import numpy as np
import gradio as gr
from PIL import Image

import torch
from transformers import MobileViTFeatureExtractor, MobileViTForSemanticSegmentation


model_checkpoint = "apple/deeplabv3-mobilevit-small"
feature_extractor = MobileViTFeatureExtractor.from_pretrained(model_checkpoint)
model = MobileViTForSemanticSegmentation.from_pretrained(model_checkpoint).eval()

palette = np.array(
[
    [  0,   0,   0], [192,   0,   0], [  0, 192,   0], [192, 192,   0],
    [  0,   0, 192], [192,   0, 192], [  0, 192, 192], [192, 192, 192],
    [128,   0,   0], [255,   0,   0], [128, 192,   0], [255, 192,   0],
    [128,   0, 192], [255,   0, 192], [128, 192, 192], [255, 192, 192],
    [  0, 128,   0], [192, 128,   0], [  0, 255,   0], [192, 255,   0],
    [  0, 128, 192]
],
dtype=np.uint8)

labels = [
    "background",
    "aeroplane",
    "bicycle",
    "bird",
    "boat",
    "bottle",
    "bus",
    "car",
    "cat",
    "chair",
    "cow",
    "diningtable",
    "dog",
    "horse",
    "motorbike",
    "person",
    "pottedplant",
    "sheep",
    "sofa",
    "train",
    "tvmonitor",
]

# Draw the labels. Light colors use black text, dark colors use white text.
inverted = [ 0, 1, 4, 5, 8, 9, 12, 13, 16, 17, 20 ]
labels_colored = []
for i in range(len(labels)):
    r, g, b = palette[i]
    label = labels[i]
    color = "white" if i in inverted else "black"
    text = "<span style='background-color: rgb(%d, %d, %d); color: %s; padding: 2px 4px;'>%s</span>" % (r, g, b, color, label)
    labels_colored.append(text)
labels_text = ", ".join(labels_colored)

title = "Semantic Segmentation with MobileViT and DeepLabV3"

description = """
The input image is resized and center cropped to 512×512 pixels. The segmentation output is 32×32 pixels.<br>
This model has been trained on <a href="http://host.robots.ox.ac.uk/pascal/VOC/">Pascal VOC</a>.
The classes are:
""" + labels_text + "</p>"

article = """
<div style='margin:20px auto;'>

<p>Sources:<p>

<p>📜 <a href="https://arxiv.org/abs/2110.02178">MobileViT: Light-weight, General-purpose, and Mobile-friendly Vision Transformer</a></p>

<p>🏋️ Original pretrained weights from <a href="https://github.com/apple/ml-cvnets">this GitHub repo</a></p>

<p>🏙 Example images from <a href="https://huggingface.co/datasets/mishig/sample_images">this dataset</a><p>

</div>
"""

examples = [
    ["cat-3.jpg"],
    ["construction-site.jpg"],
    ["dog-cat.jpg"],
    ["football-match.jpg"],
]


def predict(image):
    with torch.no_grad():
        inputs = feature_extractor(image, return_tensors="pt")
        outputs = model(**inputs)

    # Get preprocessed image. The pixel values don't need to be unnormalized
    # for this particular model.
    resized = (inputs["pixel_values"].numpy().squeeze().transpose(1, 2, 0)[..., ::-1] * 255).astype(np.uint8)

    # Class predictions for each pixel.
    classes = outputs.logits.argmax(1).squeeze().numpy().astype(np.uint8)

    # Super slow method but it works... should probably improve this.
    colored = np.zeros((classes.shape[0], classes.shape[1], 3), dtype=np.uint8)
    for y in range(classes.shape[0]):
        for x in range(classes.shape[1]):
            colored[y, x] = palette[classes[y, x]]

    # Resize predictions to input size (not original size).
    colored = Image.fromarray(colored)
    colored = colored.resize((resized.shape[1], resized.shape[0]), resample=Image.Resampling.NEAREST)

    # Keep everything that is not background.
    mask = (classes != 0) * 255
    mask = Image.fromarray(mask.astype(np.uint8)).convert("RGB")
    mask = mask.resize((resized.shape[1], resized.shape[0]), resample=Image.Resampling.NEAREST)

    # Blend with the input image.
    resized = Image.fromarray(resized)
    highlighted = Image.blend(resized, mask, 0.4)

    #colored = colored.resize((256, 256), resample=Image.Resampling.BICUBIC)
    #highlighted = highlighted.resize((256, 256), resample=Image.Resampling.BICUBIC)

    return colored, highlighted


gr.Interface(
    fn=predict,
    inputs=gr.inputs.Image(label="Upload image"),
    outputs=[gr.outputs.Image(label="Classes"), gr.outputs.Image(label="Overlay")],
    title=title,
    description=description,
    article=article,
    examples=examples,
).launch()