"""
  Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.

  Permission is hereby granted, free of charge, to any person obtaining a copy of this
  software and associated documentation files (the "Software"), to deal in the Software
  without restriction, including without limitation the rights to use, copy, modify,
  merge, publish, distribute, sublicense, and/or sell copies of the Software, and to
  permit persons to whom the Software is furnished to do so.

  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
  INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
  PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
  HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
  SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
"""
import six
from cfnlint import CloudFormationLintRule
from cfnlint import RuleMatch


class FindInMapKeys(CloudFormationLintRule):
    """Check if FindInMap values are correct"""
    id = 'W1011'
    shortdesc = 'FindInMap keys exist in the map'
    description = 'Checks the keys in a FindInMap to make sure they exist. ' \
                  'Check only if the Map Name is a string and if the key is a string.'
    source_url = 'https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/intrinsic-function-reference-findinmap.html'
    tags = ['functions', 'findinmap']

    def check_keys(self, map_name, keys, mappings, tree):
        """ Check the validity of the first key """
        matches = []
        first_key = keys[0]
        second_key = keys[1]
        if isinstance(second_key, (six.string_types, int)):
            if isinstance(map_name, (six.string_types)):
                mapping = mappings.get(map_name)
                if mapping:
                    if isinstance(first_key, (six.string_types, int)):
                        if isinstance(map_name, (six.string_types)):
                            if mapping.get(first_key) is None:
                                message = 'FindInMap first key "{0}" doesn\'t exist in map "{1}" at {3}'
                                matches.append(RuleMatch(
                                    tree[:] + [1],
                                    message.format(first_key, map_name, first_key, '/'.join(map(str, tree)))))
                        if mapping.get(first_key):
                            # Don't double error if they first key doesn't exist
                            if mapping.get(first_key, {}).get(second_key) is None:
                                message = 'FindInMap second key "{0}" doesn\'t exist in map "{1}" under "{2}" at {3}'
                                matches.append(RuleMatch(
                                    tree[:] + [2],
                                    message.format(second_key, map_name, first_key, '/'.join(map(str, tree)))))
                    else:
                        for key, value in mapping.items():
                            if value.get(second_key) is None:
                                message = 'FindInMap second key "{0}" doesn\'t exist in map "{1}" under "{2}" at {3}'
                                matches.append(RuleMatch(
                                    tree[:] + [2],
                                    message.format(second_key, map_name, key, '/'.join(map(str, tree)))))

        return matches

    def match(self, cfn):
        """Check CloudFormation GetAtt"""

        matches = []

        findinmaps = cfn.search_deep_keys('Fn::FindInMap')
        mappings = cfn.get_mappings()
        for findinmap in findinmaps:
            tree = findinmap[:-1]
            map_obj = findinmap[-1]

            if len(map_obj) == 3:
                matches.extend(self.check_keys(map_obj[0], map_obj[1:], mappings, tree))

        return matches