Step 2

Replacing blanks with guesses

src/hangman/game.py

@@ -5,7 +5,7 @@
 
 import random
 
-from hangman.constants import WORD_LIST
+from hangman.constants import BLANK, WORD_LIST
 
 
 def choose_word(words: list[str] | None = None) -> str:
@@ -25,3 +25,36 @@ def is_in_word(word: str, letter: str) -> bool:
     @return True if @p letter is in @p word.
     """
     return letter.lower() in word.lower()
+
+
+class Game:
+    """!
+    @brief State of one Hangman game.
+    """
+
+    def __init__(self, word: str) -> None:
+        """!
+        @brief Start a new game.
+        @param word The secret word.
+        """
+        ## The secret word.
+        self.word = word.lower()
+        ## Letters guessed so far.
+        self.guesses: set[str] = set()
+
+    def guess(self, letter: str) -> bool:
+        """!
+        @brief Process a guess and reveal the letter if it is in the word.
+        @param letter A single letter.
+        @return True if the letter is in the word.
+        """
+        letter = letter.lower()
+        self.guesses.add(letter)
+        return is_in_word(self.word, letter)
+
+    def display(self) -> str:
+        """!
+        @brief The word with unguessed letters replaced by blanks.
+        @return For example `"p _ n g _ i n"`.
+        """
+        return " ".join(c if c in self.guesses else BLANK for c in self.word)