Adds a username field to WC Vendors Signup and uses it when creating the user.

/**

 * Username Field

 * Description: Adds a username field to WC Vendors Signup and uses it when creating the user.

 */

defined( 'ABSPATH' ) || exit;

add_filter( 'wcv_signup_form_config', function( $config ) {

	$config = is_array( $config ) ? $config : array();

	$has_core_username = array_key_exists( 'username', $config );

	$has_custom_username = array_key_exists( 'wcv_cf_username', $config );

	// If both exist somehow, keep the admin/custom one and remove the core one to avoid duplicates.

	if ( $has_core_username && $has_custom_username ) {

		unset( $config['username'] );

		$has_core_username = false;

	}

	// If neither exists, add a custom (builder-manageable) username field with sane defaults.

	if ( ! $has_core_username && ! $has_custom_username ) {

		$config['wcv_cf_username'] = array(

			'type'        => 'text',

			'label'       => __( 'Username', 'wc-vendors-signup' ),

			'required'    => true,   // default; admin toggle can change later

			'deletable'   => false,  // prevent accidental removal if you prefer

			'editable'    => true,

			'order'       => 1,      // default position; we do not reorder other fields

			'enabled'     => true,   // default; admin toggle can change later

			'placeholder' => __( 'Choose a username', 'wc-vendors-signup' ),

			'is_default'  => false,  // it’s a custom field, not a built-in default

			'show_on_checkout' => false,

		);

	}

	return $config;

}, 5 );

function wcv_signup_get_username_field_key() {

	$config = apply_filters( 'wcv_signup_form_config', get_option( 'wcv_signup_form_config', array() ) );

	// Prefer custom if present.

	if ( isset( $config['wcv_cf_username'] ) && ! empty( $config['wcv_cf_username']['enabled'] ) ) {

		return 'wcv_cf_username';

	}

	// Fallback to legacy/core if present (we also cleaned this up above, but keep fallback just in case).

	if ( isset( $config['username'] ) && ! empty( $config['username']['enabled'] ) ) {

		return 'username';

	}

	return null;

}

add_filter( 'wcv_signup_validation_errors', function( $errors, $form_data ) {

	$username_key = wcv_signup_get_username_field_key();

	if ( ! $username_key ) {

		return $errors;

	}

	// Get the live field config after filters so toggles are respected.

	$config = apply_filters( 'wcv_signup_form_config', get_option( 'wcv_signup_form_config', array() ) );

	$field  = $config[ $username_key ];

	$is_enabled  = ! empty( $field['enabled'] );

	$is_required = ! empty( $field['required'] );

	$label       = isset( $field['label'] ) ? (string) $field['label'] : __( 'Username', 'wc-vendors-signup' );

	$raw_value   = isset( $form_data[ $username_key ] ) ? (string) $form_data[ $username_key ] : '';

	$value       = sanitize_user( $raw_value, true );

	if ( ! $is_enabled ) {

		return $errors; // field disabled; skip validation

	}

	if ( $is_required && $value === '' ) {

		$errors[ $username_key ] = array(

			'message' => __( 'Please enter a username.', 'wc-vendors-signup' ),

			'label'   => $label,

		);

		return $errors;

	}

	// If provided (required or optional), validate format and uniqueness.

	if ( $value !== '' ) {

		if ( strlen( $value ) < 3 ) {

			$errors[ $username_key ] = array(

				'message' => __( 'Username must be at least 3 characters.', 'wc-vendors-signup' ),

				'label'   => $label,

			);

			return $errors;

		}

		if ( $value !== sanitize_user( $value, true ) ) {

			$errors[ $username_key ] = array(

				'message' => __( 'Username contains invalid characters.', 'wc-vendors-signup' ),

				'label'   => $label,

			);

			return $errors;

		}

		if ( username_exists( $value ) ) {

			$errors[ $username_key ] = array(

				'message' => __( 'This username is already taken.', 'wc-vendors-signup' ),

				'label'   => $label,

			);

			return $errors;

		}

		$GLOBALS['wcv_signup_requested_username'] = $value; // store for step 3

	}

	return $errors;

}, 10, 2 );

add_filter( 'pre_user_login', function( $user_login ) {

	$is_wcv_signup = ( isset( $_POST['action'] ) && 'wcv_process_registration' === $_POST['action'] ) // phpcs:ignore

		|| isset( $_POST['wcv_registration_nonce'] ) // phpcs:ignore

		|| isset( $_POST['nonce'] ); // phpcs:ignore

	if ( ! $is_wcv_signup ) {

		return $user_login;

	}

	// Prefer the submitted value by the actual, active field key.

	$username_key = wcv_signup_get_username_field_key();

	if ( $username_key && isset( $_POST[ $username_key ] ) ) { // phpcs:ignore

		$requested = sanitize_user( (string) $_POST[ $username_key ], true ); // phpcs:ignore

		if ( $requested && ! username_exists( $requested ) ) {

			return $requested;

		}

	}

	// Fallback to the validated/stashed value if present.

	if ( ! empty( $GLOBALS['wcv_signup_requested_username'] ) ) {

		$requested = sanitize_user( (string) $GLOBALS['wcv_signup_requested_username'], true );

		if ( $requested && ! username_exists( $requested ) ) {

			return $requested;

		}

	}

	return $user_login;

}, 10 );