# coding: utf-8
#
# Copyright 2018 The Oppia Authors. All Rights Reserved.
#
# 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.

"""Unit tests for scripts/docstrings_checker."""
from __future__ import absolute_import  # pylint: disable=import-only-modules
from __future__ import unicode_literals  # pylint: disable=import-only-modules

import ast
import contextlib
import unittest

from . import docstrings_checker  # isort:skip

import astroid  # isort:skip
from pylint.checkers import utils # isort:skip


class ASTDocstringsCheckerTest(unittest.TestCase):
    """Class for testing the docstrings_checker script."""

    def test_build_regex_from_args_one_arg(self):
        docstring_checker = docstrings_checker.ASTDocStringChecker()
        args = ['arg_name0']
        expected_result = r'(Args:)[\S\s]*(arg_name0:)'
        result = docstring_checker.build_regex_from_args(args)
        self.assertEqual(result, expected_result)

    def test_build_regex_from_args_multiple_args(self):
        docstring_checker = docstrings_checker.ASTDocStringChecker()
        args = ['arg_name0', 'arg_name1']
        expected_result = r'(Args:)[\S\s]*(arg_name0:)[\S\s]*(arg_name1:)'
        result = docstring_checker.build_regex_from_args(args)
        self.assertEqual(result, expected_result)

    def test_build_regex_from_args_empty_list_returns_none(self):
        docstring_checker = docstrings_checker.ASTDocStringChecker()
        args = []
        expected_result = None
        result = docstring_checker.build_regex_from_args(args)
        self.assertEqual(result, expected_result)

    def test_compare_arg_order_one_matching_arg_returns_empty_list(self):
        docstring_checker = docstrings_checker.ASTDocStringChecker()
        func_args = ['arg_name']
        docstring_args = """Description
            Args:
                arg_name: description
            """
        expected_result = []
        result = docstring_checker.compare_arg_order(func_args, docstring_args)
        self.assertEqual(result, expected_result)

    def test_compare_arg_order_no_colon_returns_error(self):
        docstring_checker = docstrings_checker.ASTDocStringChecker()
        func_args = ['arg_name']
        docstring_args = """Description
            Args:
                arg_name
            """
        expected_result = ['Arg not followed by colon: arg_name']
        result = docstring_checker.compare_arg_order(func_args, docstring_args)
        self.assertEqual(result, expected_result)

    def test_compare_arg_order_two_matching_ordered_args_success(self):
        docstring_checker = docstrings_checker.ASTDocStringChecker()
        func_args = ['arg_name1', 'arg_name2']
        docstring_args = """Description
            Args:
                arg_name1: description,
                arg_name2: description
            """
        expected_result = []
        result = docstring_checker.compare_arg_order(func_args, docstring_args)
        self.assertEqual(result, expected_result)

    def test_compare_arg_order_empty_docstring_exits_without_error(self):
        docstring_checker = docstrings_checker.ASTDocStringChecker()
        func_args = ['arg_name1']
        docstring_args = ''
        expected_result = []
        result = docstring_checker.compare_arg_order(func_args, docstring_args)
        self.assertEqual(result, expected_result)

    def test_compare_arg_order_no_arg_header_exits_without_error(self):
        docstring_checker = docstrings_checker.ASTDocStringChecker()
        func_args = ['arg_name1']
        docstring_args = 'I only have a description.'
        expected_result = []
        result = docstring_checker.compare_arg_order(func_args, docstring_args)
        self.assertEqual(result, expected_result)

    def test_compare_arg_order_missing_arg_returns_arg(self):
        docstring_checker = docstrings_checker.ASTDocStringChecker()
        func_args = ['arg_name1', 'arg_name2']
        docstring_args = """Description
            Args:
                arg_name1: description
            """
        expected_result = ['Arg missing from docstring: arg_name2']
        result = docstring_checker.compare_arg_order(func_args, docstring_args)
        self.assertEqual(result, expected_result)

    def test_compare_arg_order_missing_first_arg_returns_one_error(self):
        docstring_checker = docstrings_checker.ASTDocStringChecker()
        func_args = ['arg_name1', 'arg_name2']
        docstring_args = """Description
            Args:
                arg_name2: description
            """
        expected_result = ['Arg missing from docstring: arg_name1']
        result = docstring_checker.compare_arg_order(func_args, docstring_args)
        self.assertEqual(result, expected_result)

