Faro.py

from LoopChain import methodLoop
from LoopChain import methodLoopLen

"""
TODO: test
"""


def positionSort(initialList: list, sortList: list):
    """
    Sorts a list using a second list with the same length. The second list indicates where entries in the first list go.

    :param initialList: A list to be sorted.
    :param sortList: A list consisting of the integers in range(len(initialList)) each appearing once.
    :return: Sorted list, or None if the lengths do not match.
    """
    if len(initialList) == len(sortList):
        listLen = len(initialList)
        retList = [initialList[i] for i in sortList]
        return retList
    else:
        return None


def inFaroGen(deckSize: int):
    """
    Generates a list for an inside Faro shuffle with a given deck size.

    :param deckSize: int; must be greater than 2 and even.
    :return: list for inside Faro shuffle, or None for an invalid deck size.
    """
    if deckSize % 2 == 0 and deckSize > 2:
        retList = []
        halfDeckSize = int(deckSize / 2)
        for i in range(halfDeckSize):
            retList.append([i, i + halfDeckSize])
        return retList
    else:
        return None


def outFaroGen(deckSize: int):
    """
    Generates a list for an outside Faro shuffle with a given deck size.

    :param deckSize: int; must be greater than 2 and even.
    :return: list for outside Faro shuffle, or None for an invalid deck size.
    """
    if deckSize % 2 == 0 and deckSize > 2:
        retList = []
        halfDeckSize = int(deckSize / 2)
        for i in range(halfDeckSize):
            retList.append([i + halfDeckSize, i])
        return retList
    else:
        return None


def faroShuffleChain(initialList: list, shuffleSequence: list) -> list:
    """
    Sorts a list based on repeated Faro shuffles using the sequence given.

    :param initialList: List to shuffle.
    :param shuffleSequence: Sequence to use; list with entries that are of the form 'I', 'O', 'In', or 'On',
    where n is the number of shuffles in a row to do.
    :return: shuffled list
    """
    inSortList = inFaroGen(len(initialList))
    outSortList = outFaroGen(len(initialList))
    retList = initialList
    for i in shuffleSequence:
        faroNum = 1
        faroType = i
        if len(i) != 1:
            faroNum = int(i[1:])
            faroType = i[1]
        for j in range(faroNum):
            if faroType == 'i' or faroType == 'I':
                retList = positionSort(retList, inSortList)
            elif faroType == 'o' or faroType == 'O':
                retList = positionSort(retList, outSortList)
    return retList


def faroChainLen(deckSize: int, shuffleSequence: list):
    initialList = [i for i in range(deckSize)]
    retNum = methodLoopLen(initialList, lambda x: faroShuffleChain(x, shuffleSequence))
    return retNum