package main

import (
	"fmt"
	"os"
	"runtime"
	"strconv"
	"time"

	"github.com/shirou/gopsutil/v3/load"
	"github.com/shirou/gopsutil/v3/mem"
)

const warnFormat = "#[bg=colour208]"

var binarySuffixes = []string{"B", "KiB", "MiB", "GiB", "TiB"}

const binaryFactor = 1024

func HBin(a uint64, precision int) string {
	f := float64(a)
	var suffix string
	for _, suffix = range binarySuffixes {
		if f < binaryFactor {
			break
		}
		f /= binaryFactor
	}
	return fmt.Sprintf("%.*f%s", precision, f, suffix)
}

func usage() {
	fmt.Fprintln(os.Stderr, "Usage:", os.Args[0], "<window_width>")
	os.Exit(2)
}

func printLoad(precision int) {
	l, err := load.Avg()
	if err != nil {
		panic(err) // fixme
	}

	if l.Load1 > float64(runtime.NumCPU()) {
		fmt.Print(warnFormat)
	}
	fmt.Printf("[%.[1]*[2]f %.[1]*[3]f %.[1]*[4]f]",
		precision, l.Load1, l.Load5, l.Load15)
}

func printMem(absolute, percent bool) {
	if !(absolute || percent) {
		return
	}

	v, err := mem.VirtualMemory()
	if err != nil {
		panic(err) //fixme
	}

	if v.UsedPercent > 90 {
		fmt.Print(warnFormat, "[")
	} else {
		fmt.Print("#[default][")
	}
	if absolute {
		fmt.Printf("%s/%s", HBin(v.Used, 1), HBin(v.Total, 1))
		if percent {
			fmt.Print(" ")
		}
	}
	if percent {
		fmt.Printf("%.0f%%", v.UsedPercent)
	}
	fmt.Print("]")
}

func printTime(format string) {
	now := time.Now()

	fmt.Print(now.Format("#[default]" + format))
}

func main() {
	if len(os.Args) != 2 {
		usage()
	}
	cols, err := strconv.Atoi(os.Args[1])
	if err != nil {
		fmt.Fprintln(os.Stderr, err)
		usage()
	}

	if cols >= 150 {
		printLoad(2)
		printMem(true, true)
		printTime(" Mon 2006-01-02 15:04")
	} else if cols >= 120 {
		printLoad(2)
		printMem(false, true)
		printTime(" 15:04")
	} else if cols >= 100 {
		printLoad(0)
		printMem(false, true)
		printTime(" 15:04")
	} else if cols >= 80 {
		printTime("15:04")
	}
}