<?php
function caz_get_product_sales_history( int $product_id, int $days = 90 ): array {
    global $wpdb;

    // Query WooCommerce order items for WooCommerce AI inventory forecast data
    $results = $wpdb->get_results( $wpdb->prepare(
        "SELECT DATE(p.post_date) as sale_date, SUM(oi_meta.meta_value) as qty
         FROM {$wpdb->prefix}woocommerce_order_items oi
         JOIN {$wpdb->prefix}woocommerce_order_itemmeta oi_meta
           ON oi.order_item_id = oi_meta.order_item_id AND oi_meta.meta_key = '_qty'
         JOIN {$wpdb->prefix}woocommerce_order_itemmeta oi_meta2
           ON oi.order_item_id = oi_meta2.order_item_id AND oi_meta2.meta_key = '_product_id'
         JOIN {$wpdb->prefix}posts p ON oi.order_id = p.ID
         WHERE oi_meta2.meta_value = %d
           AND p.post_status IN ('wc-completed', 'wc-processing')
           AND p.post_date >= DATE_SUB(NOW(), INTERVAL %d DAY)
         GROUP BY DATE(p.post_date)
         ORDER BY sale_date ASC",
        $product_id, $days
    ));

    return array_column( $results, 'qty', 'sale_date' );
}

function caz_ai_inventory_forecast( int $product_id ): array {
    $product       = wc_get_product( $product_id );
    $current_stock = $product->get_stock_quantity();
    $sales_history = caz_get_product_sales_history( $product_id, 90 );
    $lead_time_days = (int) get_post_meta( $product_id, '_supplier_lead_days', true ) ?: 14;

    $prompt = "You are a WooCommerce AI inventory forecast assistant.
Product: {$product->get_name()}
Current stock: {$current_stock} units
Supplier lead time: {$lead_time_days} days
Sales history (date: units sold): " . json_encode( $sales_history ) . "

Analyse this data and return a JSON object with:
- daily_avg: average daily sales rate
- weekly_avg: average weekly sales
- trend: 'increasing', 'stable', or 'decreasing'
- days_until_stockout: estimated days at current trend
- reorder_date: recommended reorder date (YYYY-MM-DD)
- suggested_reorder_qty: units to order to cover 60 days
- confidence: 'high', 'medium', or 'low'
Return only valid JSON, no explanation.";

    $response = wp_remote_post( 'https://api.anthropic.com/v1/messages', [
        'headers' => [
            'x-api-key'         => get_option( 'caz_claude_api_key' ),
            'anthropic-version' => '2023-06-01',
            'Content-Type'      => 'application/json',
        ],
        'body' => wp_json_encode([
            'model'      => 'claude-haiku-4-5-20251001',
            'max_tokens' => 300,
            'messages'   => [[ 'role' => 'user', 'content' => $prompt ]],
        ]),
        'timeout' => 30,
    ]);

    $body = json_decode( wp_remote_retrieve_body( $response ), true );
    $json_str = $body['content'][0]['text'] ?? '{}';
    return json_decode( $json_str, true ) ?: [];
}

<?php
// Schedule WooCommerce AI inventory forecast daily at 6am
add_action( 'init', function() {
    if ( ! as_next_scheduled_action( 'caz_run_inventory_forecast' ) ) {
        as_schedule_recurring_action( strtotime('tomorrow 6am'), DAY_IN_SECONDS, 'caz_run_inventory_forecast' );
    }
});

add_action( 'caz_run_inventory_forecast', function() {
    $at_risk = [];

    $products = wc_get_products([
        'limit'        => -1,
        'stock_status' => 'instock',
        'manage_stock' => true,
        'return'       => 'ids',
    ]);

    foreach ( $products as $product_id ) {
        $forecast = caz_ai_inventory_forecast( $product_id );
        if ( empty( $forecast['days_until_stockout'] ) ) continue;

        $lead_time = (int) get_post_meta( $product_id, '_supplier_lead_days', true ) ?: 14;

        // Alert if stockout is predicted within lead time
        if ( $forecast['days_until_stockout'] <= $lead_time + 7 ) {
            $product = wc_get_product( $product_id );
            $at_risk[] = [
                'name'            => $product->get_name(),
                'stock'           => $product->get_stock_quantity(),
                'days_remaining'  => $forecast['days_until_stockout'],
                'reorder_by'      => $forecast['reorder_date'],
                'suggested_order' => $forecast['suggested_reorder_qty'],
            ];
        }
        sleep(1); // Respect AI API rate limits
    }

    if ( ! empty( $at_risk ) ) {
        // Send WooCommerce AI inventory forecast alert email
        $message = "WooCommerce AI Inventory Forecast Alertnn";
        foreach ( $at_risk as $item ) {
            $message .= "Product: {$item['name']}n";
            $message .= "  Stock: {$item['stock']} units ({$item['days_remaining']} days remaining)n";
            $message .= "  Reorder by: {$item['reorder_by']}n";
            $message .= "  Suggested order: {$item['suggested_order']} unitsnn";
        }
        wp_mail( get_option('admin_email'), 'Inventory Reorder Alert', $message );
    }
});