from __future__ import annotations

import os
from dataclasses import dataclass
from functools import lru_cache


def _to_bool(value: str | None, default: bool) -> bool:
    if value is None:
        return default
    return value.strip().lower() in {"1", "true", "yes", "on"}


def _to_list(value: str | None) -> list[str]:
    if not value:
        return []
    return [item.strip() for item in value.split(",") if item.strip()]


@dataclass(frozen=True)
class Settings:
    app_name: str = "MAX Support Bot"
    app_env: str = "dev"
    app_host: str = "0.0.0.0"
    app_port: int = 8000

    db_path: str = "data/app.db"
    session_secret: str = "change-me-session-secret"

    web_admin_login: str = "admin"
    web_admin_password: str = "admin"

    max_bot_token: str = ""
    max_bot_api_url: str = "https://botapi.max.ru"
    max_use_webhook: bool = False
    max_webhook_url: str = ""
    max_webhook_secret: str = ""

    context_backend: str = "memory"
    redis_url: str = "redis://localhost:6379/0"

    channel_local_enabled: bool = True
    channel_external_enabled: bool = True
    external_api_create_url_with_key: str = ""

    operator_chat_ids: list[int] | None = None
    request_categories: list[str] | None = None

    @classmethod
    def from_env(cls) -> "Settings":
        operator_ids = [int(v) for v in _to_list(os.getenv("OPERATOR_CHAT_IDS")) if v.isdigit()]
        categories = _to_list(os.getenv("REQUEST_CATEGORIES")) or [
            "Общая консультация",
            "Техническая проблема",
            "Оплата",
            "Другое",
        ]
        return cls(
            app_name=os.getenv("APP_NAME", "MAX Support Bot"),
            app_env=os.getenv("APP_ENV", "dev"),
            app_host=os.getenv("APP_HOST", "0.0.0.0"),
            app_port=int(os.getenv("APP_PORT", "8000")),
            db_path=os.getenv("DB_PATH", "data/app.db"),
            session_secret=os.getenv("SESSION_SECRET", "change-me-session-secret"),
            web_admin_login=os.getenv("WEB_ADMIN_LOGIN", "admin"),
            web_admin_password=os.getenv("WEB_ADMIN_PASSWORD", "admin"),
            max_bot_token=os.getenv("MAX_BOT_TOKEN", "").strip(),
            max_bot_api_url=os.getenv("MAX_BOT_API_URL", "https://botapi.max.ru"),
            max_use_webhook=_to_bool(os.getenv("MAX_USE_WEBHOOK"), False),
            max_webhook_url=os.getenv("MAX_WEBHOOK_URL", "").strip(),
            max_webhook_secret=os.getenv("MAX_WEBHOOK_SECRET", "").strip(),
            context_backend=os.getenv("CONTEXT_BACKEND", "memory").strip().lower(),
            redis_url=os.getenv("REDIS_URL", "redis://localhost:6379/0"),
            channel_local_enabled=_to_bool(os.getenv("CHANNEL_LOCAL_ENABLED"), True),
            channel_external_enabled=_to_bool(os.getenv("CHANNEL_EXTERNAL_ENABLED"), True),
            external_api_create_url_with_key=os.getenv("EXTERNAL_API_CREATE_URL_WITH_KEY", "").strip(),
            operator_chat_ids=operator_ids,
            request_categories=categories,
        )


@lru_cache(maxsize=1)
def get_settings() -> Settings:
    return Settings.from_env()