Sync upstream Gemini-CLI v0.8.2 (#838)

packages/cli/src/ui/hooks/keyToAnsi.ts

@@ -0,0 +1,77 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import type { Key } from '../contexts/KeypressContext.js';
+
+export type { Key };
+
+/**
+ * Translates a Key object into its corresponding ANSI escape sequence.
+ * This is useful for sending control characters to a pseudo-terminal.
+ *
+ * @param key The Key object to translate.
+ * @returns The ANSI escape sequence as a string, or null if no mapping exists.
+ */
+export function keyToAnsi(key: Key): string | null {
+  if (key.ctrl) {
+    // Ctrl + letter
+    if (key.name >= 'a' && key.name <= 'z') {
+      return String.fromCharCode(
+        key.name.charCodeAt(0) - 'a'.charCodeAt(0) + 1,
+      );
+    }
+    // Other Ctrl combinations might need specific handling
+    switch (key.name) {
+      case 'c':
+        return '\x03'; // ETX (End of Text), commonly used for interrupt
+      // Add other special ctrl cases if needed
+      default:
+        break;
+    }
+  }
+
+  // Arrow keys and other special keys
+  switch (key.name) {
+    case 'up':
+      return '\x1b[A';
+    case 'down':
+      return '\x1b[B';
+    case 'right':
+      return '\x1b[C';
+    case 'left':
+      return '\x1b[D';
+    case 'escape':
+      return '\x1b';
+    case 'tab':
+      return '\t';
+    case 'backspace':
+      return '\x7f';
+    case 'delete':
+      return '\x1b[3~';
+    case 'home':
+      return '\x1b[H';
+    case 'end':
+      return '\x1b[F';
+    case 'pageup':
+      return '\x1b[5~';
+    case 'pagedown':
+      return '\x1b[6~';
+    default:
+      break;
+  }
+
+  // Enter/Return
+  if (key.name === 'return') {
+    return '\r';
+  }
+
+  // If it's a simple character, return it.
+  if (!key.ctrl && !key.meta && key.sequence) {
+    return key.sequence;
+  }
+
+  return null;
+}