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

final class IntentFlow_License {

    private static ?IntentFlow_License $instance = null;
    private string $api_url     = 'https://adaptatuweb.com/niw-api';
    private string $license_key = '';
    private string $domain      = '';
    private array  $cached_status = [];

    private const CACHE_KEY      = 'if_license_cache';
    private const CACHE_SIG_KEY  = 'if_license_cache_sig';
    private const CHECK_INTERVAL = 43200;
    private const VERSION_CONST  = 'IF_VERSION';

    public static function instance(): self {
        if (self::$instance === null) self::$instance = new self();
        return self::$instance;
    }

    private function __construct() {
        $this->license_key = (string) get_option('if_license_key', '');
        $this->domain      = $this->resolve_domain();
    }

    public function init(): void {
        add_action('if_daily_license_check', [$this, 'validate_now']);
        if (!wp_next_scheduled('if_daily_license_check')) {
            wp_schedule_event(time(), 'daily', 'if_daily_license_check');
        }
        add_action('admin_notices', [$this, 'maybe_show_notice']);
        // WordPress.org: auto-update disabled in free version
        // WordPress.org: plugin_info disabled in free version
    }

    public function activate(string $key): array {
        $key = sanitize_text_field($key);
        if ($key === '') return ['ok' => false, 'error' => 'missing_key'];
        $response = $this->api_request('POST', '/v1/license/activate', [
            'license_key'    => $key,
            'domain'         => $this->domain,
            'site_url'       => get_site_url(),
            'wp_version'     => get_bloginfo('version'),
            'php_version'    => PHP_VERSION,
            'plugin_version' => defined(self::VERSION_CONST) ? constant(self::VERSION_CONST) : '0',
        ]);
        if ($response && (!empty($response['valid']) || !empty($response['success']))) {
            update_option('if_license_key', $key);
            $this->license_key = $key;
            $this->save_cache($response);
            update_option('if_license_last_good', $response);
            update_option('if_license_last_check', time());
            return ['ok' => true, 'plan' => $response['plan'] ?? 'free'];
        }
        return ['ok' => false, 'error' => $response['error'] ?? 'activation_failed'];
    }

    public function deactivate(): void {
        if ($this->license_key) {
            $this->api_request('POST', '/v1/license/deactivate', [
                'license_key' => $this->license_key,
                'domain'      => $this->domain,
            ]);
        }
        delete_option('if_license_key');
        delete_option('if_license_last_good');
        delete_option('if_license_last_check');
        delete_transient(self::CACHE_KEY);
        delete_transient(self::CACHE_SIG_KEY);
        $this->license_key   = '';
        $this->cached_status = [];
    }

    public function validate_now(): array {
        if (!$this->license_key) return $this->free_mode();
        $response = $this->api_request('POST', '/v1/license/validate', [], [
            'X-NIW-Key'     => $this->license_key,
            'X-NIW-Domain'  => $this->domain,
            'X-NIW-Version' => defined(self::VERSION_CONST) ? constant(self::VERSION_CONST) : '0',
        ]);
        if (!$response) {
            $last_good  = get_option('if_license_last_good');
            $last_check = (int) get_option('if_license_last_check', 0);
            if ($last_good && is_array($last_good) && (time() - $last_check) < 86400) {
                $this->cached_status = $last_good;
                return $last_good;
            }
            return $this->free_mode();
        }
        if (!empty($response['valid'])) {
            $response['domain'] = $this->domain;
            $this->save_cache($response);
            update_option('if_license_last_good', $response);
            update_option('if_license_last_check', time());
            return $this->cached_status;
        }
        return $this->free_mode();
    }

    public function get_status(): array {
        if (!empty($this->cached_status)) return $this->cached_status;
        $cached = get_transient(self::CACHE_KEY);
        if ($cached && is_array($cached)) {
            $sig = (string) get_transient(self::CACHE_SIG_KEY);
            if ($this->verify_cache($cached, $sig)) {
                $this->cached_status = $cached;
                return $cached;
            }
            delete_transient(self::CACHE_KEY);
            delete_transient(self::CACHE_SIG_KEY);
        }
        if (wp_doing_ajax() || (defined('REST_REQUEST') && REST_REQUEST)) {
            return $this->free_mode();
        }
        return $this->validate_now();
    }

