//go:build linux
// +build linux

package staros

import (
	"io/ioutil"
	"strconv"
	"strings"
	"syscall"
)

// Memory 系统内存信息
func Memory() (MemStatus, error) {
	var mem MemStatus
	ram := new(syscall.Sysinfo_t)
	if err := syscall.Sysinfo(ram); err != nil {
		return mem, err
	}
	unit := uint64(ram.Unit)
	if unit == 0 {
		unit = 1
	}
	mem.All = uint64(ram.Totalram) * unit
	mem.BuffCache = uint64(ram.Bufferram) * unit
	mem.Free = uint64(ram.Freeram) * unit
	mem.Shared = uint64(ram.Sharedram) * unit
	mem.Available = mem.Free + mem.Shared + mem.BuffCache
	if available, ok := linuxMemAvailable(); ok {
		mem.Available = available
	}
	mem.SwapAll = uint64(ram.Totalswap) * unit
	mem.SwapFree = uint64(ram.Freeswap) * unit
	mem.SwapUsed = uint64(mem.SwapAll - mem.SwapFree)
	mem.Used = uint64(mem.All - mem.Free)
	return mem, nil
}

func linuxMemAvailable() (uint64, bool) {
	data, err := ioutil.ReadFile("/proc/meminfo")
	if err != nil {
		return 0, false
	}
	for _, line := range strings.Split(string(data), "\n") {
		fields := strings.Fields(line)
		if len(fields) < 2 || fields[0] != "MemAvailable:" {
			continue
		}
		value, err := strconv.ParseUint(fields[1], 10, 64)
		if err != nil {
			return 0, false
		}
		return value * 1024, true
	}
	return 0, false
}