"""
Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
SPDX-License-Identifier: MIT-0
"""
import datetime

from cfnlint.rules import CloudFormationLintRule, RuleMatch


class Base(CloudFormationLintRule):
    """Check Base Template Settings"""

    id = "E1001"
    shortdesc = "Basic CloudFormation Template Configuration"
    description = "Making sure the basic CloudFormation template components are properly configured"
    source_url = "https://github.com/aws-cloudformation/cfn-python-lint"
    tags = ["base"]

    required_keys = ["Resources"]

    def __init__(self):
        """Init"""
        super().__init__()
        self.config_definition = {"sections": {"default": "", "type": "string"}}
        self.configure()

    def _validate_version(self, template):
        results = []
        valid_version = "2010-09-09"
        if "AWSTemplateFormatVersion" in template:
            version = template.get("AWSTemplateFormatVersion")
            if not isinstance(version, (str, datetime.date)):
                message = "AWSTemplateFormatVersion only valid value is {0}"
                results.append(
                    RuleMatch(
                        ["AWSTemplateFormatVersion"], message.format(valid_version)
                    )
                )
            else:
                if (
                    version != valid_version
                    and version
                    != datetime.datetime.strptime(valid_version, "%Y-%m-%d").date()
                ):
                    message = "AWSTemplateFormatVersion only valid value is {0}"
                    results.append(
                        RuleMatch(
                            ["AWSTemplateFormatVersion"], message.format(valid_version)
                        )
                    )
        return results

    def _validate_transform(self, transforms):
        results = []
        if not isinstance(transforms, (list, str)):
            message = "Transform has to be a list or string"
            results.append(RuleMatch(["Transform"], message.format()))
            return results

        if not isinstance(transforms, list):
            transforms = [transforms]

        return results

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

        top_level = []
        for x in cfn.template:
            top_level.append(x)
            if x not in cfn.sections and x != self.config["sections"]:
                message = "Top level template section {0} is not valid"
                matches.append(RuleMatch([x], message.format(x)))

        for y in self.required_keys:
            if y not in top_level:
                message = "Missing top level template section {0}"
                matches.append(RuleMatch([y], message.format(y)))

        matches.extend(self._validate_version(cfn.template))
        if "Transform" in cfn.template:
            matches.extend(self._validate_transform(cfn.template.get("Transform")))
        return matches
