"""Server-side configuration for the n8n integration."""

from __future__ import annotations

import os
from dataclasses import dataclass
from pathlib import Path
from urllib.parse import urlparse

from dotenv import dotenv_values


DEFAULT_MAX_FILE_BYTES = 10 * 1024 * 1024
ENV_FILE = Path(__file__).resolve().parent / ".env"


class ConfigurationError(ValueError):
    """A required webhook setting is missing or invalid."""


@dataclass(frozen=True)
class Settings:
    chat_webhook_url: str = ""
    upload_webhook_url: str = ""
    chat_timeout_seconds: float = 60.0
    upload_timeout_seconds: float = 120.0
    max_file_bytes: int = DEFAULT_MAX_FILE_BYTES

    @classmethod
    def from_env(cls) -> Settings:
        # Resolve relative to the application, independently of the working directory.
        values = {**dotenv_values(ENV_FILE, encoding="utf-8-sig"), **os.environ}

        def setting(name: str, default: str) -> str:
            value = values.get(name)
            return default if value is None else value

        try:
            chat_timeout = float(setting("N8N_CHAT_TIMEOUT_SECONDS", "60"))
            upload_timeout = float(setting("N8N_UPLOAD_TIMEOUT_SECONDS", "120"))
            max_file_bytes = int(setting("N8N_MAX_FILE_BYTES", str(DEFAULT_MAX_FILE_BYTES)))
        except ValueError as exc:
            raise ConfigurationError("Некорректные числовые настройки n8n.") from exc

        if chat_timeout <= 0 or upload_timeout <= 0 or max_file_bytes <= 0:
            raise ConfigurationError("Таймауты и лимит файла должны быть положительными.")

        return cls(
            chat_webhook_url=setting("N8N_CHAT_WEBHOOK_URL", "").strip(),
            upload_webhook_url=setting("N8N_UPLOAD_WEBHOOK_URL", "").strip(),
            chat_timeout_seconds=chat_timeout,
            upload_timeout_seconds=upload_timeout,
            max_file_bytes=max_file_bytes,
        )


def require_webhook_url(value: str, label: str) -> str:
    parsed = urlparse(value)
    if parsed.scheme not in {"http", "https"} or not parsed.netloc:
        raise ConfigurationError(f"Не задан корректный полный URL webhook для {label}.")
    return value