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

import sys

from pants.backend.jvm.subsystems.scala_platform import ScalaPlatform
from pants.backend.jvm.targets.jar_library import JarLibrary
from pants.backend.jvm.targets.jvm_target import JvmTarget
from pants.backend.jvm.tasks.jvm_task import JvmTask
from pants.backend.jvm.tasks.jvm_tool_task_mixin import JvmToolTaskMixin
from pants.java.distribution.distribution import DistributionLocator
from pants.java.jar.jar_dependency import JarDependency
from pants.task.repl_task_mixin import ReplTaskMixin


class ScalaRepl(JvmToolTaskMixin, ReplTaskMixin, JvmTask):
    """Operations to create or launch Scala repls.

    :API: public
    """

    _RUNNER_MAIN = "org.pantsbuild.tools.runner.PantsRunner"

    @classmethod
    def register_options(cls, register):
        super().register_options(register)
        register(
            "--main",
            default="scala.tools.nsc.MainGenericRunner",
            help="The entry point for running the repl.",
        )
        cls.register_jvm_tool(
            register,
            "pants-runner",
            classpath=[JarDependency(org="org.pantsbuild", name="pants-runner", rev="0.0.1"),],
            main=ScalaRepl._RUNNER_MAIN,
        )

    @classmethod
    def subsystem_dependencies(cls):
        return super().subsystem_dependencies() + (DistributionLocator, ScalaPlatform)

    @classmethod
    def select_targets(cls, target):
        return isinstance(target, (JarLibrary, JvmTarget))

    def setup_repl_session(self, targets):
        repl_name = ScalaPlatform.global_instance().repl
        return (
            self.tool_classpath("pants-runner")
            + self.tool_classpath(repl_name, scope=ScalaPlatform.options_scope)
            + self.classpath(targets),
            self.preferred_jvm_distribution_for_targets(targets),
        )

    def launch_repl(self, session_setup):
        # The scala repl requires -Dscala.usejavacp=true since Scala 2.8 when launching in the way
        # we do here (not passing -classpath as a program arg to scala.tools.nsc.MainGenericRunner).
        classpath, distribution = session_setup
        jvm_options = self.jvm_options
        if not any(opt.startswith("-Dscala.usejavacp=") for opt in jvm_options):
            jvm_options.append("-Dscala.usejavacp=true")

        # NOTE: We execute with no workunit, as capturing REPL output makes it very sluggish.
        #
        # NOTE: Using PantsRunner class because the classLoader used by REPL
        # does not load Class-Path from manifest.
        distribution.execute_java(
            classpath=classpath,
            main=ScalaRepl._RUNNER_MAIN,
            jvm_options=jvm_options,
            args=[self.get_options().main] + self.args,
            create_synthetic_jar=True,
            stdin=sys.stdin,
        )