from lxmfbot import LXMFBot
from redis import Redis
from time import monotonic
from hashlib import sha256
import json
from functools import reduce

bot = LXMFBot("HSWro Conference Bot")
PASS = '34a77e61000b2ba1f56201332ef64d93f9cdc60e63ab48bc255102586ef7e592'
WRONG_LOGIN_BAN_DURATION = 60


def check_password(password: str) -> bool:
    gotten = sha256(f"hswrosalt{password}".encode(
        'utf-8'), usedforsecurity=True).hexdigest()
    return PASS == gotten


def ban_sender(r, userhash, until):
    r.rpush("hswroconference:banned", str(json.dumps({
        "hash": userhash,
        "until": str(until),
    })))


def check_banned(r, userhash):
    for raw in r.lrange("hswroconference:banned", 0, -1):
        m = json.loads(raw.decode('utf-8'))
        if m['hash'] == userhash:
            if monotonic() > float(m['until']):
                r.lrem("hswroconference:banned", 0, raw)
                print(f"Ban expired for {userhash}, unbanning")
                return False
            return True


def handle_login(msg, r, from_known_sender):
    def login_usage():
        msg.reply("Usage: `/login [NICK] [PASSWORD]`")
    parts = msg.content.split()
    if len(parts) != 3:
        login_usage()
        return
    assert parts[0] == "/login"
    if not check_password(parts[2]):
        ban_sender(r, msg.sender, monotonic() + WRONG_LOGIN_BAN_DURATION)
        return
    r.rpush("hswroconference:users", str(json.dumps({
        "hash": msg.sender,
        "nick": parts[1],
    })))
    msg.reply(f"Logged in as {parts[1]}.")


@bot.received
def echo_msg(msg):
    r = Redis(host='localhost', port=6379, db=0)
    if check_banned(r, msg.sender):
        print(f"Message from banned user: {msg.sender}")
        return
    known_senders = list(map(lambda x: json.loads(x.decode('utf-8')),
                             r.lrange("hswroconference:users", 0, -1)))
    sender_info = reduce(lambda x, y: y if (y["hash"] == msg.sender) else x,
                         known_senders, None)
    from_known_sender = sender_info is not None
    assert isinstance(msg.content, str)
    if msg.content.startswith("/login"):
        handle_login(msg, r, from_known_sender)
        return

    if not from_known_sender:
        msg.reply("Please identify with `/login [NICK] [PASSWORD]`")
    else:
        print(f"Forwarding message from {sender_info['nick']}")
        for r in known_senders:
            if r["hash"] == msg.sender:
                continue
            bot.send(r["hash"], f"<{sender_info['nick']}> {msg.content}")


bot.run()