import json
import math
import os
import random
import sys

import matplotlib.pyplot as plt
from matplotlib.patches import Polygon
from PIL import Image

multiannotation_path = "instance_segmentation/multiannotator_15imgs.json"
img_folder = "images"

if __name__ == "__main__":
    with open(multiannotation_path) as f:
        multiannotations = json.load(f)

    # Optional image name as argument, otherwise pick a random image
    name = sys.argv[1] if len(sys.argv) > 1 else random.choice(sorted(multiannotations))
    annotators = multiannotations[name]
    print(f"{name}: {len(annotators)} annotators, "
          f"{sum(len(a['polygons']) for a in annotators)} polygons")

    img = Image.open(os.path.join(img_folder, name))
    cols = min(4, len(annotators))
    rows = math.ceil(len(annotators) / cols)
    fig, axes = plt.subplots(rows, cols, figsize=(5 * cols, 3 * rows), squeeze=False)
    for ax in axes.flat:
        ax.axis("off")

    cmap = plt.get_cmap("tab20")
    for ax, annotator in zip(axes.flat, annotators):
        ax.imshow(img)
        for i, poly in enumerate(annotator["polygons"]):
            pts = [(p["x"], p["y"]) for p in poly["polygon_pts"]]
            color = cmap(i % cmap.N)
            ax.add_patch(Polygon(pts, closed=True, alpha=0.4, facecolor=color,
                                 edgecolor=color, linewidth=1.5))
        ax.set_title(f"{annotator['user_id']} ({len(annotator['polygons'])} polygons)", fontsize=9)

    fig.suptitle(name)
    fig.tight_layout()
    fig.savefig("example_image_annotations.png", dpi=100)
    plt.show()