WooCommerce

<?php
// functions.php or custom plugin

/**
 * Verify email at WooCommerce checkout
 */
add_action('woocommerce_checkout_process', 'emailverify_checkout_validation');

function emailverify_checkout_validation() {
    $email = sanitize_email($_POST['billing_email']);

    if (empty($email)) {
        return;
    }

    $result = emailverify_verify_email($email);

    if (!$result['success']) {
        // API error - allow checkout to proceed
        return;
    }

    $data = $result['data'];

    // Block invalid emails
    if ($data['status'] === 'invalid') {
        wc_add_notice(
            __('Please enter a valid email address to complete your order.', 'your-theme'),
            'error'
        );
    }

    // Block disposable emails (optional)
    if (get_option('emailverify_block_disposable', true)) {
        if ($data['result']['disposable'] ?? false) {
            wc_add_notice(
                __('Temporary email addresses are not accepted. Please use a permanent email.', 'your-theme'),
                'error'
            );
        }
    }
}

/**
 * EmailVerify API call helper
 */
function emailverify_verify_email($email) {
    $api_key = get_option('emailverify_api_key');

    // Check cache first
    $cache_key = 'bv_email_' . md5($email);
    $cached = get_transient($cache_key);

    if ($cached !== false) {
        return $cached;
    }

    $response = wp_remote_post('https://api.emailverify.ai/v1/verify', [
        'headers' => [
            'Authorization' => 'Bearer ' . $api_key,
            'Content-Type' => 'application/json',
        ],
        'body' => json_encode(['email' => $email]),
        'timeout' => 10,
    ]);

    if (is_wp_error($response)) {
        return ['success' => false, 'error' => $response->get_error_message()];
    }

    $body = json_decode(wp_remote_retrieve_body($response), true);
    $result = ['success' => true, 'data' => $body];

    // Cache for 24 hours
    set_transient($cache_key, $result, DAY_IN_SECONDS);

    return $result;
}

<?php
// Enqueue scripts
add_action('wp_enqueue_scripts', 'emailverify_wc_scripts');

function emailverify_wc_scripts() {
    if (!is_checkout()) {
        return;
    }

    wp_enqueue_script(
        'emailverify-checkout',
        get_template_directory_uri() . '/js/emailverify-checkout.js',
        ['jquery'],
        '1.0.0',
        true
    );

    wp_localize_script('emailverify-checkout', 'bv_checkout', [
        'ajax_url' => admin_url('admin-ajax.php'),
        'nonce' => wp_create_nonce('emailverify_checkout'),
    ]);
}

// AJAX handler
add_action('wp_ajax_verify_checkout_email', 'emailverify_ajax_checkout_verify');
add_action('wp_ajax_nopriv_verify_checkout_email', 'emailverify_ajax_checkout_verify');

function emailverify_ajax_checkout_verify() {
    check_ajax_referer('emailverify_checkout', 'nonce');

    $email = sanitize_email($_POST['email'] ?? '');

    if (empty($email)) {
        wp_send_json_error(['message' => 'Email is required']);
    }

    $result = emailverify_verify_email($email);

    if ($result['success']) {
        wp_send_json_success($result['data']);
    } else {
        wp_send_json_error(['message' => 'Verification failed']);
    }
}

// js/emailverify-checkout.js
jQuery(function($) {
    var $billingEmail = $('#billing_email');
    var verifyTimeout;
    var $status = $('<span class="bv-status"></span>');

    $billingEmail.after($status);

    $billingEmail.on('blur change', function() {
        var email = $(this).val();

        if (!email || !isValidEmailFormat(email)) {
            $status.html('').removeClass('valid invalid verifying');
            return;
        }

        clearTimeout(verifyTimeout);

        verifyTimeout = setTimeout(function() {
            verifyEmail(email);
        }, 500);
    });

    function verifyEmail(email) {
        $status.html('<span class="spinner"></span> Verifying...').addClass('verifying');

