import sys
import codecs
import datetime
import logging
from distutils.version import StrictVersion

import aiohttp
import pkg_resources
import traceback
from pkg_resources import DistributionNotFound


import discord
from discord.ext import commands

from . import __version__
from .data_manager import storage_type
from .utils.chat_formatting import inline, bordered, pagify, box
from .utils import fuzzy_command_search
from colorama import Fore, Style, init
from . import rpc

log = logging.getLogger("red")
sentry_log = logging.getLogger("red.sentry")
init()

INTRO = """
______         _           ______ _                       _  ______       _   
| ___ \       | |          |  _  (_)                     | | | ___ \     | |  
| |_/ /___  __| |  ______  | | | |_ ___  ___ ___  _ __ __| | | |_/ / ___ | |_ 
|    // _ \/ _` | |______| | | | | / __|/ __/ _ \| '__/ _` | | ___ \/ _ \| __|
| |\ \  __/ (_| |          | |/ /| \__ \ (_| (_) | | | (_| | | |_/ / (_) | |_ 
\_| \_\___|\__,_|          |___/ |_|___/\___\___/|_|  \__,_| \____/ \___/ \__|
"""


def should_log_sentry(exception) -> bool:
    e = exception
    while e.__cause__ is not None:
        e = e.__cause__

    tb = e.__traceback__
    tb_frame = None
    while tb is not None:
        tb_frame = tb.tb_frame
        tb = tb.tb_next

    module = tb_frame.f_globals.get("__name__")
    return module.startswith("redbot")


def init_events(bot, cli_flags):
    @bot.event
    async def on_connect():
        if bot.uptime is None:
            print("Connected to Discord. Getting ready...")

    @bot.event
    async def on_ready():
        if bot.uptime is not None:
            return

        bot.uptime = datetime.datetime.utcnow()
        packages = []

        if cli_flags.no_cogs is False:
            packages.extend(await bot.db.packages())

        if cli_flags.load_cogs:
            packages.extend(cli_flags.load_cogs)

        if packages:
            to_remove = []
            print("Loading packages...")
            for package in packages:
                try:
                    spec = await bot.cog_mgr.find_cog(package)
                    await bot.load_extension(spec)
                except Exception as e:
                    log.exception("Failed to load package {}".format(package), exc_info=e)
                    await bot.remove_loaded_package(package)
                    to_remove.append(package)
            for package in to_remove:
                packages.remove(package)
            if packages:
                print("Loaded packages: " + ", ".join(packages))

        if bot.rpc_enabled:
            await bot.rpc.initialize()

        guilds = len(bot.guilds)
        users = len(set([m for m in bot.get_all_members()]))

        try:
            data = await bot.application_info()
            invite_url = discord.utils.oauth_url(data.id)
        except:
            if bot.user.bot:
                invite_url = "Could not fetch invite url"
            else:
                invite_url = None

        prefixes = cli_flags.prefix or (await bot.db.prefix())
        lang = await bot.db.locale()
        red_version = __version__
        red_pkg = pkg_resources.get_distribution("Red-DiscordBot")
        dpy_version = discord.__version__

        INFO = [
            str(bot.user),
            "Prefixes: {}".format(", ".join(prefixes)),
            "Language: {}".format(lang),
            "Red Bot Version: {}".format(red_version),
            "Discord.py Version: {}".format(dpy_version),
            "Shards: {}".format(bot.shard_count),
        ]

        if guilds:
            INFO.extend(("Servers: {}".format(guilds), "Users: {}".format(users)))
        else:
            print("Ready. I'm not in any server yet!")

        INFO.append("{} cogs with {} commands".format(len(bot.cogs), len(bot.commands)))

        try:
            async with aiohttp.ClientSession() as session:
                async with session.get("https://pypi.python.org/pypi/red-discordbot/json") as r:
                    data = await r.json()
            if StrictVersion(data["info"]["version"]) > StrictVersion(red_version):
                INFO.append(
                    "Outdated version! {} is available "
                    "but you're using {}".format(data["info"]["version"], red_version)
                )
                owner = discord.utils.get(bot.get_all_members(), id=bot.owner_id)
                await owner.send(
                    "Your Red instance is out of date! {} is the current "
                    "version, however you are using {}!".format(
                        data["info"]["version"], red_version
                    )
                )
        except:
            pass
        INFO2 = []

        sentry = await bot.db.enable_sentry()
        mongo_enabled = storage_type() != "JSON"
        reqs_installed = {"voice": None, "docs": None, "test": None}
        for key in reqs_installed.keys():
            reqs = [x.name for x in red_pkg._dep_map[key]]
            try:
                pkg_resources.require(reqs)
            except DistributionNotFound:
                reqs_installed[key] = False
            else:
                reqs_installed[key] = True

