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

from decimal import Decimal
from ..coroutine import coroutine, STOOOP
from ..renders import tree2txt, tree2tex


__all__ = ["moify", "MO", "MOstr"]

class MOError(Exception):
    pass

@coroutine
def moify(target):
    """ Coroutine which try to convert everything into an MO """
    try:
        target_ = target()
    except TypeError:
        target_ = target

    try:
        while True:
            tok = yield
            try:
                target_.send(MOnumber(tok))
            except MOError:
                try:
                    target_.send(MOstr(tok))
                except MOError:
                    target_.send(tok)

    except STOOOP as err:
        yield target_.throw(err)


class MO(object):

    """MO for math object

    This base class is representing int and Decimal. It stocks its value in
    self.value and it

    """

    def __init__(self, value):
        """ Initiate the MO

        It should be idempotent.

        >>> a = MO(3)
        >>> a
        <MO 3>
        >>> a = MO(a)
        >>> a
        <MO 3>
        """
        try:
            self.value = value.value
        except AttributeError:
            self.value = value

        self.is_scalar = True

    @classmethod
    def factory(cls, value):
        """ Factory to ensure that a value is a MO before using it """
        if isinstance(value, str):
            return MOstr(value)
        elif isinstance(value, int) \
                or isinstance(value, Decimal) \
                or isinstance(value, float):
            return MOnumber(value)
        elif isinstance(value, MO):
            return value

        return MO(value)

    def __repr__(self):
        return f"<{self.__class__.__name__} {self.__txt__}>"

    def __str__(self):
        return str(self.value)

    @property
    def __txt__(self):
        try:
            return tree2txt(self.value)
        except AttributeError:
            return str(self.value)

    @property
    def __tex__(self):
        try:
            return tree2tex(self.value)
        except AttributeError:
            return str(self.value)


class MOnumber(MO):

    """ Base number math object (int or Decimal) """

    def __init__(self, value):
        """ Initiate a number MO

        >>> MOnumber(23)
        <MOnumber 23>
        >>> MOnumber(-23)
        <MOnumber - 23>
        >>> MOnumber(23.3)
        <MOnumber 23.300000000000000710542735760100185871124267578125>
        >>> MOnumber(Decimal("23.3"))
        <MOnumber 23.3>
        >>> MOnumber(Decimal("-23.3"))
        <MOnumber - 23.3>
        >>> a = MOnumber(23)
        >>> MOnumber(a)
        <MOnumber 23>
        >>> MOnumber("a")
        Traceback (most recent call last):
            ...
        mapytex.calculus.core.MO.mo.MOError: The value of an MOnumber need to be a int, a float or a Decimal

        """
        try:
            val = value.value
        except AttributeError:
            val = value

        if isinstance(val, (int, Decimal)):
            MO.__init__(self, value)
        elif isinstance(val, float):
            MO.__init__(self, Decimal(val))
        else:
            raise MOError("The value of an MOnumber need to be a int, a float or a Decimal")

    @property
    def __txt__(self):
        if self.value >= 0:
            return str(self.value)

        return f"- {abs(self.value)}"

    @property
    def __tex__(self):
        if self.value > 0:
            return str(self.value)

        return f"- {abs(self.value)}"

class MOstr(MO):

    """ Unknown math object like x or n"""

    def __init__(self, value):
        """ Initiate a string MO

        >>> a = MOstr("x")
        >>> a
        <MOstr x>
        >>> b = MOstr(a)
        >>> b
        <MOstr x>

        >>> a = MOstr("+")
        Traceback (most recent call last):
            ...
        mapytex.calculus.core.MO.mo.MOError: An MOstr should be initiate with a alpha string, got +
        >>> MOstr("ui")
        Traceback (most recent call last):
            ...
        mapytex.calculus.core.MO.mo.MOError: An MOstr should be initiate with a single caracter string, got ui
        >>> MOstr(2)
        Traceback (most recent call last):
            ...
        mapytex.calculus.core.MO.mo.MOError: An MOstr should be initiate with a string - the unknown, got 2

        """
        try:
            val = value.value
        except AttributeError:
            val = value

        if not isinstance(val, str):
            raise MOError(f"An MOstr should be initiate with a string - the unknown, got {val}")
        if len(val) != 1:
            raise MOError(f"An MOstr should be initiate with a single caracter string, got {val}")
        if not val.isalpha():
            raise MOError(f"An MOstr should be initiate with a alpha string, got {val}")

        MO.__init__(self, value)
        self.is_scalar = False

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