        $.ajax({
            url: bv_checkout.ajax_url,
            method: 'POST',
            data: {
                action: 'verify_checkout_email',
                nonce: bv_checkout.nonce,
                email: email
            },
            success: function(response) {
                $status.removeClass('verifying');

                if (response.success) {
                    var data = response.data;

                    if (data.status === 'valid') {
                        $status
                            .html('<span class="dashicons dashicons-yes"></span> Email verified')
                            .addClass('valid')
                            .removeClass('invalid');
                    } else if (data.status === 'invalid') {
                        $status
                            .html('<span class="dashicons dashicons-no"></span> Please enter a valid email')
                            .addClass('invalid')
                            .removeClass('valid');
                    } else if (data.result && data.result.disposable) {
                        $status
                            .html('<span class="dashicons dashicons-warning"></span> Please use a permanent email')
                            .addClass('invalid')
                            .removeClass('valid');
                    }
                }
            },
            error: function() {
                $status.html('').removeClass('verifying valid invalid');
            }
        });
    }

    function isValidEmailFormat(email) {
        return /^[^\s@]+@[^\s@]+\.[^\s@]+$/.test(email);
    }
});

/* style.css */
.bv-status {
    display: block;
    margin-top: 5px;
    font-size: 13px;
}

.bv-status.verifying {
    color: #666;
}

.bv-status.valid {
    color: #28a745;
}

.bv-status.invalid {
    color: #dc3545;
}

.bv-status .spinner {
    display: inline-block;
    width: 12px;
    height: 12px;
    border: 2px solid #ccc;
    border-top-color: #333;
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

<?php
/**
 * Verify email after order is created
 */
add_action('woocommerce_checkout_order_created', 'emailverify_verify_order_email');

function emailverify_verify_order_email($order) {
    $email = $order->get_billing_email();

    if (empty($email)) {
        return;
    }

    $result = emailverify_verify_email($email);

    if ($result['success']) {
        $data = $result['data'];

        // Store verification data as order meta
        $order->update_meta_data('_email_verification_status', $data['status']);
        $order->update_meta_data('_email_verification_score', $data['score'] ?? '');
        $order->update_meta_data('_email_is_disposable', $data['result']['disposable'] ? 'yes' : 'no');
        $order->update_meta_data('_email_verified_at', current_time('mysql'));
        $order->save();

        // Add order note
        if ($data['status'] === 'invalid') {
            $order->add_order_note(
                sprintf(
                    __('Warning: Customer email %s failed verification (Status: %s)', 'your-theme'),
                    $email,
                    $data['status']
                )
            );
        }
    }
}

/**
 * Display verification status in order details
 */
add_action('woocommerce_admin_order_data_after_billing_address', 'emailverify_show_order_email_status');

function emailverify_show_order_email_status($order) {
    $status = $order->get_meta('_email_verification_status');

    if (empty($status)) {
        return;
    }

    $score = $order->get_meta('_email_verification_score');
    $disposable = $order->get_meta('_email_is_disposable');

    $status_class = $status === 'valid' ? 'status-completed' : 'status-on-hold';

    echo '<div class="email-verification-status">';
    echo '<h3>' . __('Email Verification', 'your-theme') . '</h3>';
    echo '<p><strong>' . __('Status:', 'your-theme') . '</strong> ';
    echo '<mark class="order-status ' . esc_attr($status_class) . '">' . esc_html(ucfirst($status)) . '</mark></p>';

    if ($score) {
        echo '<p><strong>' . __('Score:', 'your-theme') . '</strong> ' . esc_html($score) . '</p>';
    }

    if ($disposable === 'yes') {
        echo '<p><span class="dashicons dashicons-warning" style="color: #d63638;"></span> ';
        echo __('Disposable email detected', 'your-theme') . '</p>';
    }

    echo '</div>';
}

<?php
/**
 * Add email status column to orders list
 */
add_filter('manage_edit-shop_order_columns', 'emailverify_orders_column');

function emailverify_orders_column($columns) {
    $new_columns = [];

    foreach ($columns as $key => $value) {
        $new_columns[$key] = $value;

        if ($key === 'order_status') {
            $new_columns['email_status'] = __('Email', 'your-theme');
        }
    }

    return $new_columns;
}

add_action('manage_shop_order_posts_custom_column', 'emailverify_orders_column_content', 10, 2);

function emailverify_orders_column_content($column, $post_id) {
    if ($column !== 'email_status') {
        return;
    }

