feat: Phase 2 - Frontend meta fields components (Level 1)

Implemented: Frontend Components for Level 1 Compatibility

Created Components:
- MetaFields.tsx - Generic meta field renderer
- useMetaFields.ts - Hook for field registry

Integrated Into:
- Orders/Edit.tsx - Meta fields after OrderForm
- Products/Edit.tsx - Meta fields after ProductForm

Features:
- Supports: text, textarea, number, date, select, checkbox
- Groups fields by section
- Zero coupling with specific plugins
- Renders any registered fields dynamically
- Read-only mode support

How It Works:
1. Backend exposes meta via API (Phase 1)
2. PHP registers fields via MetaFieldsRegistry (Phase 3 - next)
3. Fields localized to window.WooNooWMetaFields
4. useMetaFields hook reads registry
5. MetaFields component renders fields
6. User edits fields
7. Form submission includes meta
8. Backend saves via update_order_meta_data()

Result:
- Generic, reusable components
- Zero plugin-specific code
- Works with any registered fields
- Clean separation of concerns

Next: Phase 3 - PHP MetaFieldsRegistry system

admin-spa/src/components/MetaFields.tsx

@@ -0,0 +1,157 @@
+import { Card, CardContent, CardHeader, CardTitle } from '@/components/ui/card';
+import { Input } from '@/components/ui/input';
+import { Label } from '@/components/ui/label';
+import { Textarea } from '@/components/ui/textarea';
+import { Checkbox } from '@/components/ui/checkbox';
+import {
+  Select,
+  SelectContent,
+  SelectItem,
+  SelectTrigger,
+  SelectValue,
+} from '@/components/ui/select';
+
+export interface MetaField {
+  key: string;
+  label: string;
+  type: 'text' | 'textarea' | 'number' | 'select' | 'date' | 'checkbox';
+  options?: Array<{ value: string; label: string }>;
+  section?: string;
+  description?: string;
+  placeholder?: string;
+}
+
+interface MetaFieldsProps {
+  meta: Record<string, any>;
+  fields: MetaField[];
+  onChange: (key: string, value: any) => void;
+  readOnly?: boolean;
+}
+
+/**
+ * MetaFields Component
+ * 
+ * Generic component to display/edit custom meta fields from plugins.
+ * Part of Level 1 compatibility - allows plugins using standard WP/WooCommerce
+ * meta storage to have their fields displayed automatically.
+ * 
+ * Zero coupling with specific plugins - renders any registered fields.
+ */
+export function MetaFields({ meta, fields, onChange, readOnly = false }: MetaFieldsProps) {
+  // Don't render if no fields registered
+  if (fields.length === 0) {
+    return null;
+  }
+
+  // Group fields by section
+  const sections = fields.reduce((acc, field) => {
+    const section = field.section || 'Additional Fields';
+    if (!acc[section]) acc[section] = [];
+    acc[section].push(field);
+    return acc;
+  }, {} as Record<string, MetaField[]>);
+
+  return (
+    <div className="space-y-6">
+      {Object.entries(sections).map(([section, sectionFields]) => (
+        <Card key={section}>
+          <CardHeader>
+            <CardTitle>{section}</CardTitle>
+          </CardHeader>
+          <CardContent className="space-y-4">
+            {sectionFields.map((field) => (
+              <div key={field.key} className="space-y-2">
+                <Label htmlFor={field.key}>
+                  {field.label}
+                  {field.description && (
+                    <span className="text-xs text-muted-foreground ml-2">
+                      {field.description}
+                    </span>
+                  )}
+                </Label>
+
+                {field.type === 'text' && (
+                  <Input
+                    id={field.key}
+                    value={meta[field.key] || ''}
+                    onChange={(e) => onChange(field.key, e.target.value)}
+                    disabled={readOnly}
+                    placeholder={field.placeholder}
+                  />
+                )}
+
+                {field.type === 'textarea' && (
+                  <Textarea
+                    id={field.key}
+                    value={meta[field.key] || ''}
+                    onChange={(e) => onChange(field.key, e.target.value)}
+                    disabled={readOnly}
+                    placeholder={field.placeholder}
+                    rows={4}
+                  />
+                )}
+
+                {field.type === 'number' && (
+                  <Input
+                    id={field.key}
+                    type="number"
+                    value={meta[field.key] || ''}
+                    onChange={(e) => onChange(field.key, e.target.value)}
+                    disabled={readOnly}
+                    placeholder={field.placeholder}
+                  />
+                )}
+
+                {field.type === 'date' && (
+                  <Input
+                    id={field.key}
+                    type="date"
+                    value={meta[field.key] || ''}
+                    onChange={(e) => onChange(field.key, e.target.value)}
+                    disabled={readOnly}
+                  />
+                )}
+
+                {field.type === 'select' && field.options && (
+                  <Select
+                    value={meta[field.key] || ''}
+                    onValueChange={(value) => onChange(field.key, value)}
+                    disabled={readOnly}
+                  >
+                    <SelectTrigger id={field.key}>
+                      <SelectValue placeholder={field.placeholder || 'Select...'} />
+                    </SelectTrigger>
+                    <SelectContent>
+                      {field.options.map((opt) => (
+                        <SelectItem key={opt.value} value={opt.value}>
+                          {opt.label}
+                        </SelectItem>
+                      ))}
+                    </SelectContent>
+                  </Select>
+                )}
+
+                {field.type === 'checkbox' && (
+                  <div className="flex items-center space-x-2">
+                    <Checkbox
+                      id={field.key}
+                      checked={!!meta[field.key]}
+                      onCheckedChange={(checked) => onChange(field.key, checked)}
+                      disabled={readOnly}
+                    />
+                    <label
+                      htmlFor={field.key}
+                      className="text-sm cursor-pointer leading-none peer-disabled:cursor-not-allowed peer-disabled:opacity-70"
+                    >
+                      {field.placeholder || 'Enable'}
+                    </label>
+                  </div>
+                )}
+              </div>
+            ))}
+          </CardContent>
+        </Card>
+      ))}
+    </div>
+  );
+}

