"""Plugin API."""
import copy
import importlib
import logging
import operator
import os
import sys
import tkinter as tk
from builtins import object, str
from typing import Any, Callable, List, Mapping, MutableMapping, Optional, Tuple

import companion
import myNotebook as nb  # noqa: N813
from config import config
from EDMCLogging import get_main_logger

logger = get_main_logger()

# List of loaded Plugins
PLUGINS = []
PLUGINS_not_py3 = []


# For asynchronous error display
class LastError:
    """Holds the last plugin error."""

    msg: Optional[str]
    root: tk.Frame

    def __init__(self) -> None:
        self.msg = None


last_error = LastError()


class Plugin(object):
    """An EDMC plugin."""

    def __init__(self, name: str, loadfile: Optional[str], plugin_logger: Optional[logging.Logger]):
        """
        Load a single plugin.

        :param name: Base name of the file being loaded from.
        :param loadfile: Full path/filename of the plugin.
        :param plugin_logger: The logging instance for this plugin to use.
        :raises Exception: Typically ImportError or OSError
        """
        self.name: str = name  # Display name.
        self.folder: Optional[str] = name  # basename of plugin folder. None for internal plugins.
        self.module = None  # None for disabled plugins.
        self.logger: Optional[logging.Logger] = plugin_logger

        if loadfile:
            logger.info(f'loading plugin "{name.replace(".", "_")}" from "{loadfile}"')
            try:
                filename = 'plugin_'
                filename += name.encode(encoding='ascii', errors='replace').decode('utf-8').replace('.', '_')
                module = importlib.machinery.SourceFileLoader(
                    filename,
                    loadfile
                ).load_module()

                if getattr(module, 'plugin_start3', None):
                    newname = module.plugin_start3(os.path.dirname(loadfile))
                    self.name = newname and str(newname) or name
                    self.module = module
                elif getattr(module, 'plugin_start', None):
                    logger.warning(f'plugin {name} needs migrating\n')
                    PLUGINS_not_py3.append(self)
                else:
                    logger.error(f'plugin {name} has no plugin_start3() function')
            except Exception:
                logger.exception(f': Failed for Plugin "{name}"')
                raise
        else:
            logger.info(f'plugin {name} disabled')

    def _get_func(self, funcname: str) -> Optional[Callable]:
        """
        Get a function from a plugin.

        :param funcname:
        :returns: The function, or None if it isn't implemented.
        """
        return getattr(self.module, funcname, None)

    def get_app(self, parent: tk.Frame) -> Optional[tk.Frame]:
        """
        If the plugin provides mainwindow content create and return it.

        :param parent: the parent frame for this entry.
        :returns: None, a tk Widget, or a pair of tk.Widgets
        """
        plugin_app = self._get_func('plugin_app')
        if plugin_app:
            try:
                appitem = plugin_app(parent)
                if appitem is None:
                    return None

                elif isinstance(appitem, tuple):
                    if (
                        len(appitem) != 2
                        or not isinstance(appitem[0], tk.Widget)
                        or not isinstance(appitem[1], tk.Widget)
                    ):
                        raise AssertionError

                elif not isinstance(appitem, tk.Widget):
                    raise AssertionError

                return appitem

            except Exception:
                logger.exception(f'Failed for Plugin "{self.name}"')

        return None

    def get_prefs(self, parent: tk.Frame, cmdr: str, is_beta: bool) -> Optional[tk.Frame]:
        """
        If the plugin provides a prefs frame, create and return it.

        :param parent: the parent frame for this preference tab.
        :param cmdr: current Cmdr name (or None). Relevant if you want to have
           different settings for different user accounts.
        :param is_beta: whether the player is in a Beta universe.
        :returns: a myNotebook Frame
        """
        plugin_prefs = self._get_func('plugin_prefs')
        if plugin_prefs:
            try:
                frame = plugin_prefs(parent, cmdr, is_beta)
                if not isinstance(frame, nb.Frame):
                    raise AssertionError
                return frame
            except Exception:
                logger.exception(f'Failed for Plugin "{self.name}"')
        return None


def load_plugins(master: tk.Frame) -> None:  # noqa: CCR001
    """Find and load all plugins."""
    last_error.root = master

    internal = []
    for name in sorted(os.listdir(config.internal_plugin_dir_path)):
        if name.endswith('.py') and not name[0] in ['.', '_']:
            try:
                plugin = Plugin(name[:-3], os.path.join(config.internal_plugin_dir_path, name), logger)
                plugin.folder = None  # Suppress listing in Plugins prefs tab
                internal.append(plugin)
            except Exception:
                logger.exception(f'Failure loading internal Plugin "{name}"')
    PLUGINS.extend(sorted(internal, key=lambda p: operator.attrgetter('name')(p).lower()))

