('Verdict', 'sparkcore-commerce') . '</th>';
        echo '<td><span class="fcbd-health-badge fcbd-health-badge--' . esc_attr(self::profileBadgeClass($versionProfile['status'])) . '">'
            . esc_html(self::profileStatusLabel($versionProfile['status']))
            . '</span><p>' . esc_html($versionProfile['message']) . '</p></td></tr>';

        echo '</tbody></table>';
    }

    private static function profileBadgeClass(string $status): string
    {
        switch ($status) {
            case VersionProfiles::STATUS_KNOWN_GOOD:
                return 'ok';
            case VersionProfiles::STATUS_UNKNOWN_NEWER:
            case VersionProfiles::STATUS_OLDER_UNSUPPORTED:
                return 'warn';
            default:
                return 'unknown';
        }
    }

    private static function profileStatusLabel(string $status): string
    {
        switch ($status) {
            case VersionProfiles::STATUS_KNOWN_GOOD:
                return __('Known good', 'sparkcore-commerce');
            case VersionProfiles::STATUS_UNKNOWN_NEWER:
                return __('Unknown, newer', 'sparkcore-commerce');
            case VersionProfiles::STATUS_OLDER_UNSUPPORTED:
                return __('Older than supported', 'sparkcore-commerce');
            default:
                return __('Not detected', 'sparkcore-commerce');
        }
    }

    /**
     * @param array<int, array{id: string, type: string, status: string, detail: string}> $contractResults
     */
    private static function renderContractSection(array $contractResults): void
    {
        $summary = self::summarizeContracts($contractResults);

        echo '<h2>' . esc_html__('Contract status', 'sparkcore-commerce') . '</h2>';
        echo '<p class="fcbd-health-summary">';
        echo esc_html(sprintf(
            /* translators: 1: ok count, 2: warn count, 3: uncheckable count, 4: missing count. */
            __('%1$d ok, %2$d warning(s), %3$d not checkable, %4$d missing.', 'sparkcore-commerce'),
            $summary['ok'],
            $summary['warn'],
            $summary['uncheckable'],
            $summary['missing']
        ));
        echo '</p>';

        echo '<table class="widefat striped fcbd-health-table">';
        echo '<thead><tr>';
        echo '<th scope="col">' . esc_html__('Interface', 'sparkcore-commerce') . '</th>';
        echo '<th scope="col">' . esc_html__('Type', 'sparkcore-commerce') . '</th>';
        echo '<th scope="col">' . esc_html__('Status', 'sparkcore-commerce') . '</th>';
        echo '<th scope="col">' . esc_html__('Detail', 'sparkcore-commerce') . '</th>';
        echo '</tr></thead><tbody>';

        foreach ($contractResults as $entry) {
            echo '<tr>';
            echo '<td>' . esc_html((string) $entry['id']) . '</td>';
            echo '<td>' . esc_html((string) $entry['type']) . '</td>';
            echo '<td><span class="fcbd-health-badge fcbd-health-badge--' . esc_attr(self::contractBadgeClass((string) $entry['status'])) . '">'
                . esc_html(self::contractStatusLabel((string) $entry['status']))
                . '</span></td>';
            echo '<td>' . esc_html((string) $entry['detail']) . '</td>';
            echo '</tr>';
        }

        echo '</tbody></table>';
    }

    private static function contractBadgeClass(string $status): string
    {
        switch ($status) {
            case 'ok':
                return 'ok';
            case 'warn':
                return 'warn';
            case 'missing':
                return 'missing';
            default:
                return 'unknown';
        }
    }

    private static function contractStatusLabel(string $status): string
    {
        switch ($status) {
            case 'ok':
                return __('Ok', 'sparkcore-commerce');
            case 'warn':
                return __('Warning', 'sparkcore-commerce');
            case 'missing':
                return __('Missing', 'sparkcore-commerce');
            case 'uncheckable':
                return __('Not checkable (E2E)', 'sparkcore-commerce');
            default:
                return __('Unknown', 'sparkcore-commerce');
        }
    }

