/**
 * Create document from template - CORRECT FORMAT
 */
public function create_document_from_template($signer_data, $template_values = array()) {
    error_log('=== DIGIO: Create Document from Template ===');
    error_log('API URL: ' . $this->api_url);
    error_log('Template ID: ' . $this->template_key);
    error_log('Signer: ' . print_r($signer_data, true));
    error_log('Template Values: ' . print_r($template_values, true));
    
    // CORRECT endpoint for template-based signing
    $endpoint = $this->api_url . '/client/document/template';
    
    // CORRECT payload structure based on Digio documentation
    $payload = array(
        'template_id' => $this->template_key, // NOT 'templates' array!
        'signers' => array(
            array(
                'identifier' => $signer_data['email'],
                'name' => $signer_data['name'],
                'signer_tag' => 'SIGNER 1', // Must match tag in your template
                'auth_type' => 'aadhaar_otp' // Aadhaar OTP authentication
            )
        ),
        'document_data' => $template_values, // NOT 'template_values'!
        'generate_document' => true, // Generate document from template
        'notification_enabled' => true, // Send email/SMS to signer
        'expire_in_days' => 7
    );
    
    $json_payload = json_encode($payload);
    error_log('Request Payload: ' . $json_payload);
    
    // Make API request
    $response = wp_remote_post($endpoint, array(
        'headers' => array(
            'Authorization' => 'Basic ' . base64_encode($this->client_id . ':' . $this->client_secret),
            'Content-Type' => 'application/json',
            'Accept' => 'application/json'
        ),
        'body' => $json_payload,
        'timeout' => 120,
        'sslverify' => true,
        'httpversion' => '1.1'
    ));
    
    if (is_wp_error($response)) {
        error_log('CONNECTION ERROR: ' . $response->get_error_message());
        return array(
            'success' => false,
            'message' => 'Connection error: ' . $response->get_error_message()
        );
    }
    
    $status_code = wp_remote_retrieve_response_code($response);
    $response_body = wp_remote_retrieve_body($response);
    $response_data = json_decode($response_body, true);
    
    error_log('Response Status: ' . $status_code);
    error_log('Response Body: ' . $response_body);
    
    // Handle errors
    if ($status_code !== 200 && $status_code !== 201) {
        $error_msg = 'API Error';
        
        if (isset($response_data['message'])) {
            $error_msg = $response_data['message'];
        } elseif (isset($response_data['error'])) {
            $error_msg = is_string($response_data['error']) ? $response_data['error'] : json_encode($response_data['error']);
        }
        
        if (isset($response_data['details'])) {
            $error_msg .= ' (Details: ' . $response_data['details'] . ')';
        }
        
        error_log('API ERROR: ' . $error_msg);
        
        return array(
            'success' => false,
            'message' => $error_msg
        );
    }
    
    // Extract document ID and sign link
    $document_id = $response_data['id'] ?? $response_data['document_id'] ?? '';
    $sign_link = '';
    
    // Check multiple possible locations for sign link
    if (isset($response_data['signing_parties']) && is_array($response_data['signing_parties'])) {
        foreach ($response_data['signing_parties'] as $party) {
            if (isset($party['sign_link'])) {
                $sign_link = $party['sign_link'];
                break;
            }
        }
    } elseif (isset($response_data['sign_link'])) {
        $sign_link = $response_data['sign_link'];
    }
    
    if (empty($document_id)) {
        error_log('ERROR: No document ID in response');
        return array(
            'success' => false,
            'message' => 'No document ID returned'
        );
    }
    
    error_log('SUCCESS - Document ID: ' . $document_id);
    error_log('SUCCESS - Sign Link: ' . $sign_link);
    
    return array(
        'success' => true,
        'document_id' => $document_id,
        'sign_link' => $sign_link,
        'data' => $response_data
    );
}