from __future__ import annotations

import logging
from datetime import datetime
from typing import TYPE_CHECKING, Any

from sqlalchemy.orm import Session

from db.database import SessionLocal
from db.models import Message
from schemas import SendMessageRequest
from services import contact_service, conversation_service

if TYPE_CHECKING:
    from channels.telegram_channel import TelegramChannel
    from channels.whatsapp_channel import WhatsAppChannel
    from channels.sms_channel import SmsChannel

logger = logging.getLogger(__name__)

# Wird in main.py nach Initialisierung gesetzt
_telegram: "TelegramChannel | None" = None
_whatsapp: "WhatsAppChannel | None" = None
_sms: "SmsChannel | None" = None

# Callback für TUI-Benachrichtigungen bei neuen Nachrichten
_new_message_callbacks: list[Any] = []


def register_channels(telegram: Any, whatsapp: Any, sms: Any) -> None:
    global _telegram, _whatsapp, _sms
    _telegram = telegram
    _whatsapp = whatsapp
    _sms = sms


def add_new_message_callback(cb: Any) -> None:
    _new_message_callbacks.append(cb)


# ── Senden ─────────────────────────────────────────────────────────────────────

async def send(db: Session, req: SendMessageRequest) -> Message:
    # Empfänger & Konversation ermitteln
    if req.channel == "telegram":
        recipient_id = req.recipient_telegram_id
        contact = contact_service.get_or_create_by_telegram(
            db, recipient_id, name=recipient_id
        )
        channel_conv_id = recipient_id
    else:
        recipient_id = req.recipient_phone
        contact = contact_service.get_or_create_by_phone(db, recipient_id)
        # WhatsApp: channel_conv_id immer als "nummer@c.us" normalisieren
        if req.channel == "whatsapp":
            channel_conv_id = recipient_id.replace("@c.us", "").lstrip("+") + "@c.us"
        else:
            channel_conv_id = recipient_id

    conv = conversation_service.get_or_create(
        db, req.channel, channel_conv_id, contact
    )

    # Nachricht in DB anlegen (pending)
    msg = Message(
        conversation_id=conv.id,
        channel=req.channel,
        direction="outbound",
        text=req.text,
        status="pending",
        reply_to_id=req.reply_to_id,
    )
    db.add(msg)
    db.commit()
    db.refresh(msg)

    # Kanal-spezifisches Senden
    result = await _dispatch(req.channel, recipient_id, req.text, req.reply_to_id)

    # Status aktualisieren
    if result["success"]:
        msg.status = "sent"
        msg.sent_at = datetime.utcnow()
        msg.channel_message_id = result.get("channel_message_id")
    else:
        msg.status = "failed"
        msg.error_message = result.get("error")

    conv.last_message_at = datetime.utcnow()
    db.commit()
    db.refresh(msg)

    await _notify_callbacks(msg)
    return msg


async def _dispatch(channel: str, recipient: str, text: str, reply_to: str | None) -> dict:
    if channel == "telegram" and _telegram:
        return await _telegram.send_message(recipient, text, reply_to)
    if channel == "whatsapp" and _whatsapp:
        return await _whatsapp.send_message(recipient, text, reply_to)
    if channel == "sms" and _sms:
        return await _sms.send_message(recipient, text, reply_to)
    return {"success": False, "channel_message_id": None, "error": "Channel not available"}


# ── Empfangen (Inbound) ────────────────────────────────────────────────────────

async def handle_inbound(payload: dict[str, Any]) -> None:
    """Wird von den Kanal-Callbacks aufgerufen."""
    db = SessionLocal()
    try:
        channel = payload["channel"]

        if channel == "telegram":
            link_contact_id = payload.get("link_contact_id")
            if link_contact_id:
                # Kontakt aus QR-Code: telegram_id verknüpfen
                existing = contact_service.get_by_id(db, link_contact_id)
                if existing:
                    from schemas import ContactUpdate
                    contact_service.update(
                        db, existing,
                        ContactUpdate(telegram_id=payload["sender_telegram_id"])
                    )
                    contact = existing
                else:
                    contact = contact_service.get_or_create_by_telegram(
                        db,
                        payload["sender_telegram_id"],
                        name=payload.get("sender_name", "Unknown"),
                    )
            else:
                contact = contact_service.get_or_create_by_telegram(
                    db,
                    payload["sender_telegram_id"],
                    name=payload.get("sender_name", "Unknown"),
                )
            channel_conv_id = payload["chat_id"]
        else:
            contact = contact_service.get_or_create_by_phone(
                db,
                payload.get("sender_phone", "unknown"),
                name=payload.get("sender_name"),
            )
            channel_conv_id = payload.get("chat_id", payload.get("sender_phone", ""))

        conv = conversation_service.get_or_create(
            db, channel, channel_conv_id, contact, title=contact.name
        )

        # Duplikat-Prüfung via channel_message_id
        channel_msg_id = payload.get("channel_message_id")
        if channel_msg_id:
            existing = (
                db.query(Message)
                .filter(
                    Message.channel == channel,
                    Message.channel_message_id == channel_msg_id,
                )
                .first()
            )
            if existing:
                return

        msg = Message(
            conversation_id=conv.id,
            sender_id=contact.id,
            channel=channel,
            channel_message_id=channel_msg_id,
            direction="inbound",
            text=payload.get("text", ""),
            status="delivered",
            delivered_at=datetime.utcnow(),
            reply_to_id=payload.get("reply_to_id"),
        )
        db.add(msg)
        conv.last_message_at = datetime.utcnow()
        db.commit()
        db.refresh(msg)

        logger.info("[%s] Inbound from %s: %s", channel, contact.name, msg.text[:50])
        await _notify_callbacks(msg)
    except Exception as exc:
        logger.error("handle_inbound error: %s", exc)
        db.rollback()
    finally:
        db.close()


async def _notify_callbacks(msg: Message) -> None:
    for cb in _new_message_callbacks:
        try:
            await cb(msg)
        except Exception as exc:
            logger.warning("Message callback error: %s", exc)


# ── Hilfsfunktionen ────────────────────────────────────────────────────────────

def get_messages(
    db: Session, conversation_id: str, limit: int = 50, offset: int = 0
) -> list[Message]:
    return conversation_service.get_messages(db, conversation_id, limit, offset)