1 files changed, 74 insertions, 0 deletions
diff --git a/input_utils.py b/input_utils.py
new file mode 100644
index 0000000..913146a
--- /dev/null
+++ b/input_utils.py
@@ -0,0 +1,74 @@
+#!/usr/bin/env python3
+
+"""Utilities related to user input."""
+
+import readchar  # type: ignore
+import signal
+import sys
+from typing import List
+
+
+def single_keystroke_response(
+    valid_responses: List[str],
+    *,
+    prompt: str = None,
+    default_response: str = None,
+    timeout_seconds: int = None,
+) -> str:
+    class TimeoutError(Exception):
+        pass
+
+    def _handle_timeout(signum, frame) -> None:
+        raise TimeoutError()
+
+    def _single_keystroke_response_internal(
+        valid_responses: List[str], timeout_seconds=None
+    ) -> str:
+        if timeout_seconds is not None:
+            signal.signal(signal.SIGALRM, _handle_timeout)
+            signal.alarm(timeout_seconds)
+
+        try:
+            while True:
+                response = readchar.readchar()
+                if response in valid_responses:
+                    break
+            return response
+        finally:
+            if timeout_seconds is not None:
+                signal.alarm(0)
+
+    if prompt is not None:
+        print(prompt, end="")
+        sys.stdout.flush()
+    try:
+        response = _single_keystroke_response_internal(
+            valid_responses, timeout_seconds
+        )
+    except TimeoutError:
+        if default_response is not None:
+            response = default_response
+    if prompt is not None:
+        print(response)
+    return response
+
+
+def yn_response(prompt: str = None, *, timeout_seconds=None) -> str:
+    return single_keystroke_response(
+        ["y", "n", "Y", "N"], prompt=prompt, timeout_seconds=timeout_seconds
+    ).lower()
+
+
+def keystroke_helper() -> None:
+    print("Watching for keystrokes; ^C to quit.")
+    while True:
+        key = readchar.readkey()
+        if len(key) == 1:
+            print(f'That was "{key}" ({ord(key)}).')
+            if ord(key) == 3:
+                return
+        else:
+            print(f'That was sequence "{key}" (', end="")
+            for _ in key:
+                print(f" {ord(_)} ", end="")
+            print(")")