import math


def calculate_vertices_for_one_hexagon(center, edge, pointy_top):
    """
    Calculates the vertices (corners) of one hexagon.

    :param center: center point of a hexagon as a tuple (x, y)
    :param edge: size of a hexagon edge
    :param pointy_top: if True, hexagon will be oriented horizontally, otherwise vertically
    :return: list of vertices for a given hexagon
    """
    vertices = []
    x, y = center
    start_angle = 0 if pointy_top else 30
    for i in range(6):
        angle = start_angle + (360 * i / 6)
        radian = math.radians(angle)
        vertex_x = x + edge * math.sin(radian)
        vertex_y = y + edge * math.cos(radian)
        vertices.append((vertex_x, vertex_y))
    return vertices