    def test_compare_arg_order_misordered_args_returns_one_error(self):
        docstring_checker = docstrings_checker.ASTDocStringChecker()
        func_args = ['arg_name1', 'arg_name2']
        docstring_args = """Description
            Args:
                arg_name2: description
                arg_name1: description
            """
        expected_result = ['Arg ordering error in docstring.']
        result = docstring_checker.compare_arg_order(func_args, docstring_args)
        self.assertEqual(result, expected_result)

    def test_compare_arg_order_mention_arg_without_colon_has_no_effect(self):
        docstring_checker = docstrings_checker.ASTDocStringChecker()
        func_args = ['arg_name1', 'arg_name2']
        docstring_args = """Description
            Args:
                arg_name1: description involving arg_name2,
                arg_name2: description involving arg_name1
            """
        expected_result = []
        result = docstring_checker.compare_arg_order(func_args, docstring_args)
        self.assertEqual(result, expected_result)

    def test_compare_arg_order_arg_substring_not_confused(self):
        docstring_checker = docstrings_checker.ASTDocStringChecker()
        func_args = ['this_has_a_substring', 'intermediate_arg', 'substring']
        docstring_args = """Description
            Args:
                this_has_a_substring: description,
                intermediate_arg: description,
                substring: description
            """
        expected_result = []
        result = docstring_checker.compare_arg_order(func_args, docstring_args)
        self.assertEqual(result, expected_result)

    def test_compare_arg_order_multi_line_descriptions_success(self):
        docstring_checker = docstrings_checker.ASTDocStringChecker()
        func_args = ['arg_name1', 'arg_name2']
        docstring_args = """Description
            Args:
                arg_name1: description that goes on for a
                    long time.
                arg_name2: description
            """
        expected_result = []
        result = docstring_checker.compare_arg_order(func_args, docstring_args)
        self.assertEqual(result, expected_result)

    def test_space_indentation(self):
        sample_string = '     This is a sample string.'
        self.assertEqual(docstrings_checker.space_indentation(sample_string), 5)

    def test_check_docstrings_arg_order(self):
        docstring_checker = docstrings_checker.ASTDocStringChecker()

        ast_file = ast.walk(ast.parse(
            """
def func(test_var_one, test_var_two): #@
    \"\"\"Function to test docstring parameters.

    Args:
        test_var_one: int. First test variable.
        test_var_two: str. Second test variable.

    Returns:
        int. The test result.
    \"\"\"
    result = test_var_one + test_var_two
    return result"""))

        func_defs = [n for n in ast_file if isinstance(n, ast.FunctionDef)]
        self.assertEqual(len(func_defs), 1)

        func_result = docstring_checker.check_docstrings_arg_order(func_defs[0])
        self.assertEqual(func_result, [])

    def test_possible_exc_types_with_inference_error(self):

        @contextlib.contextmanager
        def swap(obj, attr, newvalue):
            """Swap an object's attribute value within the context of a
            'with' statement. The object can be anything that supports
            getattr and setattr, such as class instances, modules, etc.
            """
            original = getattr(obj, attr)
            setattr(obj, attr, newvalue)
            try:
                yield
            finally:
                setattr(obj, attr, original)

        raise_node = astroid.extract_node("""
        def func():
            raise Exception('An exception.') #@
        """)
        node_ignores_exception_swap = swap(
            utils, 'node_ignores_exception',
            lambda _, __: (_ for _ in ()).throw(astroid.InferenceError()))

        with node_ignores_exception_swap:
            exceptions = docstrings_checker.possible_exc_types(raise_node)
        self.assertEqual(exceptions, set([]))

    def test_possible_exc_types_with_exception_message(self):
        raise_node = astroid.extract_node("""
        def func():
            \"\"\"Function to test raising exceptions.\"\"\"
            raise Exception('An exception.') #@
        """)

        exceptions = docstrings_checker.possible_exc_types(raise_node)
        self.assertEqual(exceptions, set(['Exception']))

    def test_possible_exc_types_with_no_exception(self):
        raise_node = astroid.extract_node("""
        def func():
            \"\"\"Function to test raising exceptions.\"\"\"
            raise #@
        """)

        exceptions = docstrings_checker.possible_exc_types(raise_node)
        self.assertEqual(exceptions, set([]))

    def test_possible_exc_types_with_exception_inside_function(self):
        raise_node = astroid.extract_node("""
        def func():
            try:
                raise Exception('An exception.')
            except Exception:
                raise #@
        """)

        exceptions = docstrings_checker.possible_exc_types(raise_node)
        self.assertEqual(exceptions, set(['Exception']))