nextjs-dashboard/app/lib/actions.ts

'use server';

import { redirect } from 'next/navigation';
import { revalidatePath } from 'next/cache';
import { sql } from '@vercel/postgres';
import { signIn } from '@/auth';
import { z } from 'zod';

const FormSchema = z.object({
	id: z.string(),
	customerId: z.string({
		invalid_type_error: "Please select a customer.",
	}),
	amount: z.coerce
		.number()
		.gt(0, { message: "Please enter an amoint greater than $0." }),
	status: z.enum(["pending", "paid"], {
		invalid_type_error: "Please select an invoice status.",
	}),
	date: z.string(),
});

const CreateInvoice = FormSchema.omit({ id: true, date: true });
const UpdateInvoice = FormSchema.omit({ date: true });
const DeleteInvoice = FormSchema.pick({ id: true });

export type State = {
	errors?: {
		customerId?: string[];
		amount?: string[];
		status?: string[];
	};
	message?: string | null;
}

export async function createInvoice(prevState: State, formData: FormData) {
	// Validate form using Zod
	const validatedFields = CreateInvoice.safeParse({
		customerId: formData.get("customerId"),
		amount: formData.get("amount"),
		status: formData.get("status"),
	});

	// If form validation fails, return errors early. Otherwise, continue.
	if (!validatedFields.success) {
		return {
			errors: validatedFields.error.flatten().fieldErrors,
			message: "Missing Fields. Failed to Create Invoice.",
		};
	}

	// Prepare data for insertion into the database
	const { customerId, amount, status } = validatedFields.data;
	const amountInCents = amount * 100;
	const date = new Date().toISOString().split("T")[0];

	// Insert data into the database
	try {
		await sql`
      INSERT INTO invoices (customer_id, amount, status, date)
      VALUES (${customerId}, ${amountInCents}, ${status}, ${date})
    `;
	} catch (error) {
		// If a database error occurs, return a more specific error.
		return {
			message: "Database Error: Failed to Create Invoice.",
		};
	}

	// Revalidate the cache for the invoices page and redirect the user.
	revalidatePath("/dashboard/invoices");
	redirect("/dashboard/invoices");
}

export async function updateInvoice(prevState: State, formData: FormData) {
	const validatedFields = UpdateInvoice.safeParse({
		id: formData.get("id"),
		customerId: formData.get("customerId"),
		amount: formData.get("amount"),
		status: formData.get("status"),
	});

	if (!validatedFields.success) {
		return {
			errors: validatedFields.error.flatten().fieldErrors,
			message: "Missing Fields. Failed to Update Invoice.",
		};
	}

	const { id, customerId, amount, status } = validatedFields.data;
	const amountInCents = amount * 100;

	try {
		await sql`
      UPDATE invoices
      SET customer_id = ${customerId}, amount = ${amountInCents}, status = ${status}
      WHERE id = ${id}
    `;
	} catch (error) {
		return { message: "Database Error: Failed to Update Invoice." };
	}

	revalidatePath("/dashboard/invoices");
	redirect("/dashboard/invoices");
}

export async function deleteInvoice(formData: FormData) {
	 const { id } = DeleteInvoice.parse({
			id: formData.get("id"),
	 });

	try {
		await sql`DELETE FROM invoices WHERE id = ${id}`;
	} catch (error) {
		return {
			message: 'Database Error: Failed to Delete Invoice.'
		}
	}

	revalidatePath('/dashboard/invoices');
}

export async function authenticate(
	prevState: string | undefined,
	formData: FormData
) {
	try {
		await signIn("credentials", Object.fromEntries(formData));
	} catch (error) {
		if ((error as Error).message.includes("CredentialsSignin")) {
			return "CredentialSignin";
		}
		throw error;
	}
}