        options = (
            ("Error Reporting", sentry),
            ("MongoDB", mongo_enabled),
            ("Voice", reqs_installed["voice"]),
            ("Docs", reqs_installed["docs"]),
            ("Tests", reqs_installed["test"]),
        )

        on_symbol, off_symbol, ascii_border = _get_startup_screen_specs()

        for option, enabled in options:
            enabled = on_symbol if enabled else off_symbol
            INFO2.append("{} {}".format(enabled, option))

        print(Fore.RED + INTRO)
        print(Style.RESET_ALL)
        print(bordered(INFO, INFO2, ascii_border=ascii_border))

        if invite_url:
            print("\nInvite URL: {}\n".format(invite_url))

        bot.color = discord.Colour(await bot.db.color())

    @bot.event
    async def on_error(event_method, *args, **kwargs):
        sentry_log.exception("Exception in {}".format(event_method))

    @bot.event
    async def on_command_error(ctx, error):
        if isinstance(error, commands.MissingRequiredArgument):
            await ctx.send_help()
        elif isinstance(error, commands.BadArgument):
            await ctx.send_help()
        elif isinstance(error, commands.DisabledCommand):
            await ctx.send("That command is disabled.")
        elif isinstance(error, commands.CommandInvokeError):
            # Need to test if the following still works
            """
            no_dms = "Cannot send messages to this user"
            is_help_cmd = ctx.command.qualified_name == "help"
            is_forbidden = isinstance(error.original, discord.Forbidden)
            if is_help_cmd and is_forbidden and error.original.text == no_dms:
                msg = ("I couldn't send the help message to you in DM. Either"
                       " you blocked me or you disabled DMs in this server.")
                await ctx.send(msg)
                return
            """
            log.exception(
                "Exception in command '{}'" "".format(ctx.command.qualified_name),
                exc_info=error.original,
            )
            if should_log_sentry(error):
                sentry_log.exception(
                    "Exception in command '{}'" "".format(ctx.command.qualified_name),
                    exc_info=error.original,
                )

            message = (
                "Error in command '{}'. Check your console or "
                "logs for details."
                "".format(ctx.command.qualified_name)
            )
            exception_log = "Exception in command '{}'\n" "".format(ctx.command.qualified_name)
            exception_log += "".join(
                traceback.format_exception(type(error), error, error.__traceback__)
            )
            bot._last_exception = exception_log
            if not hasattr(ctx.cog, "_{0.command.cog_name}__error".format(ctx)):
                await ctx.send(inline(message))
        elif isinstance(error, commands.CommandNotFound):
            term = ctx.invoked_with + " "
            if len(ctx.args) > 1:
                term += " ".join(ctx.args[1:])
            fuzzy_result = await fuzzy_command_search(ctx, ctx.invoked_with)
            if fuzzy_result is not None:
                await ctx.maybe_send_embed(fuzzy_result)
        elif isinstance(error, commands.CheckFailure):
            pass
        elif isinstance(error, commands.NoPrivateMessage):
            await ctx.send("That command is not available in DMs.")
        elif isinstance(error, commands.CommandOnCooldown):
            await ctx.send(
                "This command is on cooldown. " "Try again in {:.2f}s" "".format(error.retry_after)
            )
        else:
            log.exception(type(error).__name__, exc_info=error)
            try:
                sentry_error = error.original
            except AttributeError:
                sentry_error = error

            if should_log_sentry(sentry_error):
                sentry_log.exception("Unhandled command error.", exc_info=sentry_error)

    @bot.event
    async def on_message(message):
        bot.counter["messages_read"] += 1
        await bot.process_commands(message)

    @bot.event
    async def on_resumed():
        bot.counter["sessions_resumed"] += 1

    @bot.event
    async def on_command(command):
        bot.counter["processed_commands"] += 1


def _get_startup_screen_specs():
    """Get specs for displaying the startup screen on stdout.

    This is so we don't get encoding errors when trying to print unicode
    emojis to stdout (particularly with Windows Command Prompt).

    Returns
    -------
    `tuple`
        Tuple in the form (`str`, `str`, `bool`) containing (in order) the
        on symbol, off symbol and whether or not the border should be pure ascii.

    """
    encoder = codecs.getencoder(sys.stdout.encoding)
    check_mark = "\N{SQUARE ROOT}"
    try:
        encoder(check_mark)
    except UnicodeEncodeError:
        on_symbol = "[X]"
        off_symbol = "[ ]"
    else:
        on_symbol = check_mark
        off_symbol = "X"

    try:
        encoder("┌┐└┘─│")  # border symbols
    except UnicodeEncodeError:
        ascii_border = True
    else:
        ascii_border = False

    return on_symbol, off_symbol, ascii_border