From 99b92dd388d57eb9ce8d233cf010d65a66695b0b Mon Sep 17 00:00:00 2001
From: vedasjad <96325125+vedasjad@users.noreply.github.com>
Date: Sat, 16 Dec 2023 13:06:41 +0530
Subject: [PATCH] Delete word by word after 3 seconds have passed since pressed

---
 lib/src/default_emoji_picker_view.dart | 41 ++++++++++++++++++--
 lib/src/emoji_picker.dart              | 52 ++++++++++++++++++++++++++
 lib/src/emoji_view_state.dart          |  4 ++
 3 files changed, 93 insertions(+), 4 deletions(-)

diff --git a/lib/src/default_emoji_picker_view.dart b/lib/src/default_emoji_picker_view.dart
index df14486..88019db 100644
--- a/lib/src/default_emoji_picker_view.dart
+++ b/lib/src/default_emoji_picker_view.dart
@@ -211,15 +211,48 @@ class _DefaultEmojiPickerViewState extends State<DefaultEmojiPickerView>
     closeSkinToneOverlay();
   }
 
+  /// Start the callback for long-pressing the backspace button.
   void _startOnBackspacePressedCallback() {
-    const callbackInterval = Duration(milliseconds: 75);
+    // Initial callback interval for short presses
+    var callbackInterval = const Duration(milliseconds: 75);
+    var millisecondsSincePressed = 0;
+
+    // Callback function executed on each timer tick
+    void _callback(Timer timer) {
+      // Accumulate elapsed time since the last tick
+      millisecondsSincePressed += callbackInterval.inMilliseconds;
+
+      // If the long-press duration exceeds 3 seconds
+      if (millisecondsSincePressed > 3000 &&
+          callbackInterval == const Duration(milliseconds: 75)) {
+        // Switch to a longer callback interval for word-by-word deletion
+        callbackInterval = const Duration(milliseconds: 300);
+
+        // Cancel the existing timer and start a new one with the updated interval
+        _onBackspacePressedCallbackTimer?.cancel();
+        _onBackspacePressedCallbackTimer =
+            Timer.periodic(callbackInterval, _callback);
+
+        // Reset the elapsed time for the new interval
+        millisecondsSincePressed = 0;
+      }
+
+      // Trigger the appropriate callback based on the interval
+      if (callbackInterval == const Duration(milliseconds: 75)) {
+        widget.state.onBackspacePressed!(); // Short-press callback
+      } else {
+        widget.state.onBackspaceLongPressed(); // Long-press callback
+      }
+    }
+
+    // Start the initial timer with the short-press interval
     _onBackspacePressedCallbackTimer =
-        Timer.periodic(callbackInterval, (timer) {
-      widget.state.onBackspacePressed!();
-    });
+        Timer.periodic(callbackInterval, _callback);
   }
 
+  /// Stop the callback for long-pressing the backspace button.
   void _stopOnBackspacePressedCallback() {
+    // Cancel the active timer
     _onBackspacePressedCallbackTimer?.cancel();
   }
 }
diff --git a/lib/src/emoji_picker.dart b/lib/src/emoji_picker.dart
index 9adf0b4..ae714a2 100644
--- a/lib/src/emoji_picker.dart
+++ b/lib/src/emoji_picker.dart
@@ -98,6 +98,9 @@ typedef void OnSkinToneDialogRequested(
 /// Callback function for backspace button
 typedef void OnBackspacePressed();
 
+/// Callback function for backspace button when long pressed
+typedef void OnBackspaceLongPressed();
+
 /// Callback function for custom view
 typedef EmojiViewBuilder = Widget Function(Config config, EmojiViewState state);
 
@@ -220,6 +223,54 @@ class EmojiPickerState extends State<EmojiPicker> {
     widget.onBackspacePressed?.call();
   }
 
+  OnBackspaceLongPressed _onBackspaceLongPressed() {
+    return () {
+      if (widget.textEditingController != null) {
+        final controller = widget.textEditingController!;
+
+        final text = controller.value.text;
+        var cursorPosition = controller.selection.base.offset;
+
+        // If cursor is not set, then place it at the end of the textfield
+        if (cursorPosition < 0) {
+          controller.selection = TextSelection(
+            baseOffset: controller.text.length,
+            extentOffset: controller.text.length,
+          );
+          cursorPosition = controller.selection.base.offset;
+        }
+
+        if (cursorPosition >= 0) {
+          final selection = controller.value.selection;
+          final newTextBeforeCursor = _deleteWordByWord(
+            selection.textBefore(text).toString(),
+          );
+          controller
+            ..text = newTextBeforeCursor + selection.textAfter(text)
+            ..selection = TextSelection.fromPosition(
+              TextPosition(offset: newTextBeforeCursor.length),
+            );
+        }
+      }
+    };
+  }
+
+  String _deleteWordByWord(String text) {
+    // Trim trailing spaces
+    text = text.trimRight();
+
+    // Find the last space to determine the start of the last word
+    final lastSpaceIndex = text.lastIndexOf(' ');
+
+    // If there is a space, remove the last word and spaces before it
+    if (lastSpaceIndex != -1) {
+      return text.substring(0, lastSpaceIndex).trimRight();
+    }
+
+    // If there is no space, remove the entire text
+    return '';
+  }
+
   // Add recent emoji handling to tap listener
   OnEmojiSelected _getOnEmojiListener() {
     return (category, emoji) {
@@ -290,6 +341,7 @@ class EmojiPickerState extends State<EmojiPicker> {
       _categoryEmoji,
       _getOnEmojiListener(),
       widget.onBackspacePressed == null ? null : _onBackspacePressed,
+      _onBackspaceLongPressed(),
     );
     if (mounted) {
       setState(() {
diff --git a/lib/src/emoji_view_state.dart b/lib/src/emoji_view_state.dart
index 3405167..36ba999 100644
--- a/lib/src/emoji_view_state.dart
+++ b/lib/src/emoji_view_state.dart
@@ -7,6 +7,7 @@ class EmojiViewState {
     this.categoryEmoji,
     this.onEmojiSelected,
     this.onBackspacePressed,
+    this.onBackspaceLongPressed,
   );
 
   /// List of all category including their emoji
@@ -17,4 +18,7 @@ class EmojiViewState {
 
   /// Callback when pressed on backspace
   final OnBackspacePressed? onBackspacePressed;
+
+  /// Callback when long pressed on backspace
+  final OnBackspaceLongPressed onBackspaceLongPressed;
 }