import pathlib
import pytest
from readme_renderer.__main__ import main
import tempfile
from unittest import mock


@pytest.fixture(params=["test_CommonMark_001.md", "test_rst_003.rst",
                        "test_GFM_001.md", "test_txt_001.txt"])
def input_file(request):
    path = pathlib.Path("tests/fixtures", request.param)
    # Skip markdown tests if the cmarkgfm optional dependency is not installed.
    if path.suffix == ".md":
        pytest.importorskip("cmarkgfm")
    return path


@pytest.mark.parametrize("output_file", [False, True])
def test_cli_input_file(input_file, output_file):
    with mock.patch("builtins.print") as print_:
        if output_file:
            with tempfile.TemporaryDirectory() as tmpdir:
                output = pathlib.Path(tmpdir) / "output.html"
                main(["-o", str(output), str(input_file)])
                with output.open() as fp:
                    result = fp.read()
        else:
            main([str(input_file)])

    print_.assert_called_once()
    (result,), kwargs = print_.call_args

    with input_file.with_suffix(".html").open() as fp:
        expected = fp.read()
    assert result.strip() == expected.strip()

    if output_file:
        assert kwargs["file"].name == str(output)


def test_cli_invalid_format():
    with mock.patch("pathlib.Path.open"), \
            pytest.raises(ValueError, match="invalid README format: invalid"):
        main(["no-file.invalid"])


def test_cli_explicit_format(input_file):
    fmt = input_file.suffix.lstrip(".")

    # The explicit-format tests present a number of technical challenges.
    #
    # 1. The filename must not have a recognized extension
    #    to ensure that the renderer is honoring the `-f` argument.
    #    Therefore, patching is used so the input filename can be faked.
    #
    # 2. docutils must be able to open stylesheet files during RST-to-HTML rendering.
    #    Therefore, patching must be limited to readme-renderer's usage.
    #
    # The strategy used here is to patch `pathlib.Path.open()` until it is first called,
    # since the first call occurs when readme-renderer reads the input file's content.
    # After that, the patch is disabled. However, this presents additional challenges:
    #
    # 3. On Python <=3.11, `patch.__exit__()` cannot be called more than once.
    # 4. `patch.stop()` cannot sufficiently undo a patch if `.__enter__()` was called.
    #
    # Therefore, the patch cannot be used as a context manager.
    # It must be manually started and stopped.

    fp = input_file.open()

    def stop_open_patch_after_one_call():
        open_patch.stop()
        return fp

    open_patch = mock.patch(
        "pathlib.Path.open",
        side_effect=stop_open_patch_after_one_call,
    )

    open_patch.start()

    try:
        with fp, mock.patch("builtins.print") as print_:
            main(["-f", fmt, "no-file.invalid"])
            print_.assert_called_once()
            (result,), _ = print_.call_args
    finally:
        # Stop the patch regardless of the test result.
        open_patch.stop()

    with input_file.with_suffix(".html").open() as fp:
        assert result.strip() == fp.read().strip()


@pytest.mark.parametrize("package, contains", [
    ("readme_renderer", "Readme Renderer is a library that will safely render"),
    ("docutils", "Docutils is a modular system for processing documentation"),
])
def test_cli_package(package, contains):
    with mock.patch("builtins.print") as print_:
        main(["-p", package])
        print_.assert_called_once()
        (result,), _ = print_.call_args
    assert contains in result