from backend.nodes.state_model import NodeStateRegistry


def choose_best_node(nodes, action, registry: NodeStateRegistry = None):

    best_node = None
    best_score = -999999

    for node in nodes:

        state = registry.get(node["name"]) if registry else None

        cpu_load = state.cpu_load if state else node.get("cpu_load", 0)
        temp = state.temp if state else node.get("temp", 0)

        score = 0
        score += (100 - cpu_load)
        score -= temp

        if node.get("policy") == "preferred":
            score += 20

        if node.get("policy") == "avoid":
            score -= 50

        if state:
            score -= state.instability * 10

        node["_computed_score"] = score

        if score > best_score:
            best_score = score
            best_node = node

    return best_node