import io
import os
import sys
from typing import List, Optional

from urllib.parse import urlparse
import cv2
from PIL import Image, ImageOps
import numpy as np
import torch
from lama_cleaner.const import MPS_SUPPORT_MODELS
from loguru import logger
from torch.hub import download_url_to_file, get_dir
import hashlib


def md5sum(filename):
    md5 = hashlib.md5()
    with open(filename, "rb") as f:
        for chunk in iter(lambda: f.read(128 * md5.block_size), b""):
            md5.update(chunk)
    return md5.hexdigest()


def switch_mps_device(model_name, device):
    if model_name not in MPS_SUPPORT_MODELS and str(device) == "mps":
        logger.info(f"{model_name} not support mps, switch to cpu")
        return torch.device("cpu")
    return device


def get_cache_path_by_url(url):
    parts = urlparse(url)
    hub_dir = get_dir()
    model_dir = os.path.join(hub_dir, "checkpoints")
    if not os.path.isdir(model_dir):
        os.makedirs(model_dir)
    filename = os.path.basename(parts.path)
    cached_file = os.path.join(model_dir, filename)
    return cached_file


def download_model(url, model_md5: str = None):
    cached_file = get_cache_path_by_url(url)
    if not os.path.exists(cached_file):
        sys.stderr.write('Downloading: "{}" to {}\n'.format(url, cached_file))
        hash_prefix = None
        download_url_to_file(url, cached_file, hash_prefix, progress=True)
        if model_md5:
            _md5 = md5sum(cached_file)
            if model_md5 == _md5:
                logger.info(f"Download model success, md5: {_md5}")
            else:
                try:
                    os.remove(cached_file)
                    logger.error(
                        f"Model md5: {_md5}, expected md5: {model_md5}, wrong model deleted. Please restart lama-cleaner."
                        f"If you still have errors, please try download model manually first https://lama-cleaner-docs.vercel.app/install/download_model_manually.\n"
                    )
                except:
                    logger.error(
                        f"Model md5: {_md5}, expected md5: {model_md5}, please delete {cached_file} and restart lama-cleaner."
                    )
                exit(-1)

    return cached_file


def ceil_modulo(x, mod):
    if x % mod == 0:
        return x
    return (x // mod + 1) * mod


def handle_error(model_path, model_md5, e):
    _md5 = md5sum(model_path)
    if _md5 != model_md5:
        try:
            os.remove(model_path)
            logger.error(
                f"Model md5: {_md5}, expected md5: {model_md5}, wrong model deleted. Please restart lama-cleaner."
                f"If you still have errors, please try download model manually first https://lama-cleaner-docs.vercel.app/install/download_model_manually.\n"
            )
        except:
            logger.error(
                f"Model md5: {_md5}, expected md5: {model_md5}, please delete {model_path} and restart lama-cleaner."
            )
    else:
        logger.error(
            f"Failed to load model {model_path},"
            f"please submit an issue at https://github.com/Sanster/lama-cleaner/issues and include a screenshot of the error:\n{e}"
        )
    exit(-1)


def load_jit_model(url_or_path, device, model_md5: str):
    if os.path.exists(url_or_path):
        model_path = url_or_path
    else:
        model_path = download_model(url_or_path, model_md5)

    logger.info(f"Loading model from: {model_path}")
    try:
        model = torch.jit.load(model_path, map_location="cpu").to(device)
    except Exception as e:
        handle_error(model_path, model_md5, e)
    model.eval()
    return model


def load_model(model: torch.nn.Module, url_or_path, device, model_md5):
    if os.path.exists(url_or_path):
        model_path = url_or_path
    else:
        model_path = download_model(url_or_path, model_md5)

    try:
        logger.info(f"Loading model from: {model_path}")
        state_dict = torch.load(model_path, map_location="cpu")
        model.load_state_dict(state_dict, strict=True)
        model.to(device)
    except Exception as e:
        handle_error(model_path, model_md5, e)
    model.eval()
    return model


def numpy_to_bytes(image_numpy: np.ndarray, ext: str) -> bytes:
    data = cv2.imencode(
        f".{ext}",
        image_numpy,
        [int(cv2.IMWRITE_JPEG_QUALITY), 100, int(cv2.IMWRITE_PNG_COMPRESSION), 0],
    )[1]
    image_bytes = data.tobytes()
    return image_bytes


