import json
import logging
from datetime import datetime, timedelta
from functools import wraps
from os import getenv, path
from typing import Dict, Optional, Union

from disnake import Asset, Client, Guild, Intents, Member, User
from disnake.guild_scheduled_event import GuildScheduledEvent
from dotenv import load_dotenv
from ics import Calendar, ContentLine, Event
from ics.alarm import DisplayAlarm
from oauthlib.oauth2 import OAuth2Error
from quart import Quart, redirect, render_template, request, session, url_for
from requests_oauthlib import OAuth2Session  # type: ignore
from uvicorn.middleware.proxy_headers import ProxyHeadersMiddleware


load_dotenv()

DISCORD_TOKEN = getenv("DISCORD_TOKEN")
OAUTH2_CLIENT_ID = getenv("OAUTH2_CLIENT_ID")
OAUTH2_CLIENT_SECRET = getenv("OAUTH2_CLIENT_SECRET")
if not DISCORD_TOKEN:
    raise Exception("Missing DISCORD_TOKEN")
if not OAUTH2_CLIENT_ID:
    raise Exception("Missing OAUTH2_CLIENT_ID")
if not OAUTH2_CLIENT_SECRET:
    raise Exception("Missing OAUTH2_CLIENT_SECRET")

QUART_DEBUG = getenv("QUART_DEBUG", False)
if QUART_DEBUG:
    logging.basicConfig(level=logging.DEBUG)

API_BASE_URL = getenv("API_BASE_URL", "https://discordapp.com/api")
AUTHORIZATION_BASE_URL = f"{API_BASE_URL}/oauth2/authorize"
TOKEN_URL = f"{API_BASE_URL}/oauth2/token"

CATALOG_CACHE = {}
EVENTS_CACHE = {}


class Discord(Client):
    async def on_ready(self):
        print(f"Logged on as {self.user}!", flush=True)

        for guild in self.guilds:
            for scheduled_event in guild.scheduled_events:
                EVENTS_CACHE[scheduled_event.id] = [
                    member.id
                    for member in await scheduled_event.fetch_users().flatten()
                ]

        print("Events synchronised!", flush=True)

    async def on_guild_scheduled_event_subscribe(
        self, event: GuildScheduledEvent, user: Union[Member, User]
    ):
        EVENTS_CACHE[event.id].append(user.id)

    async def on_guild_scheduled_event_unsubscribe(
        self, event: GuildScheduledEvent, user: Union[Member, User]
    ):
        EVENTS_CACHE[event.id].remove(user.id)

    async def on_guild_scheduled_event_create(self, event: GuildScheduledEvent):
        EVENTS_CACHE[event.id] = [
            member.id for member in await event.fetch_users().flatten()
        ]

    async def on_guild_scheduled_event_delete(self, event: GuildScheduledEvent):
        EVENTS_CACHE.pop(event.id)


intents = Intents.default()
intents.guild_scheduled_events = True
intents.members = True
client = Discord(intents=intents)

app = Quart(__name__)
app.config["SECRET_KEY"] = OAUTH2_CLIENT_SECRET
app.config["EXPLAIN_TEMPLATE_LOADING"] = QUART_DEBUG
app.asgi_app = ProxyHeadersMiddleware(app.asgi_app, "*")  # type: ignore


def get_guild_by_id(guild_id: str) -> Optional[Guild]:
    if guild_id:
        for guild in client.guilds:
            if str(guild.id) == guild_id or guild.vanity_url_code == guild_id:
                return guild
    return None


@app.errorhandler(500)
async def errorhandler(error: Exception):
    print(f"\33[31m{error}\33[m", flush=True)
    return await render_template("error.html.j2", error=str(error)), 500


@app.errorhandler(404)
async def not_found(error: Exception):
    return await render_template("error.html.j2", error=str(error)), 404


def token_updater(token: str):
    session["oauth2_token"] = token


def make_session(
    token: Optional[Dict[str, str]] = None, state: Optional[str] = None
) -> OAuth2Session:
    return OAuth2Session(
        client_id=OAUTH2_CLIENT_ID,
        token=token,
        state=state,
        scope=["identify", "guilds"],
        redirect_uri=f"{request.host_url}callback",
        auto_refresh_kwargs={
            "client_id": OAUTH2_CLIENT_ID,
            "client_secret": OAUTH2_CLIENT_SECRET,
        },
        auto_refresh_url=TOKEN_URL,
        token_updater=token_updater,
    )


def i18n(str: str) -> str:
    lang = request.accept_languages.best_match(["en", "fr"])

    if lang not in CATALOG_CACHE:
        catalog_file = f"{path.dirname(__file__)}/translations/{lang}.json"
        if path.exists(catalog_file):
            with open(catalog_file) as catalog_json:
                catalog = json.load(catalog_json)
                CATALOG_CACHE[lang] = catalog

    if lang in CATALOG_CACHE and str in CATALOG_CACHE[lang]:
        return CATALOG_CACHE[lang][str]

    return str


def days_before_failure() -> int:
    nextYear = datetime.today().year + 5 - ((datetime.today().year + 5) % 5)
    nextDate = datetime(year=nextYear, month=6, day=3)
    nextDelta = nextDate - datetime.now()

    return nextDelta.days


@app.context_processor
def context_processor():
    return dict(
        _=i18n,
        client=client,
        days_before_failure=days_before_failure(),
    )


def login_required(fn):
    @wraps(fn)
    async def wrapper(*args, **kwargs):
        if session.get("oauth2_token"):
            return await fn(*args, **kwargs)

        session["redirect_url"] = request.path
        return redirect(url_for(".login"))

    return wrapper


@app.route("/")
async def index():
    return await render_template("index.html.j2")


