#!/usr/bin/env python

import asyncio
import functools
import getpass
import json
import logging
import os
import pip
import pkg_resources
import platform
import shutil
import signal
import sys
from argparse import Namespace
from copy import deepcopy
from pathlib import Path
from typing import NoReturn

import discord
import rich

# Set the event loop policies here so any subsequent `new_event_loop()`
# calls, in particular those as a result of the following imports,
# return the correct loop object.
from redbot import _early_init, __version__

_early_init()

import redbot.logging
from redbot.core.bot import Red, ExitCodes
from redbot.core.cli import interactive_config, confirm, parse_cli_flags
from redbot.setup import get_data_dir, get_name, save_config
from redbot.core import data_manager, drivers
from redbot.core._sharedlibdeprecation import SharedLibImportWarner


log = logging.getLogger("red.main")

#
#               Red - Discord Bot v3
#
#         Made by Twentysix, improved by many
#


def _get_instance_names():
    with data_manager.config_file.open(encoding="utf-8") as fs:
        data = json.load(fs)
    return sorted(data.keys())


def list_instances():
    if not data_manager.config_file.exists():
        print(
            "No instances have been configured! Configure one "
            "using `redbot-setup` before trying to run the bot!"
        )
        sys.exit(1)
    else:
        text = "Configured Instances:\n\n"
        for instance_name in _get_instance_names():
            text += "{}\n".format(instance_name)
        print(text)
        sys.exit(0)


def debug_info():
    """Shows debug information useful for debugging."""
    if sys.platform == "linux":
        import distro  # pylint: disable=import-error

    IS_WINDOWS = os.name == "nt"
    IS_MAC = sys.platform == "darwin"
    IS_LINUX = sys.platform == "linux"

    pyver = sys.version
    pipver = pip.__version__
    redver = __version__
    dpy_version = discord.__version__
    if IS_WINDOWS:
        os_info = platform.uname()
        osver = "{} {} (version {})".format(os_info.system, os_info.release, os_info.version)
    elif IS_MAC:
        os_info = platform.mac_ver()
        osver = "Mac OSX {} {}".format(os_info[0], os_info[2])
    else:
        osver = f"{distro.name()} {distro.version()}".strip()
    user_who_ran = getpass.getuser()
    info = (
        "Debug Info for Red\n\n"
        + "Red version: {}\n".format(redver)
        + "Python version: {}\n".format(pyver)
        + "Python executable: {}\n".format(sys.executable)
        + "Discord.py version: {}\n".format(dpy_version)
        + "Pip version: {}\n".format(pipver)
        + "OS version: {}\n".format(osver)
        + "System arch: {}\n".format(platform.machine())
        + "User: {}\n".format(user_who_ran)
        + "Metadata file: {}\n".format(data_manager.config_file)
    )
    print(info)
    sys.exit(0)


async def edit_instance(red, cli_flags):
    no_prompt = cli_flags.no_prompt
    token = cli_flags.token
    owner = cli_flags.owner
    prefix = cli_flags.prefix
    old_name = cli_flags.instance_name
    new_name = cli_flags.edit_instance_name
    data_path = cli_flags.edit_data_path
    copy_data = cli_flags.copy_data
    confirm_overwrite = cli_flags.overwrite_existing_instance

    if data_path is None and copy_data:
        print("--copy-data can't be used without --edit-data-path argument")
        sys.exit(1)
    if new_name is None and confirm_overwrite:
        print("--overwrite-existing-instance can't be used without --edit-instance-name argument")
        sys.exit(1)
    if (
        no_prompt
        and all(to_change is None for to_change in (token, owner, new_name, data_path))
        and not prefix
    ):
        print(
            "No arguments to edit were provided."
            " Available arguments (check help for more information):"
            " --edit-instance-name, --edit-data-path, --copy-data, --owner, --token, --prefix"
        )
        sys.exit(1)

    await _edit_token(red, token, no_prompt)
    await _edit_prefix(red, prefix, no_prompt)
    await _edit_owner(red, owner, no_prompt)

    data = deepcopy(data_manager.basic_config)
    name = _edit_instance_name(old_name, new_name, confirm_overwrite, no_prompt)
    _edit_data_path(data, name, data_path, copy_data, no_prompt)

    save_config(name, data)
    if old_name != name:
        save_config(old_name, {}, remove=True)


async def _edit_token(red, token, no_prompt):
    if token:
        if not len(token) >= 50:
            print(
                "The provided token doesn't look a valid Discord bot token."
                " Instance's token will remain unchanged.\n"
            )
            return
        await red._config.token.set(token)
    elif not no_prompt and confirm("Would you like to change instance's token?", default=False):
        await interactive_config(red, False, True, print_header=False)
        print("Token updated.\n")


