from __future__ import annotations

import os
from dataclasses import dataclass
from functools import lru_cache


@dataclass(frozen=True)
class Settings:
    app_base_url: str | None
    auth_secret_key: str | None
    auth_cookie_secure: bool
    cors_allow_origins: tuple[str, ...]
    forgejo_base_url: str
    forgejo_token: str | None
    forgejo_oauth_client_id: str | None
    forgejo_oauth_client_secret: str | None
    forgejo_oauth_scopes: tuple[str, ...]
    forgejo_general_discussion_repo: str | None
    forgejo_webhook_secret: str | None
    forgejo_repo_scan_limit: int
    forgejo_recent_issue_limit: int
    forgejo_cache_ttl_seconds: float
    forgejo_request_timeout_seconds: float
    calendar_feed_urls: tuple[str, ...]
    calendar_event_limit: int


def _normalize_base_url(raw_value: str | None) -> str:
    value = (raw_value or "").strip()
    if not value:
        return "https://aksal.cloud"
    if value.startswith(("http://", "https://")):
        return value.rstrip("/")
    return f"https://{value.rstrip('/')}"


def _parse_calendar_feed_urls(raw_value: str | None) -> tuple[str, ...]:
    return _parse_csv_values(raw_value)


def _parse_csv_values(raw_value: str | None) -> tuple[str, ...]:
    value = (raw_value or "").strip()
    if not value:
        return ()

    return tuple(entry.strip() for entry in value.replace("\n", ",").split(",") if entry.strip())


def _parse_scopes(raw_value: str | None) -> tuple[str, ...]:
    value = (raw_value or "").strip()
    if not value:
        return ("openid", "profile")
    return tuple(scope for scope in value.replace(",", " ").split() if scope)


def _parse_bool(raw_value: str | None, *, default: bool = False) -> bool:
    value = (raw_value or "").strip().lower()
    if not value:
        return default
    return value in {"1", "true", "yes", "on"}


def _cors_allow_origins(app_base_url: str | None, raw_value: str | None) -> tuple[str, ...]:
    configured_origins = _parse_csv_values(raw_value)
    if configured_origins:
        return configured_origins
    if app_base_url:
        return (app_base_url,)
    return ("*",)


@lru_cache(maxsize=1)
def get_settings() -> Settings:
    app_base_url = (
        _normalize_base_url(os.getenv("APP_BASE_URL")) if os.getenv("APP_BASE_URL") else None
    )
    return Settings(
        app_base_url=app_base_url,
        auth_secret_key=os.getenv("AUTH_SECRET_KEY") or None,
        auth_cookie_secure=_parse_bool(os.getenv("AUTH_COOKIE_SECURE")),
        cors_allow_origins=_cors_allow_origins(app_base_url, os.getenv("CORS_ALLOW_ORIGINS")),
        forgejo_base_url=_normalize_base_url(os.getenv("FORGEJO_BASE_URL")),
        forgejo_token=os.getenv("FORGEJO_TOKEN") or None,
        forgejo_oauth_client_id=os.getenv("FORGEJO_OAUTH_CLIENT_ID") or None,
        forgejo_oauth_client_secret=os.getenv("FORGEJO_OAUTH_CLIENT_SECRET") or None,
        forgejo_oauth_scopes=_parse_scopes(os.getenv("FORGEJO_OAUTH_SCOPES")),
        forgejo_general_discussion_repo=os.getenv("FORGEJO_GENERAL_DISCUSSION_REPO") or None,
        forgejo_webhook_secret=os.getenv("FORGEJO_WEBHOOK_SECRET") or None,
        forgejo_repo_scan_limit=int(os.getenv("FORGEJO_REPO_SCAN_LIMIT", "30")),
        forgejo_recent_issue_limit=int(os.getenv("FORGEJO_RECENT_ISSUE_LIMIT", "50")),
        forgejo_cache_ttl_seconds=float(os.getenv("FORGEJO_CACHE_TTL_SECONDS", "60.0")),
        forgejo_request_timeout_seconds=float(
            os.getenv("FORGEJO_REQUEST_TIMEOUT_SECONDS", "10.0"),
        ),
        calendar_feed_urls=_parse_calendar_feed_urls(os.getenv("CALENDAR_FEED_URLS")),
        calendar_event_limit=int(os.getenv("CALENDAR_EVENT_LIMIT", "3")),
    )