from __future__ import annotations

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


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


def _csv_with_defaults(value: str | None, defaults: list[str]) -> list[str]:
    items = _csv(value, [])
    seen = set(items)
    for item in defaults:
        if item not in seen:
            items.append(item)
            seen.add(item)
    return items


def _default_allowed_download_hosts(base_url: str) -> list[str]:
    parsed = urlparse(base_url)
    if parsed.hostname:
        return [parsed.hostname]
    return ["package.pnkr.cloud"]


@dataclass(frozen=True)
class Settings:
    agent_version: str
    host: str
    port: int
    robot_package_base_url: str
    allowed_origins: list[str]
    allowed_download_hosts: list[str]
    allowed_docker_registries: list[str]
    cache_dir: Path
    app_dir: Path
    log_dir: Path
    db_path: Path
    allow_remove: bool
    allow_purge: bool
    allow_docker: bool
    allow_docker_compose: bool
    auto_install_docker: bool
    command_timeout_seconds: int


def _bool(name: str, default: bool) -> bool:
    value = os.getenv(name)
    if value is None:
        return default
    return value.strip().lower() in {"1", "true", "yes", "on"}


@lru_cache(maxsize=1)
def get_settings() -> Settings:
    robot_package_base_url = os.getenv("ROBOT_PACKAGE_BASE_URL", "https://package.pnkr.cloud").rstrip("/")
    return Settings(
        agent_version=os.getenv("AGENT_VERSION", "1.0.0"),
        host=os.getenv("AGENT_HOST", "0.0.0.0"),
        port=int(os.getenv("AGENT_PORT", "5010")),
        robot_package_base_url=robot_package_base_url,
        allowed_origins=_csv(
            os.getenv("ALLOWED_ORIGINS"),
            [
                "https://app.pnkr.cloud",
                "https://package.pnkr.cloud",
                "http://localhost:3000",
                "http://127.0.0.1:3000",
                "http://localhost:5173",
                "http://127.0.0.1:5173",
                "http://localhost:8080",
                "http://127.0.0.1:8080",
            ],
        ),
        allowed_download_hosts=_csv(
            os.getenv("ALLOWED_DOWNLOAD_HOSTS"),
            _default_allowed_download_hosts(robot_package_base_url),
        ),
        allowed_docker_registries=_csv_with_defaults(
            os.getenv("ALLOWED_DOCKER_REGISTRIES"),
            ["registry.robot.package", "docker.io"],
        ),
        cache_dir=Path(os.getenv("CACHE_DIR", "/var/cache/local-installer-agent/packages")),
        app_dir=Path(os.getenv("APP_DIR", "/opt/robot-apps")),
        log_dir=Path(os.getenv("LOG_DIR", "/var/log/local-installer-agent")),
        db_path=Path(os.getenv("DB_PATH", "/var/lib/local-installer-agent/agent.db")),
        allow_remove=_bool("ALLOW_REMOVE", True),
        allow_purge=_bool("ALLOW_PURGE", False),
        allow_docker=_bool("ALLOW_DOCKER", True),
        allow_docker_compose=_bool("ALLOW_DOCKER_COMPOSE", False),
        auto_install_docker=_bool("AUTO_INSTALL_DOCKER", True),
        command_timeout_seconds=int(os.getenv("COMMAND_TIMEOUT_SECONDS", "900")),
    )


settings = get_settings()