# Copyright 2020 Pants project contributors (see CONTRIBUTORS.md).
# Licensed under the Apache License, Version 2.0 (see LICENSE).

from abc import ABC

from pants.backend.jvm.subsystems.jvm_platform import JvmPlatform
from pants.base.payload import Payload
from pants.base.payload_field import PrimitiveField


class RuntimePlatformMixin(ABC):
    """A mixin that identifies a root target type as one that can have a jvm runtime_platform.

    Mixin Usage

    Add RuntimePlatformMixin to the superclass list ahead of Target. Otherwise you'll get
    UnknownArgumentError from Target's argument validation.

    Change __init__:
      - Add runtime_platform=None to the kwargs.
      - Add the following to the doc string:
      :param str runtime_platform: The name of the platform (defined under the jvm-platform subsystem)
        to use for runtime (that is, a key into the --jvm-platform-platforms dictionary). If
        unspecified, the platform will default to the first one of these that exist: (1) the
        default_runtime_platform specified for jvm-platform, (2) the platform that would be used for
        the platform kwarg.

    :API: public
    """

    def __init__(self, payload, runtime_platform=None, **kwargs):
        payload = payload or Payload()
        payload.add_fields(
            {"runtime_platform": PrimitiveField(runtime_platform),}
        )
        super(RuntimePlatformMixin, self).__init__(payload=payload, **kwargs)

    @property
    def runtime_platform(self):
        """Runtime platform associated with this target.

        :return: The jvm platform object.
        :rtype: JvmPlatformSettings
        """
        return JvmPlatform.global_instance().get_runtime_platform_for_target(self)