# Copyright 2017 Pants project contributors (see CONTRIBUTORS.md).
# Licensed under the Apache License, Version 2.0 (see LICENSE).

from pex.pex_info import PexInfo

from pants.backend.python.subsystems.ipython import IPython
from pants.backend.python.targets.python_requirement_library import PythonRequirementLibrary
from pants.backend.python.targets.python_target import PythonTarget
from pants.backend.python.tasks.python_execution_task_base import PythonExecutionTaskBase
from pants.base.deprecated import resolve_conflicting_options
from pants.base.exception_sink import ExceptionSink
from pants.task.repl_task_mixin import ReplTaskMixin


class PythonRepl(ReplTaskMixin, PythonExecutionTaskBase):
    """Launch an interactive Python interpreter session."""

    def _resolve_conflicting_options(self, *, old_option: str, new_option: str):
        return resolve_conflicting_options(
            old_option=old_option,
            new_option=new_option,
            old_scope="repl-py",
            new_scope="ipython",
            old_container=self.get_options(),
            new_container=IPython.global_instance().options,
        )

    @classmethod
    def register_options(cls, register):
        super().register_options(register)
        register(
            "--ipython",
            type=bool,
            fingerprint=True,
            help="Run an IPython REPL instead of the standard python one.",
        )
        register(
            "--ipython-entry-point",
            advanced=True,
            default="IPython:start_ipython",
            removal_version="1.27.0.dev0",
            removal_hint="Use `--ipython-entry-point` instead of `--repl-py-ipython-entry-point`.",
            fingerprint=True,
            help="The IPython REPL entry point.",
        )
        register(
            "--ipython-requirements",
            advanced=True,
            type=list,
            default=["ipython==5.8.0"],
            removal_version="1.27.0.dev0",
            removal_hint="Use `--ipython-version` and `--ipython-extra-requirements` instead of "
            "`--repl-py-ipython-requirements`.",
            fingerprint=True,
            help="The IPython interpreter version to use.",
        )

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

    @classmethod
    def select_targets(cls, target):
        return isinstance(target, (PythonTarget, PythonRequirementLibrary))

    def extra_requirements(self):
        if not self.get_options().ipython:
            return []
        ipython_version = self._resolve_conflicting_options(
            old_option="ipython_requirements", new_option="version",
        )
        ipython_extra_requirements = self._resolve_conflicting_options(
            old_option="ipython_requirements", new_option="extra_requirements",
        )
        if isinstance(ipython_version, list):
            return self.get_options().ipython_requirements
        return [ipython_version, *ipython_extra_requirements]

    def setup_repl_session(self, targets):
        if self.get_options().ipython:
            entry_point = self._resolve_conflicting_options(
                old_option="ipython_entry_point", new_option="entry_point",
            )
        else:
            entry_point = "code:interact"
        pex_info = PexInfo.default()
        pex_info.entry_point = entry_point
        return self.create_pex(pex_info)

    def _run_repl(self, pex, **pex_run_kwargs):
        env = self.prepare_pex_env(env=pex_run_kwargs.pop("env", None))
        pex.run(env=env, **pex_run_kwargs)

    # N.B. **pex_run_kwargs is used by tests only.
    def launch_repl(self, pex, **pex_run_kwargs):
        # While the repl subprocess is synchronously spawned, we rely on process group
        # signalling for a SIGINT to reach the repl subprocess directly - and want to
        # do nothing in response on the parent side.
        #
        # NB: We use ExceptionSink.ignoring_sigint instead of ExceptionSink.trapped_signals here
        # because this code may be running from a non-main thread when run under pantsd, and therefore
        # will crash if we try to install new signal handlers.
        with ExceptionSink.ignoring_sigint():
            self._run_repl(pex, **pex_run_kwargs)