# Copyright (c) 2016-2018, 2020 Claudiu Popa <pcmanticore@gmail.com>
# Copyright (c) 2016 Łukasz Rogalski <rogalski.91@gmail.com>
# Copyright (c) 2016 Luis Escobar <lescobar@vauxoo.com>
# Copyright (c) 2019, 2021 Pierre Sassoulas <pierre.sassoulas@gmail.com>
# Copyright (c) 2020 hippo91 <guillaume.peillex@gmail.com>
# Copyright (c) 2020 Anthony Sottile <asottile@umich.edu>

# Licensed under the GPL: https://www.gnu.org/licenses/old-licenses/gpl-2.0.html
# For details: https://github.com/PyCQA/pylint/blob/master/COPYING

import linecache

from pylint import checkers
from pylint.checkers.utils import check_messages
from pylint.interfaces import HIGH, IAstroidChecker


class DocStringStyleChecker(checkers.BaseChecker):
    """Checks format of docstrings based on PEP 0257"""

    __implements__ = IAstroidChecker
    name = "docstyle"

    msgs = {
        "C0198": (
            'Bad docstring quotes in %s, expected """, given %s',
            "bad-docstring-quotes",
            "Used when a docstring does not have triple double quotes.",
        ),
        "C0199": (
            "First line empty in %s docstring",
            "docstring-first-line-empty",
            "Used when a blank line is found at the beginning of a docstring.",
        ),
    }

    @check_messages("docstring-first-line-empty", "bad-docstring-quotes")
    def visit_module(self, node):
        self._check_docstring("module", node)

    def visit_classdef(self, node):
        self._check_docstring("class", node)

    def visit_functiondef(self, node):
        ftype = "method" if node.is_method() else "function"
        self._check_docstring(ftype, node)

    visit_asyncfunctiondef = visit_functiondef

    def _check_docstring(self, node_type, node):
        docstring = node.doc
        if docstring and docstring[0] == "\n":
            self.add_message(
                "docstring-first-line-empty",
                node=node,
                args=(node_type,),
                confidence=HIGH,
            )

        # Use "linecache", instead of node.as_string(), because the latter
        # looses the original form of the docstrings.

        if docstring:
            lineno = node.fromlineno + 1
            line = linecache.getline(node.root().file, lineno).lstrip()
            if line and line.find('"""') == 0:
                return
            if line and "'''" in line:
                quotes = "'''"
            elif line and line[0] == '"':
                quotes = '"'
            elif line and line[0] == "'":
                quotes = "'"
            else:
                quotes = False
            if quotes:
                self.add_message(
                    "bad-docstring-quotes",
                    node=node,
                    args=(node_type, quotes),
                    confidence=HIGH,
                )


def register(linter):
    """Required method to auto register this checker.

    :param linter: Main interface object for Pylint plugins
    :type linter: Pylint object
    """
    linter.register_checker(DocStringStyleChecker(linter))
