MIL-008: Choose level

Review record RC-041 (Go, autonomous mode, not independent).

Task: MIL-008#1
Task: MIL-008#2
Task: MIL-008#3
Task: MIL-008#4
Task: MIL-008#5
Task: MIL-008#6
Task: MIL-008#7
Task: MIL-008#8

src/flash_card/presentation/features/level/level_view_model.py

@@ -0,0 +1,53 @@
+"""View model of the level screen.
+
+@file level_view_model.py
+@brief Exposes the title and the level choices; free of any Tkinter import.
+"""
+
+from collections.abc import Sequence
+from dataclasses import dataclass
+
+from flash_card.constants import LEVEL_CHOICES, LEVEL_TITLE
+from flash_card.domain.value_objects.level import Level
+
+
+@dataclass(frozen=True, slots=True)
+class LevelChoice:
+    """One choice on the level screen."""
+
+    ## @brief Text of the choice.
+    label: str
+    ## @brief The level the choice stands for.
+    level: Level
+
+
+class LevelViewModel:
+    """Data the level view shows."""
+
+    def __init__(self, choices: Sequence[tuple[str, int | None]] | None = None) -> None:
+        """Create the view model.
+
+        @param choices Label and word limit of each choice, or None for the
+            choices of the program.
+        """
+        source = LEVEL_CHOICES if choices is None else choices
+        ## @brief The choices in display order.
+        self._choices = tuple(
+            LevelChoice(label, Level(limit)) for label, limit in source
+        )
+
+    @property
+    def title(self) -> str:
+        """Return the title of the screen.
+
+        @return The title text.
+        """
+        return LEVEL_TITLE
+
+    @property
+    def choices(self) -> tuple[LevelChoice, ...]:
+        """Return the choices.
+
+        @return The choices in display order.
+        """
+        return self._choices