Centralize Key Binding Logic and Refactor (Reopen) (#5356)

Co-authored-by: Lee-WonJun <[email protected]>

1 files changed, 105 insertions, 0 deletions

diff --git a/packages/cli/src/ui/keyMatchers.ts b/packages/cli/src/ui/keyMatchers.ts
new file mode 100644
index 00000000..651343af
--- /dev/null
+++ b/packages/cli/src/ui/keyMatchers.ts
@@ -0,0 +1,105 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import type { Key } from './hooks/useKeypress.js';
+import {
+  Command,
+  KeyBinding,
+  KeyBindingConfig,
+  defaultKeyBindings,
+} from '../config/keyBindings.js';
+
+/**
+ * Matches a KeyBinding against an actual Key press
+ * Pure data-driven matching logic
+ */
+function matchKeyBinding(keyBinding: KeyBinding, key: Key): boolean {
+  // Either key name or sequence must match (but not both should be defined)
+  let keyMatches = false;
+
+  if (keyBinding.key !== undefined) {
+    keyMatches = keyBinding.key === key.name;
+  } else if (keyBinding.sequence !== undefined) {
+    keyMatches = keyBinding.sequence === key.sequence;
+  } else {
+    // Neither key nor sequence defined - invalid binding
+    return false;
+  }
+
+  if (!keyMatches) {
+    return false;
+  }
+
+  // Check modifiers - follow original logic:
+  // undefined = ignore this modifier (original behavior)
+  // true = modifier must be pressed
+  // false = modifier must NOT be pressed
+
+  if (keyBinding.ctrl !== undefined && key.ctrl !== keyBinding.ctrl) {
+    return false;
+  }
+
+  if (keyBinding.shift !== undefined && key.shift !== keyBinding.shift) {
+    return false;
+  }
+
+  if (keyBinding.command !== undefined && key.meta !== keyBinding.command) {
+    return false;
+  }
+
+  if (keyBinding.paste !== undefined && key.paste !== keyBinding.paste) {
+    return false;
+  }
+
+  return true;
+}
+
+/**
+ * Checks if a key matches any of the bindings for a command
+ */
+function matchCommand(
+  command: Command,
+  key: Key,
+  config: KeyBindingConfig = defaultKeyBindings,
+): boolean {
+  const bindings = config[command];
+  return bindings.some((binding) => matchKeyBinding(binding, key));
+}
+
+/**
+ * Key matcher function type
+ */
+type KeyMatcher = (key: Key) => boolean;
+
+/**
+ * Type for key matchers mapped to Command enum
+ */
+export type KeyMatchers = {
+  readonly [C in Command]: KeyMatcher;
+};
+
+/**
+ * Creates key matchers from a key binding configuration
+ */
+export function createKeyMatchers(
+  config: KeyBindingConfig = defaultKeyBindings,
+): KeyMatchers {
+  const matchers = {} as { [C in Command]: KeyMatcher };
+
+  for (const command of Object.values(Command)) {
+    matchers[command] = (key: Key) => matchCommand(command, key, config);
+  }
+
+  return matchers as KeyMatchers;
+}
+
+/**
+ * Default key binding matchers using the default configuration
+ */
+export const keyMatchers: KeyMatchers = createKeyMatchers(defaultKeyBindings);
+
+// Re-export Command for convenience
+export { Command };