"""
Errors that can occur when solving a linear game.
"""

class GameUnsolvableException(Exception):
    """
    Every linear game has a solution (this follows from a general
    min-max theorem). If we can't solve the conic program associated
    with a linear game, then something is wrong with either the model of
    the input.
    """
    def __init__(self, solution_dict):
        """
        Create a new GameUnsolvableException object.

        INPUT:

        - ``primal`` -- the objective value of the primal cone program.

        - ``dual`` -- the objective value of the dual cone program.

        - ``solution_dict`` -- the solution dictionary returned from the cone program.

        """
        tpl = 'solution failed with error: {:s}\n' \
              'CVXOPT returned:\n{!s}'
        self.message = tpl.format(solution_dict['status'], solution_dict)


class GameValueMismatchException(Exception):
    """
    This error occurs when the primal and dual objective value of the
    conic program associated with a linear game do not agree. By
    construction, every conic program derived from a linear game must
    have a solution and the same objective value (the "value of the
    game") is shared by both players.

    Each instance of this class will know the two mismatched values, and
    its ``message`` field will explain why they can't be so.
    """
    def __init__(self, primal, dual, solution_dict):
        """
        Create a new GameValueMismatchException.

        INPUT:

        - ``primal`` -- the objective value of the primal cone program.

        - ``dual`` -- the objective value of the dual cone program.

        - ``solution_dict`` -- the solution dictionary returned from the cone program.

        """
        tpl = 'game value mismatch for player1={:.7f}, player2={:.7f}\n' \
              'CVXOPT returned:\n{!s}'
        self.message = tpl.format(primal, dual, solution_dict)