import numpy as np
import cv2
import os
import platform
import json
import errno



def weak_check(detect_res):
    return sum([len(faces) for faces in detect_res]) > len(detect_res) * 0.75


def get_crop_box(shape, box, scale=0.5):
    height, width = shape
    box = np.rint(box).astype(np.int32)
    new_box = box.reshape(2, 2)
    size = new_box[1] - new_box[0]
    diff = scale * size
    diff = diff[None, :] * np.array([-1, 1])[:, None]
    new_box = new_box + diff
    new_box[:, 0] = np.clip(new_box[:, 0], 0, width - 1)
    new_box[:, 1] = np.clip(new_box[:, 1], 0, height - 1)
    new_box = np.rint(new_box).astype(np.int32)
    return new_box.reshape(-1)


def get_fps(input_file):
    reader = cv2.VideoCapture(input_file)
    fps = reader.get(cv2.CAP_PROP_FPS)
    reader.release()
    return fps



def mkdir_p(dirname):
    """Like "mkdir -p", make a dir recursively, but do nothing if the dir exists
    这个是线程安全的, from Lingzhi Li
    Args:
        dirname(str):
    """
    assert dirname is not None
    if dirname == "" or os.path.isdir(dirname):
        return
    try:
        os.makedirs(dirname)
    except OSError as e:
        if e.errno != errno.EEXIST:
            raise e


def mkdir(*args):
    for folder in args:
        if not os.path.isdir(folder):
            mkdir_p(folder)


def make_join(*args):
    folder = os.path.join(*args)
    mkdir(folder)
    return folder


def list_dir(folder, condition=None, key=lambda x: x, reverse=False, co_join=[]):
    files = os.listdir(folder)
    if condition is not None:
        files = filter(condition, files)
    co_join = [folder] + co_join
    if key is not None:
        files = sorted(files, key=key, reverse=reverse)
    files = [(file, *[os.path.join(fold, file) for fold in co_join]) for file in files]
    return files

def get_jointer(file):
    def jointer(folder):
        return os.path.join(folder, file)

    return jointer

def flatten(l):
    return [item for sublist in l for item in sublist]


def is_win():
    return platform.system() == "Windows"


def get_postfix(post_fix):
    return lambda x: x.endswith(post_fix)


def partition(images, size):
    """
    Returns a new list with elements
    of which is a list of certain size.

        >>> partition([1, 2, 3, 4], 3)
        [[1, 2, 3], [4]]
    """
    return [
        images[i : i + size] if i + size <= len(images) else images[i:]
        for i in range(0, len(images), size)
    ]


def load_json(file):
    with open(file, "r") as f:
        res = json.load(f)
    return res


def save_json(file, obj):
    with open(file, "w", encoding="utf-8") as f:
        json.dump(obj, f, indent=4, ensure_ascii=False)