"""Configuration loader for the Farm Manager server.

Reads node definitions from a JSON config file. The path defaults to
``/app/config.json`` but can be overridden via the ``CONFIG_PATH``
environment variable.
"""

import json
import os

_config = None


def _load_config():
    global _config
    if _config is None:
        config_path = os.environ.get("CONFIG_PATH", "/app/config.json")
        with open(config_path) as f:
            _config = json.load(f)
    return _config


def get_nodes() -> list[dict]:
    """Return the list of node definitions from the config file."""
    return _load_config()["nodes"]


def get_node_url(node_name: str) -> str | None:
    """Return the agent base URL for *node_name*, or ``None`` if unknown."""
    for node in get_nodes():
        if node["name"] == node_name:
            return f"http://{node['host']}:{node['agent_port']}"
    return None