    $order = wc_get_order($post_id);
    $status = $order->get_meta('_email_verification_status');

    if (empty($status)) {
        echo '<span class="dashicons dashicons-minus" title="Not verified"></span>';
        return;
    }

    if ($status === 'valid') {
        echo '<span class="dashicons dashicons-yes-alt" style="color: #28a745;" title="Valid"></span>';
    } else {
        echo '<span class="dashicons dashicons-dismiss" style="color: #dc3545;" title="Invalid"></span>';
    }

    $disposable = $order->get_meta('_email_is_disposable');
    if ($disposable === 'yes') {
        echo '<span class="dashicons dashicons-warning" style="color: #d63638;" title="Disposable"></span>';
    }
}

<?php
/**
 * Register REST API endpoint for email verification
 */
add_action('rest_api_init', 'emailverify_register_wc_endpoint');

function emailverify_register_wc_endpoint() {
    register_rest_route('emailverify/v1', '/verify-checkout', [
        'methods' => 'POST',
        'callback' => 'emailverify_rest_verify_checkout',
        'permission_callback' => '__return_true',
        'args' => [
            'email' => [
                'required' => true,
                'type' => 'string',
                'format' => 'email',
                'sanitize_callback' => 'sanitize_email',
            ],
        ],
    ]);
}

function emailverify_rest_verify_checkout($request) {
    $email = $request->get_param('email');

    // Rate limiting
    $ip = $_SERVER['REMOTE_ADDR'];
    $rate_key = 'bv_rate_' . md5($ip);
    $rate_count = get_transient($rate_key) ?: 0;

    if ($rate_count >= 20) {
        return new WP_Error(
            'rate_limited',
            'Too many verification requests',
            ['status' => 429]
        );
    }

    set_transient($rate_key, $rate_count + 1, MINUTE_IN_SECONDS);

    // Verify email
    $result = emailverify_verify_email($email);

    if (!$result['success']) {
        return new WP_Error(
            'verification_failed',
            'Email verification failed',
            ['status' => 503]
        );
    }

    $data = $result['data'];

    return new WP_REST_Response([
        'valid' => $data['status'] === 'valid',
        'status' => $data['status'],
        'disposable' => $data['result']['disposable'] ?? false,
        'score' => $data['score'] ?? null,
    ], 200);
}

// Headless checkout verification
async function verifyCheckoutEmail(email) {
    const response = await fetch('/wp-json/emailverify/v1/verify-checkout', {
        method: 'POST',
        headers: {
            'Content-Type': 'application/json',
        },
        body: JSON.stringify({ email }),
    });

    if (!response.ok) {
        if (response.status === 429) {
            throw new Error('Too many requests. Please wait.');
        }
        throw new Error('Verification failed');
    }

    return response.json();
}

// Usage
try {
    const result = await verifyCheckoutEmail('customer@example.com');

    if (!result.valid) {
        showError('Please enter a valid email address');
    } else if (result.disposable) {
        showError('Please use a permanent email address');
    } else {
        proceedToPayment();
    }
} catch (error) {
    // Allow checkout on error
    proceedToPayment();
}

<?php
/**
 * WP-CLI command for bulk customer verification
 */
if (defined('WP_CLI') && WP_CLI) {
    WP_CLI::add_command('emailverify verify-customers', function($args, $assoc_args) {
        $batch_size = $assoc_args['batch'] ?? 100;
        $dry_run = isset($assoc_args['dry-run']);

        global $wpdb;

        // Get customers without verification status
        $customers = $wpdb->get_results("
            SELECT DISTINCT pm.meta_value as email, pm.post_id as order_id
            FROM {$wpdb->postmeta} pm
            LEFT JOIN {$wpdb->postmeta} pm2 ON pm.post_id = pm2.post_id
                AND pm2.meta_key = '_email_verification_status'
            WHERE pm.meta_key = '_billing_email'
            AND pm.meta_value != ''
            AND pm2.meta_id IS NULL
            LIMIT {$batch_size}
        ");

        if (empty($customers)) {
            WP_CLI::success('All customers are verified!');
            return;
        }

