import collections
import threading

import imgviz
import numpy as np
import onnxruntime
import skimage

from ..logger import logger

from . import _utils


class SegmentAnythingModel:
    def __init__(self, encoder_path, decoder_path):
        self._image_size = 1024

        self._encoder_session = onnxruntime.InferenceSession(encoder_path)
        self._decoder_session = onnxruntime.InferenceSession(decoder_path)

        self._lock = threading.Lock()
        self._image_embedding_cache = collections.OrderedDict()

        self._thread = None

    def set_image(self, image: np.ndarray):
        with self._lock:
            self._image = image
            self._image_embedding = self._image_embedding_cache.get(
                self._image.tobytes()
            )

        if self._image_embedding is None:
            self._thread = threading.Thread(
                target=self._compute_and_cache_image_embedding
            )
            self._thread.start()

    def _compute_and_cache_image_embedding(self):
        with self._lock:
            logger.debug("Computing image embedding...")
            self._image_embedding = _compute_image_embedding(
                image_size=self._image_size,
                encoder_session=self._encoder_session,
                image=self._image,
            )
            if len(self._image_embedding_cache) > 10:
                self._image_embedding_cache.popitem(last=False)
            self._image_embedding_cache[
                self._image.tobytes()
            ] = self._image_embedding
            logger.debug("Done computing image embedding.")

    def _get_image_embedding(self):
        if self._thread is not None:
            self._thread.join()
            self._thread = None
        with self._lock:
            return self._image_embedding

    def predict_mask_from_points(self, points, point_labels):
        return _compute_mask_from_points(
            image_size=self._image_size,
            decoder_session=self._decoder_session,
            image=self._image,
            image_embedding=self._get_image_embedding(),
            points=points,
            point_labels=point_labels,
        )

    def predict_polygon_from_points(self, points, point_labels):
        mask = self.predict_mask_from_points(
            points=points, point_labels=point_labels
        )
        return _utils.compute_polygon_from_mask(mask=mask)


def _compute_scale_to_resize_image(image_size, image):
    height, width = image.shape[:2]
    if width > height:
        scale = image_size / width
        new_height = int(round(height * scale))
        new_width = image_size
    else:
        scale = image_size / height
        new_height = image_size
        new_width = int(round(width * scale))
    return scale, new_height, new_width


def _resize_image(image_size, image):
    scale, new_height, new_width = _compute_scale_to_resize_image(
        image_size=image_size, image=image
    )
    scaled_image = imgviz.resize(
        image,
        height=new_height,
        width=new_width,
        backend="pillow",
    ).astype(np.float32)
    return scale, scaled_image


def _compute_image_embedding(image_size, encoder_session, image):
    image = imgviz.asrgb(image)

    scale, x = _resize_image(image_size, image)
    x = (x - np.array([123.675, 116.28, 103.53], dtype=np.float32)) / np.array(
        [58.395, 57.12, 57.375], dtype=np.float32
    )
    x = np.pad(
        x,
        (
            (0, image_size - x.shape[0]),
            (0, image_size - x.shape[1]),
            (0, 0),
        ),
    )
    x = x.transpose(2, 0, 1)[None, :, :, :]

    output = encoder_session.run(output_names=None, input_feed={"x": x})
    image_embedding = output[0]

    return image_embedding


def _compute_mask_from_points(
    image_size, decoder_session, image, image_embedding, points, point_labels
):
    input_point = np.array(points, dtype=np.float32)
    input_label = np.array(point_labels, dtype=np.int32)

    onnx_coord = np.concatenate([input_point, np.array([[0.0, 0.0]])], axis=0)[
        None, :, :
    ]
    onnx_label = np.concatenate([input_label, np.array([-1])], axis=0)[
        None, :
    ].astype(np.float32)

    scale, new_height, new_width = _compute_scale_to_resize_image(
        image_size=image_size, image=image
    )
    onnx_coord = (
        onnx_coord.astype(float)
        * (new_width / image.shape[1], new_height / image.shape[0])
    ).astype(np.float32)

    onnx_mask_input = np.zeros((1, 1, 256, 256), dtype=np.float32)
    onnx_has_mask_input = np.array([-1], dtype=np.float32)

    decoder_inputs = {
        "image_embeddings": image_embedding,
        "point_coords": onnx_coord,
        "point_labels": onnx_label,
        "mask_input": onnx_mask_input,
        "has_mask_input": onnx_has_mask_input,
        "orig_im_size": np.array(image.shape[:2], dtype=np.float32),
    }

    masks, _, _ = decoder_session.run(None, decoder_inputs)
    mask = masks[0, 0]  # (1, 1, H, W) -> (H, W)
    mask = mask > 0.0

    MIN_SIZE_RATIO = 0.05
    skimage.morphology.remove_small_objects(
        mask, min_size=mask.sum() * MIN_SIZE_RATIO, out=mask
    )

    if 0:
        imgviz.io.imsave(
            "mask.jpg", imgviz.label2rgb(mask, imgviz.rgb2gray(image))
        )
    return mask