import numpy as np
from plyfile import PlyData, PlyElement


def read_ply(path):
    with open(path, 'rb') as f:
        plydata = PlyData.read(f)
        x = np.array(plydata['vertex']['x'])
        y = np.array(plydata['vertex']['y'])
        z = np.array(plydata['vertex']['z'])
        vertex = np.stack([x, y, z], axis=1)
    return vertex


def write_ply(points, filename, text=False):
    """ input: Nx3, write points to filename as PLY format. """
    points = [(points[i,0], points[i,1], points[i,2]) for i in range(points.shape[0])]
    vertex = np.array(points, dtype=[('x', 'f4'), ('y', 'f4'),('z', 'f4')])
    el = PlyElement.describe(vertex, 'vertex', comments=['vertices'])
    with open(filename, mode='wb') as f:
        PlyData([el], text=text).write(f)