"""
系统与网卡指标（供仪表盘轮询）。下行/上行为全机网卡合计速率（估算）。
"""
from __future__ import annotations

import time
from typing import Any, Optional

import psutil

_last_net_time: float = 0.0
_last_net: Optional[dict[str, tuple[int, int]]] = None  # name -> (sent, recv)


def _net_rates_mbps() -> tuple[Optional[float], Optional[float], dict[str, Any]]:
    """返回 (上行 Mbps, 下行 Mbps, 原始片段)。"""
    global _last_net_time, _last_net
    now = time.monotonic()
    per = psutil.net_io_counters(pernic=True)
    cur: dict[str, tuple[int, int]] = {k: (v.bytes_sent, v.bytes_recv) for k, v in per.items()}
    detail: dict[str, Any] = {}
    up_mbps = down_mbps = None
    if _last_net is not None and _last_net_time > 0:
        dt = now - _last_net_time
        if dt > 0.05:
            ds = dr = 0
            for name, (sent, recv) in cur.items():
                if name in _last_net:
                    ps0, pr0 = _last_net[name]
                    ds += max(0, sent - ps0)
                    dr += max(0, recv - pr0)
            up_mbps = round((ds * 8) / dt / 1_000_000, 3)
            down_mbps = round((dr * 8) / dt / 1_000_000, 3)
            detail["delta_seconds"] = round(dt, 3)
    _last_net = cur
    _last_net_time = now
    for name, (sent, recv) in cur.items():
        detail.setdefault("interfaces", {})[name] = {
            "bytes_sent": sent,
            "bytes_recv": recv,
        }
    return up_mbps, down_mbps, detail


def snapshot() -> dict[str, Any]:
    try:
        psutil.cpu_percent(interval=None)
        cpu = psutil.cpu_percent(interval=0.15)
    except Exception:
        cpu = None
    try:
        vm = psutil.virtual_memory()
        mem = {
            "percent": vm.percent,
            "used": vm.used,
            "total": vm.total,
            "available": vm.available,
        }
    except Exception:
        mem = {}
    try:
        sm = psutil.swap_memory()
        swap = {"percent": sm.percent, "used": sm.used, "total": sm.total}
    except Exception:
        swap = {}

    disks = []
    try:
        for part in psutil.disk_partitions(all=False):
            try:
                usage = psutil.disk_usage(part.mountpoint)
                disks.append(
                    {
                        "device": part.device,
                        "mountpoint": part.mountpoint,
                        "fstype": part.fstype,
                        "percent": usage.percent,
                        "free": usage.free,
                        "total": usage.total,
                    }
                )
            except (PermissionError, OSError):
                continue
    except Exception:
        pass

    up_mbps, down_mbps, net_detail = _net_rates_mbps()

    boot = None
    try:
        boot = int(psutil.boot_time())
    except Exception:
        pass

    ffmpeg_procs = []
    try:
        for p in psutil.process_iter(["pid", "name", "memory_info"]):
            try:
                name = (p.info.get("name") or "").lower()
                if "ffmpeg" not in name:
                    continue
                mi = p.info.get("memory_info")
                ffmpeg_procs.append(
                    {
                        "pid": p.info["pid"],
                        "name": p.info.get("name"),
                        "rss": mi.rss if mi else 0,
                    }
                )
            except (psutil.NoSuchProcess, psutil.AccessDenied):
                continue
    except Exception:
        pass

    return {
        "ts": time.time(),
        "cpu_percent": cpu,
        "cpu_count_logical": psutil.cpu_count(logical=True),
        "memory": mem,
        "swap": swap,
        "disks": disks,
        "network": {
            "up_mbps": up_mbps,
            "down_mbps": down_mbps,
            "detail": net_detail,
        },
        "boot_time_unix": boot,
        "ffmpeg_processes": ffmpeg_procs[:24],
    }