async def _edit_prefix(red, prefix, no_prompt):
    if prefix:
        prefixes = sorted(prefix, reverse=True)
        await red._config.prefix.set(prefixes)
    elif not no_prompt and confirm("Would you like to change instance's prefixes?", default=False):
        print(
            "Enter the prefixes, separated by a space (please note "
            "that prefixes containing a space will need to be added with [p]set prefix)"
        )
        while True:
            prefixes = input("> ").strip().split()
            if not prefixes:
                print("You need to pass at least one prefix!")
                continue
            prefixes = sorted(prefixes, reverse=True)
            await red._config.prefix.set(prefixes)
            print("Prefixes updated.\n")
            break


async def _edit_owner(red, owner, no_prompt):
    if owner:
        if not (15 <= len(str(owner)) <= 20):
            print(
                "The provided owner id doesn't look like a valid Discord user id."
                " Instance's owner will remain unchanged."
            )
            return
        await red._config.owner.set(owner)
    elif not no_prompt and confirm("Would you like to change instance's owner?", default=False):
        print(
            "Remember:\n"
            "ONLY the person who is hosting Red should be owner."
            " This has SERIOUS security implications."
            " The owner can access any data that is present on the host system.\n"
        )
        if confirm("Are you sure you want to change instance's owner?", default=False):
            print("Please enter a Discord user id for new owner:")
            while True:
                owner_id = input("> ").strip()
                if not (15 <= len(owner_id) <= 20 and owner_id.isdecimal()):
                    print("That doesn't look like a valid Discord user id.")
                    continue
                owner_id = int(owner_id)
                await red._config.owner.set(owner_id)
                print("Owner updated.")
                break
        else:
            print("Instance's owner will remain unchanged.")
        print()


def _edit_instance_name(old_name, new_name, confirm_overwrite, no_prompt):
    if new_name:
        name = new_name
        if name in _get_instance_names() and not confirm_overwrite:
            name = old_name
            print(
                "An instance with this name already exists.\n"
                "If you want to remove the existing instance and replace it with this one,"
                " run this command with --overwrite-existing-instance flag."
            )
    elif not no_prompt and confirm("Would you like to change the instance name?", default=False):
        name = get_name()
        if name in _get_instance_names():
            print(
                "WARNING: An instance already exists with this name. "
                "Continuing will overwrite the existing instance config."
            )
            if not confirm(
                "Are you absolutely certain you want to continue with this instance name?",
                default=False,
            ):
                print("Instance name will remain unchanged.")
                name = old_name
            else:
                print("Instance name updated.")
        else:
            print("Instance name updated.")
        print()
    else:
        name = old_name
    return name


def _edit_data_path(data, instance_name, data_path, copy_data, no_prompt):
    # This modifies the passed dict.
    if data_path:
        new_path = Path(data_path)
        try:
            exists = new_path.exists()
        except OSError:
            print(
                "We were unable to check your chosen directory."
                " Provided path may contain an invalid character."
                " Data location will remain unchanged."
            )

        if not exists:
            try:
                new_path.mkdir(parents=True, exist_ok=True)
            except OSError:
                print(
                    "We were unable to create your chosen directory."
                    " Data location will remain unchanged."
                )
        data["DATA_PATH"] = data_path
        if copy_data and not _copy_data(data):
            print("Can't copy data to non-empty location. Data location will remain unchanged.")
            data["DATA_PATH"] = data_manager.basic_config["DATA_PATH"]
    elif not no_prompt and confirm("Would you like to change the data location?", default=False):
        data["DATA_PATH"] = get_data_dir(instance_name)
        if confirm("Do you want to copy the data from old location?", default=True):
            if not _copy_data(data):
                print("Can't copy the data to non-empty location.")
                if not confirm("Do you still want to use the new data location?"):
                    data["DATA_PATH"] = data_manager.basic_config["DATA_PATH"]
                    print("Data location will remain unchanged.")
                    return
            print("Old data has been copied over to the new location.")
        print("Data location updated.")


def _copy_data(data):
    if Path(data["DATA_PATH"]).exists():
        if any(os.scandir(data["DATA_PATH"])):
            return False
        else:
            # this is needed because copytree doesn't work when destination folder exists
            # Python 3.8 has `dirs_exist_ok` option for that
            os.rmdir(data["DATA_PATH"])
    shutil.copytree(data_manager.basic_config["DATA_PATH"], data["DATA_PATH"])
    return True


def handle_edit(cli_flags: Namespace):
    """
    This one exists to not log all the things like it's a full run of the bot.
    """
    loop = asyncio.new_event_loop()
    asyncio.set_event_loop(loop)
    data_manager.load_basic_configuration(cli_flags.instance_name)
    red = Red(cli_flags=cli_flags, description="Red V3", dm_help=None)
    try:
        driver_cls = drivers.get_driver_class()
        loop.run_until_complete(driver_cls.initialize(**data_manager.storage_details()))
        loop.run_until_complete(edit_instance(red, cli_flags))
        loop.run_until_complete(driver_cls.teardown())
    except (KeyboardInterrupt, EOFError):
        print("Aborted!")
    finally:
        loop.run_until_complete(asyncio.sleep(1))
        asyncio.set_event_loop(None)
        loop.stop()
        loop.close()
        sys.exit(0)


async def run_bot(red: Red, cli_flags: Namespace) -> None:
    """
    This runs the bot.

