import logging

import requests

from infrasynth.shared.enums import ChannelType
from infrasynth.shared.results import Result

from .base import BaseChannel

logger = logging.getLogger(__name__)


class TelegramChannel(BaseChannel):
    """Chat channel that sends via the Telegram Bot API.

    Configuration keys (read from ``ChannelConfig.config``):
    - ``bot_token`` (required)
    - ``chat_id`` (optional default chat, overridden by recipient)
    - ``timeout``
    """

    channel_type = ChannelType.TELEGRAM
    API_BASE = "https://api.telegram.org/bot{token}/{method}"

    def __init__(self, bot_token=None, chat_id=None, timeout=30):
        self.bot_token = bot_token
        self.chat_id = chat_id
        self.timeout = timeout

    @classmethod
    def from_config(cls, config: dict) -> "TelegramChannel":
        config = {str(key).lower(): value for key, value in (config or {}).items()}
        return cls(**config)

    def send(
        self,
        recipient: str,
        subject: str,
        body: str,
        is_html: bool = True,
        attachments=None,
    ) -> Result[bool, str]:
        if not self.bot_token:
            return Result.err("Telegram bot token not configured")
        chat_id = recipient or self.chat_id
        if not chat_id:
            return Result.err("No chat_id provided")
        try:
            payload = {
                "chat_id": chat_id,
                "text": body or subject,
            }
            if is_html:
                payload["parse_mode"] = "HTML"
            response = requests.post(
                self.API_BASE.format(token=self.bot_token, method="sendMessage"),
                json=payload,
                timeout=self.timeout,
            )
        except requests.RequestException as exc:
            logger.exception("Telegram send failed for chat %s", chat_id)
            return Result.err(str(exc))

        data = response.json()
        if not data.get("ok"):
            description = data.get("description") or f"HTTP {response.status_code}"
            return Result.err(f"Telegram error: {description}")
        return Result.ok(True)

    def health_check(self) -> bool:
        return bool(self.bot_token)