import json
from dataclasses import dataclass
from enum import Enum, StrEnum
from typing import Optional

import aiofiles
import nio

from alerting.common import CONFIG_FILE
from misc import cvars


class AlertType(StrEnum):
    TEST = "TEST"
    ERROR = "ERROR"
    RAM = "RAM"
    CPU = "CPU"
    TEMP = "TEMP"
    VULN = "VULN"
    LOGIN = "LOGIN"  # TODO
    SMART = "SMART"  # TODO
    RAID = "RAID"
    DISKS = "DISKS"
    UPS = "UPS"
    UPDATE = "UPDATE"


class Severity(StrEnum):
    INFO = "INFO"
    WARNING = "WARNING"
    CRITICAL = "CRITICAL"


@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
        async with aiofiles.open(CONFIG_FILE) as f:
            contents = await f.read()
        cvars.config.set(json.loads(contents))
        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()