"""history.py: catch-up for your chat rooms, in Python. Pikoman keeps no messages; this bot does,
the last 50 of each room in its own file (history.jsonl), and when someone comes back it sends
them what they missed, to them alone. A member can also ask for the history ("history" event).
Python 3.10+. pip install -r requirements.txt, then python history.py (reads .env).

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

import json
import time

from pikoman_bot import Bot, env

ROOMS = env("ROOMS", "presence-chat-lobby").split(",")
FILE = env("HISTORY_FILE", "history.jsonl")
KEEP = 50  # messages kept per room
FIRST_VISIT = 20  # what someone who has never been here gets

history = {}  # room -> [{at, name, user_id, text}]
last_seen = {}  # (room, user) -> when that user was last in the room

# Its own storage: one JSON line per message, read back at start.
try:
    with open(FILE, encoding="utf-8") as file:
        for line in file:
            if line.strip():
                message = json.loads(line)
                room_name = message.pop("room")
                history[room_name] = (history.get(room_name, []) + [message])[-KEEP:]
except FileNotFoundError:
    pass  # no file yet: nothing kept

bot = Bot("History", access=3)


def keep(room):
    user_of = {}  # connection -> user id, while they are in

    # Every chat message, kept with who sent it: the name and user id your backend signed.
    @room.on("message")
    def message(sender, data, info):
        if room.is_bot(sender):
            return
        member = room.member(sender)
        kept = {"at": int(time.time() * 1000), "name": member.get("name", "Someone"),
                "user_id": member.get("user_id"), "text": str((data or {}).get("text", ""))[:500]}
        history[room.name] = (history.get(room.name, []) + [kept])[-KEEP:]
        with open(FILE, "a", encoding="utf-8") as file:
            file.write(json.dumps({"room": room.name, **kept}) + "\n")

    # Someone joined: what they missed, to that connection alone.
    @room.on_join
    async def joined(connection, data):
        if room.is_bot(connection) or not isinstance(data, dict) or "user_id" not in data:
            return
        user = str(data["user_id"])
        user_of[connection] = user
        kept = history.get(room.name, [])
        since = last_seen.get((room.name, user))
        missed = kept[-FIRST_VISIT:] if since is None else [m for m in kept if m["at"] > since]
        if missed:
            await room.send_to(connection, "missed", {"since": since, "messages": missed})

    @room.on_leave
    def left(connection, data):
        user = user_of.pop(connection, None)
        if user:
            last_seen[(room.name, user)] = int(time.time() * 1000)

    # Asked for: all that is kept, to the one who asked.
    @room.on("history")
    async def asked(sender, data, info):
        await room.send_to(sender, "history", {"messages": history.get(room.name, [])})


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

print(f"Keeping history of {', '.join(ROOMS)} in {FILE}")
bot.start()