Writing Prompts That Generate APIs with Lovable

// Vague prompt — AI guesses the schema, probably wrong
// "Create a database for my e-commerce app"

// Specific prompt that produces the exact schema you need:
//
// "Create these database tables for my e-commerce app:
//
//  1. categories table:
//     - id (uuid, primary key, auto-generated)
//     - name (text, required, unique)
//     - slug (text, required, unique)
//
//  2. products table:
//     - id (uuid, primary key, auto-generated)
//     - name (text, required)
//     - description (text, optional)
//     - price (numeric, required, must be >= 0)
//     - image_url (text, optional)
//     - category_id (uuid, foreign key to categories.id)
//     - in_stock (boolean, default true)
//     - created_at (timestamptz, auto-set to now)
//
//  3. orders table:
//     - id (uuid, primary key, auto-generated)
//     - user_id (uuid, foreign key to auth.users, required)
//     - total_amount (numeric, required)
//     - status (text, default 'pending', allowed: pending/confirmed/shipped/delivered)
//     - created_at (timestamptz, auto-set)
//
//  Add RLS policies:
//  - Anyone can read products and categories
//  - Only authenticated users can create orders
//  - Users can only read their own orders"

// Vague prompt — AI creates a generic CRUD endpoint
// "Create an API for products"

// Specific endpoint prompt:
//
// "Create a Supabase Edge Function called 'get-products' that:
//  - Accepts GET requests
//  - Query parameters: category (optional string), limit (optional number, default 20, max 100),
//    offset (optional number, default 0)
//  - Queries the products table joined with categories
//  - Filters by category slug if the category parameter is provided
//  - Only returns in-stock products (in_stock = true)
//  - Returns JSON: { data: [{ id, name, price, image_url, category_name }], total: number }
//  - Handles errors: return 400 for invalid parameters, 500 for database errors
//  - Does not require authentication (products are public)"

// No authentication or validation — anyone can create orders with any data
serve(async (req) => {
  const body = await req.json();
  const { data } = await supabase.from("orders").insert(body);
  return new Response(JSON.stringify(data));
});

// Authenticated, validated write endpoint
import { serve } from "https://deno.land/std@0.168.0/http/server.ts";
import { createClient } from "https://esm.sh/@supabase/supabase-js@2";
serve(async (req) => {
  try {
    // Verify authentication
    const authHeader = req.headers.get("Authorization");
    if (!authHeader) {
      return new Response(JSON.stringify({ error: "Not authenticated" }), { status: 401 });
    }
    const supabase = createClient(
      Deno.env.get("SUPABASE_URL")!,
      Deno.env.get("SUPABASE_ANON_KEY")!,
      { global: { headers: { Authorization: authHeader } } }
    );
    const { data: { user } } = await supabase.auth.getUser();
    if (!user) {
      return new Response(JSON.stringify({ error: "Invalid token" }), { status: 401 });
    }
    // Validate input
    const { products } = await req.json();
    if (!products || !Array.isArray(products) || products.length === 0) {
      return new Response(
        JSON.stringify({ error: "Products array is required" }),
        { status: 400 }
      );
    }
    // Calculate total and create order
    const { data: order, error } = await supabase
      .from("orders")
      .insert({ user_id: user.id, total_amount: 0, status: "pending" })
      .select()
      .single();
    if (error) throw error;
    return new Response(JSON.stringify({ orderId: order.id }), {
      headers: { "Content-Type": "application/json" },
    });
  } catch (err) {
    console.error("Create order error:", err.message);
    return new Response(JSON.stringify({ error: "Failed to create order" }), { status: 500 });
  }
});

// Frontend component with no data connection
function ProductList() {
  return <div>Products will go here</div>;
}

// Prompt to connect the API:
// "Update @src/pages/Products.tsx to:
//  1. Call the get-products Edge Function on page load
//  2. Display products in a 3-column grid using shadcn/ui Cards
//  3. Add a category filter dropdown at the top
//  4. Add pagination (20 products per page)
//  5. Show a loading spinner while data is being fetched
//  6. Show an error message if the API call fails
//  Use supabase.functions.invoke('get-products', { body: { category, limit, offset } })"