from __future__ import annotations

import os
from dataclasses import dataclass
from pathlib import Path


ROOT_DIR = Path(__file__).resolve().parents[1]


def _load_env_file(path: Path) -> dict[str, str]:
    values: dict[str, str] = {}
    if not path.exists():
        return values

    for raw_line in path.read_text(encoding="utf-8").splitlines():
        line = raw_line.strip()
        if not line or line.startswith("#") or "=" not in line:
            continue
        key, value = line.split("=", 1)
        key = key.strip()
        value = value.strip().strip('"').strip("'")
        if key:
            values[key] = value
    return values


def _get_env(name: str, default: str, file_values: dict[str, str]) -> str:
    return os.environ.get(name, file_values.get(name, default))


def _as_int(value: str, default: int) -> int:
    try:
        return int(value)
    except (TypeError, ValueError):
        return default


def _resolve_path(value: str) -> Path:
    path = Path(value)
    if path.is_absolute():
        return path
    return ROOT_DIR / path


@dataclass(frozen=True)
class ControllerConfig:
    root_dir: Path
    host: str
    port: int
    database_path: Path
    static_dir: Path
    controller_name: str
    deployment_mode: str
    public_base_url: str
    agent_stale_after_seconds: int

    @classmethod
    def from_env(cls) -> "ControllerConfig":
        file_values = _load_env_file(ROOT_DIR / ".env")
        port = _as_int(_get_env("CONTROLLER_PORT", "8001", file_values), 8001)
        host = _get_env("CONTROLLER_HOST", "0.0.0.0", file_values)
        public_base_url = _get_env(
            "CONTROLLER_PUBLIC_BASE_URL",
            f"http://127.0.0.1:{port}",
            file_values,
        ).rstrip("/")
        stale_after = _as_int(
            _get_env("AGENT_STALE_AFTER_SECONDS", "5", file_values),
            5,
        )

        return cls(
            root_dir=ROOT_DIR,
            host=host,
            port=port,
            database_path=_resolve_path(
                _get_env("CONTROLLER_DATABASE", "data/controller.db", file_values)
            ),
            static_dir=_resolve_path(_get_env("CONTROLLER_STATIC_DIR", "web", file_values)),
            controller_name=_get_env(
                "CONTROLLER_NAME",
                "System Test Controller",
                file_values,
            ),
            deployment_mode=_get_env("CONTROLLER_DEPLOYMENT_MODE", "script", file_values),
            public_base_url=public_base_url,
            agent_stale_after_seconds=stale_after,
        )