admin-spa/src/hooks/useMetaFields.ts

@@ -0,0 +1,70 @@
+import { useState, useEffect } from 'react';
+import type { MetaField } from '@/components/MetaFields';
+
+interface MetaFieldsRegistry {
+  orders: MetaField[];
+  products: MetaField[];
+}
+
+// Global registry exposed by PHP via wp_localize_script
+declare global {
+  interface Window {
+    WooNooWMetaFields?: MetaFieldsRegistry;
+  }
+}
+
+/**
+ * useMetaFields Hook
+ * 
+ * Retrieves registered meta fields from global registry (set by PHP).
+ * Part of Level 1 compatibility - allows plugins to register their fields
+ * via PHP filters, which are then exposed to the frontend.
+ * 
+ * Zero coupling with specific plugins - just reads the registry.
+ * 
+ * @param type - 'orders' or 'products'
+ * @returns Array of registered meta fields
+ * 
+ * @example
+ * ```tsx
+ * const metaFields = useMetaFields('orders');
+ * 
+ * return (
+ *   <MetaFields
+ *     meta={order.meta}
+ *     fields={metaFields}
+ *     onChange={handleMetaChange}
+ *   />
+ * );
+ * ```
+ */
+export function useMetaFields(type: 'orders' | 'products'): MetaField[] {
+  const [fields, setFields] = useState<MetaField[]>([]);
+
+  useEffect(() => {
+    // Get fields from global registry (set by PHP via wp_localize_script)
+    const registry = window.WooNooWMetaFields || { orders: [], products: [] };
+    setFields(registry[type] || []);
+
+    // Listen for dynamic field registration (for future extensibility)
+    const handleFieldsUpdated = (e: CustomEvent) => {
+      if (e.detail.type === type) {
+        setFields(e.detail.fields);
+      }
+    };
+
+    window.addEventListener(
+      'woonoow:meta_fields_updated',
+      handleFieldsUpdated as EventListener
+    );
+
+    return () => {
+      window.removeEventListener(
+        'woonoow:meta_fields_updated',
+        handleFieldsUpdated as EventListener
+      );
+    };
+  }, [type]);
+
+  return fields;
+}

admin-spa/src/routes/Orders/Edit.tsx

@@ -1,4 +1,4 @@
-import React, { useEffect, useRef } from 'react';
+import React, { useEffect, useRef, useState } from 'react';
 import { useParams, useNavigate } from 'react-router-dom';
 import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
 import OrderForm from '@/routes/Orders/partials/OrderForm';
@@ -10,6 +10,8 @@ import { __, sprintf } from '@/lib/i18n';
 import { usePageHeader } from '@/contexts/PageHeaderContext';
 import { Button } from '@/components/ui/button';
 import { useFABConfig } from '@/hooks/useFABConfig';
+import { MetaFields } from '@/components/MetaFields';
+import { useMetaFields } from '@/hooks/useMetaFields';
 
 export default function OrdersEdit() {
   const { id } = useParams();
@@ -19,6 +21,10 @@ export default function OrdersEdit() {
   const { setPageHeader, clearPageHeader } = usePageHeader();
   const formRef = useRef<HTMLFormElement>(null);
   
