from enum import Enum
from PIL import Image


class ResizeMode(Enum):
    RESIZE = 0  # just resize
    RESIZE_TO_FILL = 1  # crop and resize
    RESIZE_TO_FIT = 2  # resize and fill


def resize_image(im: Image.Image, width: int, height: int, resize_mode=ResizeMode.RESIZE_TO_FIT):
    """
    Resizes an image with the specified resize_mode, width, and height.

    Args:
        resize_mode: The mode to use when resizing the image.
            0: Resize the image to the specified width and height.
            1: Resize the image to fill the specified width and height, maintaining the aspect ratio, and then center the image within the dimensions, cropping the excess.
            2: Resize the image to fit within the specified width and height, maintaining the aspect ratio, and then center the image within the dimensions, filling empty with data from image.
        im: The image to resize.
        width: The width to resize the image to.
        height: The height to resize the image to.
        upscaler_name: The name of the upscaler to use. If not provided, defaults to opts.upscaler_for_img2img.
    """

    def resize(im: Image.Image, w, h):
        return im.resize((w, h), resample=Image.LANCZOS)

    if resize_mode == ResizeMode.RESIZE:
        res = resize(im, width, height)

    elif resize_mode == ResizeMode.RESIZE_TO_FILL:
        ratio = width / height
        src_ratio = im.width / im.height

        src_w = width if ratio > src_ratio else im.width * height // im.height
        src_h = height if ratio <= src_ratio else im.height * width // im.width

        resized = resize(im, src_w, src_h)
        res = Image.new("RGB", (width, height))
        res.paste(resized, box=(width // 2 - src_w // 2, height // 2 - src_h // 2))

    else:
        ratio = width / height
        src_ratio = im.width / im.height

        src_w = width if ratio < src_ratio else im.width * height // im.height
        src_h = height if ratio >= src_ratio else im.height * width // im.width

        resized = resize(im, src_w, src_h)
        res = Image.new("RGB", (width, height))
        res.paste(resized, box=(width // 2 - src_w // 2, height // 2 - src_h // 2))

        if ratio < src_ratio:
            fill_height = height // 2 - src_h // 2
            if fill_height > 0:
                res.paste(resized.resize((width, fill_height), box=(0, 0, width, 0)), box=(0, 0))
                res.paste(
                    resized.resize((width, fill_height), box=(0, resized.height, width, resized.height)),
                    box=(0, fill_height + src_h),
                )
        elif ratio > src_ratio:
            fill_width = width // 2 - src_w // 2
            if fill_width > 0:
                res.paste(resized.resize((fill_width, height), box=(0, 0, 0, height)), box=(0, 0))
                res.paste(
                    resized.resize((fill_width, height), box=(resized.width, 0, resized.width, height)),
                    box=(fill_width + src_w, 0),
                )

    return res


def flatten_image(im: Image.Image, bgcolor="#ffffff"):
    """replaces transparency with bgcolor (example: "#ffffff"), returning an RGB mode image with no transparency"""

    if im.mode == "RGBA":
        background = Image.new("RGBA", im.size, bgcolor)
        background.paste(im, mask=im)
        im = background

    return im.convert("RGB")