from random import randint
def mapRandoms(target,current,precision=1.01,testRepeat=10000):
    a, b = target, current
    countA = {i+1:0 for i in range(a)}
    countB = {i+1:0 for i in range(b)}
    def randomB():
        result = randint(1,b)
        countB[result] += 1
        return result

    if target < current:
        raise ArithmeticError("target can't be smaller then current")
    elif target <= 1 or current <= 1:
        raise ArithmeticError("random values should be more than 1")

    print("================ Mapping",target,"to",current,"================")
    i,j = 1,1
    powerA, powerB = a, b
    while True:
        j += 1
        powerA *= a
        while powerB < powerA:
            i += 1
            powerB *= b

        if powerB/powerA < precision:
            print("Coefficients to use:", i, j, "with coverage difference of only", round((powerB/powerA-1)*100,2), "% chance to repeat.")
            break

    coeffA = j
    coeffB = i
    rolls = []
    def statefulRandom():
        if target == current:
            return randomB()
        threshold = pow(a, coeffA)
        def generateRolls():
            result = threshold
            while result >= threshold:
                result = 0
                for i in range(coeffB):
                    result = (result*b) + randomB()-1
            while result:
                rolls.append(result%a+1)
                result //= 7
            while len(rolls) < coeffA:
                rolls.append(1)
        if not rolls: generateRolls()
        return rolls.pop()
    for i in range(testRepeat):
        countA[statefulRandom()] += 1
    percentages = {i:round(countA[i]*100/testRepeat,2) for i in countA}
    print("Percent distribuiton of results: ", percentages)
    print(round(sum(countB.values())/testRepeat,2), "rolls on average per function.\n")
# Test here
mapRandoms(7,5)
mapRandoms(10,2)
mapRandoms(100,84)