from dataclasses import dataclass
from typing import Optional

import nio

from alerting.enum import AlertType, Severity
from misc import cvars
from misc.config import get_config


@dataclass
class Alert:
    alert_type: AlertType
    message: str
    severity: Severity
    html_message: Optional[str] = None


async def get_client() -> nio.AsyncClient:
    """
    Returns a Matrix client.
    It is better to call get_client once and use it for multiple send_alert calls
    """
    matrix_cfg = cvars.config.get().matrix
    client = nio.AsyncClient(matrix_cfg.homeserver)
    client.access_token = matrix_cfg.access_token
    client.user_id = matrix_cfg.user_id
    client.device_id = matrix_cfg.device_id
    return client


def format_message(alert: Alert) -> str:
    match alert.severity:
        case Severity.INFO:
            severity_emoji = "ℹ️"
        case Severity.WARNING:
            severity_emoji = "⚠️"
        case Severity.CRITICAL:
            severity_emoji = "🆘"
    message = f"{severity_emoji} {alert.alert_type} Alert\n{alert.message}"
    if alert.html_message:
        html_message = f"{severity_emoji} {alert.alert_type} Alert<br>{alert.html_message}"
        return message, html_message
    else:
        return message, None


async def send_alert(alert: Alert) -> None:
    try:
        client = cvars.matrix_client.get()
    except LookupError:  # being called standalone
        cvars.config.set(get_config())
        temp_client = True
        client = await get_client()
        cvars.matrix_client.set(client)
    else:
        temp_client = False
    room_id = cvars.config.get().matrix.room_id
    message, html_message = format_message(alert)
    content = {
        "msgtype": "m.text",
        "body": message,
    }
    if html_message:
        content["format"] = "org.matrix.custom.html"
        content["formatted_body"] = html_message
    await client.room_send(
        room_id=room_id,
        message_type="m.room.message",
        content=content,
    )
    if temp_client:
        await client.close()