"""Read-only Linux collector, executed via SSH stdin; never imports router code."""
import csv
import json
import time
import subprocess
import os
import shutil
from pathlib import Path

PROC = Path(os.environ.get('DECK_HOST_PROC', '/proc'))
DATA_DISK = Path(os.environ.get('DECK_HOST_DATA_DISK', '/var/lib/deck'))
_network_previous = None


def read(path):
    try:
        return Path(path).read_text().strip()
    except OSError:
        return ''


def number(value):
    try:
        return float(value)
    except (ValueError, TypeError):
        return None


def ticks():
    values = list(map(int, read(PROC/'stat').splitlines()[0].split()[1:9]))
    return sum(values), sum(values[3:5])


def collect():
    global _network_previous
    errors = []
    cpu = {'name': None, 'percent': None, 'temperature_c': None}
    try:
        a, ai = ticks()
        time.sleep(.25)
        b, bi = ticks()
        cpu['percent'] = round(100 * (1 - (bi-ai)/(b-a)), 1) if b > a else None
    except (ValueError, IndexError):
        errors.append('CPU-Auslastung nicht verfügbar')
    for line in read(PROC/'cpuinfo').splitlines():
        if line.startswith('model name'):
            cpu['name'] = line.split(':', 1)[1].strip()
            break
    for path in Path('/sys/class/hwmon').glob('hwmon*'):
        if read(path / 'name') in ('k10temp', 'coretemp'):
            value = number(read(path / 'temp1_input'))
            cpu['temperature_c'] = value / 1000 if value is not None else None
            break
    mem = {}
    for line in read(PROC/'meminfo').splitlines():
        parts = line.split()
        if parts[0] in ('MemTotal:', 'MemAvailable:'):
            mem[parts[0][:-1]] = int(parts[1]) * 1024
    total, available = mem.get('MemTotal'), mem.get('MemAvailable')
    ram = {'total_bytes': total, 'used_bytes': total-available if total is not None and available is not None else None}
    gpus = []
    try:
        result = subprocess.run(['nvidia-smi', '--query-gpu=index,name,uuid,memory.total,memory.used,utilization.gpu,temperature.gpu,utilization.memory,memory.free,power.draw,power.limit,clocks.current.graphics,clocks.current.memory,fan.speed,pstate', '--format=csv,noheader,nounits'], capture_output=True, text=True, timeout=4, check=True)
        for row in csv.reader(result.stdout.splitlines(), skipinitialspace=True):
            if len(row)!=15:continue
            index, name, uuid, total, used, usage, temp, memory_usage, free, power, power_limit, graphics_clock, memory_clock, fan, pstate = row
            gpus.append(dict(index=int(index), name=name, uuid=uuid, total_mib=number(total), used_mib=number(used), percent=number(usage), temperature_c=number(temp),memory_controller_percent=number(memory_usage),free_mib=number(free),power_w=number(power),power_limit_w=number(power_limit),graphics_clock_mhz=number(graphics_clock),memory_clock_mhz=number(memory_clock),fan_percent=number(fan),pstate=pstate))
    except (OSError, subprocess.SubprocessError, ValueError):
        errors.append('GPU-Messwerte nicht verfügbar')
    gpu_processes=[]
    try:
        result=subprocess.run(['nvidia-smi','--query-compute-apps=gpu_uuid,pid,process_name,used_memory','--format=csv,noheader,nounits'],capture_output=True,text=True,timeout=4,check=True)
        for row in csv.reader(result.stdout.splitlines(),skipinitialspace=True):
            if len(row)==4:gpu_processes.append(dict(gpu_uuid=row[0],pid=number(row[1]),name=row[2],memory_mib=number(row[3])))
    except (OSError,subprocess.SubprocessError):pass
    try:load=[float(x) for x in read(PROC/'loadavg').split()[:3]]
    except ValueError:load=[]
    try:uptime=float(read(PROC/'uptime').split()[0])
    except (ValueError,IndexError):uptime=None
    try:
        disk=shutil.disk_usage(DATA_DISK)
        disk_data=dict(total=disk.total,used=disk.used,free=disk.free)
    except OSError:disk_data={}
    rx=tx=interfaces=0
    # A bind-mounted /proc/net is a self/net symlink and would show the
    # container namespace. PID 1 in the host proc mount has the host network.
    host_net=PROC/'1/net/dev' if (PROC/'1/net/dev').exists() else PROC/'net/dev'
    for line in read(host_net).splitlines()[2:]:
        if ':' not in line:continue
        name,raw=line.split(':',1)
        if name.strip()=='lo':continue
        parts=raw.split()
        if len(parts)<9:continue
        try:rx+=int(parts[0]);tx+=int(parts[8]);interfaces+=1
        except ValueError:pass
    now=time.monotonic();rates=dict(rx_bytes_per_second=None,tx_bytes_per_second=None)
    if _network_previous and now>_network_previous[0]:
        elapsed=now-_network_previous[0]
        rates=dict(rx_bytes_per_second=round(max(0,rx-_network_previous[1])/elapsed,1),tx_bytes_per_second=round(max(0,tx-_network_previous[2])/elapsed,1))
    _network_previous=(now,rx,tx)
    return dict(source='Debian-Server · /proc + hwmon + nvidia-smi', sampled_at=time.time(), cpu={**cpu,'logical_cpus':os.cpu_count(),'load':load,'host_uptime_seconds':uptime,'disk_data':disk_data,'network':dict(interfaces=interfaces,rx_bytes=rx,tx_bytes=tx,**rates)}, ram=ram, gpus=gpus,gpu_processes=gpu_processes, errors=errors)


if __name__ == '__main__':
    print(json.dumps(collect()))