// Package sysinfo — metrik host ringan untuk dashboard (F-027).
// Linux: baca /proc. OS lain: nilai nol (degrade anggun, tidak pernah panic).
package sysinfo

import (
	"os"
	"strconv"
	"strings"
)

type Stats struct {
	MemTotal uint64  // KB
	MemAvail uint64  // KB
	Load1    float64 // load average 1 menit
	Uptime   float64 // detik
}

func Read() Stats {
	var s Stats
	if b, err := os.ReadFile("/proc/meminfo"); err == nil {
		parseMeminfo(string(b), &s)
	}
	if b, err := os.ReadFile("/proc/loadavg"); err == nil {
		parseLoadavg(string(b), &s)
	}
	if b, err := os.ReadFile("/proc/uptime"); err == nil {
		parseUptime(string(b), &s)
	}
	return s
}

func parseMeminfo(s string, st *Stats) {
	for _, ln := range strings.Split(s, "\n") {
		f := strings.Fields(ln)
		if len(f) < 2 {
			continue
		}
		v, err := strconv.ParseUint(f[1], 10, 64)
		if err != nil {
			continue
		}
		switch f[0] {
		case "MemTotal:":
			st.MemTotal = v
		case "MemAvailable:":
			st.MemAvail = v
		}
	}
}

func parseLoadavg(s string, st *Stats) {
	if f := strings.Fields(s); len(f) > 0 {
		st.Load1, _ = strconv.ParseFloat(f[0], 64)
	}
}

func parseUptime(s string, st *Stats) {
	if f := strings.Fields(s); len(f) > 0 {
		st.Uptime, _ = strconv.ParseFloat(f[0], 64)
	}
}