Mapytex/mapytex/calculus/random/core/int_gene.py

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

"""
Function to create random integer

"""
import random

__all__ = ["reject_random", "filter_random", "FilterRandom"]


def reject_random(min_value=-10, max_value=10, rejected=[0, 1], accept_callbacks=[]):
    """Generate a random integer with the rejection method

    :param name: name of the Integer
    :param min_value: minimum value
    :param max_value: maximum value
    :param rejected: rejected values
    :param accept_callbacks: list of function for value rejection

    :example:
    >>> a = reject_random()
    >>> a not in [0, 1]
    True
    >>> a >= -10
    True
    >>> a <= 10
    True
    >>> a = reject_random(min_value=3, max_value=11, rejected=[5, 7])
    >>> a not in [5, 7]
    True
    >>> a >= 3
    True
    >>> a <= 11
    True
    >>> a = reject_random(accept_callbacks=[lambda x: x%2])
    >>> a%2
    1
    >>> random.seed(0)
    >>> reject_random()
    2
    >>> random.seed(1)
    >>> reject_random()
    -6

    """
    conditions = [lambda x: x not in rejected] + accept_callbacks

    candidate = random.randint(min_value, max_value)
    while not all(c(candidate) for c in conditions):
        candidate = random.randint(min_value, max_value)

    return candidate


def filter_random(min_value=-10, max_value=10, rejected=[0, 1], accept_callbacks=[]):
    """Generate a random integer by filtering then choosing a candidate

    :param name: name of the Integer
    :param min_value: minimum value
    :param max_value: maximum value
    :param rejected: rejected values
    :param accept_callbacks: list of function for value rejection

    :example:
    >>> a = filter_random()
    >>> a not in [0, 1]
    True
    >>> a >= -10
    True
    >>> a <= 10
    True
    >>> a = filter_random(min_value=3, max_value=11, rejected=[5, 7])
    >>> a not in [5, 7]
    True
    >>> a >= 3
    True
    >>> a <= 11
    True
    >>> a = filter_random(accept_callbacks=[lambda x: x%2])
    >>> a%2
    1
    >>> random.seed(0)
    >>> filter_random()
    -7
    >>> random.seed(1)
    >>> filter_random()
    6
    """
    candidates = set(range(min_value, max_value + 1))
    candidates = {c for c in candidates if c not in rejected}

    candidates = [
        candidate
        for candidate in candidates
        if all(c(candidate) for c in accept_callbacks)
    ]

    if len(candidates) == 0:
        raise OverflowError(
            "There is no candidates for this range and those conditions"
        )
    return random.choice(candidates)


class FilterRandom(object):

    """Integer random generator which filter then choose candidate"""

    # TODO: Faire un cache pour éviter de reconstruire les listes à chaque fois |ven. déc. 21 19:07:42 CET 2018

    def __init__(
        self, rejected=[0, 1], accept_callbacks=[], min_value=-10, max_value=10
    ):
        self.conditions = (lambda x: x not in rejected,) + tuple(accept_callbacks)

        self._min = min_value
        self._max = max_value

        candidates = set(range(self._min, self._max + 1))

        self._candidates = {
            candidate
            for candidate in candidates
            if all(c(candidate) for c in self.conditions)
        }

    def add_candidates(self, low, high):
        """Add candidates between low and high to _candidates"""
        if low < self._min:
            self._min = low
            useless_low = False
        else:
            useless_low = True
        if high > self._max:
            self._max = high
            useless_high = False
        else:
            useless_high = True

        if not (useless_low and useless_high):
            candidates = set(range(low, high + 1))

            self._candidates = self._candidates.union(
                {
                    candidate
                    for candidate in candidates
                    if all(c(candidate) for c in self.conditions)
                }
            )

    def candidates(self, min_value=-10, max_value=10):
        """Return candidates between min_value and max_value"""
        return [c for c in self._candidates if (c > min_value and c < max_value)]

    def __call__(self, min_value=-10, max_value=10):
        """Randomly choose on candidate"""
        self.add_candidates(min_value, max_value)
        return random.choice(self.candidates(min_value, max_value))


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