"""
Channel registry and reply delivery for the Adolf multi-channel gateway.

Each channel registers an async send callback:
    channels.register("telegram", telegram_send)
    channels.register("cli", cli_send)

When the agent is done, it calls:
    await channels.deliver(session_id, channel, text)

Replies are also placed into per-session asyncio Queues so the
GET /reply/{session_id} SSE endpoint can stream them to polling clients.
"""

import asyncio
import os
from typing import Awaitable, Callable

import httpx

# ── channel registry ──────────────────────────────────────────────────────────

_callbacks: dict[str, Callable[[str, str], Awaitable[None]]] = {}
# session_id → Queue that receives the final reply text
pending_replies: dict[str, asyncio.Queue] = {}


def register(channel: str, callback: Callable[[str, str], Awaitable[None]]) -> None:
    """Register an async send callback for a channel name."""
    _callbacks[channel] = callback


async def deliver(session_id: str, channel: str, text: str) -> None:
    """
    Deliver a reply to the originating channel AND put it in the pending
    queue so SSE /reply/{session_id} clients get it.
    """
    # Always enqueue first so SSE listeners aren't missed
    q = pending_replies.setdefault(session_id, asyncio.Queue())
    await q.put(text)

    cb = _callbacks.get(channel)
    if cb:
        await cb(session_id, text)
    else:
        print(f"[channels] no callback for channel={channel!r}, reply queued only", flush=True)


# ── built-in channel adapters ─────────────────────────────────────────────────

GRAMMY_URL = os.getenv("GRAMMY_URL", "http://grammy:3001")


async def _telegram_send(session_id: str, text: str) -> None:
    """Send reply to Telegram via Grammy's POST /send endpoint."""
    chat_id = session_id.removeprefix("tg-")
    MAX_TG = 4000
    chunks = [text[i:i + MAX_TG] for i in range(0, len(text), MAX_TG)]
    async with httpx.AsyncClient(timeout=15) as client:
        for chunk in chunks:
            await client.post(
                f"{GRAMMY_URL}/send",
                json={"chat_id": chat_id, "text": chunk},
            )


async def _cli_send(session_id: str, text: str) -> None:
    """CLI replies are handled entirely through the pending_replies queue — no-op here."""
    pass


def register_defaults() -> None:
    """Register the built-in Telegram and CLI channel adapters."""
    register("telegram", _telegram_send)
    register("cli", _cli_send)