//go:build linux

package loadaverage

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
	"strings"
)

func getLinuxLoadAverage() (LoadAverageInformation, error) {
	loadFile, err := os.Open("/proc/loadavg")
	if err != nil {
		return LoadAverageInformation{}, fmt.Errorf("Could not find /proc/loadavg. Are you sure you are on linux?")
	}
	defer loadFile.Close()

	fileReader := bufio.NewScanner(loadFile)

	var one_m float64
	var five_m float64
	var fifteen_m float64

	fileReader.Scan()
	if fileReader.Err() != nil {
		return LoadAverageInformation{}, fmt.Errorf("Could not read /proc/uptime.")
	}

	data := fileReader.Text()

	/*
	 * fields[0] One minute load average
	 * fields[1] Five minute load average
	 * fields[2] Fifteen minute load average
	 * fields[3] Currently executing/total scheduled
	 * fields[4] Most recent process PID
	 */
	fields := strings.Split(data, " ")

	one_m, _ = strconv.ParseFloat(fields[0], 64)
	five_m, _ = strconv.ParseFloat(fields[1], 64)
	fifteen_m, _ = strconv.ParseFloat(fields[2], 64)

	return LoadAverageInformation{
		Load1:  one_m,
		Load5:  five_m,
		Load15: fifteen_m,
	}, nil
}

func GetLoadAverage() (LoadAverageInformation, error) {
	return getLinuxLoadAverage()
}