"""Test topics around the usage of JavaScript in PDF documents."""
from typing import Any

import pytest

from pypdf import PdfReader, PdfWriter
from tests import RESOURCE_ROOT


@pytest.fixture
def pdf_file_writer():
    reader = PdfReader(RESOURCE_ROOT / "issue-604.pdf")
    writer = PdfWriter()
    writer.append_pages_from_reader(reader)
    return writer


def test_add_js(pdf_file_writer):
    pdf_file_writer.add_js("this.print({bUI:true,bSilent:false,bShrinkToFit:true});")

    assert (
        "/Names" in pdf_file_writer._root_object
    ), "add_js should add a name catalog in the root object."
    assert (
        "/JavaScript" in pdf_file_writer._root_object["/Names"]
    ), "add_js should add a JavaScript name tree under the name catalog."


def test_added_js(pdf_file_writer):
    def get_javascript_name() -> Any:
        assert "/Names" in pdf_file_writer._root_object
        assert "/JavaScript" in pdf_file_writer._root_object["/Names"]
        assert "/Names" in pdf_file_writer._root_object["/Names"]["/JavaScript"]
        return pdf_file_writer._root_object["/Names"]["/JavaScript"]["/Names"][
            -2
        ]  # return -2 in order to get the latest javascript

    pdf_file_writer.add_js("this.print({bUI:true,bSilent:false,bShrinkToFit:true});")
    first_js = get_javascript_name()

    pdf_file_writer.add_js("this.print({bUI:true,bSilent:false,bShrinkToFit:true});")
    second_js = get_javascript_name()

    assert (
        first_js != second_js
    ), "add_js should add to the previous script in the catalog."