added implementation in GO lang

internal/modes/findkey.go

@@ -0,0 +1,100 @@
+package modes
+
+import (
+	"image/color"
+	"path/filepath"
+	"time"
+
+	"github.com/hajimehoshi/ebiten/v2"
+
+	"kidskeyboard/internal/ui"
+)
+
+type FindKeyMode struct {
+	ctx          Context
+	target       rune
+	successTicks int
+	errorTicks   int
+	lastJingle   int
+}
+
+const findChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
+
+func NewFindKeyMode(ctx Context) *FindKeyMode {
+	m := &FindKeyMode{ctx: ctx, lastJingle: -1}
+	m.pickNext()
+	return m
+}
+
+func (m *FindKeyMode) Name() string { return "CTRL+F5 Find Key" }
+func (m *FindKeyMode) OnEnter()     {}
+func (m *FindKeyMode) OnLeave()     {}
+
+func (m *FindKeyMode) HandleInput() {
+	if m.successTicks > 0 {
+		return
+	}
+	for _, key := range justPressedKeys() {
+		if !childKey(key) {
+			continue
+		}
+		r, ok := keyRune(key)
+		if ok && r == m.target {
+			m.successTicks = 180
+			m.errorTicks = 0
+			m.playJingle()
+			return
+		}
+		m.errorTicks = 18
+		m.ctx.Audio.PlayError()
+		return
+	}
+}
+
+func (m *FindKeyMode) Update() {
+	if m.errorTicks > 0 {
+		m.errorTicks--
+	}
+	if m.successTicks > 0 {
+		m.successTicks--
+		if m.successTicks == 0 {
+			m.pickNext()
+		}
+	}
+}
+
+func (m *FindKeyMode) Draw(screen *ebiten.Image) {
+	screen.Fill(color.Black)
+	w, h := screen.Bounds().Dx(), screen.Bounds().Dy()
+	ui.Text(screen, "CTRL+F5", 20, 20, color.White, 2)
+
+	var clr color.Color = color.White
+	if m.errorTicks > 0 {
+		clr = color.NRGBA{R: 255, A: 255}
+	}
+	if m.successTicks > 0 {
+		clr = color.NRGBA{G: 255, A: 255}
+	}
+	ui.CenteredText(screen, string(m.target), w/2, h/2, clr, 18)
+}
+
+func (m *FindKeyMode) pickNext() {
+	m.target = rune(findChars[m.ctx.RNG.Intn(len(findChars))])
+}
+
+func (m *FindKeyMode) playJingle() {
+	const count = 4
+	next := m.ctx.RNG.Intn(count)
+	if count > 1 {
+		for next == m.lastJingle {
+			next = m.ctx.RNG.Intn(count)
+		}
+	}
+	m.lastJingle = next
+	path := filepath.Join("assets", "sounds", "jingle"+string(rune('1'+next))+".wav")
+	if m.ctx.Audio.PlayWAV(path, true) {
+		return
+	}
+	freq := 520 + float64(next)*120
+	m.ctx.Audio.PlayToneInterrupt(freq, 180*time.Millisecond, 0.28)
+}