from __future__ import annotations

import os
import socket
from dataclasses import dataclass
from pathlib import Path
from typing import Final

from .version import VERSION

DEFAULT_REPORT_INTERVAL_SECONDS: Final[int] = 60


@dataclass(frozen=True)
class AgentConfig:
    hostname: str
    node_file: str
    version: str
    master_endpoint: str
    report_interval_seconds: int
    health_dir: str
    request_timeout_seconds: int = 10


def _normalise_master_endpoint(value: str) -> str:
    value = value.strip()
    if not value:
        raise ValueError("MASTER_ENDPOINT environment variable is required")
    if not value.startswith("http://") and not value.startswith("https://"):
        value = f"http://{value}"
    return value.rstrip("/")


def _read_report_interval(raw_value: str | None) -> int:
    if raw_value is None or raw_value.strip() == "":
        return DEFAULT_REPORT_INTERVAL_SECONDS
    try:
        interval = int(raw_value)
    except ValueError as exc:
        raise ValueError("REPORT_INTERVAL_SECONDS must be an integer") from exc
    if interval <= 0:
        raise ValueError("REPORT_INTERVAL_SECONDS must be positive")
    return interval


def _resolve_hostname() -> str:
    return os.environ.get("AGENT_HOSTNAME") or socket.gethostname()


def load_config() -> AgentConfig:
    """从环境变量推导配置，移除了外部配置文件依赖。"""

    hostname = _resolve_hostname()
    node_file = f"/private/argus/agent/{hostname}/node.json"
    health_dir = f"/private/argus/agent/{hostname}/health/"

    master_endpoint_env = os.environ.get("MASTER_ENDPOINT")
    if master_endpoint_env is None:
        raise ValueError("MASTER_ENDPOINT environment variable is not set")
    master_endpoint = _normalise_master_endpoint(master_endpoint_env)

    report_interval_seconds = _read_report_interval(os.environ.get("REPORT_INTERVAL_SECONDS"))

    Path(node_file).parent.mkdir(parents=True, exist_ok=True)
    Path(health_dir).mkdir(parents=True, exist_ok=True)

    return AgentConfig(
        hostname=hostname,
        node_file=node_file,
        version=VERSION,
        master_endpoint=master_endpoint,
        report_interval_seconds=report_interval_seconds,
        health_dir=health_dir,
    )