// ✅ DO: Explicit types
function calculateTotal(items: CartItem[]): number {
  return items.reduce((sum, item) => sum + item.price, 0)
}

// ❌ DON'T: Using 'any'
function processData(data: any) { }

// ✅ DO: Use type guards
function isCartItem(obj: unknown): obj is CartItem {
  return typeof obj === 'object' && obj !== null && 'price' in obj
}

// ✅ DO: Server Component (default)
export default async function DashboardPage() {
  const projects = await prisma.project.findMany()
  return <ProjectList projects={projects} />
}

// ✅ DO: Client Component (when needed)
'use client'
export function InteractiveButton() {
  const [count, setCount] = useState(0)
  return <button onClick={() => setCount(count + 1)}>{count}</button>
}

// ❌ DON'T: Async Client Component
'use client'
export default async function BadComponent() { } // ERROR

// ✅ DO: Validate all API input
import { z } from 'zod'

const createProjectSchema = z.object({
  name: z.string().min(1).max(100),
  description: z.string().optional(),
})

export async function POST(request: Request) {
  const body = await request.json()
  const validated = createProjectSchema.parse(body) // Throws if invalid
  // ... use validated data
}

// ❌ DON'T: Unvalidated input
export async function POST(request: Request) {
  const { name, description } = await request.json() // No validation
}

// ✅ DO: Use ShadCN UI components
import { Button } from "@/components/ui/button"
import { Dialog, DialogContent, DialogHeader, DialogTitle } from "@/components/ui/dialog"
import { Form, FormField, FormItem, FormLabel, FormControl } from "@/components/ui/form"

// ✅ DO: Use DialogTrigger with asChild
<DialogTrigger asChild>
  <Button>Open</Button>
</DialogTrigger>

// ❌ DON'T: Create custom buttons without ShadCN
<button className="px-4 py-2 bg-blue-500">Bad</button>

// ✅ DO: Use Form component with React Hook Form + Zod
const form = useForm<z.infer<typeof schema>>({
  resolver: zodResolver(schema),
})

<Form {...form}>
  <FormField ... />
</Form>

// ❌ DON'T: Use uncontrolled forms
<form>
  <input name="email" /> {/* No validation */}
</form>

// ❌ DON'T: Hardcoded secrets
const apiKey = 'sk_live_abc123'

// ✅ DO: Environment variables
const apiKey = process.env.OPENAI_API_KEY
if (!apiKey) throw new Error('OPENAI_API_KEY not configured')

// ❌ DON'T: SQL injection
const query = `SELECT * FROM users WHERE email = '${email}'`

// ✅ DO: Parameterized queries (Drizzle)
const user = await db.query.users.findFirst({ where: eq(users.email, email) })