"""
Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
SPDX-License-Identifier: MIT-0
"""
from cfnlint.rules import CloudFormationLintRule, RuleMatch


class ImportValue(CloudFormationLintRule):
    """Check if ImportValue values are correct"""

    id = "E1016"
    shortdesc = "ImportValue validation of parameters"
    description = "Making sure the ImportValue function is properly configured"
    source_url = "https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/intrinsic-function-reference-importvalue.html"
    tags = ["functions", "importvalue"]

    def match(self, cfn):
        matches = []

        iv_objs = cfn.search_deep_keys("Fn::ImportValue")

        supported_functions = [
            "Fn::Base64",
            "Fn::FindInMap",
            "Fn::If",
            "Fn::Join",
            "Fn::Select",
            "Fn::Split",
            "Fn::Sub",
            "Ref",
        ]

        unsupported_locations = ["Conditions"]

        for iv_obj in iv_objs:
            iv_value = iv_obj[-1]
            tree = iv_obj[:-1]
            if iv_obj[0] in unsupported_locations:
                message = "ImportValue cannot be used inside {0} at {1}"
                matches.append(
                    RuleMatch(
                        tree, message.format(iv_obj[0], "/".join(map(str, tree[:-1])))
                    )
                )
            if isinstance(iv_value, dict):
                if len(iv_value) == 1:
                    for key, _ in iv_value.items():
                        if key not in supported_functions:
                            message = (
                                "ImportValue should be using supported function for {0}"
                            )
                            matches.append(
                                RuleMatch(
                                    tree, message.format("/".join(map(str, tree[:-1])))
                                )
                            )
                else:
                    message = "ImportValue should have one mapping for {0}"
                    matches.append(
                        RuleMatch(tree, message.format("/".join(map(str, tree[:-1]))))
                    )
            elif not isinstance(iv_value, str):
                message = "ImportValue should have supported function or string for {0}"
                matches.append(
                    RuleMatch(tree, message.format("/".join(map(str, tree))))
                )
        return matches
