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


class TaskDefinitionEssentialContainer(CloudFormationLintRule):
    """Check ECS TaskDefinition ContainerDefinitions Property Specifies at least one Essential Container"""

    id = "E3042"
    shortdesc = "Check at least one essential container is specified"
    description = (
        "Check that every TaskDefinition specifies at least one essential container"
    )
    source_url = "https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-ecs-taskdefinition-containerdefinitions.html#cfn-ecs-taskdefinition-containerdefinition-essential"
    tags = ["properties", "ecs", "task", "container", "fargate"]

    def match(self, cfn):
        """Check at least one essential container is specified"""

        matches = []

        results = cfn.get_resource_properties(
            ["AWS::ECS::TaskDefinition", "ContainerDefinitions"]
        )

        for result in results:
            path = result["Path"]

            has_essential_container = False

            for container in result["Value"]:
                if "Essential" in container:
                    if container["Essential"]:
                        has_essential_container = True
                    else:
                        pass
                else:
                    # If 'Essential' is not specified, it defaults to an essential container
                    has_essential_container = True

            if not has_essential_container:
                error_message = (
                    f"No essential containers defined for {'/'.join(map(str, path))}"
                )
                rule_match = RuleMatch(path, error_message)
                matches.append(rule_match)

        return matches