<?php
class WC_WhatsApp_Cloud_API {

    private string $phone_number_id;
    private string $access_token;
    private string $api_version = 'v20.0';

    public function __construct( string $phone_number_id, string $access_token ) {
        $this->phone_number_id = $phone_number_id;
        $this->access_token    = $access_token;
    }

    /**
     * Send a WooCommerce WhatsApp Meta Cloud API PHP template message.
     *
     * @param string $to      Recipient phone in E.164 format (e.g. 919876543210)
     * @param string $template Template name as approved in Meta Business Manager
     * @param string $lang    Template language code (e.g. en, en_GB, hi, ar)
     * @param array  $components Template body variable values
     * @return array          Meta API response body
     */
    public function send_template(
        string $to,
        string $template,
        string $lang,
        array  $components = []
    ): array {
        $url  = "https://graph.facebook.com/{$this->api_version}/{$this->phone_number_id}/messages";
        $body = [
            'messaging_product' => 'whatsapp',
            'to'                => $to,
            'type'              => 'template',
            'template'          => [
                'name'       => $template,
                'language'   => [ 'code' => $lang ],
                'components' => $components,
            ],
        ];

        $response = wp_remote_post( $url, [
            'headers' => [
                'Authorization' => 'Bearer ' . $this->access_token,
                'Content-Type'  => 'application/json',
            ],
            'body'    => wp_json_encode( $body ),
            'timeout' => 15,
        ]);

        if ( is_wp_error( $response ) ) {
            throw new RuntimeException( 'WooCommerce WhatsApp Meta Cloud API PHP error: ' . $response->get_error_message() );
        }

        return json_decode( wp_remote_retrieve_body( $response ), true ) ?: [];
    }

    /**
     * Build the components array for a WooCommerce WhatsApp Meta Cloud API PHP order template.
     */
    public static function order_components( WC_Order $order ): array {
        return [[
            'type'       => 'body',
            'parameters' => [
                [ 'type' => 'text', 'text' => get_bloginfo('name') ],
                [ 'type' => 'text', 'text' => $order->get_billing_first_name() ],
                [ 'type' => 'text', 'text' => (string) $order->get_order_number() ],
                [ 'type' => 'text', 'text' => $order->get_formatted_order_total() ],
            ],
        ]];
    }
}

<?php
add_action( 'woocommerce_order_status_changed', 'caz_queue_whatsapp_order_notification', 10, 3 );

function caz_queue_whatsapp_order_notification( int $order_id, string $old_status, string $new_status ): void {
    // Map WooCommerce statuses to WooCommerce WhatsApp Meta Cloud API PHP template names
    $status_template_map = apply_filters( 'caz_whatsapp_status_templates', [
        'processing' => 'wc_order_confirmed',
        'shipped'    => 'wc_order_shipped',
        'completed'  => 'wc_order_delivered',
        'cancelled'  => 'wc_order_cancelled',
    ]);

    if ( ! isset( $status_template_map[ $new_status ] ) ) return;

    $order = wc_get_order( $order_id );
    if ( ! $order ) return;

    $phone = $order->get_billing_phone();
    if ( ! $phone ) return;

    // Normalise to E.164 — WooCommerce WhatsApp Meta Cloud API PHP requirement
    $phone = preg_replace( '/[^0-9]/', '', $phone );
    if ( strlen( $phone ) === 10 ) $phone = '91' . $phone; // prepend India country code if bare

    // Queue via Action Scheduler for WooCommerce WhatsApp Meta Cloud API PHP
    as_enqueue_async_action( 'caz_send_whatsapp_order_notification', [
        'order_id' => $order_id,
        'phone'    => $phone,
        'template' => $status_template_map[ $new_status ],
    ], 'caz-whatsapp' );
}

// Process the queued WooCommerce WhatsApp Meta Cloud API PHP send
add_action( 'caz_send_whatsapp_order_notification', 'caz_process_whatsapp_send' );

function caz_process_whatsapp_send( int $order_id, string $phone, string $template ): void {
    $order  = wc_get_order( $order_id );
    $api    = new WC_WhatsApp_Cloud_API(
        get_option( 'caz_whatsapp_phone_number_id' ),
        get_option( 'caz_whatsapp_access_token' )
    );
    $result = $api->send_template( $phone, $template, 'en', WC_WhatsApp_Cloud_API::order_components( $order ) );
    $order->add_order_note( 'WooCommerce WhatsApp Meta Cloud API PHP: ' . ( $result['messages'][0]['id'] ?? 'error' ) );
}

<?php
// Register the webhook REST endpoint for WooCommerce WhatsApp Meta Cloud API PHP
add_action( 'rest_api_init', function() {
    register_rest_route( 'caz-whatsapp/v1', '/webhook', [
        [ 'methods' => 'GET',  'callback' => 'caz_whatsapp_webhook_verify',  'permission_callback' => '__return_true' ],
        [ 'methods' => 'POST', 'callback' => 'caz_whatsapp_webhook_receive', 'permission_callback' => '__return_true' ],
    ]);
});

// Handle Meta webhook verification challenge
function caz_whatsapp_webhook_verify( WP_REST_Request $req ): WP_REST_Response {
    $verify_token = get_option( 'caz_whatsapp_verify_token' );
    if ( $req->get_param('hub_verify_token') === $verify_token ) {
        return new WP_REST_Response( (int) $req->get_param('hub_challenge'), 200 );
    }
    return new WP_REST_Response( 'Forbidden', 403 );
}

// Receive and process WooCommerce WhatsApp Meta Cloud API PHP incoming messages
function caz_whatsapp_webhook_receive( WP_REST_Request $req ): WP_REST_Response {
    // HMAC verification — always validate WooCommerce WhatsApp Meta Cloud API PHP webhooks
    $app_secret = get_option( 'caz_whatsapp_app_secret' );
    $payload    = $req->get_body();
    $sig_header = $_SERVER['HTTP_X_HUB_SIGNATURE_256'] ?? '';
    $expected   = 'sha256=' . hash_hmac( 'sha256', $payload, $app_secret );

    if ( ! hash_equals( $expected, $sig_header ) ) {
        return new WP_REST_Response( 'Invalid signature', 403 );
    }

    $data = $req->get_json_params();

    // Extract incoming message from WooCommerce WhatsApp Meta Cloud API PHP event
    foreach ( $data['entry'] ?? [] as $entry ) {
        foreach ( $entry['changes'] ?? [] as $change ) {
            foreach ( $change['value']['messages'] ?? [] as $msg ) {
                $from = $msg['from'];   // customer phone number
                $text = $msg['text']['body'] ?? '';
                // Fire action for handlers (COD OTP, returns flow, etc.)
                do_action( 'caz_whatsapp_incoming_message', $from, $text, $msg );
            }
        }
    }

    return new WP_REST_Response( [ 'status' => 'ok' ], 200 );
}