"""greeter.py: welcomes each person who joins a presence room, to them alone, in Python:
"Welcome, Ada! Bo and Cy are here." Someone who was here before (since the bot started) gets
"Welcome back, Ada!". Python 3.10+. pip install -r requirements.txt, then python greeter.py
(reads .env).

Its key (dashboard, New API key): rights subscribe and client_events, kind presence, channels:
prefix presence-chat-.

Names come from the member data the app's backend signed into each join token ({ name, user_id }),
never from anything a member sends. The greeting goes to one connection (send_to).
"""

import asyncio

from pikoman_bot import Bot, env

ROOMS = [r.strip() for r in env("ROOMS", "presence-chat-lobby").split(",") if r.strip()]

bot = Bot("Greeter", access=3)
queue = asyncio.Queue()  # greetings wait their turn: eight a second, under the limit of 10
seen = {}  # room -> people seen there since the bot started (in memory: a restart forgets them)


def who(connection, data):
    """Who a member is, from its signed member data: its user id, or its connection without one."""
    data = data if isinstance(data, dict) else {}
    return f"user:{data['user_id']}" if "user_id" in data else f"connection:{connection}"


def name_of(data):
    name = data.get("name") if isinstance(data, dict) else None
    return name.strip()[:40] if isinstance(name, str) and name.strip() else "there"


def listed(names):
    """"Bo", "Bo and Cy", "Bo, Cy and Di", "Bo, Cy, Di and 4 others"."""
    if len(names) <= 1:
        return "".join(names)
    if len(names) <= 3:
        return f"{', '.join(names[:-1])} and {names[-1]}"
    return f"{', '.join(names[:3])} and {len(names) - 3} others"


def greet(room):
    before = seen.setdefault(room.name, set())

    @room.on_join
    async def joined(connection, data):
        if room.is_bot(connection):
            return  # other bots are not greeted
        person = who(connection, data)
        others = [(c, d) for c, d in room.members.items() if c != connection and not room.is_bot(c)]
        if any(who(c, d) == person for c, d in others):
            return  # the same person in a second tab: greeted once
        names = list({who(c, d): name_of(d) for c, d in others}.values())
        text = f"Welcome back, {name_of(data)}!" if person in before else f"Welcome, {name_of(data)}!"
        if not names:
            text += " You're the first one here."
        else:
            text += f" {listed(names)} {'is' if len(names) == 1 else 'are'} here."
        before.add(person)
        await queue.put((room, connection, text))


async def send_greetings():
    while True:
        room, connection, text = await queue.get()
        # To that connection alone: nobody else in the room sees it.
        await room.send_to(connection, "welcome", {"text": text})
        await asyncio.sleep(0.125)


for name in ROOMS:
    greet(bot.join(name))

print(f"Greeting in {', '.join(ROOMS)}")
bot.start(send_greetings())