    # Add plugin folder to load path so packages can be loaded from plugin folder
    sys.path.append(config.plugin_dir)

    found = []
    # Load any plugins that are also packages first
    for name in sorted(
        os.listdir(config.plugin_dir_path),
        key=lambda n: (not os.path.isfile(os.path.join(config.plugin_dir_path, n, '__init__.py')), n.lower())
    ):
        if not os.path.isdir(os.path.join(config.plugin_dir_path, name)) or name[0] in ['.', '_']:
            pass
        elif name.endswith('.disabled'):
            name, discard = name.rsplit('.', 1)
            found.append(Plugin(name, None, logger))
        else:
            try:
                # Add plugin's folder to load path in case plugin has internal package dependencies
                sys.path.append(os.path.join(config.plugin_dir_path, name))

                # Create a logger for this 'found' plugin.  Must be before the
                # load.py is loaded.
                import EDMCLogging

                plugin_logger = EDMCLogging.get_plugin_logger(name)
                found.append(Plugin(name, os.path.join(config.plugin_dir_path, name, 'load.py'), plugin_logger))
            except Exception:
                logger.exception(f'Failure loading found Plugin "{name}"')
                pass
    PLUGINS.extend(sorted(found, key=lambda p: operator.attrgetter('name')(p).lower()))


def provides(fn_name: str) -> List[str]:
    """
    Find plugins that provide a function.

    :param fn_name:
    :returns: list of names of plugins that provide this function
    .. versionadded:: 3.0.2
    """
    return [p.name for p in PLUGINS if p._get_func(fn_name)]


def invoke(
    plugin_name: str, fallback: str, fn_name: str, *args: Tuple
) -> Optional[str]:
    """
    Invoke a function on a named plugin.

    :param plugin_name: preferred plugin on which to invoke the function
    :param fallback: fallback plugin on which to invoke the function, or None
    :param fn_name:
    :param *args: arguments passed to the function
    :returns: return value from the function, or None if the function was not found
    .. versionadded:: 3.0.2
    """
    for plugin in PLUGINS:
        if plugin.name == plugin_name:
            plugin_func = plugin._get_func(fn_name)
            if plugin_func is not None:
                return plugin_func(*args)

    for plugin in PLUGINS:
        if plugin.name == fallback:
            plugin_func = plugin._get_func(fn_name)
            assert plugin_func, plugin.name  # fallback plugin should provide the function
            return plugin_func(*args)

    return None


def notify_stop() -> Optional[str]:
    """
    Notify each plugin that the program is closing.

    If your plugin uses threads then stop and join() them before returning.
    .. versionadded:: 2.3.7
    """
    error = None
    for plugin in PLUGINS:
        plugin_stop = plugin._get_func('plugin_stop')
        if plugin_stop:
            try:
                logger.info(f'Asking plugin "{plugin.name}" to stop...')
                newerror = plugin_stop()
                error = error or newerror
            except Exception:
                logger.exception(f'Plugin "{plugin.name}" failed')

    logger.info('Done')

    return error


def notify_prefs_cmdr_changed(cmdr: str, is_beta: bool) -> None:
    """
    Notify plugins that the Cmdr was changed while the settings dialog is open.

    Relevant if you want to have different settings for different user accounts.
    :param cmdr: current Cmdr name (or None).
    :param is_beta: whether the player is in a Beta universe.
    """
    for plugin in PLUGINS:
        prefs_cmdr_changed = plugin._get_func('prefs_cmdr_changed')
        if prefs_cmdr_changed:
            try:
                prefs_cmdr_changed(cmdr, is_beta)
            except Exception:
                logger.exception(f'Plugin "{plugin.name}" failed')


def notify_prefs_changed(cmdr: str, is_beta: bool) -> None:
    """
    Notify plugins that the settings dialog has been closed.

