# Copyright 2014 Pants project contributors (see CONTRIBUTORS.md).
# Licensed under the Apache License, Version 2.0 (see LICENSE).

from pants.backend.jvm.targets.java_library import JavaLibrary
from pants.base.exceptions import TargetDefinitionException


class JavaAgent(JavaLibrary):
    """A Java agent entrypoint."""

    def __init__(
        self,
        name,
        sources=None,
        excludes=None,
        premain=None,
        agent_class=None,
        can_redefine=False,
        can_retransform=False,
        can_set_native_method_prefix=False,
        **kwargs
    ):
        """
        :param string premain: When an agent is specified at JVM launch time this attribute specifies
          the agent class. Exactly one of ``premain`` or ``agent_class`` must be specified.
        :param string agent_class: If an implementation supports a mechanism to start agents sometime
          after the VM has started then this attribute specifies the agent class. Exactly one of
          ``premain`` or ``agent_class`` must be specified.
        :param bool can_redefine: `True` if the ability to redefine classes is needed by this agent;
          `False` by default.
        :param bool can_retransform: `True` if the ability to retransform classes is needed by this
          agent; `False` by default.
        :param bool can_set_native_method_prefix: `True` if the ability to set he native method prefix
          is needed by this agent; `False` by default.
        """

        super().__init__(
            name=name,
            sources=sources,
            provides=None,
            excludes=self.assert_list(excludes, key_arg="excludes"),
            **kwargs
        )

        if not (premain or agent_class):
            raise TargetDefinitionException(
                self, "Must have at least one of 'premain' or 'agent_class' " "defined."
            )
        if premain and not isinstance(premain, str):
            raise TargetDefinitionException(
                self,
                "The premain must be a fully qualified class name, "
                "given {} of type {}".format(premain, type(premain)),
            )

        if agent_class and not isinstance(agent_class, str):
            raise TargetDefinitionException(
                self,
                "The agent_class must be a fully qualified class name, given "
                "{} of type {}".format(agent_class, type(agent_class)),
            )

        self._premain = premain
        self._agent_class = agent_class
        self._can_redefine = can_redefine
        self._can_retransform = can_retransform
        self._can_set_native_method_prefix = can_set_native_method_prefix

    @property
    def premain(self):
        """The launch time agent fully qualified class name.

        Either ``agent_class`` or ``premain`` will be defined and the other will be `None`.
        """
        return self._premain

    @property
    def agent_class(self):
        """The post-launch-time agent fully qualified class name.

        Either ``agent_class`` or ``premain`` will be defined and the other will be `None`.
        """
        return self._agent_class

    @property
    def can_redefine(self):
        """Returns `True` if the ability to redefine classes is needed by this agent."""
        return self._can_redefine

    @property
    def can_retransform(self):
        """Returns `True` if the ability to retransform classes is needed by this agent."""
        return self._can_retransform

    @property
    def can_set_native_method_prefix(self):
        """Returns `True` if the ability to set he native method prefix is needed by this agent."""
        return self._can_set_native_method_prefix