feat(main): refactor main not to violate DRY

knowledge_verificator/main.py

@@ -7,7 +7,7 @@
 from knowledge_verificator.materials import MaterialDatabase
 from knowledge_verificator.nli import NaturalLanguageInference, Relation
 from knowledge_verificator.qg import QuestionGeneration
-from knowledge_verificator.utils.string import clip_text
+from knowledge_verificator.utils.menu import choose_from_menu
 
 
 if __name__ == '__main__':
@@ -40,51 +40,19 @@
                     )
                     continue
 
-                console.print('Available materials:')
-                for i, material in enumerate(material_db.materials):
-                    console.print(f'[{i+1}] {material.title}')
-                material_choice = input('Your choice: ')
-                console.print()
-
-                INCORRECT_CHOICE_WARNING = (
-                    'This is incorrect choice. Next time, provide a number '
-                    'next to a material from the list of available ones.'
-                )
-                if not material_choice.isnumeric():
-                    console.print(INCORRECT_CHOICE_WARNING)
-                    continue
-
-                chosen_index = int(material_choice) - 1
-                if chosen_index < 0 or chosen_index >= len(
-                    material_db.materials
-                ):
-                    console.print(INCORRECT_CHOICE_WARNING)
-                    continue
-
-                material = material_db.materials[chosen_index]
-
-                MAX_LENGTH_OF_CLIPPED_PARAGRAPH = 15
-                console.print('Available paragraphs: ')
-                for i, paragraph in enumerate(material.paragraphs):
-                    console.print(
-                        f'{i+1} {clip_text(paragraph, MAX_LENGTH_OF_CLIPPED_PARAGRAPH)}'
-                    )
-
-                console.print('Which paragraph you want to learn? ')
-                paragraph_choice = input()
-
-                if not paragraph_choice.isnumeric():
-                    console.print(INCORRECT_CHOICE_WARNING)
+                material_titles = [
+                    material.title for material in material_db.materials
+                ]
+                material = choose_from_menu(material_titles, 'materials')
+                if material is None:
                     continue
 
-                chosen_index = int(paragraph_choice) - 1
-                if chosen_index < 0 or chosen_index >= len(material.paragraphs):
-                    console.print(INCORRECT_CHOICE_WARNING)
+                paragraph = str(
+                    choose_from_menu(material.paragraphs, 'paragraphs')
+                )
+                if paragraph is None:
                     continue
 
-                # TODO: Refactor this fragment to apply DRY principle.
-                paragraph = material.paragraphs[chosen_index]
-
                 console.print('Learn this paragraph: ')
                 console.print(paragraph)
                 console.print()

knowledge_verificator/utils/menu.py

@@ -0,0 +1,43 @@
+"""Module with utilities supporting creation of CLI menus."""
+
+from typing import Any
+from knowledge_verificator.io_handler import console
+from knowledge_verificator.utils.string import clip_text
+
+
+def choose_from_menu(
+    menu_elements: list[str], plural_name: str, max_line_width: int = 40
+) -> Any | None:
+    """
+    Prompt a user to choose an element from a list via terminal.
+
+    Args:
+        menu_elements (list[str]): List of elements to choose from.
+            Elements should be convertible to `str` (implement `__str__` method).
+        plural_name (str): Plural name of the elements. For example: options, paragraphs or names.
+        max_line_width (int): Maximum line width in number of columns. By default: 40.
+
+    Returns:
+        any | None: Element of a list or None if a user provided incorrect
+            value via a terminal.
+    """
+    console.print(f'Available {plural_name}:')
+    for i, element in enumerate(menu_elements):
+        console.print(f'[{i+1}] {clip_text(element, max_line_width)}')
+    material_choice = input('Your choice: ')
+    console.print()
+
+    incorrect_choice_warning = (
+        'This is incorrect choice. Next time, provide a number '
+        'next to a element from the list of available ones.'
+    )
+    if not material_choice.isnumeric():
+        console.print(incorrect_choice_warning)
+        return None
+
+    chosen_index = int(material_choice) - 1
+    if chosen_index < 0 or chosen_index >= len(menu_elements):
+        console.print(incorrect_choice_warning)
+        return None
+
+    return menu_elements[chosen_index]