"""
  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
from cfnlint.helpers import RESOURCE_SPECS
import cfnlint.helpers


class ValueRefGetAtt(CloudFormationLintRule):
    """Check if Resource Properties are correct"""
    id = 'E3008'
    shortdesc = 'Check values of properties for valid Refs and GetAtts'
    description = 'Checks resource properties for Ref and GetAtt values'
    tags = ['resources']

    def initialize(self, cfn):
        """Initialize the rule"""
        for resource_type_spec in RESOURCE_SPECS.get(cfn.regions[0]).get('ResourceTypes'):
            self.resource_property_types.append(resource_type_spec)
        for property_type_spec in RESOURCE_SPECS.get(cfn.regions[0]).get('PropertyTypes'):
            self.resource_sub_property_types.append(property_type_spec)

    def is_value_a_list(self, path, property_name):
        """
            Determines if the value checked is a list or a value in a list
            We need to handle conditions in the path that could be nested, etc.
            ['Resources', 'LoadBalancer', 'Properties', 'Subnets', 'Fn::If', 2, 'Fn::If', 2]
            Numbers preceeded by a Fn::If should be removed and check repeated.
        """
        if path[-1] != property_name:
            # Property doesn't match the property name
            # Check if its a number and a condition
            if isinstance(path[-1], int) and path[-2] == 'Fn::If':
                return self.is_value_a_list(path[:-2], property_name)

            return False

        return True

    def check_value_ref(self, value, path, **kwargs):
        """Check Ref"""
        matches = list()
        cfn = kwargs.get('cfn')
        value_specs = kwargs.get('value_specs', {}).get('Ref')
        list_value_specs = kwargs.get('list_value_specs', {}).get('Ref')
        property_type = kwargs.get('property_type')
        property_name = kwargs.get('property_name')
        if path[-1] == 'Ref' and property_type == 'List' and self.is_value_a_list(path[:-1], property_name):
            specs = list_value_specs
        else:
            specs = value_specs

        if not specs:
            # If no Ref's are specified, just skip
            # Opposite of GetAtt you will always have a Ref to a Parameter so if this is
            # None it just hasn't been defined and we can skip
            return matches

        if value in cfn.template.get('Parameters', {}):
            param = cfn.template.get('Parameters').get(value, {})
            parameter_type = param.get('Type')
            valid_parameter_types = []
            for parameter in specs.get('Parameters'):
                for param_type in RESOURCE_SPECS.get(cfn.regions[0]).get('ParameterTypes').get(parameter):
                    valid_parameter_types.append(param_type)

            if not specs.get('Parameters'):
                message = 'Property "{0}" has no valid Refs to Parameters at {1}'
                matches.append(RuleMatch(path, message.format(property_name, '/'.join(map(str, path)))))
            elif parameter_type not in valid_parameter_types:
                message = 'Property "{0}" can Ref to parameter of types [{1}] at {2}'
                matches.append(
                    RuleMatch(
                        path,
                        message.format(
                            property_name,
                            ', '.join(map(str, valid_parameter_types)),
                            '/'.join(map(str, path)))))
        if value in cfn.template.get('Resources', {}):
            resource = cfn.template.get('Resources').get(value, {})
            resource_type = resource.get('Type')
            if not specs.get('Resources'):
                message = 'Property "{0}" has no valid Refs to Resources at {1}'
                matches.append(RuleMatch(path, message.format(property_name, '/'.join(map(str, path)))))
            elif resource_type not in specs.get('Resources'):
                message = 'Property "{0}" can Ref to resources of types [{1}] at {2}'
                matches.append(
                    RuleMatch(
                        path,
                        message.format(
                            property_name,
                            ', '.join(map(str, specs.get('Resources'))),
                            '/'.join(map(str, path)))))

