from ortools.sat.python import cp_model


class IntermediateSolutionPrinter(cp_model.CpSolverSolutionCallback):
    """Callback that prints intermediate solutions."""

    def __init__(self, variables, *, scale=1.0):
        cp_model.CpSolverSolutionCallback.__init__(self)
        self._variables = variables
        self._solution_count = 0
        self.scale = scale

    def on_solution_callback(self):
        """Called each time an improving solution is found."""
        print("\n--- Solution ---")
        for name, var in self._variables.items():
            print(f"{name} = {self.scale * self.Value(var)}")

    @property
    def solution_count(self):
        return self._solution_count