eucledian-rythms.py

import unittest
import itertools
from typing import List


def flatten(f):
    def wrapper(*args, **kwargs):
        nested = f(*args, **kwargs)
        return list(itertools.chain(*nested))

    return wrapper


@flatten
def ecd(on: int, total: int) -> List[int]:
	"""Source: https://github.com/dbkaplun/euclidean-rhythm/blob/master/euclidean-rhythm.js"""
    if total < 0:
        raise ArgumentException("total must be larger than zero")
    if total == 0:
        return []
    if on == 0:
        return [[0]] * total
    if on == total:
        return [[1]] * total

    # Example ecd(3,4)
    # groups = [[1],[1],[1],[0]]
    groups = [[int(x < on)] for x in range(0, total)]

    l = len(groups) - 1
    while l > 0:
        start = 0
        first = groups[0]
        while start < l and first == groups[start]:
            start += 1
        if start == l:
            break

        end = l
        last = groups[l]
        while end > 0 and last == groups[end]:
            end -= 1
        if end == 0:
            break

        cnt = min(start, l - end)
        t_group = groups[0:cnt]
        t_group = [group + groups[l - i] for (i, group) in enumerate(t_group)]
        groups = t_group + groups[cnt:-cnt]

        l = len(groups) - 1
    return groups


class TestECD(unittest.TestCase):
    def test_ecd(self):
        for (args, expected) in [
            ((1, 2), [1, 0]),
            ((0, 4), [0, 0, 0, 0]),
            ((5, 5), [1, 1, 1, 1, 1]),
            ((2, 4), [1, 0, 1, 0]),
            ((5, 6), [1, 1, 1, 1, 1, 0]),
            ((5, 7), [1, 0, 1, 1, 0, 1, 1]),
            ((5, 8), [1, 0, 1, 1, 0, 1, 1, 0]),
        ]:
            self.assertEqual(ecd(*args), expected)


if __name__ == "__main__":
    unittest.main()