        WP_CLI::log(sprintf('Found %d customers to verify', count($customers)));

        $progress = \WP_CLI\Utils\make_progress_bar('Verifying', count($customers));

        $stats = ['valid' => 0, 'invalid' => 0, 'error' => 0];

        foreach ($customers as $customer) {
            $result = emailverify_verify_email($customer->email);

            if ($result['success']) {
                $status = $result['data']['status'];
                $stats[$status === 'valid' ? 'valid' : 'invalid']++;

                if (!$dry_run) {
                    update_post_meta($customer->order_id, '_email_verification_status', $result['data']['status']);
                    update_post_meta($customer->order_id, '_email_verification_score', $result['data']['score'] ?? '');
                }
            } else {
                $stats['error']++;
            }

            $progress->tick();

            // Rate limiting
            usleep(100000); // 100ms delay
        }

        $progress->finish();

        WP_CLI::success(sprintf(
            'Verification complete: %d valid, %d invalid, %d errors',
            $stats['valid'],
            $stats['invalid'],
            $stats['error']
        ));
    });
}

# Verify 100 customers (default)
wp emailverify verify-customers

# Verify 500 customers
wp emailverify verify-customers --batch=500

# Dry run (no database changes)
wp emailverify verify-customers --dry-run

<?php
/**
 * Flag high-risk orders based on email verification
 */
add_action('woocommerce_checkout_order_processed', 'emailverify_fraud_check', 10, 3);

function emailverify_fraud_check($order_id, $posted_data, $order) {
    $risk_score = 0;
    $risk_reasons = [];

    $email = $order->get_billing_email();
    $result = emailverify_verify_email($email);

    if ($result['success']) {
        $data = $result['data'];

        // Invalid email = high risk
        if ($data['status'] === 'invalid') {
            $risk_score += 50;
            $risk_reasons[] = 'Invalid email address';
        }

        // Disposable email = high risk
        if ($data['result']['disposable'] ?? false) {
            $risk_score += 40;
            $risk_reasons[] = 'Disposable email detected';
        }

        // Low score = medium risk
        if (($data['score'] ?? 1) < 0.5) {
            $risk_score += 20;
            $risk_reasons[] = 'Low email score';
        }

        // Role-based email = slight risk
        if ($data['result']['role'] ?? false) {
            $risk_score += 10;
            $risk_reasons[] = 'Role-based email address';
        }
    }

    // Store risk assessment
    $order->update_meta_data('_fraud_risk_score', $risk_score);
    $order->update_meta_data('_fraud_risk_reasons', $risk_reasons);

    // Flag high-risk orders for manual review
    if ($risk_score >= 50) {
        $order->set_status('on-hold', __('High fraud risk - manual review required', 'your-theme'));

        // Notify admin
        $admin_email = get_option('admin_email');
        wp_mail(
            $admin_email,
            sprintf(__('High-Risk Order #%s Needs Review', 'your-theme'), $order_id),
            sprintf(
                __("Order #%s has been flagged as high risk.\n\nRisk Score: %d\nReasons:\n- %s\n\nPlease review the order.", 'your-theme'),
                $order_id,
                $risk_score,
                implode("\n- ", $risk_reasons)
            )
        );
    }

    $order->save();
}

// Always allow checkout if API fails
$result = emailverify_verify_email($email);

if (!$result['success']) {
    error_log('EmailVerify API error: ' . ($result['error'] ?? 'Unknown'));
    return; // Don't block checkout
}

// Cache verification results to reduce API calls
$cache_key = 'bv_email_' . md5($email);
$cached = get_transient($cache_key);

if ($cached !== false) {
    return $cached;
}

// ... make API call ...

set_transient($cache_key, $result, DAY_IN_SECONDS);

// Provide helpful, non-technical error messages
$messages = [
    'invalid' => __('This email address appears to be invalid. Please check and try again.', 'your-theme'),
    'disposable' => __('Temporary email addresses cannot be used for orders. Please use your regular email.', 'your-theme'),
];