const test = require('node:test');
const assert = require('node:assert/strict');
const fs = require('node:fs');
const path = require('node:path');
const vm = require('node:vm');
const zlib = require('node:zlib');

const runtime = {window: {}, Blob, Response, DecompressionStream, TextDecoder, Uint8Array};
vm.createContext(runtime);
vm.runInContext(fs.readFileSync(path.join(__dirname, 'docview.js'), 'utf8'), runtime);

function pdfWithStream(content, compressed = false) {
  const stream = compressed ? zlib.deflateSync(Buffer.from(content, 'latin1')) : Buffer.from(content, 'latin1');
  const filter = compressed ? ' /Filter /FlateDecode' : '';
  const prefix = `%PDF-1.4\n1 0 obj\n<< /Length ${stream.length}${filter} >>\nstream\n`;
  return Buffer.concat([Buffer.from(prefix, 'latin1'), stream, Buffer.from('\nendstream\nendobj\n%%EOF', 'latin1')]);
}

test('PDF text extraction handles literal strings and escaped parentheses', async () => {
  const pdf = pdfWithStream('BT /F1 12 Tf 72 700 Td (Hello \\(PDF\\)) Tj ET');
  assert.equal(await runtime.window.DocView.pdf(pdf), 'Hello (PDF)');
});

test('PDF text extraction inflates streams and keeps TJ word spacing', async () => {
  const pdf = pdfWithStream('BT /F1 12 Tf [(lightweight) -250 ( parser)] TJ ET', true);
  assert.equal(await runtime.window.DocView.pdf(pdf), 'lightweight parser');
});

test('PDF text extraction reports scanned or non-text PDFs without OCR', async () => {
  const pdf = pdfWithStream('q 0 0 100 100 re f Q');
  await assert.rejects(runtime.window.DocView.pdf(pdf), /без OCR/);
});