package main

import (
	"image/color"
	"machine"
	"time"

	"tinygo.org/x/drivers/encoders"
	"tinygo.org/x/drivers/ws2812"
)

func main() {
	// WS2812 LEDs are on pin P1_11
	neo := machine.P1_11
	neo.Configure(machine.PinConfig{Mode: machine.PinOutput})

	leds := ws2812.New(neo)
	ledColors := make([]color.RGBA, 2)

	// rotary encoder: A=P1_00, B=P0_24; push button=P0_22
	enc := encoders.NewQuadratureViaInterrupt(machine.P1_00, machine.P0_24)
	enc.Configure(encoders.QuadratureConfig{Precision: 4})

	btnRot := machine.P0_22
	btnRot.Configure(machine.PinConfig{Mode: machine.PinInputPullup})

	var k uint8
	for {
		// pressing the rotary button resets position to zero
		if !btnRot.Get() {
			enc.SetPosition(0)
		}

		// encoder position cycles through the rainbow
		k = uint8(enc.Position())

		ledColors[0] = getRainbowRGB(k)
		ledColors[1] = getRainbowRGB(k + 85)
		leds.WriteColors(ledColors)

		time.Sleep(20 * time.Millisecond)
	}
}

func getRainbowRGB(i uint8) color.RGBA {
	if i < 85 {
		return color.RGBA{i * 3, 255 - i*3, 0, 255}
	} else if i < 170 {
		i -= 85
		return color.RGBA{255 - i*3, 0, i * 3, 255}
	}
	i -= 170
	return color.RGBA{0, i * 3, 255 - i*3, 255}
}