"""DanBooru IMage Utility functions"""

import cv2
import numpy as np
from PIL import Image


def fill_transparent(image: Image.Image, color='WHITE'):
    image = image.convert('RGBA')
    new_image = Image.new('RGBA', image.size, color)
    new_image.paste(image, mask=image)
    image = new_image.convert('RGB')
    return image


def resize(pic: Image.Image, size: int, keep_ratio=True) -> Image.Image:
    if not keep_ratio:
        target_size = (size, size)
    else:
        min_edge = min(pic.size)
        target_size = (
            int(pic.size[0] / min_edge * size),
            int(pic.size[1] / min_edge * size),
        )

    target_size = (target_size[0] & ~3, target_size[1] & ~3)

    return pic.resize(target_size, resample=Image.Resampling.LANCZOS)


def smart_imread(img, flag=cv2.IMREAD_UNCHANGED):
    """ Read an image, convert to 24-bit if necessary """
    if img.endswith(".gif"):
        img = Image.open(img)
        img = img.convert("RGB")
        img = cv2.cvtColor(np.array(img), cv2.COLOR_RGB2BGR)
    else:
        img = cv2.imread(img, flag)
    return img


def smart_24bit(img):
    """ Convert an image to 24-bit if necessary """
    if img.dtype is np.dtype(np.uint16):
        img = (img / 257).astype(np.uint8)

    if len(img.shape) == 2:
        img = cv2.cvtColor(img, cv2.COLOR_GRAY2BGR)
    elif img.shape[2] == 4:
        trans_mask = img[:, :, 3] == 0
        img[trans_mask] = [255, 255, 255, 255]
        img = cv2.cvtColor(img, cv2.COLOR_BGRA2BGR)
    return img


def make_square(img, target_size):
    """ Make an image square """
    old_size = img.shape[:2]
    desired_size = max(old_size)
    desired_size = max(desired_size, target_size)

    delta_w = desired_size - old_size[1]
    delta_h = desired_size - old_size[0]
    top, bottom = delta_h // 2, delta_h - (delta_h // 2)
    left, right = delta_w // 2, delta_w - (delta_w // 2)

    color = [255, 255, 255]
    new_im = cv2.copyMakeBorder(
        img, top, bottom, left, right, cv2.BORDER_CONSTANT, value=color
    )
    return new_im


def smart_resize(img, size):
    """ Resize an image """
    # Assumes the image has already gone through make_square
    if img.shape[0] > size:
        img = cv2.resize(img, (size, size), interpolation=cv2.INTER_AREA)
    elif img.shape[0] < size:
        img = cv2.resize(img, (size, size), interpolation=cv2.INTER_CUBIC)
    return img