From 381e00c58461e9b1156a9141e3637483189aa7b8 Mon Sep 17 00:00:00 2001
From: Sam Hadow <sam.hadow@proton.me>
Date: Mon, 4 May 2026 11:00:29 +0200
Subject: [PATCH] prompt_list helper

---
 src/tea3/cli.py | 58 ++++++++++++++++++++++++++++---------------------
 1 file changed, 33 insertions(+), 25 deletions(-)

diff --git a/src/tea3/cli.py b/src/tea3/cli.py
index 6233250..c2b084e 100644
--- a/src/tea3/cli.py
+++ b/src/tea3/cli.py
@@ -30,6 +30,32 @@ def prompt_choice(message: str, choices: set[int]) -> int:
             return value
         print(f"Value must be one of: {choices_str}")
 
+def prompt_list(prompt: str, item_name: str, min_value: int, max_value: int):
+    while True:
+        raw = input(prompt).strip()
+        if not raw:
+            print(f"Please enter at least one {item_name}.")
+            continue
+
+        try:
+            values = [int(x) for x in raw.split()]
+        except ValueError:
+            print("Please enter only numbers separated by spaces.")
+            continue
+
+        if any(v < min_value or v > max_value for v in values):
+            print(f"Each {item_name} must be between {min_value} and {max_value}.")
+            continue
+
+        seen = set()
+        values = [v for v in values if not (v in seen or seen.add(v))]
+
+        if not values:
+            print(f"Please enter at least one valid {item_name}.")
+            continue
+
+        return values
+
 
 def run_classic_cli():
     print("\nR registers are indexed 0–7; bits within each register are 0–7.")
@@ -74,37 +100,19 @@ def run_exhaustive_cli():
     print("\n" + "=" * 50)
     print("Done.")
 
+
 def run_variable_xor_cli():
     print("\nR registers are indexed 0–7; bits within each register are 0–7.")
     print("Enter the bit positions to XOR, e.g. `0 1`.")
 
     steps = prompt_int("How many steps? (1–100): ", 1, 100)
     target_reg = prompt_int("Target register (0–7): ", 0, 7)
-
-    while True:
-        raw = input("Bits to XOR (0–7, separated by spaces): ").strip()
-        if not raw:
-            print("Please enter at least one bit index.")
-            continue
-
-        try:
-            bits_to_xor = [int(x) for x in raw.split()]
-        except ValueError:
-            print("Please enter only numbers separated by spaces.")
-            continue
-
-        if any(bit < 0 or bit > 7 for bit in bits_to_xor):
-            print("Each bit must be between 0 and 7.")
-            continue
-
-        seen = set()
-        bits_to_xor = [b for b in bits_to_xor if not (b in seen or seen.add(b))]
-
-        if not bits_to_xor:
-            print("Please enter at least one valid bit.")
-            continue
-
-        break
+    bits_to_xor = prompt_list(
+        "Bits to XOR (0–7, separated by spaces): ",
+        item_name="bit",
+        min_value=0,
+        max_value=7,
+    )
 
     print("-" * 50)
     run_variable_xor(steps, target_reg, bits_to_xor)