import { readFile } from 'node:fs/promises';
import { pathToFileURL } from 'node:url';
import { z } from 'zod';
import { VelrimClient, type VelrimClientOptions } from '@velrim/sdk';

export const Invoice = z.object({
	invoice_number: z.string(),
	total: z.number(),
	currency: z.enum(['USD', 'EUR']),
	po_number: z.string().nullable().optional(),
});

export async function extractInvoice(bytes: Uint8Array, options: VelrimClientOptions = {}) {
	const client = new VelrimClient(options);
	const result = await client.extract(Invoice, { bytes });
	// Validation enforces types. Field metadata describes extraction evidence.
	return { invoice: result.data, fields: result.fields, meta: result.meta };
}

if (process.argv[1] && import.meta.url === pathToFileURL(process.argv[1]).href) {
	const path = process.argv[2];
	if (!path) throw new Error('Usage: npx tsx invoice.ts invoice.pdf');
	const result = await extractInvoice(await readFile(path));
	// Content-free output; inspect invoice and fields inside your application.
	console.log({ request_id: result.meta.request_id, billed_pages: result.meta.billed_pages });
}