def pil_to_bytes(pil_img, ext: str, quality: int = 95, exif=None) -> bytes:
    with io.BytesIO() as output:
        pil_img.save(output, format=ext, exif=exif, quality=quality)
        image_bytes = output.getvalue()
    return image_bytes


def load_img(img_bytes, gray: bool = False, return_exif: bool = False):
    alpha_channel = None
    image = Image.open(io.BytesIO(img_bytes))

    try:
        if return_exif:
            exif = image.getexif()
    except:
        exif = None
        logger.error("Failed to extract exif from image")

    try:
        image = ImageOps.exif_transpose(image)
    except:
        pass

    if gray:
        image = image.convert("L")
        np_img = np.array(image)
    else:
        if image.mode == "RGBA":
            np_img = np.array(image)
            alpha_channel = np_img[:, :, -1]
            np_img = cv2.cvtColor(np_img, cv2.COLOR_RGBA2RGB)
        else:
            image = image.convert("RGB")
            np_img = np.array(image)

    if return_exif:
        return np_img, alpha_channel, exif
    return np_img, alpha_channel


def norm_img(np_img):
    if len(np_img.shape) == 2:
        np_img = np_img[:, :, np.newaxis]
    np_img = np.transpose(np_img, (2, 0, 1))
    np_img = np_img.astype("float32") / 255
    return np_img


def resize_max_size(
    np_img, size_limit: int, interpolation=cv2.INTER_CUBIC
) -> np.ndarray:
    # Resize image's longer size to size_limit if longer size larger than size_limit
    h, w = np_img.shape[:2]
    if max(h, w) > size_limit:
        ratio = size_limit / max(h, w)
        new_w = int(w * ratio + 0.5)
        new_h = int(h * ratio + 0.5)
        return cv2.resize(np_img, dsize=(new_w, new_h), interpolation=interpolation)
    else:
        return np_img


def pad_img_to_modulo(
    img: np.ndarray, mod: int, square: bool = False, min_size: Optional[int] = None
):
    """

    Args:
        img: [H, W, C]
        mod:
        square: 是否为正方形
        min_size:

    Returns:

    """
    if len(img.shape) == 2:
        img = img[:, :, np.newaxis]
    height, width = img.shape[:2]
    out_height = ceil_modulo(height, mod)
    out_width = ceil_modulo(width, mod)

    if min_size is not None:
        assert min_size % mod == 0
        out_width = max(min_size, out_width)
        out_height = max(min_size, out_height)

    if square:
        max_size = max(out_height, out_width)
        out_height = max_size
        out_width = max_size

    return np.pad(
        img,
        ((0, out_height - height), (0, out_width - width), (0, 0)),
        mode="symmetric",
    )


def boxes_from_mask(mask: np.ndarray) -> List[np.ndarray]:
    """
    Args:
        mask: (h, w, 1)  0~255

    Returns:

    """
    height, width = mask.shape[:2]
    _, thresh = cv2.threshold(mask, 127, 255, 0)
    contours, _ = cv2.findContours(thresh, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)

    boxes = []
    for cnt in contours:
        x, y, w, h = cv2.boundingRect(cnt)
        box = np.array([x, y, x + w, y + h]).astype(int)

        box[::2] = np.clip(box[::2], 0, width)
        box[1::2] = np.clip(box[1::2], 0, height)
        boxes.append(box)

    return boxes


def only_keep_largest_contour(mask: np.ndarray) -> List[np.ndarray]:
    """
    Args:
        mask: (h, w)  0~255

    Returns:

    """
    _, thresh = cv2.threshold(mask, 127, 255, 0)
    contours, _ = cv2.findContours(thresh, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)

    max_area = 0
    max_index = -1
    for i, cnt in enumerate(contours):
        area = cv2.contourArea(cnt)
        if area > max_area:
            max_area = area
            max_index = i

    if max_index != -1:
        new_mask = np.zeros_like(mask)
        return cv2.drawContours(new_mask, contours, max_index, 255, -1)
    else:
        return mask