    Any shutdown which is a result of not being able to log in needs to raise
    a SystemExit exception.

    If the bot starts normally, the bot should be left to handle the exit case.
    It will raise SystemExit in a task, which will reach the event loop and
    interrupt running forever, then trigger our cleanup process, and does not
    need additional handling in this function.
    """

    driver_cls = drivers.get_driver_class()

    await driver_cls.initialize(**data_manager.storage_details())

    redbot.logging.init_logging(
        level=cli_flags.logging_level,
        location=data_manager.core_data_path() / "logs",
        cli_flags=cli_flags,
    )

    log.debug("====Basic Config====")
    log.debug("Data Path: %s", data_manager._base_data_path())
    log.debug("Storage Type: %s", data_manager.storage_type())

    # lib folder has to be in sys.path before trying to load any 3rd-party cog (GH-3061)
    # We might want to change handling of requirements in Downloader at later date
    LIB_PATH = data_manager.cog_data_path(raw_name="Downloader") / "lib"
    LIB_PATH.mkdir(parents=True, exist_ok=True)
    if str(LIB_PATH) not in sys.path:
        sys.path.append(str(LIB_PATH))

        # "It's important to note that the global `working_set` object is initialized from
        # `sys.path` when `pkg_resources` is first imported, but is only updated if you do
        # all future `sys.path` manipulation via `pkg_resources` APIs. If you manually modify
        # `sys.path`, you must invoke the appropriate methods on the `working_set` instance
        # to keep it in sync."
        # Source: https://setuptools.readthedocs.io/en/latest/pkg_resources.html#workingset-objects
        pkg_resources.working_set.add_entry(str(LIB_PATH))
    sys.meta_path.insert(0, SharedLibImportWarner())

    if cli_flags.token:
        token = cli_flags.token
    else:
        token = os.environ.get("RED_TOKEN", None)
        if not token:
            token = await red._config.token()

    prefix = cli_flags.prefix or await red._config.prefix()

    if not (token and prefix):
        if cli_flags.no_prompt is False:
            new_token = await interactive_config(
                red, token_set=bool(token), prefix_set=bool(prefix)
            )
            if new_token:
                token = new_token
        else:
            log.critical("Token and prefix must be set in order to login.")
            sys.exit(1)

    if cli_flags.dry_run:
        await red.http.close()
        sys.exit(0)
    try:
        await red.start(token, bot=True, cli_flags=cli_flags)
    except discord.LoginFailure:
        log.critical("This token doesn't seem to be valid.")
        db_token = await red._config.token()
        if db_token and not cli_flags.no_prompt:
            if confirm("\nDo you want to reset the token?"):
                await red._config.token.set("")
                print("Token has been reset.")
                sys.exit(0)
        sys.exit(1)
    except discord.PrivilegedIntentsRequired:
        console = rich.get_console()
        console.print(
            "Red requires all Privileged Intents to be enabled.\n"
            "You can find out how to enable Privileged Intents with this guide:\n"
            "https://docs.discord.red/en/stable/bot_application_guide.html#enabling-privileged-intents",
            style="red",
        )
        sys.exit(1)

    return None


def handle_early_exit_flags(cli_flags: Namespace):
    if cli_flags.list_instances:
        list_instances()
    elif cli_flags.version:
        print("Red V3")
        print("Current Version: {}".format(__version__))
        sys.exit(0)
    elif cli_flags.debuginfo:
        debug_info()
    elif not cli_flags.instance_name and (not cli_flags.no_instance or cli_flags.edit):
        print("Error: No instance name was provided!")
        sys.exit(1)


async def shutdown_handler(red, signal_type=None, exit_code=None):
    if signal_type:
        log.info("%s received. Quitting...", signal_type)
        # Do not collapse the below line into other logic
        # We need to renter this function
        # after it interrupts the event loop.
        sys.exit(ExitCodes.SHUTDOWN)
    elif exit_code is None:
        log.info("Shutting down from unhandled exception")
        red._shutdown_mode = ExitCodes.CRITICAL

