WordPress 註冊表單自訂：多問幾個欄位、讓使用者自己設密碼（含 WooCommerce 我的帳號）

// 1. 註冊表單多三個欄位：姓名、手機、自己設定密碼
add_action( 'register_form', function () {
	$name  = sanitize_text_field( wp_unslash( $_POST['zw_name'] ?? '' ) );
	$phone = sanitize_text_field( wp_unslash( $_POST['zw_phone'] ?? '' ) );
	?>
	<p>
		<label for="zw_name">姓名</label>
		<input type="text" name="zw_name" id="zw_name" class="input" value="<?php echo esc_attr( $name ); ?>" autocomplete="name">
	</p>
	<p>
		<label for="zw_phone">手機（選填）</label>
		<input type="tel" name="zw_phone" id="zw_phone" class="input" value="<?php echo esc_attr( $phone ); ?>" autocomplete="tel" placeholder="0912345678">
	</p>
	<p>
		<label for="zw_pass1">密碼（至少 8 個字元）</label>
		<input type="password" name="zw_pass1" id="zw_pass1" class="input" autocomplete="new-password">
	</p>
	<p>
		<label for="zw_pass2">再輸入一次密碼</label>
		<input type="password" name="zw_pass2" id="zw_pass2" class="input" autocomplete="new-password">
	</p>
	<?php
} );

// 2. 送出時檢查欄位，有錯就擋下來
add_filter( 'registration_errors', function ( $errors ) {
	$name  = trim( sanitize_text_field( wp_unslash( $_POST['zw_name'] ?? '' ) ) );
	$phone = trim( sanitize_text_field( wp_unslash( $_POST['zw_phone'] ?? '' ) ) );
	$pass1 = wp_unslash( $_POST['zw_pass1'] ?? '' );
	$pass2 = wp_unslash( $_POST['zw_pass2'] ?? '' );
	if ( '' === $name ) {
		$errors->add( 'zw_name', '<strong>錯誤</strong>：請填寫姓名。' );
	}
	if ( '' !== $phone && ! preg_match( '/^09\d{8}$/', $phone ) ) {
		$errors->add( 'zw_phone', '<strong>錯誤</strong>：手機請填 09 開頭的 10 位數字。' );
	}
	if ( strlen( $pass1 ) < 8 ) {
		$errors->add( 'zw_pass', '<strong>錯誤</strong>：密碼至少要 8 個字元。' );
	} elseif ( $pass1 !== $pass2 ) {
		$errors->add( 'zw_pass', '<strong>錯誤</strong>：兩次輸入的密碼不一樣。' );
	}
	return $errors;
} );

// 3. 註冊成功：存姓名、手機，改成使用者自己設的密碼
add_action( 'register_new_user', function ( $user_id ) {
	wp_update_user( array(
		'ID'           => $user_id,
		'first_name'   => sanitize_text_field( wp_unslash( $_POST['zw_name'] ?? '' ) ),
		'display_name' => sanitize_text_field( wp_unslash( $_POST['zw_name'] ?? '' ) ),
	) );
	update_user_meta( $user_id, 'zw_phone', sanitize_text_field( wp_unslash( $_POST['zw_phone'] ?? '' ) ) );
	wp_set_password( wp_unslash( $_POST['zw_pass1'] ), $user_id );
}, 5 );

// 4. 密碼已經自己設了，就不要再寄「設定密碼」的連結給新會員，只通知管理員
remove_action( 'register_new_user', 'wp_send_new_user_notifications' );
add_action( 'register_new_user', function ( $user_id ) {
	wp_new_user_notification( $user_id, null, 'admin' );
} );

// 5. 註冊完成的提示改成「可以直接登入」
add_filter( 'registration_redirect', function () {
	return add_query_arg( 'zw-registered', '1', wp_login_url() );
} );
add_filter( 'login_message', function ( $message ) {
	if ( isset( $_GET['zw-registered'] ) ) {
		$message .= '<p class="message">註冊完成，請用剛才設定的密碼登入。</p>';
	}
	return $message;
} );

