From 183a426efa93e7a1b25730e85e194246523ef1c8 Mon Sep 17 00:00:00 2001
From: 739C1AE2 <134778074+739C1AE2@users.noreply.github.com>
Date: Sat, 6 Dec 2025 17:59:43 +0800
Subject: [PATCH] Fix UTF-16 surrogate pair handling on Windows input (#1160)

Fix(Windows): Correctly handle UTF-16 surrogate pairs for non-BMP input.

Co-authored-by: ArthurSonzogni <sonzogniarthur@gmail.com>
---
 CHANGELOG.md                               |  3 +++
 src/ftxui/component/screen_interactive.cpp | 10 ++++++++--
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1e2c4533a..c9d86f6df 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -37,6 +37,9 @@ Next
   output. Thanks @zozowell in #1064.
 - Fix vertical `ftxui::Slider`. The "up" key was previously decreasing the
   value. Thanks @its-pablo in #1093 for reporting the issue.
+- Fix Windows UTF-16 key input handling. Emoji and other code points outside the
+  Basic Multilingual Plane (BMP) are now correctly processed. Thanks @739C1AE2
+  in #1160 for fixing the issue.
 
 ### Dom
 - Fix integer overflow in `ComputeShrinkHard`. Thanks @its-pablo in #1137 for
diff --git a/src/ftxui/component/screen_interactive.cpp b/src/ftxui/component/screen_interactive.cpp
index 6dc982f0c..e5207a141 100644
--- a/src/ftxui/component/screen_interactive.cpp
+++ b/src/ftxui/component/screen_interactive.cpp
@@ -1098,6 +1098,7 @@ void ScreenInteractive::FetchTerminalEvents() {
   // Convert the input events to FTXUI events.
   // For each event, we call the terminal input parser to convert it to
   // Event.
+  std::wstring wstring;
   for (const auto& r : records) {
     switch (r.EventType) {
       case KEY_EVENT: {
@@ -1106,11 +1107,16 @@ void ScreenInteractive::FetchTerminalEvents() {
         if (key_event.bKeyDown == FALSE) {
           continue;
         }
-        std::wstring wstring;
-        wstring += key_event.uChar.UnicodeChar;
+        const wchar_t wc = key_event.uChar.UnicodeChar;
+        wstring += wc;
+        if (wc >= 0xd800 && wc <= 0xdbff) {
+          // Wait for the Low Surrogate to arrive in the next record.
+          continue;
+        }
         for (auto it : to_string(wstring)) {
           internal_->terminal_input_parser.Add(it);
         }
+        wstring.clear();
       } break;
       case WINDOW_BUFFER_SIZE_EVENT:
         Post(Event::Special({0}));