@app.route("/login")
async def login():
    discord = make_session()
    authorization_url, state = discord.authorization_url(AUTHORIZATION_BASE_URL)
    session["oauth2_state"] = state
    return redirect(authorization_url)


@app.route("/callback")
async def callback():
    request_values = await request.values
    if request_values.get("error"):
        return errorhandler(request_values.get("error"))

    try:
        discord = make_session(state=session.get("oauth2_state"))
        token = discord.fetch_token(
            TOKEN_URL,
            client_secret=OAUTH2_CLIENT_SECRET,
            authorization_response=request.url,
        )
        token_updater(token)
    except OAuth2Error as e:
        return errorhandler(e)

    return redirect(session.pop("redirect_url", url_for(".guilds")))


@app.route("/guilds")
@login_required
async def guilds():
    guild = request.args.get("guild")

    if guild:
        return redirect(url_for(".subscribe", entity_id=guild))

    try:
        discord = make_session(token=session.get("oauth2_token"))
        user = discord.get(f"{API_BASE_URL}/users/@me").json()
        user_guilds = discord.get(f"{API_BASE_URL}/users/@me/guilds").json()
    except OAuth2Error:
        return redirect(url_for(".login"))

    common_guilds = []
    for bot_guild in client.guilds:
        for user_guild in user_guilds:
            if str(bot_guild.id) == user_guild["id"]:
                common_guilds.append(bot_guild)

    return await render_template(
        "guilds.html.j2",
        user=user,
        avatar=Asset._from_avatar(None, user["id"], user["avatar"]),
        common_guilds=common_guilds,
    )


@app.route("/subscribe/<entity_id>")
@login_required
async def subscribe(entity_id: str):
    guild = get_guild_by_id(entity_id)

    if guild:
        try:
            discord = make_session(token=session.get("oauth2_token"))
            user_guilds = discord.get(f"{API_BASE_URL}/users/@me/guilds").json()
        except OAuth2Error:
            return redirect(url_for(".login"))

        if not any(str(guild.id) == user_guild["id"] for user_guild in user_guilds):
            return redirect(url_for(".login"))

        return await render_template(
            "subscribe.html.j2",
            avatar=guild.icon,
            entity_id=guild.vanity_url_code or guild.id,
        )

    try:
        user = await client.get_or_fetch_user(int(entity_id))
    except ValueError:
        return redirect(url_for(".login"))

    if user and str(user.id) == entity_id:
        return await render_template(
            "subscribe.html.j2", avatar=user.avatar, entity_id=user.id
        )

    return redirect(url_for(".login"))


def make_event(scheduled_event: GuildScheduledEvent) -> Event:
    event = Event()

    event.summary = scheduled_event.name
    event.begin = scheduled_event.scheduled_start_time
    event.end = scheduled_event.scheduled_end_time
    event.duration = timedelta(hours=2)
    event.uid = str(scheduled_event.id)
    event.description = scheduled_event.description
    event.url = scheduled_event.url
    event.location = (
        scheduled_event.entity_metadata.location
        if scheduled_event.entity_metadata
        else None
    )

    alarm = DisplayAlarm()
    alarm.trigger = timedelta(hours=-1)
    event.alarms.append(alarm)

    return event


@app.route("/<entity_id>.ics")
async def ical(entity_id: str):
    guild = get_guild_by_id(entity_id)

    if guild:
        calendar = Calendar()

        calendar.extra.append(ContentLine(name="REFRESH-INTERVAL", value="PT1H"))
        calendar.extra.append(ContentLine(name="X-PUBLISHED-TTL", value="PT1H"))

        calendar.extra.append(ContentLine(name="NAME", value=guild.name))
        calendar.extra.append(ContentLine(name="X-WR-CALNAME", value=guild.name))

        if guild.description:
            calendar.extra.append(
                ContentLine(name="DESCRIPTION", value=guild.description)
            )
            calendar.extra.append(
                ContentLine(name="X-WR-CALDESC", value=guild.description)
            )

        for scheduled_event in guild.scheduled_events:
            event = make_event(scheduled_event)
            calendar.events.append(event)

        return calendar.serialize()

    try:
        user = await client.get_or_fetch_user(int(entity_id))
    except ValueError:
        return redirect(url_for(".login"))

    if user:
        calendar = Calendar()

        calendar.extra.append(ContentLine(name="REFRESH-INTERVAL", value="PT1H"))
        calendar.extra.append(ContentLine(name="X-PUBLISHED-TTL", value="PT1H"))

        calendar.extra.append(ContentLine(name="NAME", value=client.user.display_name))
        calendar.extra.append(
            ContentLine(name="X-WR-CALNAME", value=client.user.display_name)
        )

        for guild in client.guilds:
            for scheduled_event in guild.scheduled_events:
                if user.id in EVENTS_CACHE[scheduled_event.id]:
                    event = make_event(scheduled_event)
                    calendar.events.append(event)

        return calendar.serialize()

    return redirect(url_for(".login"))


def run():
    client.loop.create_task(client.start(DISCORD_TOKEN))
    app.run("0.0.0.0", loop=client.loop)