package main

import (
  "bufio"
  "fmt"
  "os"
  "time"
  "golang.org/x/sys/unix"
	"os/exec"
	"strconv"
  "strings"
  "io/ioutil"
)

var (
	data, connectedWiFi, memPercentage, cpuTemp, cpuPercentage, volumeLevel string
  batteryLevel, chargingStatus string
  text string = "\n"
	moduleColor0, moduleColor1 string = "#9b1bed", "#ff0aa3"
)

func dataLoop() {
  for {
    data = getData()
    time.Sleep(time.Second / 10)
  }
}

func stdinLoop() {
  reader := bufio.NewReader(os.Stdin)
  for {
    text, _ = reader.ReadString('\n')
  }
}

// to update modules every 5 seconds
func fiveSecLoop() {
  for {
	  memPercentage = getMemUsage()
	  cpuTemp = getCPUTemp()
    cpuPercentage = getCPUUsage()

    time.Sleep(time.Second * 5)
  }
}

// to update modules every 10 seconds
func tenSecLoop() {
  for {
    connectedWiFi = getWiFiName()
    chargingStatus, batteryLevel = getBatteryInfo()

    time.Sleep(time.Second * 10)
  }
}

// very creative name
// used to update modules like volume, etc
// don't want lag on those modules!
func veryFastLoop() {
  for {
	  volumeLevel = getVolumeLevel()
    time.Sleep(time.Second / 10)
  }
}

func main() {
  go dataLoop()
  go stdinLoop()
  go fiveSecLoop()
  go tenSecLoop()
  go veryFastLoop()

  for {
    fmt.Print(data + text)
    time.Sleep(time.Second / 10)
  }
}

func getData() string {
	time     := "%{F" + moduleColor0 + "} "       + getTime()        + "%{F-} "
	wifiName := "%{F" + moduleColor1 + "} WiFI: " + connectedWiFi    + "%{F-} "
	rootFree := "%{F" + moduleColor0 + "} / "     + getDisk("/")     + "%%{F-} "
	homeFree := "%{F" + moduleColor1 + "} /home " + getDisk("/home") + "%%{F-} "
	hddFree  := "%{F" + moduleColor0 + "} /hdd "  + getDisk("/hdd")  + "%%{F-} "
	cpuUsage := "%{F" + moduleColor1 + "} CPU: "  + cpuPercentage    + "%%{F-} "
	cpuTemp  := "%{F" + moduleColor0 + "} TEMP: " + cpuTemp          + "%{F-} "
	memUsage := "%{F" + moduleColor1 + "} MEM: "  + memPercentage    + "%{F-} "

	volume   := "%{F" + moduleColor0 + "}"
  if volumeLevel != "muted" {
	  volume = volume + "} VOL: " + volumeLevel + "%{F-} "
  } else {
	  volume = volume + "} MUTED%{F-} "
  }

  // shows battery level in different color
  // depending on charging status
  // hidden when full
	var battery string
  btlvl, _ := strconv.Atoi(batteryLevel)
  if btlvl < 100 {
    col := moduleColor1
    if chargingStatus == "Charging" { col = moduleColor0 }
    battery = fmt.Sprintf("%%{F%s} BATT: %s%%{F-} ", col, batteryLevel)
  }

  // TODO add brightness (new)
  return time + wifiName + rootFree + homeFree + hddFree + cpuUsage + cpuTemp + "%{r}" + memUsage + battery
}

func getWiFiName() string {
	// script located in ~/.scripts/
	// look at github.com/MikunoNaka/dots
	cmd := exec.Command("get_wifi_name.sh")
	name, _ := cmd.Output()
	return string(name)
}

func getMemUsage() string {
	// script located in ~/.scripts/
	// look at github.com/MikunoNaka/dots
	cmd := exec.Command("ram_usage.sh")
	usage, _ := cmd.Output()
	return string(usage)
}


func getCPUTemp() string {
	// script located in ~/.scripts/
	// look at github.com/MikunoNaka/dots
	cmd := exec.Command("cpu_temp.sh")
	temp, _ := cmd.Output()
	return string(temp)
}

func getVolumeLevel() string {
	// script located in ~/.scripts/
	// look at github.com/MikunoNaka/dots
	cmd := exec.Command("volume_level.sh")
	level, _ := cmd.Output()
	return string(level)
}

func getBatteryInfo() (string, string) {
	// scripts located in ~/.scripts/
	// look at github.com/MikunoNaka/dots
	statCmd := exec.Command("charging_status.sh")
	stat, _ := statCmd.Output()

  levelCmd := exec.Command("battery_level.sh")
	level, _ := levelCmd.Output()

	return string(stat), string(level)
}

// TODO: maybe add dates on click
func getTime() string {
	now := time.Now()
	return now.Format(" 3:04 PM")
}

// TODO: maybe show percentages instead of free space
func getDisk(mountPoint string) string {
	var stat unix.Statfs_t
  unix.Statfs(mountPoint, &stat)

	// this is witchcraft. I wrote this but I have -10000 idea how AND IF it works
	totalSize := float64(stat.Blocks) * float64(stat.Bsize) / 1073741824
  usedSpace := float64(stat.Bfree)  * float64(stat.Bsize) / 1073741824

  return strconv.FormatFloat((100 - (usedSpace / totalSize) * 100), 'f', 0, 64)
}

func getCPUSample() (idle, total uint64) {
  contents, err := ioutil.ReadFile("/proc/stat")
  if err != nil {
    return
  }
  lines := strings.Split(string(contents), "\n")
  for _, line := range(lines) {
    fields := strings.Fields(line)
    if fields[0] == "cpu" {
      numFields := len(fields)
      for i := 1; i < numFields; i++ {
        val, err := strconv.ParseUint(fields[i], 10, 64)
        if err != nil {
          fmt.Println("Error: ", i, fields[i], err)
        }
        total += val // tally up all the numbers to get total ticks
        if i == 4 {  // idle is the 5th field in the cpu line
          idle = val
        }
      }
      return
    }
  }
  return
}

func getCPUUsage() string {
  idle0, total0 := getCPUSample()
  time.Sleep(3 * time.Second)
  idle1, total1 := getCPUSample()

  idleTicks := float64(idle1 - idle0)
  totalTicks := float64(total1 - total0)
  cpuUsage := 100 * (totalTicks - idleTicks) / totalTicks

  return strconv.Itoa(int(cpuUsage))
}