        return matches

    def check_value_getatt(self, value, path, **kwargs):
        """Check GetAtt"""
        matches = []
        cfn = kwargs.get('cfn')
        value_specs = kwargs.get('value_specs', {}).get('GetAtt')
        list_value_specs = kwargs.get('list_value_specs', {}).get('GetAtt')
        property_type = kwargs.get('property_type')
        property_name = kwargs.get('property_name')
        # You can sometimes get a list or a string with . in it
        if isinstance(value, list):
            resource_name = value[0]
            if len(value[1:]) == 1:
                resource_attribute = value[1].split('.')
            else:
                resource_attribute = value[1:]
        elif isinstance(value, six.string_types):
            resource_name = value.split('.')[0]
            resource_attribute = value.split('.')[1:]
        is_value_a_list = self.is_value_a_list(path[:-1], property_name)
        if path[-1] == 'Fn::GetAtt' and property_type == 'List' and is_value_a_list:
            specs = list_value_specs
        else:
            specs = value_specs

        resource_type = cfn.template.get('Resources', {}).get(resource_name, {}).get('Type')

        if cfnlint.helpers.is_custom_resource(resource_type):
            #  A custom resource voids the spec.  Move on
            return matches

        if resource_type == 'AWS::CloudFormation::Stack' and resource_attribute[0] == 'Outputs':
            # Nested Stack Outputs
            # if its a string type we are good and return matches
            # if its a list its a failure as Outputs can only be strings
            if is_value_a_list and property_type == 'List':
                message = 'CloudFormation stack outputs need to be strings not lists at {0}'
                matches.append(RuleMatch(path, message.format('/'.join(map(str, path)))))

            return matches

        if specs is None:
            # GetAtt specs aren't specified skip
            return matches
        if not specs:
            # GetAtt is specified but empty so there are no valid options
            message = 'Property "{0}" has no valid Fn::GetAtt options at {1}'
            matches.append(RuleMatch(path, message.format(property_name, '/'.join(map(str, path)))))
            return matches

        if resource_type not in specs:
            message = 'Property "{0}" can Fn::GetAtt to a resource of types [{1}] at {2}'
            matches.append(
                RuleMatch(
                    path,
                    message.format(
                        property_name,
                        ', '.join(map(str, specs)),
                        '/'.join(map(str, path)))))
        elif '.'.join(map(str, resource_attribute)) != specs[resource_type]:
            message = 'Property "{0}" can Fn::GetAtt to a resource attribute "{1}" at {2}'
            matches.append(
                RuleMatch(
                    path,
                    message.format(
                        property_name,
                        specs[resource_type],
                        '/'.join(map(str, path)))))

        return matches

    def check(self, cfn, properties, value_specs, property_specs, path):
        """Check itself"""
        matches = list()
        for p_value, p_path in properties.items_safe(path[:]):
            for prop in p_value:
                if prop in value_specs:
                    value = value_specs.get(prop).get('Value', {})
                    if value:
                        value_type = value.get('ValueType', '')
                        list_value_type = value.get('ListValueType', '')
                        property_type = property_specs.get('Properties').get(prop).get('Type')
                        matches.extend(
                            cfn.check_value(
                                p_value, prop, p_path,
                                check_ref=self.check_value_ref,
                                check_get_att=self.check_value_getatt,
                                value_specs=RESOURCE_SPECS.get(cfn.regions[0]).get('ValueTypes').get(value_type, {}),
                                list_value_specs=RESOURCE_SPECS.get(cfn.regions[0]).get('ValueTypes').get(list_value_type, {}),
                                cfn=cfn, property_type=property_type, property_name=prop
                            )
                        )

        return matches

    def match_resource_sub_properties(self, properties, property_type, path, cfn):
        """Match for sub properties"""
        matches = list()

        specs = RESOURCE_SPECS.get(cfn.regions[0]).get('PropertyTypes').get(property_type, {}).get('Properties', {})
        property_specs = RESOURCE_SPECS.get(cfn.regions[0]).get('PropertyTypes').get(property_type)
        matches.extend(self.check(cfn, properties, specs, property_specs, path))

        return matches

    def match_resource_properties(self, properties, resource_type, path, cfn):
        """Check CloudFormation Properties"""
        matches = list()

        specs = RESOURCE_SPECS.get(cfn.regions[0]).get('ResourceTypes').get(resource_type, {}).get('Properties', {})
        resource_specs = RESOURCE_SPECS.get(cfn.regions[0]).get('ResourceTypes').get(resource_type)
        matches.extend(self.check(cfn, properties, specs, resource_specs, path))

        return matches