    /**
     * @param array<int, array{id: string, type: string, status: string, detail: string}> $contractResults
     * @return array{ok: int, warn: int, missing: int, uncheckable: int}
     */
    public static function summarizeContracts(array $contractResults): array
    {
        $summary = ['ok' => 0, 'warn' => 0, 'missing' => 0, 'uncheckable' => 0];

        foreach ($contractResults as $entry) {
            $status = (string) ($entry['status'] ?? '');
            if (array_key_exists($status, $summary)) {
                $summary[$status]++;
            }
        }

        return $summary;
    }

    // =====================================================================
    // (b) environment status section
    // =====================================================================

    /**
     * @return array{
     *   wp_version: string,
     *   php_version: string,
     *   fluentcart_version: string,
     *   fluentcart_pro_version: string,
     *   breakdance_version: string,
     *   takeover_enabled: bool,
     *   atomized_checkout_enabled: bool,
     *   preview_product_id: int
     * }
     */
    public static function gatherEnvironment(): array
    {
        $unknown = __('not active', 'sparkcore-commerce');

        return [
            'wp_version' => function_exists('get_bloginfo') ? (string) get_bloginfo('version') : $unknown,
            'php_version' => PHP_VERSION,
            'fluentcart_version' => defined('FLUENTCART_VERSION') ? (string) FLUENTCART_VERSION : $unknown,
            'fluentcart_pro_version' => defined('FLUENTCART_PRO_PLUGIN_VERSION') ? (string) FLUENTCART_PRO_PLUGIN_VERSION : $unknown,
            'breakdance_version' => defined('__BREAKDANCE_VERSION') ? (string) __BREAKDANCE_VERSION : $unknown,
            'takeover_enabled' => function_exists('get_option') && (bool) get_option(TemplateRegistry::TAKEOVER_OPTION, false),
            'atomized_checkout_enabled' => function_exists('get_option') && (bool) get_option(self::ATOMIZED_CHECKOUT_OPTION, false),
            'preview_product_id' => class_exists(EditorSupport::class) ? EditorSupport::previewProductId() : 0,
        ];
    }

    /**
     * @param array{
     *   wp_version: string,
     *   php_version: string,
     *   fluentcart_version: string,
     *   fluentcart_pro_version: string,
     *   breakdance_version: string,
     *   takeover_enabled: bool,
     *   atomized_checkout_enabled: bool,
     *   preview_product_id: int
     * } $environment
     */
    private static function renderEnvironmentSection(array $environment): void
    {
        echo '<h2>' . esc_html__('Environment status', 'sparkcore-commerce') . '</h2>';
        echo '<table class="widefat fcbd-health-table">';
        echo '<tbody>';

        $rows = [
            __('WordPress', 'sparkcore-commerce') => $environment['wp_version'],
            __('PHP', 'sparkcore-commerce') => $environment['php_version'],
            __('FluentCart', 'sparkcore-commerce') => $environment['fluentcart_version'],
            __('FluentCart Pro', 'sparkcore-commerce') => $environment['fluentcart_pro_version'],
            __('Breakdance', 'sparkcore-commerce') => $environment['breakdance_version'],
        ];

        foreach ($rows as $label => $value) {
            echo '<tr><th scope="row">' . esc_html($label) . '</th><td>' . esc_html($value) . '</td></tr>';
        }

        echo '<tr><th scope="row">' . esc_html__('Template takeover (fcbd_takeover)', 'sparkcore-commerce') . '</th><td>'
            . esc_html(self::flagLabel($environment['takeover_enabled']))
            . '</td></tr>';

        echo '<tr><th scope="row">' . esc_html__('Atomized checkout (fcbd_atomized_checkout)', 'sparkcore-commerce') . '</th><td>'
            . esc_html(self::flagLabel($environment['atomized_checkout_enabled']))
            . ' <span class="fcbd-health-note">' . esc_html__('The checkout family is built (WP9); this flag is deliberately off until the real purchase gate (wave 3).', 'sparkcore-commerce') . '</span>'
            . '</td></tr>';

        echo '<tr><th scope="row">' . esc_html__('Editor preview product', 'sparkcore-commerce') . '</th><td>'
            . ($environment['preview_product_id'] > 0
                ? esc_html(sprintf(
                    /* translators: %d: WordPress post ID. */
                    __('Set to product ID %d.', 'sparkcore-commerce'),
                    $environment['preview_product_id']
                ))
                : esc_html__('Not set.', 'sparkcore-commerce'))
            . '</td></tr>';

        echo '</tbody></table>';
    }

    private static function flagLabel(bool $enabled): string
    {
        return $enabled ? __('on', 'sparkcore-commerce') : __('off', 'sparkcore-commerce');
    }

