"""NAPALM ``get_environment`` from host quick stats and hardware sensors."""

from __future__ import annotations

from typing import Any

_SENSORS = "runtime.healthSystemRuntime.systemHealthInfo.numericSensorInfo"
_MB = 1024 * 1024


def _reading(sensor: dict[str, Any]) -> float:
    return float(sensor.get("currentReading", 0)) * 10 ** int(sensor.get("unitModifier", 0))


def _health(sensor: dict[str, Any]) -> str:
    return (sensor.get("healthState") or {}).get("key", "unknown")


def _cpu_percent(host: dict[str, Any]) -> float:
    hardware = host.get("summary.hardware") or {}
    capacity = int(hardware.get("cpuMhz") or 0) * int(hardware.get("numCpuCores") or 0)
    used = (host.get("summary.quickStats") or {}).get("overallCpuUsage") or 0
    return round(used / capacity * 100, 2) if capacity else 0.0


def _add_sensors(env: dict[str, Any], host: dict[str, Any], prefix: str) -> None:
    for sensor in host.get(_SENSORS) or []:
        name = f"{prefix}{sensor.get('name', '')}"
        kind = sensor.get("sensorType")
        health = _health(sensor)
        if kind == "temperature":
            env["temperature"][name] = {
                "temperature": _reading(sensor),
                "is_alert": health in ("yellow", "red"),
                "is_critical": health == "red",
            }
        elif kind == "fan":
            env["fans"][name] = {"status": health == "green"}
        elif kind == "power":
            env["power"][name] = {
                "status": health == "green",
                "capacity": -1.0,
                "output": _reading(sensor),
            }


def environment(hosts: list[dict[str, Any]]) -> dict[str, Any]:
    """One host: keyed like a single device. Several (vCenter): keyed by host."""
    env: dict[str, Any] = {
        "fans": {},
        "temperature": {},
        "power": {},
        "cpu": {},
        "memory": {"available_ram": 0, "used_ram": 0},
    }
    single = len(hosts) == 1
    for host in hosts:
        key = "0" if single else host.get("name", host["_moref"])
        env["cpu"][key] = {"%usage": _cpu_percent(host)}
        hardware = host.get("summary.hardware") or {}
        stats = host.get("summary.quickStats") or {}
        env["memory"]["available_ram"] += int(hardware.get("memorySize") or 0)
        env["memory"]["used_ram"] += int(stats.get("overallMemoryUsage") or 0) * _MB
        _add_sensors(env, host, "" if single else f"{key}/")
    return env