# -*- coding: utf-8 -*-

# Copyright (c) 2020 Detlev Offenbach <detlev@die-offenbachs.de>
#

"""
Module implementing a check for not auto escaping in jinja2.
"""

#
# This is a modified version of the one found in the bandit package.
#
# Original Copyright 2014 Hewlett-Packard Development Company, L.P.
#
# SPDX-License-Identifier: Apache-2.0
#

import ast


def getChecks():
    """
    Public method to get a dictionary with checks handled by this module.
    
    @return dictionary containing checker lists containing checker function and
        list of codes
    @rtype dict
    """
    return {
        "Call": [
            (checkJinja2Autoescape, ("S701",)),
        ],
    }


def checkJinja2Autoescape(reportError, context, config):
    """
    Function to check for not auto escaping in jinja2.
    
    @param reportError function to be used to report errors
    @type func
    @param context security context object
    @type SecurityContext
    @param config dictionary with configuration data
    @type dict
    """
    if isinstance(context.callFunctionNameQual, str):
        qualnameList = context.callFunctionNameQual.split('.')
        func = qualnameList[-1]
        if 'jinja2' in qualnameList and func == 'Environment':
            for node in ast.walk(context.node):
                if isinstance(node, ast.keyword):
                    # definite autoescape = False
                    if (
                        getattr(node, 'arg', None) == 'autoescape' and
                        (
                            getattr(node.value, 'id', None) == 'False' or
                            getattr(node.value, 'value', None) is False
                        )
                    ):
                        reportError(
                            context.node.lineno - 1,
                            context.node.col_offset,
                            "S701.1",
                            "H",
                            "H",
                        )
                        return
                    
                    # found autoescape
                    if getattr(node, 'arg', None) == 'autoescape':
                        value = getattr(node, 'value', None)
                        if (
                            getattr(value, 'id', None) == 'True' or
                            getattr(value, 'value', None) is True
                        ):
                            return
                        
                        # Check if select_autoescape function is used.
                        elif (
                            isinstance(value, ast.Call) and
                            (getattr(value.func, 'id', None) ==
                             'select_autoescape')
                        ):
                            return
                        
                        else:
                            reportError(
                                context.node.lineno - 1,
                                context.node.col_offset,
                                "S701.1",
                                "H",
                                "M",
                            )
                            return
            
            # We haven't found a keyword named autoescape, indicating default
            # behavior
            reportError(
                context.node.lineno - 1,
                context.node.col_offset,
                "S701.2",
                "H",
                "H",
            )