    // =====================================================================
    // (c) cache advice section
    // =====================================================================

    /**
     * Detects known full-page-cache plugins via class/constant checks (never
     * by naming assumption alone; every constant below is verified against
     * the real plugin source, see this fork's report for file:line evidence)
     * and pairs each with the exact exclusion advice already documented in
     * readme.txt's cache FAQ.
     *
     * @return array<int, array{id: string, name: string, active: bool, evidence: string, advice: string}>
     */
    public static function detectCachePlugins(): array
    {
        return [
            [
                'id' => 'flyingpress',
                'name' => 'FlyingPress',
                'active' => defined('FLYING_PRESS_VERSION'),
                'evidence' => 'FLYING_PRESS_VERSION',
                'advice' => __('Settings > Cache > Excluded URLs: add the cart, checkout, account and receipt page paths (or the FluentCart page setting slugs if you changed them).', 'sparkcore-commerce'),
            ],
            [
                'id' => 'litespeed',
                'name' => 'LiteSpeed Cache',
                'active' => defined('LSCWP_V'),
                'evidence' => 'LSCWP_V',
                'advice' => __('Cache > Excludes > Do Not Cache URIs: add the same page paths.', 'sparkcore-commerce'),
            ],
            [
                'id' => 'wp_rocket',
                'name' => 'WP Rocket',
                'active' => defined('WP_ROCKET_VERSION'),
                'evidence' => 'WP_ROCKET_VERSION',
                'advice' => __('Cache > Never Cache URL(s): add the same page paths.', 'sparkcore-commerce'),
            ],
        ];
    }

    /**
     * @param array<int, array{id: string, name: string, active: bool, evidence: string, advice: string}> $cacheAdvice
     */
    private static function renderCacheAdviceSection(array $cacheAdvice): void
    {
        echo '<h2>' . esc_html__('Cache advice', 'sparkcore-commerce') . '</h2>';
        echo '<p>' . esc_html__('This plugin already marks the cart, checkout, account and receipt routes as no-cache. As a second line of defense, also add the same paths to your cache plugin\'s exclusion list:', 'sparkcore-commerce') . '</p>';

        $anyActive = false;
        echo '<ul class="fcbd-health-cache-list">';
        foreach ($cacheAdvice as $entry) {
            if (!$entry['active']) {
                continue;
            }

            $anyActive = true;
            echo '<li><strong>' . esc_html($entry['name']) . '</strong>: ' . esc_html($entry['advice']) . '</li>';
        }
        echo '</ul>';

        if (!$anyActive) {
            echo '<p class="fcbd-health-note">' . esc_html__('No supported full-page cache plugin detected (FlyingPress, LiteSpeed Cache, WP Rocket).', 'sparkcore-commerce') . '</p>';
        }
    }

    // =====================================================================
    // (d) copyable diagnostic report
    // =====================================================================

    private static function renderReportSection(string $reportText): void
    {
        echo '<h2>' . esc_html__('Copyable diagnostics report', 'sparkcore-commerce') . '</h2>';
        echo '<p>' . esc_html__('Contains no email addresses, order data or keys. Safe to share with a support request.', 'sparkcore-commerce') . '</p>';
        echo '<textarea readonly class="large-text fcbd-health-report" rows="18" onclick="this.select();">'
            . esc_textarea($reportText)
            . '</textarea>';
    }

