# Copyright 2015 Pants project contributors (see CONTRIBUTORS.md).
# Licensed under the Apache License, Version 2.0 (see LICENSE).

import logging

from pants.subsystem.subsystem import Subsystem
from pants.util.strutil import safe_shlex_split

logger = logging.getLogger(__name__)


class JVM(Subsystem):
    """A JVM invocation.

    :API: public
    """

    options_scope = "jvm"

    # Broken out here instead of being inlined in the registration stanza,
    # because various tests may need to access these.
    options_default = [
        "-Xmx256m",
        # Always bump MaxFDLimit - this means that Java will listen to the environmental FD limit,
        # rather than imposing its own. This should just be what the JVM does by default. Boo.
        "-XX:-MaxFDLimit",
    ]

    @classmethod
    def register_options(cls, register):
        super().register_options(register)
        # TODO(benjy): Options to specify the JVM version?
        register(
            "--options",
            type=list,
            metavar="<option>...",
            default=cls.options_default,
            help="Run with these extra JVM options.",
        )
        register(
            "--program-args",
            type=list,
            metavar="<arg>...",
            help="Run with these extra program args.",
        )
        register("--debug", type=bool, help="Run the JVM with remote debugging.")
        register(
            "--debug-port",
            advanced=True,
            type=int,
            default=5005,
            help="The JVM will listen for a debugger on this port.",
        )
        register(
            "--debug-args",
            advanced=True,
            type=list,
            default=[
                "-Xdebug",
                "-Xrunjdwp:transport=dt_socket,server=y,suspend=y,address={debug_port}",
            ],
            help="The JVM remote-debugging arguments. {debug_port} will be replaced with "
            "the value of the --debug-port option.",
        )
        register(
            "--synthetic-classpath",
            advanced=True,
            type=bool,
            default=True,
            help="Use synthetic jar to work around classpath length restrictions.",
        )

    def get_jvm_options(self):
        """Return the options to run this JVM with.

        These are options to the JVM itself, such as -Dfoo=bar, -Xmx=1g, -XX:-UseParallelGC and so on.

        Thus named because get_options() already exists (and returns this object's Pants options).
        """
        ret = []
        for opt in self.get_options().options:
            ret.extend(safe_shlex_split(opt))

        if (
            self.get_options().debug
            or self.get_options().is_flagged("debug_port")
            or self.get_options().is_flagged("debug_args")
        ):
            debug_port = self.get_options().debug_port
            ret.extend(arg.format(debug_port=debug_port) for arg in self.get_options().debug_args)
        return ret

    def get_program_args(self):
        """Get the program args to run this JVM with.

        These are the arguments passed to main() and are program-specific.
        """
        ret = []
        for arg in self.get_options().program_args:
            ret.extend(safe_shlex_split(arg))
        return ret