Sudoku refactor

starter/app.py

@@ -1,5 +1,6 @@
-from flask import Flask, render_template, jsonify, request
-import sudoku_logic
+from flask import Flask
+
+from routes import bp, set_current_store
 
 app = Flask(__name__)
 
@@ -9,31 +10,9 @@
     'solution': None
 }
 
-@app.route('/')
-def index():
-    return render_template('index.html')
-
-@app.route('/new')
-def new_game():
-    clues = int(request.args.get('clues', 35))
-    puzzle, solution = sudoku_logic.generate_puzzle(clues)
-    CURRENT['puzzle'] = puzzle
-    CURRENT['solution'] = solution
-    return jsonify({'puzzle': puzzle})
+set_current_store(CURRENT)
+app.register_blueprint(bp)
 
-@app.route('/check', methods=['POST'])
-def check_solution():
-    data = request.json
-    board = data.get('board')
-    solution = CURRENT.get('solution')
-    if solution is None:
-        return jsonify({'error': 'No game in progress'}), 400
-    incorrect = []
-    for i in range(sudoku_logic.SIZE):
-        for j in range(sudoku_logic.SIZE):
-            if board[i][j] != solution[i][j]:
-                incorrect.append([i, j])
-    return jsonify({'incorrect': incorrect})
 
 if __name__ == '__main__':
     app.run(debug=True)

starter/generator.py

@@ -0,0 +1,34 @@
+import copy
+import random
+
+from solver import fill_board
+
+SIZE = 9
+EMPTY = 0
+
+
+def deep_copy(board):
+    return copy.deepcopy(board)
+
+
+def create_empty_board():
+    return [[EMPTY for _ in range(SIZE)] for _ in range(SIZE)]
+
+
+def remove_cells(board, clues):
+    attempts = SIZE * SIZE - clues
+    while attempts > 0:
+        row = random.randrange(SIZE)
+        col = random.randrange(SIZE)
+        if board[row][col] != EMPTY:
+            board[row][col] = EMPTY
+            attempts -= 1
+
+
+def generate_puzzle(clues=35):
+    board = create_empty_board()
+    fill_board(board)
+    solution = deep_copy(board)
+    remove_cells(board, clues)
+    puzzle = deep_copy(board)
+    return puzzle, solution

starter/instruction.md

@@ -0,0 +1,15 @@
+# Copilot Instructions
+Use Python best practices.
+Keep functions small.
+Use Flask Blueprints where appropriate.
+Use type hints.
+Avoid duplicated code.
+Write reusable modules.
+Follow PEP8.
+Add comments only when necessary.
+Use Bootstrap or clean CSS.
+Prefer readability over clever code.
+Use localStorage for leaderboard.
+Make responsive layouts.
+Support dark mode.
+Create unit tests with pytest.

starter/requirements.txt

@@ -1 +1,2 @@
 Flask>=2.0
+pytest>=8.0

starter/routes.py

@@ -0,0 +1,51 @@
+from flask import Blueprint, jsonify, render_template, request
+
+from generator import generate_puzzle
+from validator import find_incorrect_cells
+
+bp = Blueprint('main', __name__)
+
+CURRENT = None
+
+
+def set_current_store(store):
+    global CURRENT
+    CURRENT = store
+
+
+@bp.route('/')
+def index():
+    return render_template('index.html')
+
+
+@bp.route('/new')
+def new_game():
+    difficulty = request.args.get('difficulty', '').lower()
+    clues = request.args.get('clues')
+
+    if clues is None:
+        clue_map = {
+            'easy': 45,
+            'medium': 35,
+            'hard': 25,
+        }
+        clues = clue_map.get(difficulty, 35)
+    else:
+        clues = int(clues)
+
+    puzzle, solution = generate_puzzle(clues)
+    CURRENT['puzzle'] = puzzle
+    CURRENT['solution'] = solution
+    return jsonify({'puzzle': puzzle, 'solution': solution})
+
+
+@bp.route('/check', methods=['POST'])
+def check_solution():
+    data = request.json
+    board = data.get('board')
+    solution = CURRENT.get('solution')
+    if solution is None:
+        return jsonify({'error': 'No game in progress'}), 400
+
+    incorrect = find_incorrect_cells(board, solution)
+    return jsonify({'incorrect': incorrect})

starter/solver.py

@@ -0,0 +1,34 @@
+import random
+
+SIZE = 9
+EMPTY = 0
+
+
+def is_safe(board, row, col, num):
+    for x in range(SIZE):
+        if board[row][x] == num or board[x][col] == num:
+            return False
+
+    start_row = row - row % 3
+    start_col = col - col % 3
+    for i in range(3):
+        for j in range(3):
+            if board[start_row + i][start_col + j] == num:
+                return False
+    return True
+
+
+def fill_board(board):
+    for row in range(SIZE):
+        for col in range(SIZE):
+            if board[row][col] == EMPTY:
+                possible = list(range(1, SIZE + 1))
+                random.shuffle(possible)
+                for candidate in possible:
+                    if is_safe(board, row, col, candidate):
+                        board[row][col] = candidate
+                        if fill_board(board):
+                            return True
+                        board[row][col] = EMPTY
+                return False
+    return True