From dd6f5c4565b5481ffbe756329d570e7fbd2d5ecd Mon Sep 17 00:00:00 2001
From: Hajime Hoshi <hajimehoshi@gmail.com>
Date: Tue, 6 Feb 2024 00:57:50 +0900
Subject: [PATCH] exp/textinput: bug fix: flaky behavior on iOS Safari

Closes #2898
---
 examples/textinput/main.go    | 46 +++++++++++++++++++----------------
 exp/textinput/textinput_js.go | 35 ++++++++++++++++++++++----
 2 files changed, 55 insertions(+), 26 deletions(-)

diff --git a/examples/textinput/main.go b/examples/textinput/main.go
index 5e43048b7..38b250f67 100644
--- a/examples/textinput/main.go
+++ b/examples/textinput/main.go
@@ -64,11 +64,11 @@ func (t *TextField) Contains(x, y int) bool {
 }
 
 func (t *TextField) SetSelectionStartByCursorPosition(x, y int) bool {
+	t.cleanUp()
 	idx, ok := t.textIndexByCursorPosition(x, y)
 	if !ok {
 		return false
 	}
-
 	t.selectionStart = idx
 	t.selectionEnd = idx
 	return true
@@ -136,29 +136,33 @@ func (t *TextField) Blur() {
 	t.focused = false
 }
 
+func (t *TextField) cleanUp() {
+	if t.ch != nil {
+		select {
+		case state, ok := <-t.ch:
+			if ok && state.Committed {
+				t.text = t.text[:t.selectionStart] + state.Text + t.text[t.selectionEnd:]
+				t.selectionStart += len(state.Text)
+				t.selectionEnd = t.selectionStart
+				t.state = textinput.State{}
+			}
+			t.state = state
+		default:
+			break
+		}
+	}
+	if t.end != nil {
+		t.end()
+		t.ch = nil
+		t.end = nil
+		t.state = textinput.State{}
+	}
+}
+
 func (t *TextField) Update() {
 	if !t.focused {
 		// If the text field still has a session, read the last state and process it just in case.
-		if t.ch != nil {
-			select {
-			case state, ok := <-t.ch:
-				if ok && state.Committed {
-					t.text = t.text[:t.selectionStart] + state.Text + t.text[t.selectionEnd:]
-					t.selectionStart += len(state.Text)
-					t.selectionEnd = t.selectionStart
-					t.state = textinput.State{}
-				}
-				t.state = state
-			default:
-				break
-			}
-		}
-		if t.end != nil {
-			t.end()
-			t.ch = nil
-			t.end = nil
-			t.state = textinput.State{}
-		}
+		t.cleanUp()
 		return
 	}
 
diff --git a/exp/textinput/textinput_js.go b/exp/textinput/textinput_js.go
index 34d5dde62..0a65e4e6e 100644
--- a/exp/textinput/textinput_js.go
+++ b/exp/textinput/textinput_js.go
@@ -15,6 +15,7 @@
 package textinput
 
 import (
+	"fmt"
 	"syscall/js"
 
 	"github.com/hajimehoshi/ebiten/v2/internal/ui"
@@ -77,6 +78,10 @@ func (t *textInput) init() {
 		if e.Get("code").String() == "Tab" {
 			e.Call("preventDefault")
 		}
+		if e.Get("code").String() == "Enter" || e.Get("key").String() == "Enter" {
+			// Ignore Enter key to avoid ebiten.IsKeyPressed(ebiten.KeyEnter) unexpectedly becomes true, especially for iOS Safari.
+			return nil
+		}
 		if !e.Get("isComposing").Bool() {
 			ui.Get().UpdateInputFromEvent(e)
 		}
@@ -104,6 +109,7 @@ func (t *textInput) init() {
 			t.trySend(true)
 			return nil
 		}
+		// Though `isComposing` is false, send the text as being not committed for text completion on mobile browsers.
 		t.trySend(false)
 		return nil
 	}))
@@ -143,18 +149,37 @@ func (t *textInput) Start(x, y int) (chan State, func()) {
 		return nil, nil
 	}
 
-	if t.session != nil {
-		t.session.end()
-		t.session = nil
-	}
-
 	if js.Global().Get("_ebitengine_textinput_ready").Truthy() {
+		if t.session != nil {
+			t.session.end()
+		}
 		s := newSession()
 		t.session = s
 		js.Global().Get("window").Set("_ebitengine_textinput_ready", js.Undefined())
 		return s.ch, s.end
 	}
 
+	// If a textarea is focused, create a session immediately.
+	// A virtual keyboard should already be shown on mobile browsers.
+	if document.Get("activeElement").Equal(t.textareaElement) {
+		t.textareaElement.Set("value", "")
+		t.textareaElement.Call("focus")
+		style := t.textareaElement.Get("style")
+		style.Set("left", fmt.Sprintf("%dpx", x))
+		style.Set("top", fmt.Sprintf("%dpx", y))
+
+		if t.session == nil {
+			s := newSession()
+			t.session = s
+		}
+		return t.session.ch, t.session.end
+	}
+
+	if t.session != nil {
+		t.session.end()
+		t.session = nil
+	}
+
 	// On iOS Safari, `focus` works only in user-interaction events (#2898).
 	// Assuming Start is called every tick, defer the starting process to the next user-interaction event.
 	js.Global().Get("window").Set("_ebitengine_textinput_x", x)