    /**
     * Pure text-assembly, deliberately free of any WordPress data lookup
     * beyond the arguments it is given, so it can be exercised directly by
     * tests/admin/run-admin.php with a stubbed contract/version/environment
     * fixture. Never includes an email address, order record, or secret: only
     * plugin/theme version strings, boolean feature flags, and Contracts::
     * verify()'s own capability-level detail strings.
     *
     * @param array<int, array{id: string, type: string, status: string, detail: string}> $contractResults
     * @param array{version: string|null, status: string, message: string} $versionProfile
     * @param array{
     *   wp_version: string,
     *   php_version: string,
     *   fluentcart_version: string,
     *   fluentcart_pro_version: string,
     *   breakdance_version: string,
     *   takeover_enabled: bool,
     *   atomized_checkout_enabled: bool,
     *   preview_product_id: int
     * } $environment
     * @param array<int, array{id: string, name: string, active: bool, evidence: string, advice: string}> $cacheAdvice
     */
    public static function buildReportText(
        array $contractResults,
        array $versionProfile,
        array $environment,
        array $cacheAdvice
    ): string {
        $summary = self::summarizeContracts($contractResults);

        $lines = [];
        $lines[] = __('SparkCore Commerce diagnostics report', 'sparkcore-commerce');
        $lines[] = str_repeat('=', 48);
        $lines[] = '';
        $lines[] = __('Environment', 'sparkcore-commerce');
        $lines[] = sprintf('WordPress: %s', $environment['wp_version']);
        $lines[] = sprintf('PHP: %s', $environment['php_version']);
        $lines[] = sprintf('FluentCart: %s', $environment['fluentcart_version']);
        $lines[] = sprintf('FluentCart Pro: %s', $environment['fluentcart_pro_version']);
        $lines[] = sprintf('Breakdance: %s', $environment['breakdance_version']);
        $lines[] = sprintf('fcbd_takeover: %s', self::flagLabel($environment['takeover_enabled']));
        $lines[] = sprintf('fcbd_atomized_checkout: %s', self::flagLabel($environment['atomized_checkout_enabled']));
        $lines[] = '';
        $lines[] = __('Verified baselines', 'sparkcore-commerce');
        $lines[] = sprintf('FluentCart: %s', self::auditedFluentCartProfilesLabel());
        $lines[] = sprintf('Breakdance: %s', Contracts::VERIFIED_BREAKDANCE_VERSION);
        $lines[] = '';
        $lines[] = __('Version profile', 'sparkcore-commerce');
        $lines[] = sprintf('Status: %s', self::profileStatusLabel($versionProfile['status']));
        $lines[] = (string) $versionProfile['message'];
        $lines[] = '';
        $lines[] = __('Contract status', 'sparkcore-commerce');
        $lines[] = sprintf(
            '%d ok, %d warn, %d uncheckable, %d missing',
            $summary['ok'],
            $summary['warn'],
            $summary['uncheckable'],
            $summary['missing']
        );

        foreach ($contractResults as $entry) {
            $lines[] = sprintf(
                '- [%s] %s (%s): %s',
                strtoupper((string) $entry['status']),
                (string) $entry['id'],
                (string) $entry['type'],
                (string) $entry['detail']
            );
        }

        $lines[] = '';
        $lines[] = __('Cache advice', 'sparkcore-commerce');
        $activeCache = false;
        foreach ($cacheAdvice as $entry) {
            if (!$entry['active']) {
                continue;
            }

            $activeCache = true;
            $lines[] = sprintf('- %s: %s', $entry['name'], $entry['advice']);
        }

        if (!$activeCache) {
            $lines[] = __('No supported full-page cache plugin detected.', 'sparkcore-commerce');
        }

        return implode("\n", $lines);
    }

    /**
     * Every audited (known-good) FluentCart profile, oldest first, so the
     * Health page shows the full audited range instead of only the oldest
     * baseline constant (which deliberately stays 1.3.27 as the minimum).
     */
    private static function auditedFluentCartProfilesLabel(): string
    {
        $known = [];
        foreach (VersionProfiles::profiles() as $version => $profile) {
            if (($profile['status'] ?? '') === VersionProfiles::STATUS_KNOWN_GOOD) {
                $known[] = (string) $version;
            }
        }

        if ($known === []) {
            return Contracts::VERIFIED_VERSION;
        }

        usort($known, 'version_compare');

        return implode(', ', $known);
    }
}