    if exit_code is not None:
        red._shutdown_mode = exit_code

    try:
        await red.close()
    finally:
        # Then cancels all outstanding tasks other than ourselves
        pending = [t for t in asyncio.all_tasks() if t is not asyncio.current_task()]
        [task.cancel() for task in pending]
        await asyncio.gather(*pending, return_exceptions=True)


def global_exception_handler(red, loop, context):
    """
    Logs unhandled exceptions in other tasks
    """
    exc = context.get("exception")
    # These will get handled later when it *also* kills loop.run_forever
    if exc is not None and isinstance(exc, (KeyboardInterrupt, SystemExit)):
        return
    # Maybe in the future we should handle some of the other things
    # that the default exception handler handles, but this should work fine for now.
    log.critical(
        "Caught unhandled exception in %s:\n%s",
        context.get("future", "event loop"),
        context["message"],
        exc_info=exc,
    )


def red_exception_handler(red, red_task: asyncio.Future):
    """
    This is set as a done callback for Red

    must be used with functools.partial

    If the main bot.run dies for some reason,
    we don't want to swallow the exception and hang.
    """
    try:
        red_task.result()
    except (SystemExit, KeyboardInterrupt, asyncio.CancelledError):
        pass  # Handled by the global_exception_handler, or cancellation
    except Exception as exc:
        log.critical("The main bot task didn't handle an exception and has crashed", exc_info=exc)
        log.warning("Attempting to die as gracefully as possible...")
        red.loop.create_task(shutdown_handler(red))


def main():
    red = None  # Error handling for users misusing the bot
    cli_flags = parse_cli_flags(sys.argv[1:])
    handle_early_exit_flags(cli_flags)
    if cli_flags.edit:
        handle_edit(cli_flags)
        return
    try:
        loop = asyncio.new_event_loop()
        asyncio.set_event_loop(loop)

        if cli_flags.no_instance:
            print(
                "\033[1m"
                "Warning: The data will be placed in a temporary folder and removed on next system "
                "reboot."
                "\033[0m"
            )
            cli_flags.instance_name = "temporary_red"
            data_manager.create_temp_config()

        data_manager.load_basic_configuration(cli_flags.instance_name)

        red = Red(cli_flags=cli_flags, description="Red V3", dm_help=None)

        if os.name != "nt":
            # None of this works on windows.
            # At least it's not a redundant handler...
            signals = (signal.SIGHUP, signal.SIGTERM, signal.SIGINT)
            for s in signals:
                loop.add_signal_handler(
                    s, lambda s=s: asyncio.create_task(shutdown_handler(red, s))
                )

        exc_handler = functools.partial(global_exception_handler, red)
        loop.set_exception_handler(exc_handler)
        # We actually can't (just) use asyncio.run here
        # We probably could if we didn't support windows, but we might run into
        # a scenario where this isn't true if anyone works on RPC more in the future
        fut = loop.create_task(run_bot(red, cli_flags))
        r_exc_handler = functools.partial(red_exception_handler, red)
        fut.add_done_callback(r_exc_handler)
        loop.run_forever()
    except KeyboardInterrupt:
        # We still have to catch this here too. (*joy*)
        log.warning("Please do not use Ctrl+C to Shutdown Red! (attempting to die gracefully...)")
        log.error("Received KeyboardInterrupt, treating as interrupt")
        if red is not None:
            loop.run_until_complete(shutdown_handler(red, signal.SIGINT))
    except SystemExit as exc:
        # We also have to catch this one here. Basically any exception which normally
        # Kills the python interpreter (Base Exceptions minus asyncio.cancelled)
        # We need to do something with prior to having the loop close
        log.info("Shutting down with exit code: %s", exc.code)
        if red is not None:
            loop.run_until_complete(shutdown_handler(red, None, exc.code))
    except Exception as exc:  # Non standard case.
        log.exception("Unexpected exception (%s): ", type(exc), exc_info=exc)
        if red is not None:
            loop.run_until_complete(shutdown_handler(red, None, ExitCodes.CRITICAL))
    finally:
        # Allows transports to close properly, and prevent new ones from being opened.
        # Transports may still not be closed correctly on windows, see below
        loop.run_until_complete(loop.shutdown_asyncgens())
        # *we* aren't cleaning up more here, but it prevents
        # a runtime error at the event loop on windows
        # with resources which require longer to clean up.
        # With other event loops, a failure to cleanup prior to here
        # results in a resource warning instead
        log.info("Please wait, cleaning up a bit more")
        loop.run_until_complete(asyncio.sleep(2))
        asyncio.set_event_loop(None)
        loop.stop()
        loop.close()
        exit_code = red._shutdown_mode if red is not None else 1
        sys.exit(exit_code)


if __name__ == "__main__":
    main()