From a8b6a0b95acd63e8d39f65411621fe1da261fe39 Mon Sep 17 00:00:00 2001
From: sspanak <doftor.livain@gmail.com>
Date: Thu, 1 May 2025 14:43:24 +0300
Subject: [PATCH] prevented an unnecessary call to getTextBeforeCursor() when
 Backspace is pressed

---
 .../io/github/sspanak/tt9/hacks/AppHacks.java     | 13 ++++++++-----
 .../io/github/sspanak/tt9/ime/TypingHandler.java  |  2 +-
 .../io/github/sspanak/tt9/ime/helpers/Key.java    | 15 +++++++++++----
 3 files changed, 20 insertions(+), 10 deletions(-)

diff --git a/app/src/main/java/io/github/sspanak/tt9/hacks/AppHacks.java b/app/src/main/java/io/github/sspanak/tt9/hacks/AppHacks.java
index 84294cc4..e3c337d2 100644
--- a/app/src/main/java/io/github/sspanak/tt9/hacks/AppHacks.java
+++ b/app/src/main/java/io/github/sspanak/tt9/hacks/AppHacks.java
@@ -5,10 +5,12 @@ import android.view.KeyEvent;
 import androidx.annotation.NonNull;
 
 import io.github.sspanak.tt9.ime.helpers.CursorOps;
+import io.github.sspanak.tt9.ime.helpers.Key;
 import io.github.sspanak.tt9.ime.helpers.SuggestionOps;
 import io.github.sspanak.tt9.ime.helpers.TextField;
 import io.github.sspanak.tt9.ime.helpers.TextSelection;
 import io.github.sspanak.tt9.ime.modes.InputMode;
+import io.github.sspanak.tt9.preferences.settings.SettingsStore;
 
 public class AppHacks {
 	private final InputType inputType;
@@ -41,17 +43,19 @@ public class AppHacks {
 	 * Performs extra Backspace operations and returns "false", or completely replaces Backspace and returns "true". When "true" is
 	 * returned, you must not attempt to delete text. This function has already done everything necessary.
 	 */
-	public boolean onBackspace(InputMode inputMode) {
+	public boolean onBackspace(@NonNull SettingsStore settings, @NonNull InputMode inputMode) {
 		if (inputType.isKindleInvertedTextField()) {
 			inputMode.clearWordStem();
 		} else if (inputType.isTermux()) {
 			return false;
 		}
 
-		// When no text is selected and the cursor is at the beginning,
-		// allow double function keys to function normally (e.g. "Back" navigates back)
+		// When Backspace function is assigned to a different key (not hardware Backspace), we must
+		// allow the key to function normally if there is nothing to delete (e.g. "Back" navigates back).
 		return
-			inputMode.getSuggestions().isEmpty()
+			Key.exists(settings.getKeyBackspace())
+			&& !Key.isHardwareBackspace(settings.getKeyBackspace())
+			&& inputMode.getSuggestions().isEmpty()
 			&& textSelection.isEmpty()
 			&& textField.getStringBeforeCursor(1).isEmpty();
 	}
@@ -87,7 +91,6 @@ public class AppHacks {
 	/**
 	 * Performs extra operations when the cursor moves and returns "true" if the selection was handled,
 	 * "false" otherwise.
-	 *
 	 * CURSOR RESET
 	 * When sending messages using the Viber or the SMS app SEND button, it does so and clears the text
 	 * field, but without notifying the keyboard. This means, after sending the message, the InputMode
diff --git a/app/src/main/java/io/github/sspanak/tt9/ime/TypingHandler.java b/app/src/main/java/io/github/sspanak/tt9/ime/TypingHandler.java
index ef740458..9efdc1fe 100644
--- a/app/src/main/java/io/github/sspanak/tt9/ime/TypingHandler.java
+++ b/app/src/main/java/io/github/sspanak/tt9/ime/TypingHandler.java
@@ -115,7 +115,7 @@ public abstract class TypingHandler extends KeyPadHandler {
 			return false;
 		}
 
-		if (appHacks.onBackspace(mInputMode)) {
+		if (appHacks.onBackspace(settings, mInputMode)) {
 			mInputMode.reset();
 			return false;
 		}
diff --git a/app/src/main/java/io/github/sspanak/tt9/ime/helpers/Key.java b/app/src/main/java/io/github/sspanak/tt9/ime/helpers/Key.java
index 74b2add1..7c0bb3eb 100644
--- a/app/src/main/java/io/github/sspanak/tt9/ime/helpers/Key.java
+++ b/app/src/main/java/io/github/sspanak/tt9/ime/helpers/Key.java
@@ -40,11 +40,18 @@ public class Key {
 	}
 
 
+	public static boolean exists(int keyCode) {
+		return keyCode != KeyEvent.KEYCODE_UNKNOWN;
+	}
+
+
 	public static boolean isBackspace(SettingsStore settings, int keyCode) {
-		return
-			keyCode == KeyEvent.KEYCODE_DEL
-			|| keyCode == KeyEvent.KEYCODE_CLEAR
-			|| keyCode == settings.getKeyBackspace();
+		return isHardwareBackspace(keyCode) || keyCode == settings.getKeyBackspace();
+	}
+
+
+	public static boolean isHardwareBackspace(int keyCode) {
+		return keyCode == KeyEvent.KEYCODE_DEL || keyCode == KeyEvent.KEYCODE_CLEAR;
 	}