import gradio as gr

from transformers import SegformerFeatureExtractor, SegformerForSemanticSegmentation
from PIL import Image
import requests
from matplotlib import gridspec
import matplotlib.pyplot as plt
import numpy as np
import tensorflow as tf

feature_extractor = SegformerFeatureExtractor.from_pretrained(
    "nvidia/segformer-b0-finetuned-ade-512-512")
model = SegformerForSemanticSegmentation.from_pretrained(
    "segments-tobias/segformer-b0-finetuned-segments-sidewalk")

def ade_palette():
    """ADE20K palette that maps each class to RGB values."""
    return [
        [204, 87, 90],
        [112, 185, 212],
        [45, 189, 106],
        [234, 123, 67],
        [78, 56, 123],
        [210, 32, 89],
        [90, 180, 56],
        [155, 102, 200],
        [33, 147, 176],
        [255, 183, 76],
        [67, 123, 89],
        [190, 60, 45],
        [134, 112, 200],
        [56, 45, 189],
        [200, 56, 123],
        [87, 92, 204],
        [120, 56, 123],
        [45, 78, 123],
        [156, 200, 56],
        [32, 90, 210],
        [56, 123, 67],
        [180, 56, 123],
        [123, 67, 45],
        [45, 134, 200],
        [67, 56, 123],
        [78, 123, 67],
        [32, 210, 90],
        [45, 56, 189],
        [123, 56, 123],
        [56, 156, 200],
        [189, 56, 45],
        [112, 200, 56],
        [56, 123, 45],
        [200, 32, 90],
        [123, 45, 78],
    ]

labels_list = []

with open(r'labels.txt', 'r') as fp:
    for line in fp:
        labels_list.append(line[:-1])

colormap = np.asarray(ade_palette())

def label_to_color_image(label):
    if label.ndim != 2:
        raise ValueError("Expect 2-D input label")

    if np.max(label) >= len(colormap):
        raise ValueError("label value too large.")
    return colormap[label]

def draw_plot(pred_img, seg):
    fig = plt.figure(figsize=(20, 15))

    grid_spec = gridspec.GridSpec(1, 2, width_ratios=[6, 1])

    plt.subplot(grid_spec[0])
    plt.imshow(pred_img)
    plt.axis('off')
    LABEL_NAMES = np.asarray(labels_list)
    FULL_LABEL_MAP = np.arange(len(LABEL_NAMES)).reshape(len(LABEL_NAMES), 1)
    FULL_COLOR_MAP = label_to_color_image(FULL_LABEL_MAP)

    unique_labels = np.unique(seg.numpy().astype("uint8"))
    ax = plt.subplot(grid_spec[1])
    plt.imshow(FULL_COLOR_MAP[unique_labels].astype(np.uint8), interpolation="nearest")
    ax.yaxis.tick_right()
    plt.yticks(range(len(unique_labels)), LABEL_NAMES[unique_labels])
    plt.xticks([], [])
    ax.tick_params(width=0.0, labelsize=25)
    return fig

def sepia(input_img):
    input_img = Image.fromarray(input_img)

    inputs = feature_extractor(images=input_img, return_tensors="tf")
    outputs = model(**inputs)
    logits = outputs.logits

    logits = tf.transpose(logits, [0, 2, 3, 1])
    logits = tf.image.resize(
        logits, input_img.size[::-1]
    )  # We reverse the shape of `image` because `image.size` returns width and height.
    seg = tf.math.argmax(logits, axis=-1)[0]

    color_seg = np.zeros(
        (seg.shape[0], seg.shape[1], 3), dtype=np.uint8
    )  # height, width, 3
    for label, color in enumerate(colormap):
        color_seg[seg.numpy() == label, :] = color

    # Show image + mask
    pred_img = np.array(input_img) * 0.5 + color_seg * 0.5
    pred_img = pred_img.astype(np.uint8)

    fig = draw_plot(pred_img, seg)
    return fig

demo = gr.Interface(fn=sepia,
                    inputs=gr.Image(),
                    outputs=['plot'],
                    examples=["Sidewalk_1.jpg", "Sidewalk_2.jpg", "Sidewalk_3.jpg"],
                    allow_flagging='never')


demo.launch()