statusmonitor/ui.go

package main

import (
	"fmt"
	"time"

	"github.com/gizak/termui"
)

const HeaderHeight = 3

// UI represents UI layout.
type UI struct {
	Headers    []*termui.Par
	Sparklines *termui.Sparklines

	CPULine *termui.Sparkline

	// fields needed only for UI display
	interval time.Duration
	maxCPU   float64
}

func initUI(pid int64, interval time.Duration) *UI {
	err := termui.Init()
	if err != nil {
		panic(err)
	}

	ui := &UI{
		interval: interval,
	}
	ui.createHeader(pid)
	ui.createSparklines()
	ui.createLayout()

	ui.Align()
	ui.Render()

	return ui
}

func stopUI() {
	termui.Close()
}

// UpdateCPU updates CPU widget with new values from data.
func (ui *UI) UpdateCPU(data []float64) {
	intData := make([]int, len(data))

	// multiply by 100, to account for 2 decimals after the point
	for i := range data {
		intData[i] = int(data[i] * 100)
	}
	ui.Sparklines.Lines[0].Data = intData

	if len(data) == 0 {
		return
	}

	currentCPU := data[len(data)-1]
	if currentCPU > ui.maxCPU {
		ui.maxCPU = currentCPU
	}
	ui.Sparklines.Lines[0].TitleColor = termui.ColorYellow
	ui.Sparklines.Lines[0].Title = fmt.Sprintf("Current: %.2f%%, Max: %.2f%%", currentCPU, ui.maxCPU)
}

// Render rerenders UI.
func (ui *UI) Render() {
	termui.Body.Align()

	// Update widgets:
	// history time estimation based on new size and interval
	ui.Sparklines.BorderLabel = fmt.Sprintf("CPU (last %v)", time.Duration(termui.TermWidth()-2)*ui.interval)
	// time in header
	ui.Headers[3].Text = fmt.Sprintf("%v", time.Now().Format("15:04:05"))

	// TODO: prettify this
	termui.Render(ui.Headers[0], ui.Headers[1], ui.Headers[2], ui.Headers[3], ui.Sparklines)
}

// Align recalculates layout and aligns widgets.
func (ui *UI) Align() {
	termui.Body.Align()
}

func (ui *UI) createLayout() {
	if len(ui.Headers) != 4 {
		panic("update headers code")
	}
	termui.Body.AddRows(
		termui.NewRow(
			termui.NewCol(6, 0, ui.Headers[0]),
			termui.NewCol(2, 0, ui.Headers[1]),
			termui.NewCol(2, 0, ui.Headers[2]),
			termui.NewCol(2, 0, ui.Headers[3]),
		),
		termui.NewRow(
			termui.NewCol(12, 0, ui.Sparklines),
		),
	)
}

func (ui *UI) createHeader(pid int64) {
	p := termui.NewPar("")
	p.Height = HeaderHeight
	p.TextFgColor = termui.ColorWhite
	p.BorderLabel = "Monitoring Status.im via adb"
	p.BorderFg = termui.ColorCyan
	p.Text = "press 'q' to exit"

	p1 := termui.NewPar("")
	p1.Height = HeaderHeight
	p1.TextFgColor = termui.ColorWhite
	p1.BorderLabel = "PID"
	p1.BorderFg = termui.ColorCyan
	p1.Text = fmt.Sprintf("%d", pid)

	p2 := termui.NewPar("")
	p2.Height = HeaderHeight
	p2.TextFgColor = termui.ColorWhite
	p2.BorderLabel = "Polling interval"
	p2.BorderFg = termui.ColorCyan
	p2.Text = fmt.Sprintf("%v", ui.interval)

	p3 := termui.NewPar("")
	p3.Height = HeaderHeight
	p3.TextFgColor = termui.ColorYellow
	p3.BorderLabel = "Time"
	p3.BorderFg = termui.ColorCyan
	p3.Text = fmt.Sprintf("%v", time.Now().Format("15:04:05"))

	ui.Headers = []*termui.Par{p, p1, p2, p3}
}

func (ui *UI) createSparklines() {
	s := termui.NewSparkline()
	s.Height = termui.TermHeight() - HeaderHeight - 3 // - border
	s.LineColor = termui.ColorGreen

	ui.CPULine = &s

	// single
	ss := termui.NewSparklines(s)
	ss.Height = termui.TermHeight() - HeaderHeight
	ss.Border = true
	ss.BorderLabel = fmt.Sprintf("CPU (last %v)", time.Duration(termui.TermWidth()-2)*ui.interval)

	ui.Sparklines = ss
}

func (ui *UI) HandleKeys() {
	// handle key q pressing
	termui.Handle("/sys/kbd/q", func(termui.Event) {
		termui.StopLoop()
	})
}

// AddTimer adds handler for repeatable functions that interact with UI.
func (ui *UI) AddTimer(d time.Duration, fn func(e termui.Event)) {
	durationStr := fmt.Sprintf("/timer/%s", d)
	termui.Handle(durationStr, fn)
}

// Loop starts event loop and blocks.
func (ui *UI) Loop() {
	termui.Loop()
}