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

from cvxopt import matrix


def _pretty_print_dict(dictionary):
    """
    Return a pretty-printed string representation of a dictionary
    containing CVXOPT matrices.
    """
    result = ''
    for (key, value) in dictionary.items():
        if isinstance(value, matrix):
            # Display matrices on their own lines, indented.
            result += '  {:s}:'.format(key)
            colvec = '\n{!s}'.format(value)
            result += '\n    '.join(colvec.splitlines())
            result += '\n'
        else:
            result += '  {:s}: {!s}\n'.format(key, value)

    return result


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:

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

        """
        super().__init__()
        self._solution_dict = solution_dict


    def __str__(self):
        tpl = 'Solution failed with result "{:s}."\n' \
              'CVXOPT returned:\n{!s}'
        return tpl.format(self._solution_dict['status'],
                          _pretty_print_dict(self._solution_dict))