+  // Level 1 compatibility: Meta fields from plugins
+  const metaFields = useMetaFields('orders');
+  const [metaData, setMetaData] = useState<Record<string, any>>({});
+  
   // Hide FAB on edit page
   useFABConfig('none');
 
@@ -46,6 +52,13 @@ export default function OrdersEdit() {
   }, [countriesQ.data]);
 
   const order = orderQ.data || {};
+  
+  // Sync meta data from order
+  useEffect(() => {
+    if (order.meta) {
+      setMetaData(order.meta);
+    }
+  }, [order.meta]);
 
   // Set page header with back button and save button
   useEffect(() => {
@@ -104,11 +117,22 @@ export default function OrdersEdit() {
         formRef={formRef}
         hideSubmitButton={true}
         onSubmit={(form) => {
-          const payload = { ...form } as any;
+          const payload = { ...form, meta: metaData } as any;
           upd.mutate(payload);
         }}
       />
 
+      {/* Level 1 compatibility: Custom meta fields from plugins */}
+      {metaFields.length > 0 && (
+        <MetaFields
+          meta={metaData}
+          fields={metaFields}
+          onChange={(key, value) => {
+            setMetaData(prev => ({ ...prev, [key]: value }));
+          }}
+        />
+      )}
+
     </div>
   );
 }

admin-spa/src/routes/Products/Edit.tsx

@@ -1,4 +1,4 @@
-import React, { useRef, useEffect } from 'react';
+import React, { useRef, useEffect, useState } from 'react';
 import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
 import { useNavigate, useParams } from 'react-router-dom';
 import { api } from '@/lib/api';
@@ -11,6 +11,8 @@ import { Button } from '@/components/ui/button';
 import { ErrorCard } from '@/components/ErrorCard';
 import { getPageLoadErrorMessage } from '@/lib/errorHandling';
 import { Skeleton } from '@/components/ui/skeleton';
+import { MetaFields } from '@/components/MetaFields';
+import { useMetaFields } from '@/hooks/useMetaFields';
 
 export default function ProductEdit() {
   const { id } = useParams<{ id: string }>();
@@ -19,6 +21,10 @@ export default function ProductEdit() {
   const formRef = useRef<HTMLFormElement>(null);
   const { setPageHeader, clearPageHeader } = usePageHeader();
 
+  // Level 1 compatibility: Meta fields from plugins
+  const metaFields = useMetaFields('products');
+  const [metaData, setMetaData] = useState<Record<string, any>>({});
+
   // Hide FAB on edit product page
   useFABConfig('none');
 
@@ -48,7 +54,9 @@ export default function ProductEdit() {
   });
 
   const handleSubmit = async (data: ProductFormData) => {
-    await updateMutation.mutateAsync(data);
+    // Merge meta data with form data (Level 1 compatibility)
+    const payload = { ...data, meta: metaData };
+    await updateMutation.mutateAsync(payload);
   };
 
   // Set page header with back button and save button
@@ -95,6 +103,13 @@ export default function ProductEdit() {
 
   const product = productQ.data;
 
+  // Sync meta data from product
+  useEffect(() => {
+    if (product?.meta) {
+      setMetaData(product.meta);
+    }
+  }, [product?.meta]);
+
   return (
     <div className="space-y-4">
       <ProductForm
@@ -104,6 +119,17 @@ export default function ProductEdit() {
         formRef={formRef}
         hideSubmitButton={true}
       />
+
+      {/* Level 1 compatibility: Custom meta fields from plugins */}
+      {metaFields.length > 0 && (
+        <MetaFields
+          meta={metaData}
+          fields={metaFields}
+          onChange={(key, value) => {
+            setMetaData(prev => ({ ...prev, [key]: value }));
+          }}
+        />
+      )}
     </div>
   );
 }