package main

import (
	"fmt"
	"os"
	"time"

	"github.com/stianeikeland/go-rpio/v4"
)

func busySleep(d time.Duration) {
	//time.Sleep(d)
	stop := time.Now().Add(d)
	for time.Now().Before(stop) {}
}

type VectorKeyboard struct {
	Pin rpio.Pin
}

func (k *VectorKeyboard) Start() {
	k.Pin.Output()
	k.Pin.High()
}

func (k *VectorKeyboard) Type(c byte) {
	k.bit(false);
	for i := 1; i < 7; i++ {
		k.bit((c&1) == 1)
		c >>= 1
	}
	k.bit(false);
	k.Pin.High()
	time.Sleep(71 * time.Millisecond)
}

func (k *VectorKeyboard) bit(b bool) {
	stop := time.Now().Add(3350 * time.Microsecond)
	if (b) {
		k.Pin.High()
	} else {
		k.Pin.Low()
	}
	//busySleep(3350 * time.Microsecond)
	for time.Now().Before(stop) {}
}

func main() {
	if err := rpio.Open(); err != nil {
		fmt.Println("rpio open failed:", err)
		return
	}
	defer rpio.Close()

	kbd := VectorKeyboard{rpio.Pin(2)}
	kbd.Start()

	fmt.Println("Type:")
	var bs [1]byte
	for {
		if _, err := os.Stdin.Read(bs[:]); err != nil {
			fmt.Println("Read failed:", err)
			return
		}
		kbd.Type(bs[0])
	}
}