package main

import (
	"log"
	"time"

	"github.com/nsf/termbox-go"
)

func main() {
	t := NewTB()
	t.Run()
}

type TB struct {
	viewX, viewY int
	vcenter      int
	hcenter      int

	arms [][]rune
	arm  int
}

func NewTB() *TB {
	return &TB{
		arms: [][]rune{
			{'.', '.'},
			{'.', '.'},
			{'-', '-'},
			{'\\', '/'},
			{'\'', '/'},
			{'\\', '/'},
			{'\\', '\''},
			{'-', '-'},
		},
	}
}

func (tb *TB) Run() {
	err := termbox.Init()
	if err != nil {
		log.Fatal(err)
	}

	defer termbox.Close()

	tb.viewX, tb.viewY = termbox.Size()
	tb.vcenter = tb.viewY / 2.0
	tb.hcenter = tb.viewX / 2.0

	events := make(chan termbox.Event)
	go func() {
		for {
			events <- termbox.PollEvent()
		}
	}()

	termbox.HideCursor()

	func() {

		tick := time.Tick(200 * time.Millisecond)
		for {
			termbox.Clear(termbox.ColorBlack, termbox.ColorBlack)
			tb.draw()
			err := termbox.Flush()
			if err != nil {
				log.Fatal(err)
			}

			select {
			case <-tick:
			case event := <-events:
				switch event.Type {
				case termbox.EventKey:
					switch event.Key {
					case termbox.KeyCtrlZ, termbox.KeyCtrlC:
						log.Printf("exiting ...")
						return
					}

					switch event.Ch {
					case 'q':
						return
					}

				case termbox.EventResize:
					tb.viewX, tb.viewY = event.Width, event.Height
					tb.vcenter = tb.viewY / 2.0
					tb.hcenter = tb.viewX / 2.0
				case termbox.EventError:
					log.Fatalf("Quitting because of termbox error: \n%s\n", event.Err)
				}
			}
		}
	}()
}

func (tb *TB) draw() {
	termbox.SetCell(
		tb.hcenter-1,
		tb.vcenter,
		tb.arms[tb.arm%len(tb.arms)][0],
		termbox.ColorWhite|termbox.AttrBold, termbox.ColorBlack,
	)
	termbox.SetCell(
		tb.hcenter,
		tb.vcenter,
		'o',
		termbox.ColorWhite|termbox.AttrBold, termbox.ColorBlack,
	)
	termbox.SetCell(
		tb.hcenter+1,
		tb.vcenter,
		tb.arms[tb.arm%len(tb.arms)][1],
		termbox.ColorWhite|termbox.AttrBold, termbox.ColorBlack,
	)
	tb.arm += 1
}