import numpy as np
import cv2

def resize_and_pad(image, box):
    '''Fitting an image to the box region while keeping the aspect ratio.'''
    y1,y2,x1,x2 = box
    H,W = y2-y1, x2-x1
    h,w =  image.shape[0], image.shape[1]
    r_box = W / H 
    r_image = w / h
    if r_box >= r_image:
        h_target = H
        w_target = int(w * H / h) 
        image = cv2.resize(image, (w_target, h_target))

        w1 = (W - w_target) // 2
        w2 = W - w_target - w1
        pad_param = ((0,0),(w1,w2),(0,0))
        image = np.pad(image, pad_param, 'constant', constant_values=255)
    else:
        w_target = W 
        h_target = int(h * W / w)
        image = cv2.resize(image, (w_target, h_target))

        h1 = (H-h_target) // 2 
        h2 = H - h_target - h1
        pad_param =((h1,h2),(0,0),(0,0))
        image = np.pad(image, pad_param, 'constant', constant_values=255)
    return image



def expand_image_mask(image, mask, ratio=1.4):
    h,w = image.shape[0], image.shape[1]
    H,W = int(h * ratio), int(w * ratio) 
    h1 = int((H - h) // 2)
    h2 = H - h - h1
    w1 = int((W -w) // 2)
    w2 = W -w - w1

    pad_param_image = ((h1,h2),(w1,w2),(0,0))
    pad_param_mask = ((h1,h2),(w1,w2))
    image = np.pad(image, pad_param_image, 'constant', constant_values=255)
    mask = np.pad(mask, pad_param_mask, 'constant', constant_values=0)
    return image, mask


def expand_image(image, ratio=1.4):
    h,w = image.shape[0], image.shape[1]
    H,W = int(h * ratio), int(w * ratio) 
    h1 = int((H - h) // 2)
    h2 = H - h - h1
    w1 = int((W -w) // 2)
    w2 = W -w - w1

    pad_param_image = ((h1,h2),(w1,w2),(0,0))
    image = np.pad(image, pad_param_image, 'constant', constant_values=255)
    return image


def expand_bbox(mask,yyxx,ratio=[1.2,2.0], min_crop=0):
    y1,y2,x1,x2 = yyxx
    ratio = np.random.randint( ratio[0] * 10,  ratio[1] * 10 ) / 10
    H,W = mask.shape[0], mask.shape[1]
    xc, yc = 0.5 * (x1 + x2), 0.5 * (y1 + y2)
    h = ratio * (y2-y1+1)
    w = ratio * (x2-x1+1)
    h = max(h,min_crop)
    w = max(w,min_crop)

    x1 = int(xc - w * 0.5)
    x2 = int(xc + w * 0.5)
    y1 = int(yc - h * 0.5)
    y2 = int(yc + h * 0.5)

    x1 = max(0,x1)
    x2 = min(W,x2)
    y1 = max(0,y1)
    y2 = min(H,y2)
    return (y1,y2,x1,x2)


def box2squre(image, box):
    H,W = image.shape[0], image.shape[1]
    y1,y2,x1,x2 = box
    cx = (x1 + x2) // 2
    cy = (y1 + y2) // 2
    h,w = y2-y1, x2-x1

    if h >= w:
        x1 = cx - h//2
        x2 = cx + h//2
    else:
        y1 = cy - w//2
        y2 = cy + w//2
    x1 = max(0,x1)
    x2 = min(W,x2)
    y1 = max(0,y1)
    y2 = min(H,y2)
    return (y1,y2,x1,x2)


def pad_to_square(image, pad_value = 255, random = False):
    H,W = image.shape[0], image.shape[1]
    if H == W:
        return image

    padd = abs(H - W)
    if random:
        padd_1 = int(np.random.randint(0,padd))
    else:
        padd_1 = int(padd / 2)
    padd_2 = padd - padd_1

    if H > W:
        pad_param = ((0,0),(padd_1,padd_2),(0,0))
    else:
        pad_param = ((padd_1,padd_2),(0,0),(0,0))

    image = np.pad(image, pad_param, 'constant', constant_values=pad_value)
    return image

def get_bbox_from_mask(mask):
    h,w = mask.shape[0],mask.shape[1]

    if mask.sum() < 10:
        return 0, h, 0, w
    rows = np.any(mask, axis=1)
    cols = np.any(mask, axis=0)
    y1,y2 = np.where(rows)[0][[0, -1]]
    x1,x2 = np.where(cols)[0][[0, -1]]
    return (y1, y2, x1, x2)

def box_in_box(small_box, big_box):
    y1, y2, x1, x2 = small_box
    y1_b, _, x1_b, _ = big_box
    y1, y2, x1, x2 = y1 - y1_b ,y2 - y1_b, x1 - x1_b, x2 - x1_b
    return (y1, y2, x1, x2)

def crop_back(pred, tar_image, extra_sizes, tar_box_yyxx_crop, tar_box_yyxx_crop2, is_masked=False):
    H1, W1, H2, W2 = extra_sizes
    y1, x1, y2, x2 = tar_box_yyxx_crop
    y1_, x1_, y2_, x2_ = tar_box_yyxx_crop2
    m = 0 # maigin_pixel

    if H1 < W1:
        pad1 = int((W1 - H1) / 2)
        pad2 = W1 - H1 - pad1
        pred = pred[pad1: -pad2, :, :]
    elif H1 > W1:
        pad1 = int((H1 - W1) / 2)
        pad2 = H1 - W1 - pad1
        pred = pred[:,pad1: -pad2, :]

    if is_masked:
        gen_image = tar_image.copy()
        gen_image[y1+m :y2-m, x1+m:x2-m, :] = pred[y1+m :y2-m, x1+m:x2-m, :]
        gen_image[y1_+m :y2_-m, x1_+m:x2_-m, :] = pred[y1_+m :y2_-m, x1_+m:x2_-m, :]
    else: 
        gen_image = pred
    return gen_image