Added Pagination to Choice Prompt

src/databricks/labs/blueprint/tui.py

@@ -3,6 +3,7 @@
 from __future__ import annotations
 
 import logging
+import os
 import re
 from collections.abc import Callable
 from typing import Any
@@ -45,20 +46,88 @@ def choice_from_dict(self, text: str, choices: dict[str, Any], *, sort: bool = T
         key = self.choice(text, list(choices.keys()), sort=sort)
         return choices[key]
 
-    def choice(self, text: str, choices: list[Any], *, max_attempts: int = 10, sort: bool = True) -> str:
-        """Use to select a value from a list
+    @staticmethod
+    def _clear_screen():
+        """Clear terminal screen cross-platform"""
+        os.system("cls" if os.name == "nt" else "clear")
+
+    def _display_page_and_get_input(
+        self, text: str, page_choices: list[Any], current_page: int, total_pages: int, start: int, end: int
+    ) -> str:
+        """Display current page and get user input"""
+        display = [f"\033[1m[{start + i}]\033[0m \033[36m{choice}\033[0m" for i, choice in enumerate(page_choices)]
+        numbered = "\n".join(display)
+
+        nav_info = []
+        if current_page > 0:
+            nav_info.append("\033[1m\033[36m'p' for previous\033[0m")
+        if current_page < total_pages - 1:
+            nav_info.append("\033[1m\033[36m'n' for next\033[0m")
+        nav_text = f" ({', '.join(nav_info)})" if nav_info else ""
+
+        page_info = f"\033[1m\033[36mPage {current_page + 1} of {total_pages}\033[0m"
+        prompt = (
+            f"\033[1m{text}\033[0m ({page_info}){nav_text}\n{numbered}\nEnter a number between {start} and {end - 1}"
+        )
+
+        return self.question(prompt, valid_number=False)
+
+    def _paginate_choices(self, text: str, choices: list[Any], *, max_attempts: int = 10, page_size: int = 10) -> str:
+        """Handle paginated choice selection for large lists"""
+        total_pages = (len(choices) + page_size - 1) // page_size
+        current_page = 0
+        attempt = 0
+
+        while attempt < max_attempts:
+            start = current_page * page_size
+            end = min(start + page_size, len(choices))
+            page_choices = choices[start:end]
+
+            user_input = self._display_page_and_get_input(text, page_choices, current_page, total_pages, start, end)
+
+            if user_input.lower() == "p" and current_page > 0:
+                current_page -= 1
+                self._clear_screen()
+                continue
+
+            if user_input.lower() == "n" and current_page < total_pages - 1:
+                current_page += 1
+                self._clear_screen()
+                continue
+
+            try:
+                res = int(user_input)
+                if start <= res < end:
+                    return choices[res]
+                print(f"\033[31m[ERROR] Out of range: {res}\033[0m\n")
+            except ValueError:
+                print(f"\033[31m[ERROR] Invalid input: {user_input}\033[0m\n")
+
+            attempt += 1
+
+        raise ValueError(f"Max attempts ({max_attempts}) exceeded")
+
+    def choice(
+        self, text: str, choices: list[Any], *, max_attempts: int = 10, sort: bool = True, page_size: int = 10
+    ) -> str:
+        """Use to select a value from a list with automatic pagination for large lists
 
         :param text: str:
         :param choices: list[Any]:
         :param *:
         :param max_attempts: int:  (Default value = 10)
         :param sort: bool:  (Default value = True)
-
+        :param page_size: int:  (Default value = 10)
         """
         if sort:
             choices = sorted(choices, key=str.casefold)
+
+        if len(choices) > page_size:
+            return self._paginate_choices(text, choices, max_attempts=max_attempts, page_size=page_size)
+
         numbered = "\n".join(f"\033[1m[{i}]\033[0m \033[36m{v}\033[0m" for i, v in enumerate(choices))
         prompt = f"\033[1m{text}\033[0m\n{numbered}\nEnter a number between 0 and {len(choices) - 1}"
+
         attempt = 0
         while attempt < max_attempts:
             attempt += 1
@@ -67,6 +136,7 @@ def choice(self, text: str, choices: list[Any], *, max_attempts: int = 10, sort:
                 print(f"\033[31m[ERROR] Out of range: {res}\033[0m\n")
                 continue
             return choices[res]
+
         msg = f"cannot get answer within {max_attempts} attempt"
         raise ValueError(msg)
 

tests/unit/test_tui.py

@@ -49,3 +49,28 @@ def test_extend_prompts():
     # Test that new question is still not mocked in the original prompts
     with pytest.raises(ValueError, match="not mocked: new_question"):
         prompts.question("new_question")
+
+
+def test_choice_uses_pagination(mocker):
+    """Test that choice() uses pagination when list > 10 items"""
+    prompts = Prompts()
+    # Test that pagination is show and input n will change to page 2 and select option 11
+    mocker.patch("builtins.input", side_effect=["n", "12"])
+
+    choices = [
+        "a",
+        "b",
+        "c",
+        "d",
+        "e",
+        "f",
+        "g",
+        "h",
+        "i",
+        "j",
+        "k",
+        "l",
+        "m",
+    ]
+    res = prompts.choice("foo", choices)
+    assert "m" == res