Refactor to extract state from game

play.py

@@ -4,11 +4,12 @@ from ttt_player import TTTHumanPlayer
 
 player0 = TTTHumanPlayer("Player 1")
 player1 = TTTHumanPlayer("Player 2")
-game = TTTGame(player0, player1)
-view = TTTView()
+game = TTTGame()
+view = TTTView(player0, player1)
 
-view.greet(game)
-while not game.is_over(game.state):
-    action = view.get_action(game)
-    game.play_action(action)
-view.conclude(game)
+state = game.get_initial_state()
+view.greet()
+while not game.is_over(state):
+    action = view.get_action(state)
+    state = game.get_next_state(state, action)
+view.conclude(state)

ttt_game.py

@@ -1,18 +1,11 @@
 class TTTGame:
     "Models a tic-tac-toe game."
 
-    def __init__(self, playerX, playerO):
-        self.state = self.get_initial_state()
-        self.players = {
-            'X': playerX,
-            'O': playerO,
-        }
-
     def get_initial_state(self):
         "Returns the game's initial state."
         return {
             "board": ['-', '-', '-', '-', '-', '-', '-', '-', '-'],
-            "player": "X",
+            "player_x": True,
         }
 
     def get_next_state(self, state, action):
@@ -21,14 +14,10 @@ class TTTGame:
         in an empty board space, and it is the opposite player's turn.
         """
         new_board = state["board"].copy()
-        new_board[action] = state["player"]
-        if state["player"] == "O":
-            new_player = "X"
-        else:
-            new_player = "O"
+        new_board[action] = 'X' if state["player_x"] else 'O'
         return {
             "board": new_board,
-            "player": new_player,
+            "player_x": not state["player_x"],
         }
 
     def get_actions(self, state):
@@ -58,20 +47,7 @@ class TTTGame:
         want opposite things, so we set X's objective to the built-in function `max`
         (which chooses the largest number), and we set O's objective to the built-in function `min`.
         """
-        if state["player"] == 'X':
-            return max
-        elif state["player"] == 'O':
-            return min
-        else:
-            raise ValueError(f"Unrecognized player {state['player']}")
-
-    def play_action(self, action):
-        "Plays a move, updating the game's state."
-        self.state = self.get_next_state(self.state, action)
-
-    def is_valid_move(self, move):
-        "Checks whether a move is valid"
-        return move in self.get_valid_moves()
+        return max if state["player_x"] else min
 
     def board_is_full(self, state):
         "Checks whether all the spaces in the board are occupied."
@@ -83,6 +59,3 @@ class TTTGame:
     def check_winner(self, state, symbol):
         "Checks whether the player with `symbol` has won the game."
         return False
-
-
-

ttt_player.py

@@ -1,5 +1,6 @@
 from click import Choice, prompt
 from strategy import RandomStrategy
+from ttt_game import TTTGame
 import random
 
 class TTTHumanPlayer:
@@ -8,12 +9,14 @@ class TTTHumanPlayer:
     def __init__(self, name):
         "Sets up the player."
         self.name = name
+        self.game = TTTGame()
 
-    def choose_action(self, game):
+    def choose_action(self, state):
         "Chooses an action by prompting the player for a choice."
-        choices = Choice([str(i) for i in game.get_actions(game.state)])
-        move = prompt("> ", type=choices, show_choices=False)
-        return int(move)
+        actions = self.game.get_actions(state)
+        choices = Choice([str(action) for action in actions])
+        action = int(prompt("> ", type=choices, show_choices=False))
+        return action
 
 class TTTComputerPlayer:
     "A computer tic tac toe player"
@@ -21,19 +24,10 @@ class TTTComputerPlayer:
     def __init__(self, name):
         "Sets up the player."
         self.name = name
+        self.strategy = RandomStrategy(TTTGame())
 
-    def choose_action(self, game):
+    def choose_action(self, state):
         "Chooses a random move from the moves available."
-        strategy = RandomStrategy(game)
-        action = strategy.choose_action(game.state)
+        action = self.strategy.choose_action(state)
         print(f"{self.name} chooses {action}.")
-        return move
-
-    def get_symbol(self, game):
-        "Returns this player's symbol in the game."
-        if game.players['X'] == self:
-            return 'X'
-        elif game.players['O'] == self:
-            return 'O'
-        else:
-            raise ValueError(f"Player {self.name} isn't in this game!")
+        return action

ttt_view.py

@@ -1,3 +1,4 @@
+from ttt_game import TTTGame
 import click
 
 class TTTView:
@@ -9,54 +10,61 @@ class TTTView:
     o_color = "blue"
     option_color = "bright_black"
 
-    def greet(self, game):
+    def __init__(self, playerX, playerO):
+        self.game = TTTGame()
+        self.players = {
+            "X": playerX, 
+            "O": playerO,
+        }
+
+    def greet(self):
         "Starts a new game by greeting the players."
-        x_name = game.players['X'].name
-        o_name = game.players['O'].name
+        x_name = self.players['X'].name
+        o_name = self.players['O'].name
         print(self.greeting)
         print(f"{x_name} will play as X.")
         print(f"{o_name} will play as O.")
 
-    def get_action(self, game):
+    def get_action(self, state):
         "Shows the board and asks the current player for their choice of action."
-        self.print_board_with_options(game)
-        current_player_symbol = game.state["player"]
-        player = game.players[current_player_symbol]
+        self.print_board(state)
+        current_player_symbol = 'X' if state["player_x"] else 'O'
+        player = self.players[current_player_symbol]
         print(f"{player.name}, it's your move.")
-        return player.choose_action(game)
+        return player.choose_action(state)
 
-    def print_board_with_options(self, game):
+    def print_board(self, state):
         "Prints the current board, showing indices of available spaces"
-        print(self.format_row(game, [0, 1, 2]))
+        print(self.format_row(state, [0, 1, 2]))
         print(self.divider)
-        print(self.format_row(game, [3, 4, 5]))
+        print(self.format_row(state, [3, 4, 5]))
         print(self.divider)
-        print(self.format_row(game, [6, 7, 8]))
+        print(self.format_row(state, [6, 7, 8]))
 
-    def format_row(self, game, indices):
+    def format_row(self, state, indices):
         "Returns a string for one row in the board, like ' X | O | X '"
-        spaces = [self.format_value(game, i) for i in indices]
+        spaces = [self.format_value(state, i) for i in indices]
         return f" {spaces[0]} | {spaces[1]} | {spaces[2]} "
 
-    def format_value(self, game, index):
+    def format_value(self, state, index):
         """Formats the value for a single space on the board. 
         If the game board already has a symbol in that space, formats that value for the Terminal.
         If the space is empty, instead formats the index of the space. 
         """
-        if game.state["board"][index] == 'X':
+        if state["board"][index] == 'X':
             return click.style('X', fg=self.x_color)
-        elif game.state["board"][index] == 'O':
+        elif state["board"][index] == 'O':
             return click.style('O', fg=self.o_color)
         else:
             return click.style(index, fg=self.option_color)
 
-    def conclude(self, game):
+    def conclude(self, state):
         """Says goodbye.
         """
-        self.print_board_with_options(game)
-        if game.check_winner(game.state, 'X'):
+        self.print_board(state)
+        if self.game.check_winner(state, 'X'):
             winner = game.players['X']
-        elif game.check_winner(game.state, 'O'):
+        elif self.game.check_winner(game.state, 'O'):
             winner = game.players['O']
         else:
             winner = None
@@ -65,6 +73,3 @@ class TTTView:
             print(f"Congratulations to {winner.name}.")
         else:
             print("Nobody won this game.")
-
-
-