"""Legacy scheduler scoring — kept for backward compatibility.

Re-exported by :mod:`backend.scheduler` so existing callers
(``from backend.scheduler import score_node, build_distcc_hosts``)
keep working.
"""

from __future__ import annotations

import logging
from typing import Any, List, Mapping

from backend.governor import thermal_cap

log = logging.getLogger(__name__)


def score_node(node: Mapping[str, Any]) -> float:
    """Return a 0..N scheduling score for ``node`` (higher = better)."""
    if node["state"] == "offline":
        return 0.0

    agent = node.get("agent") or {}

    try:
        load = float(str(agent.get("load", "1 1 1")).split()[0])
    except (ValueError, IndexError, AttributeError):
        log.debug("could not parse load=%r from node %s; falling back to 1.0",
                  agent.get("load"), node.get("name"))
        load = 1.0

    base = 10.0
    capacity = node.get("max_jobs", 8)

    score = (base + capacity) - (load * 3.0)

    return max(score, 0.1) * thermal_cap(agent)


def build_distcc_hosts(nodes: List[Mapping[str, Any]]) -> str:
    """Build a ``DISTCC_HOSTS`` string weighted by :func:`score_node`."""
    scored = [(n, score_node(n)) for n in nodes]

    total = sum(s for _, s in scored) or 1.0

    hosts: List[str] = []

    for node, score in scored:
        if node["state"] == "offline":
            continue

        weight = int((score / total) * 64)
        weight = max(1, weight)

        hosts.append(f"{node['host']}/{weight}")

    return " ".join(hosts)