import { readFile, writeFile } from 'node:fs/promises';
import { pathToFileURL } from 'node:url';
import { createHash } from 'node:crypto';
import { VelrimClient, type PollOptions } from '@velrim/sdk';

// Raw JSON Schema preserves partial data; validate before a downstream write.
export const schema = {
	type: 'object',
	properties: { invoice_number: { type: 'string' }, total: { type: 'number' } },
	required: ['invoice_number', 'total'],
	additionalProperties: false,
};

export async function submitJob(
	client: VelrimClient,
	bytes: Uint8Array,
	idempotencyKey: string,
	save: (receipt: { job_id: string; request_id: string }) => Promise<void>,
) {
	if (!idempotencyKey || idempotencyKey.length > 255)
		throw new Error('Supply a stable request key (1–255 characters).');
	const job = await client.jobs.create(schema, { bytes }, { idempotencyKey });
	// Persist before polling. A rejected save must reach the caller.
	await save({ job_id: job.job_id, request_id: job.request_id });
	return job;
}

export function resumeJob(client: VelrimClient, jobId: string, options: PollOptions = {}) {
	return client.jobs.poll(jobId, schema, { intervalMs: 1500, timeoutMs: 60_000, ...options });
}

if (process.argv[1] && import.meta.url === pathToFileURL(process.argv[1]).href) {
	const [mode, receiptPath, pdfPath, key] = process.argv.slice(2);
	if (
		!receiptPath ||
		(mode !== 'submit' && mode !== 'resume') ||
		(mode === 'submit' && (!pdfPath || !key))
	) {
		throw new Error(
			'Usage: npx tsx async-extraction.ts submit receipt.json invoice.pdf stable-key | resume receipt.json',
		);
	}
	const client = new VelrimClient();
	if (mode === 'submit') {
		const bytes = await readFile(pdfPath);
		const pending = {
			idempotency_key: key,
			created_at: new Date().toISOString(),
			document_sha256: createHash('sha256').update(bytes).digest('hex'),
			schema,
		};
		// Exclusive creation prevents accidental reuse of an existing receipt file.
		await writeFile(receiptPath, JSON.stringify(pending, null, 2), {
			encoding: 'utf8',
			flag: 'wx',
		});
		await submitJob(client, bytes, key, async (job) => {
			await writeFile(receiptPath, JSON.stringify({ ...pending, ...job }, null, 2), 'utf8');
		});
		console.log({ next: 'resume', receipt: receiptPath });
	} else {
		const receipt: unknown = JSON.parse(await readFile(receiptPath, 'utf8'));
		if (
			typeof receipt !== 'object' ||
			receipt === null ||
			!('job_id' in receipt) ||
			typeof receipt.job_id !== 'string' ||
			!receipt.job_id
		) {
			throw new Error(
				'Pending receipt: reconcile submission using the original key and exact body; do not create a new key.',
			);
		}
		const result = await resumeJob(client, receipt.job_id);
		await writeFile(
			`${receiptPath}.result.json`,
			JSON.stringify({ data: result.data, fields: result.fields, meta: result.meta }, null, 2),
			{ encoding: 'utf8', flag: 'wx' },
		);
		console.log({ request_id: result.meta.request_id, billed_pages: result.meta.billed_pages });
	}
}