# -*- coding: utf-8 -*-
#
# Copyright (c) 2009- Spyder Project Contributors
#
# Distributed under the terms of the MIT License
# (see spyder/__init__.py for details)

"""
Main interpreter Plugin.
"""

# Standard library imports
import os.path as osp

# Third-party import
from qtpy.QtCore import Signal

# Local imports
from spyder.api.plugins import Plugins, SpyderPluginV2
from spyder.api.plugin_registration.decorators import (
    on_plugin_available, on_plugin_teardown)
from spyder.api.translations import _
from spyder.plugins.maininterpreter.confpage import MainInterpreterConfigPage
from spyder.plugins.maininterpreter.container import MainInterpreterContainer
from spyder.utils.misc import get_python_executable


class MainInterpreter(SpyderPluginV2):
    """
    Main interpreter Plugin.
    """

    NAME = "main_interpreter"
    REQUIRES = [Plugins.Preferences]
    CONTAINER_CLASS = MainInterpreterContainer
    CONF_WIDGET_CLASS = MainInterpreterConfigPage
    CONF_SECTION = NAME
    CONF_FILE = False
    CAN_BE_DISABLED = False

    # ---- Signals
    # -------------------------------------------------------------------------
    sig_environments_updated = Signal(dict)
    """
    This signal is emitted when the conda, pyenv or custom environments tracked
    by this plugin were updated.

    Parameters
    ----------
    envs: dict
        Environments dictionary in the format given by
        :py:meth:`spyder.utils.envs.get_list_envs`.
    """

    sig_interpreter_changed = Signal(str)
    """
    Signal to report that the main interpreter has changed.

    Parameters
    ----------
    path: str
        Path to the new interpreter.
    """

    # ---- SpyderPluginV2 API
    # -------------------------------------------------------------------------
    @staticmethod
    def get_name():
        return _("Python interpreter")

    @staticmethod
    def get_description():
        return _(
            "Manage the default Python interpreter used to run, analyze and "
            "profile your code in Spyder."
        )

    @classmethod
    def get_icon(cls):
        return cls.create_icon('python')

    def on_initialize(self):
        container = self.get_container()

        # Connect container signals
        container.sig_environments_updated.connect(
            self.sig_environments_updated
        )
        container.sig_interpreter_changed.connect(self.sig_interpreter_changed)

        # Validate that the custom interpreter from the previous session
        # still exists
        if self.get_conf('custom'):
            interpreter = self.get_conf('custom_interpreter')
            if not osp.isfile(interpreter):
                self.set_conf('custom', False)
                self.set_conf('default', True)
                self.set_conf('executable', get_python_executable())

    @on_plugin_available(plugin=Plugins.Preferences)
    def on_preferences_available(self):
        # Register conf page
        preferences = self.get_plugin(Plugins.Preferences)
        preferences.register_plugin_preferences(self)

    @on_plugin_teardown(plugin=Plugins.Preferences)
    def on_preferences_teardown(self):
        # Deregister conf page
        preferences = self.get_plugin(Plugins.Preferences)
        preferences.deregister_plugin_preferences(self)

    # ---- Public API
    # -------------------------------------------------------------------------
    def set_custom_interpreter(self, interpreter):
        """Set given interpreter as the current selected one."""
        self.get_container().add_to_custom_interpreters(interpreter)
        self.set_conf("default", False)
        self.set_conf("custom", True)
        self.set_conf("custom_interpreter", interpreter)
        self.set_conf("executable", interpreter)