import subprocess
import logging
import cv2
import platform
import readline
import os

def image_resize(image, width = None, height = None, inter = cv2.INTER_AREA):
    # initialize the dimensions of the image to be resized and
    # grab the image size
    dim = None
    (h, w) = image.shape[:2]

    # if both the width and height are None, then return the
    # original image
    if width is None and height is None:
        return image

    # check to see if the width is None
    if width is None:
        # calculate the ratio of the height and construct the
        # dimensions
        r = height / float(h)
        dim = (int(w * r), height)

    # otherwise, the height is None
    else:
        # calculate the ratio of the width and construct the
        # dimensions
        r = width / float(w)
        dim = (width, int(h * r))

    # resize the image
    resized = cv2.resize(image, dim, interpolation = inter)

    # return the resized image
    return resized

'''
Fetch input prompt with prefilled text.

Parameters:
prompt: Prompt message.
text: Prefilled input.
'''
def input_with_prefill(prompt, text):
    def hook():
        readline.insert_text(text)
        readline.redisplay()
    readline.set_pre_input_hook(hook)
    result = input(prompt)
    readline.set_pre_input_hook()
    return result

'''
Checks if the given string is a valid path.

Parameters:
string: String to be checked.
'''
def dir_path(string):
    if os.path.isdir(string):
        return string
    else:
        raise NotADirectoryError(string)

'''
Opens the given file with the platform default handler.

Parameters:
file: Path to the file.
'''
def open_system(file):
    if platform.system() == 'Darwin':       # macOS
        subprocess.call(('open', file))
    elif platform.system() == 'Windows':    # Windows
        os.startfile(file)
    else:                                   # linux variants
        subprocess.call(('xdg-open', file))