    public function get_plan(): string { return $this->get_status()['plan'] ?? 'free'; }
    public function is_pro(): bool { return in_array($this->get_plan(), ['intent_flow_pro','pro','premium','agency'], true); }
    public function can(string $feature): bool { return in_array($feature, (array)($this->get_status()['features'] ?? []), true); }
    public function get_key(): string { return $this->license_key; }

    public function maybe_show_notice(): void {
        if (!current_user_can('manage_options')) return;
        $screen = get_current_screen();
        if (!$screen || strpos($screen->id, 'mmi') === false) return;
        if (!$this->license_key) {
            echo '<div class="notice notice-info is-dismissible"><p>';
            printf('<strong>Intent Flow Pro:</strong> Introduce tu clave de licencia para activar WooCommerce, Google Sheets y más. <a href="%s">Activar ahora →</a>', esc_url(admin_url('admin.php?page=mmi-license')));
            echo '</p></div>';
        }
    }

    public function check_update($transient) {
        if (empty($transient->checked)) return $transient;
        $update = get_transient('if_pending_update');
        if (!$update || empty($update['version'])) return $transient;
        $slug    = plugin_basename(IF_PLUGIN_FILE);
        $current = $transient->checked[$slug] ?? (defined(self::VERSION_CONST) ? constant(self::VERSION_CONST) : '0');
        if (version_compare($update['version'], $current, '<=')) return $transient;
        $transient->response[$slug] = (object)[
            'slug'         => 'intent-flow',
            'plugin'       => $slug,
            'new_version'  => $update['version'],
            'url'          => $this->api_url . '/v1/update/check',
            'package'      => $update['download_url'] ?? '',
            'requires'     => $update['requires_wp']  ?? '6.0',
            'requires_php' => $update['requires_php'] ?? '8.0',
            'tested'       => $update['tested_wp']    ?? '',
        ];
        return $transient;
    }

    public function plugin_info($result, string $action, $args) {
        if ($action !== 'plugin_information' || ($args->slug ?? '') !== 'intent-flow') return $result;
        $update = get_transient('if_pending_update');
        if (!$update) return $result;
        return (object)[
            'name'          => 'Intent Flow',
            'slug'          => 'intent-flow',
            'version'       => $update['version'] ?? '',
            'author'        => 'Alvaro Martinez - adaptatuweb.com',
            'requires'      => $update['requires_wp'] ?? '6.0',
            'tested'        => $update['tested_wp']   ?? '',
            'sections'      => ['changelog' => nl2br($update['changelog'] ?? '')],
            'download_link' => $update['download_url'] ?? '',
        ];
    }

    private function api_request(string $method, string $endpoint, array $body = [], array $extra_headers = []): ?array {
        $url     = rtrim($this->api_url, '/') . $endpoint;
        $headers = array_merge(['Content-Type' => 'application/json', 'User-Agent' => 'IntentFlow/' . (defined(self::VERSION_CONST) ? constant(self::VERSION_CONST) : '0')], $extra_headers);
        $args    = ['method' => $method, 'headers' => $headers, 'timeout' => 8, 'sslverify' => true];
        if ($method === 'POST' && !empty($body)) $args['body'] = wp_json_encode($body);
        $response = wp_remote_request($url, $args);
        if (is_wp_error($response)) { return null; }
        $code = wp_remote_retrieve_response_code($response);
        $data = json_decode(wp_remote_retrieve_body($response), true);
        if ($code >= 500) return null;
        return is_array($data) ? $data : null;
    }

    private function resolve_domain(): string { return strtolower(wp_parse_url(get_site_url(), PHP_URL_HOST) ?? ''); }
    private function sign_cache(array $data): string { return hash_hmac('sha256', json_encode($data) . $this->domain, $this->license_key . AUTH_KEY); }
    private function verify_cache(array $data, string $sig): bool { return hash_equals($this->sign_cache($data), $sig); }
    private function save_cache(array $data): void {
        $this->cached_status = $data;
        set_transient(self::CACHE_KEY, $data, self::CHECK_INTERVAL + 3600);
        set_transient(self::CACHE_SIG_KEY, $this->sign_cache($data), self::CHECK_INTERVAL + 3600);
    }
    private function free_mode(): array {
        $free = ['plan' => 'free', 'valid' => true, 'features' => ['triggers_basic','actions_basic','scheduler','audit_log','webhooks']];
        $this->cached_status = $free;
        return $free;
    }
}