/*
Plugin Name: Eboli Price Analyzer
Description: Analisi differenziale dei prezzi tramite Google Content API for Shopping.
Version: 1.1
Author: Vito
*/

if (!defined('ABSPATH')) {
    exit;
}

// Percorso assoluto del JSON Service Account
define('GOOGLE_SA_PATH', '/home/vito/outletscarpeonline.it/NOME_DEL_TUO_FILE.json');

class Eboli_Price_Analyzer {

    private $merchant_id = '121246158';

    public function __construct() {
        add_action('admin_menu', array($this, 'add_admin_menu'));
    }

    public function add_admin_menu() {
        add_submenu_page(
            'woocommerce',
            'Price Analyzer',
            'Analisi Prezzi',
            'manage_options',
            'eboli-price-analyzer',
            array($this, 'render_page')
        );
    }

    /**
     * Base64 URL-safe (obbligatorio per JWT Google)
     */
    private function base64url_encode($data) {
        return rtrim(strtr(base64_encode($data), '+/', '-_'), '=');
    }

    /**
     * Genera Access Token OAuth2 firmando JWT RS256
     */
    private function get_access_token() {

        if (!file_exists(GOOGLE_SA_PATH)) {
            return false;
        }

        $json = json_decode(file_get_contents(GOOGLE_SA_PATH), true);
        if (!isset($json['client_email']) || !isset($json['private_key'])) {
            return false;
        }

        $header = $this->base64url_encode(json_encode([
            'alg' => 'RS256',
            'typ' => 'JWT'
        ]));

        $payload = $this->base64url_encode(json_encode([
            'iss'   => $json['client_email'],
            'scope' => 'https://www.googleapis.com/auth/content',
            'aud'   => 'https://oauth2.googleapis.com/token',
            'exp'   => time() + 3600,
            'iat'   => time()
        ]));

        $signature = '';
        openssl_sign($header . '.' . $payload, $signature, $json['private_key'], OPENSSL_ALGO_SHA256);
        $jwt = $header . '.' . $payload . '.' . $this->base64url_encode($signature);

        $ch = curl_init('https://oauth2.googleapis.com/token');
        curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query([
            'grant_type' => 'urn:ietf:params:oauth:grant-type:jwt-bearer',
            'assertion'  => $jwt
        ]));
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($ch, CURLOPT_TIMEOUT, 10);

        $res = json_decode(curl_exec($ch), true);
        curl_close($ch);

        return $res['access_token'] ?? false;
    }

    /**
     * Pagina admin
     */
    public function render_page() {

        $paged = isset($_GET['paged']) ? intval($_GET['paged']) : 1;
        $limit = 20;
        $offset = ($paged - 1) * $limit;

        // Query WooCommerce corretta con offset
        $products = wc_get_products([
            'orderby'  => 'meta_value_num',
            'meta_key' => 'total_sales',
            'order'    => 'DESC',
            'limit'    => $limit,
            'offset'   => $offset
        ]);

        $token = $this->get_access_token();

        echo '<div class="wrap">';
        echo '<h1>Analisi Prezzi Competitivi</h1>';
        echo '<p>Prodotti ordinati per vendite totali.</p>';

        if (!$token) {
            echo '<div class="notice notice-error"><p>Errore autenticazione Google. Controlla il file JSON.</p></div>';
        }

        echo '<table class="widefat fixed striped" style="margin-top:20px;">';
        echo '<thead><tr>';
        echo '<th>Prodotto</th>';
        echo '<th>Tuo Prezzo</th>';
        echo '<th>Benchmark Concorrenza</th>';
        echo '<th>Stato Mercato</th>';
        echo '</tr></thead><tbody>';

        if (empty($products)) {
            echo '<tr><td colspan="4">Nessun prodotto trovato.</td></tr>';
        } else {

            foreach ($products as $product) {

                $sku = $product->get_sku();
                $price = floatval($product->get_price());
                $comp_price = 'N/A';

                if ($token && $sku) {

                    $endpoint = "https://shoppingcontent.googleapis.com/content/v2.1/{$this->merchant_id}/products/online:it:IT:$sku";

                    $ch = curl_init($endpoint);
                    curl_setopt($ch, CURLOPT_HTTPHEADER, ["Authorization: Bearer $token"]);
                    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
                    curl_setopt($ch, CURLOPT_TIMEOUT, 3);

                    $resp = json_decode(curl_exec($ch), true);
                    curl_close($ch);

                    if (isset($resp['competitivePricing']['competitivePrices'][0]['price']['value'])) {
                        $comp_price = floatval($resp['competitivePricing']['competitivePrices'][0]['price']['value']);
                    }
                }

                echo '<tr>';
                echo '<td>' . esc_html($product->get_name()) . ' <small>(SKU: ' . esc_html($sku) . ')</small></td>';
                echo '<td>' . number_format($price, 2) . ' €</td>';

                echo '<td>';
                echo ($comp_price !== 'N/A')
                    ? number_format($comp_price, 2) . ' €'
                    : '<span style="color:#999;">Non rilevato</span>';
                echo '</td>';

                echo '<td>';

                if ($comp_price !== 'N/A') {
                    if ($price > $comp_price) {
                        echo '<strong style="color:#e53e3e;">Fuori Mercato</strong>';
                    } else {
                        echo '<strong style="color:#38a169;">In Linea</strong>';
                    }
                } else {
                    echo '<span style="color:#999;">Nessun dato</span>';
                }

                echo '</td>';
                echo '</tr>';
            }
        }

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

        echo '<p style="margin-top:20px;">';
        echo '<a href="?page=eboli-price-analyzer&paged=' . ($paged + 1) . '" class="button button-primary">Carica altri 20 prodotti</a>';
        echo '</p>';

        echo '</div>';
    }
}

new Eboli_Price_Analyzer();