# Copyright 2017 the GPflow authors.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import glob
import itertools
import os
import sys
import traceback
from typing import Sequence

import jupytext
import nbformat
import pytest
from nbconvert.preprocessors import ExecutePreprocessor
from nbconvert.preprocessors.execute import CellExecutionError

NOTEBOOK_DIR = "../../doc/source/notebooks"


def _nbpath() -> str:
    this_dir = os.path.dirname(__file__)
    return os.path.join(this_dir, NOTEBOOK_DIR)


def test_notebook_dir_exists() -> None:
    assert os.path.isdir(_nbpath())


# To blacklist a notebook, add its full base name (including .pct.py or .md
# extension, but without any directory component). NOTE that if there are
# several notebooks in different directories with the same base name, they will
# all get blacklisted (change the blacklisting check to something else in that
# case, if need be!)
BLACKLISTED_NOTEBOOKS: Sequence[str] = []


def get_notebooks() -> Sequence[str]:
    """
    Returns all notebooks in `_nbpath` that are not blacklisted.
    """

    def notebook_blacklisted(nb: str) -> bool:
        blacklisted_notebooks_basename = [os.path.basename(bnb) for bnb in BLACKLISTED_NOTEBOOKS]
        return os.path.basename(nb) in blacklisted_notebooks_basename

    # recursively traverse the notebook directory in search for ipython notebooks
    all_py_notebooks = glob.iglob(os.path.join(_nbpath(), "**", "*.pct.py"), recursive=True)
    all_md_notebooks = glob.iglob(os.path.join(_nbpath(), "**", "*.md"), recursive=True)
    all_notebooks = itertools.chain(all_md_notebooks, all_py_notebooks)
    notebooks_to_test = [nb for nb in all_notebooks if not notebook_blacklisted(nb)]
    return notebooks_to_test


def _preproc() -> ExecutePreprocessor:
    pythonkernel = "python" + str(sys.version_info[0])
    return ExecutePreprocessor(timeout=300, kernel_name=pythonkernel, interrupt_on_timeout=True)


def _exec_notebook(notebook_filename: str) -> None:
    with open(notebook_filename) as notebook_file:
        nb = jupytext.read(notebook_file, as_version=nbformat.current_nbformat)
        try:
            meta_data = {"path": os.path.dirname(notebook_filename)}
            _preproc().preprocess(nb, {"metadata": meta_data})
        except CellExecutionError as cell_error:
            traceback.print_exc(file=sys.stdout)
            msg = "Error executing the notebook {0}. See above for error.\nCell error: {1}"
            pytest.fail(msg.format(notebook_filename, str(cell_error)))


@pytest.mark.notebooks
@pytest.mark.parametrize("notebook_file", get_notebooks())
def test_notebook(notebook_file: str) -> None:
    _exec_notebook(notebook_file)


def test_has_notebooks() -> None:
    assert len(get_notebooks()) >= 35, "there are probably some notebooks that were not discovered"