// 後台「個人資料」頁顯示手機，管理員也可以修改
function zw_profile_phone_field( $user ) {
	?>
	<h2>聯絡資料</h2>
	<table class="form-table" role="presentation">
		<tr>
			<th><label for="zw_phone">手機</label></th>
			<td><input type="tel" name="zw_phone" id="zw_phone" class="regular-text" value="<?php echo esc_attr( get_user_meta( $user->ID, 'zw_phone', true ) ); ?>"></td>
		</tr>
	</table>
	<?php
}
add_action( 'show_user_profile', 'zw_profile_phone_field' );
add_action( 'edit_user_profile', 'zw_profile_phone_field' );

function zw_profile_phone_save( $user_id ) {
	if ( current_user_can( 'edit_user', $user_id ) && isset( $_POST['zw_phone'] ) ) {
		update_user_meta( $user_id, 'zw_phone', sanitize_text_field( wp_unslash( $_POST['zw_phone'] ) ) );
	}
}
add_action( 'personal_options_update', 'zw_profile_phone_save' );
add_action( 'edit_user_profile_update', 'zw_profile_phone_save' );

// WooCommerce「我的帳號」註冊表單：最上面加姓名、手機
add_action( 'woocommerce_register_form_start', function () {
	$name  = sanitize_text_field( wp_unslash( $_POST['billing_first_name'] ?? '' ) );
	$phone = sanitize_text_field( wp_unslash( $_POST['billing_phone'] ?? '' ) );
	?>
	<p class="form-row form-row-wide">
		<label for="reg_billing_first_name">姓名&nbsp;<span class="required">*</span></label>
		<input type="text" class="input-text" name="billing_first_name" id="reg_billing_first_name" value="<?php echo esc_attr( $name ); ?>" autocomplete="name">
	</p>
	<p class="form-row form-row-wide">
		<label for="reg_billing_phone">手機</label>
		<input type="tel" class="input-text" name="billing_phone" id="reg_billing_phone" value="<?php echo esc_attr( $phone ); ?>" autocomplete="tel" placeholder="0912345678">
	</p>
	<?php
} );

// 密碼欄位下面加「再輸入一次密碼」（後台設定讓顧客自己設密碼時才會有密碼欄）
add_action( 'woocommerce_register_form', function () {
	if ( 'no' !== get_option( 'woocommerce_registration_generate_password' ) ) {
		return;
	}
	?>
	<p class="form-row form-row-wide">
		<label for="reg_password2">再輸入一次密碼&nbsp;<span class="required">*</span></label>
		<input type="password" class="input-text" name="zw_password2" id="reg_password2" autocomplete="new-password">
	</p>
	<?php
} );

// 檢查欄位
add_action( 'woocommerce_register_post', function ( $username, $email, $errors ) {
	$name  = trim( sanitize_text_field( wp_unslash( $_POST['billing_first_name'] ?? '' ) ) );
	$phone = trim( sanitize_text_field( wp_unslash( $_POST['billing_phone'] ?? '' ) ) );
	if ( '' === $name ) {
		$errors->add( 'zw_name', '請填寫姓名。' );
	}
	if ( '' !== $phone && ! preg_match( '/^09\d{8}$/', $phone ) ) {
		$errors->add( 'zw_phone', '手機請填 09 開頭的 10 位數字。' );
	}
	if ( 'no' === get_option( 'woocommerce_registration_generate_password' )
		&& wp_unslash( $_POST['password'] ?? '' ) !== wp_unslash( $_POST['zw_password2'] ?? '' ) ) {
		$errors->add( 'zw_password2', '兩次輸入的密碼不一樣。' );
	}
}, 10, 3 );

// 存成 WooCommerce 的帳單姓名、電話，結帳時會自動帶入
add_action( 'woocommerce_created_customer', function ( $customer_id ) {
	$customer = new WC_Customer( $customer_id );
	$name     = sanitize_text_field( wp_unslash( $_POST['billing_first_name'] ?? '' ) );
	$customer->set_first_name( $name );
	$customer->set_display_name( $name );
	$customer->set_billing_first_name( $name );
	$customer->set_billing_phone( sanitize_text_field( wp_unslash( $_POST['billing_phone'] ?? '' ) ) );
	$customer->save();
} );