#! /usr/bin/env python
# -*- coding: utf-8 -*-
# vim:fenc=utf-8
#
# Copyright © 2017 lafrite <lafrite@Poivre>
#
# Distributed under terms of the MIT license.

"""
Minus MO: take the opposit
"""

from ..tree import Tree
from ..operator import OPERATORS
from ..MO.mo import MO, MOnumber, MOstr
from ..MO.fraction import MOFraction
from .exceptions import MinusError
from .arithmetic import lcm


def minus(left, right):
    """ Perform the minusition of left and right

    :param left: left MO
    :param right: right MO
    :returns: Tree or MO

    >>> a = MOnumber(4)
    >>> minus(None, a)
    <MOnumber - 4>
    >>> a = MOnumber(-4)
    >>> minus(None, a)
    <MOnumber 4>
    >>> b = MOnumber(0)
    >>> minus(None, b)
    <MOnumber 0>

    """
    if not left is None:
        raise MinusError(f"'-' is a 1 arity operator, left should be None (got {left})")

    return MINUSFUNCTIONS[type(right)](right)

def monumber(right):
    """ Minusing monumber

    :param right: right MOnumber
    :returns: MONumber

    >>> a = MOnumber(4)
    >>> monumber(a)
    <MOnumber - 4>

    """
    return MO.factory(- right.value)

def mofraction(right):
    """ Minusing a mofraction

    :param right: a mofraction
    :returns: Tree with the number converted into a mofraction

    >>> a = MOFraction(6, 5)
    >>> print(mofraction(a))
    -
     > None
     > /
     | > 6
     | > 5
    >>> a = MOFraction(6, 5, True)
    >>> print(mofraction(a))
    /
     > 6
     > 5
    """
    if right.negative:
        return MOFraction(right._numerator, right._denominator)

    try:
        if right._numerator < 0:
            return MOFraction(-right._numerator, right._denominator)
    except TypeError:
        pass
    try:

        if right._denominator < 0:
            return MOFraction(right._numerator, -right._denominator)
    except TypeError:
        pass

    return MOFraction(right._numerator, right._denominator, True)

# TODO: Faire un décorateur pour un enregistrement automatique |dim. mars 11 18:24:32 EAT 2018
MINUSFUNCTIONS = {
        MOnumber: monumber,
        MOFraction: mofraction,
        }

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