#!/usr/bin/env python3
"""System metrics collector - outputs JSON to stdout."""

import json
import os
import shutil

def get_disk_usage():
    """Get disk usage for root filesystem."""
    usage = shutil.disk_usage('/')
    return {
        "total": usage.total,
        "used": usage.used,
        "free": usage.free,
        "percent_used": round(usage.used / usage.total * 100, 2)
    }

def get_memory_usage():
    """Get memory usage from /proc/meminfo."""
    meminfo = {}
    with open('/proc/meminfo', 'r') as f:
        for line in f:
            parts = line.split()
            key = parts[0].rstrip(':')
            value = int(parts[1])
            meminfo[key] = value
    
    total = meminfo.get('MemTotal', 0) * 1024
    available = meminfo.get('MemAvailable', meminfo.get('MemFree', 0)) * 1024
    used = total - available
    
    return {
        "total": total,
        "used": used,
        "available": available,
        "percent_used": round(used / total * 100, 2) if total > 0 else 0
    }

def get_load_average():
    """Get system load average."""
    load1, load5, load15 = os.getloadavg()
    return {
        "1min": load1,
        "5min": load5,
        "15min": load15
    }

def get_uptime():
    """Get system uptime in seconds."""
    with open('/proc/uptime', 'r') as f:
        uptime_seconds = float(f.readline().split()[0])
    return round(uptime_seconds, 2)

def main():
    metrics = {
        "disk": get_disk_usage(),
        "memory": get_memory_usage(),
        "load_average": get_load_average(),
        "uptime_seconds": get_uptime()
    }
    print(json.dumps(metrics, indent=2))

if __name__ == "__main__":
    main()