    The prefs frame and any widgets you created in your `get_prefs()` callback
    will be destroyed on return from this function, so take a copy of any
    values that you want to save.
    :param cmdr: current Cmdr name (or None).
    :param is_beta: whether the player is in a Beta universe.
    """
    for plugin in PLUGINS:
        prefs_changed = plugin._get_func('prefs_changed')
        if prefs_changed:
            try:
                prefs_changed(cmdr, is_beta)
            except Exception:
                logger.exception(f'Plugin "{plugin.name}" failed')


def notify_journal_entry(
    cmdr: str, is_beta: bool, system: str, station: str,
    entry: MutableMapping[str, Any],
    state: Mapping[str, Any]
) -> Optional[str]:
    """
    Send a journal entry to each plugin.

    :param cmdr: The Cmdr name, or None if not yet known
    :param system: The current system, or None if not yet known
    :param station: The current station, or None if not docked or not yet known
    :param entry: The journal entry as a dictionary
    :param state: A dictionary containing info about the Cmdr, current ship and cargo
    :param is_beta: whether the player is in a Beta universe.
    :returns: Error message from the first plugin that returns one (if any)
    """
    if entry['event'] in ('Location'):
        logger.trace_if('journal.locations', 'Notifying plugins of "Location" event')

    error = None
    for plugin in PLUGINS:
        journal_entry = plugin._get_func('journal_entry')
        if journal_entry:
            try:
                # Pass a copy of the journal entry in case the callee modifies it
                newerror = journal_entry(cmdr, is_beta, system, station, dict(entry), dict(state))
                error = error or newerror
            except Exception:
                logger.exception(f'Plugin "{plugin.name}" failed')
    return error


def notify_journal_entry_cqc(
    cmdr: str, is_beta: bool,
    entry: MutableMapping[str, Any],
    state: Mapping[str, Any]
) -> Optional[str]:
    """
    Send an in-CQC journal entry to each plugin.

    :param cmdr: The Cmdr name, or None if not yet known
    :param entry: The journal entry as a dictionary
    :param state: A dictionary containing info about the Cmdr, current ship and cargo
    :param is_beta: whether the player is in a Beta universe.
    :returns: Error message from the first plugin that returns one (if any)
    """
    error = None
    for plugin in PLUGINS:
        cqc_callback = plugin._get_func('journal_entry_cqc')
        if cqc_callback is not None and callable(cqc_callback):
            try:
                # Pass a copy of the journal entry in case the callee modifies it
                newerror = cqc_callback(cmdr, is_beta, copy.deepcopy(entry), copy.deepcopy(state))
                error = error or newerror

            except Exception:
                logger.exception(f'Plugin "{plugin.name}" failed while handling CQC mode journal entry')

    return error


def notify_dashboard_entry(
    cmdr: str, is_beta: bool,
    entry: MutableMapping[str, Any],
) -> Optional[str]:
    """
    Send a status entry to each plugin.

    :param cmdr: The piloting Cmdr name
    :param is_beta: whether the player is in a Beta universe.
    :param entry: The status entry as a dictionary
    :returns: Error message from the first plugin that returns one (if any)
    """
    error = None
    for plugin in PLUGINS:
        status = plugin._get_func('dashboard_entry')
        if status:
            try:
                # Pass a copy of the status entry in case the callee modifies it
                newerror = status(cmdr, is_beta, dict(entry))
                error = error or newerror
            except Exception:
                logger.exception(f'Plugin "{plugin.name}" failed')
    return error


def notify_newdata(
    data: companion.CAPIData,
    is_beta: bool
) -> Optional[str]:
    """
    Send the latest EDMC data from the FD servers to each plugin.

    :param data:
    :param is_beta: whether the player is in a Beta universe.
    :returns: Error message from the first plugin that returns one (if any)
    """
    error = None
    for plugin in PLUGINS:
        cmdr_data = plugin._get_func('cmdr_data')
        if cmdr_data:
            try:
                newerror = cmdr_data(data, is_beta)
                error = error or newerror
            except Exception:
                logger.exception(f'Plugin "{plugin.name}" failed')
    return error


def show_error(err: str) -> None:
    """
    Display an error message in the status line of the main window.

    Will be NOP during shutdown to avoid Tk hang.
    :param err:
    .. versionadded:: 2.3.7
    """
    if config.shutting_down:
        logger.info(f'Called during shutdown: "{str(err)}"')
        return

    if err and last_error.root:
        last_error.msg = str(err)
        last_error.root.event_generate('<<PluginError>>', when="tail")