import { afterAll, beforeAll, describe, expect, it } from 'vitest';
import { mkdtemp, mkdir, rm, symlink, writeFile } from 'node:fs/promises';
import { tmpdir } from 'node:os';
import path from 'node:path';
import { parseRange, safeResolve, streamFile } from './files';

let root: string;
beforeAll(async () => {
	root = await mkdtemp(path.join(tmpdir(), 'books-'));
	await mkdir(path.join(root, 'library', 'a'), { recursive: true });
	await writeFile(path.join(root, 'library', 'a', 'book.epub'), '0123456789');
	await writeFile(path.join(root, 'secret.txt'), 'nope');
	await symlink(path.join(root, 'secret.txt'), path.join(root, 'library', 'escape.epub'));
});
afterAll(() => rm(root, { recursive: true, force: true }));

describe('safeResolve', () => {
	it('finds files inside the library', async () => {
		expect(await safeResolve('library', 'a/book.epub', root)).toBe(
			path.join(root, 'library', 'a', 'book.epub')
		);
	});
	it.each([
		'../secret.txt',
		'a/../../secret.txt',
		'/etc/passwd',
		'escape.epub',
		'a',
		'',
		'missing.pdf'
	])('refuses %s', async (relative) => {
		expect(await safeResolve('library', relative, root)).toBeNull();
	});
});

describe('parseRange', () => {
	it('parses single ranges', () => {
		expect(parseRange('bytes=0-3', 10)).toEqual({ start: 0, end: 3 });
		expect(parseRange('bytes=5-', 10)).toEqual({ start: 5, end: 9 });
		expect(parseRange('bytes=-4', 10)).toEqual({ start: 6, end: 9 });
		expect(parseRange('bytes=8-100', 10)).toEqual({ start: 8, end: 9 });
	});
	it('ignores or rejects bad ranges', () => {
		expect(parseRange(null, 10)).toBeNull();
		expect(parseRange('bytes=0-1,4-5', 10)).toBeNull();
		expect(parseRange('bytes=10-', 10)).toBe('invalid');
		expect(parseRange('bytes=5-2', 10)).toBe('invalid');
	});
});

describe('streamFile', () => {
	const file = () => path.join(root, 'library', 'a', 'book.epub');
	it('serves the whole file', async () => {
		const res = await streamFile(file(), new Request('http://x/'), {});
		expect(res.status).toBe(200);
		expect(res.headers.get('content-type')).toBe('application/epub+zip');
		expect(await res.text()).toBe('0123456789');
	});
	it('serves partial content', async () => {
		const res = await streamFile(
			file(),
			new Request('http://x/', { headers: { range: 'bytes=2-4' } }),
			{}
		);
		expect(res.status).toBe(206);
		expect(res.headers.get('content-range')).toBe('bytes 2-4/10');
		expect(await res.text()).toBe('234');
	});
	it('answers 416 for unsatisfiable ranges', async () => {
		const res = await streamFile(
			file(),
			new Request('http://x/', { headers: { range: 'bytes=20-' } }),
			{}
		);
		expect(res.status).toBe(416);
	});
});