finance_app/app/Http/Controllers/Api/CategoryRuleController.php

<?php

namespace App\Http\Controllers\Api;

use App\Http\Controllers\Controller;
use App\Models\CategoryRule;
use Illuminate\Http\Request;
use Illuminate\Foundation\Auth\Access\AuthorizesRequests;

class CategoryRuleController extends Controller
{
    use AuthorizesRequests;

    /**
     * 新增自動分類規則
     * POST /api/category-rules
     */
    public function store(Request $request)
    {
        $validated = $request->validate([
            'keyword'     => 'required|string|max:255',
            'category_id' => 'required|exists:categories,id',
        ]);

        $rule = CategoryRule::create([
            ...$validated,
            'user_id' => $request->user()->id,
        ]);

        // 🟢 核心優化：必須預先載入 category 關聯，否則前端拿到這筆規則物件時，會無法渲染它的分類標籤
        $rule->load('category');

        return response()->json($rule, 201);
    }

    /**
     * 刪除自動分類規則
     * DELETE /api/category-rules/{categoryRule}
     */
    public function destroy(CategoryRule $categoryRule)
    {
        if ($categoryRule->user_id !== $request->user()->id) {
            return response()->json(['error' => '未經授權'], 403);
        }

        $categoryRule->delete();

        return response()->json(['message' => '自動分類規則刪除成功']);
    }
}