import json
import sys

from PIL import Image, ImageDraw
from pathlib import Path


def safe_user_path(path_value, base_dir="."):
    """Resolve a CLI path under the current workspace."""
    if base_dir != ".":
        raise ValueError("Custom base directories are not supported for CLI paths")
    base_path = Path.cwd().resolve()
    resolved_path = Path(path_value).expanduser().resolve()
    try:
        resolved_path.relative_to(base_path)
    except ValueError as exc:
        raise ValueError(f"Path escapes allowed directory: {path_value}") from exc
    return resolved_path


# Creates "validation" images with rectangles for the bounding box information that
# Claude creates when determining where to add text annotations in PDFs. See forms.md.


def create_validation_image(page_number, fields_json_path, input_path, output_path):
    # Input file should be in the `fields.json` format described in forms.md.
    with open(fields_json_path, 'r') as f:
        data = json.load(f)

        img = Image.open(input_path)
        draw = ImageDraw.Draw(img)
        num_boxes = 0
        
        for field in data["form_fields"]:
            if field["page_number"] == page_number:
                entry_box = field['entry_bounding_box']
                label_box = field['label_bounding_box']
                # Draw red rectangle over entry bounding box and blue rectangle over the label.
                draw.rectangle(entry_box, outline='red', width=2)
                draw.rectangle(label_box, outline='blue', width=2)
                num_boxes += 2
        
        img.save(output_path)
        print(f"Created validation image at {output_path} with {num_boxes} bounding boxes")


if __name__ == "__main__":
    if len(sys.argv) != 5:
        print("Usage: create_validation_image.py [page number] [fields.json file] [input image path] [output image path]")
        sys.exit(1)
    page_number = int(sys.argv[1])
    fields_json_path = safe_user_path(sys.argv[2])
    input_image_path = safe_user_path(sys.argv[3])
    output_image_path = safe_user_path(sys.argv[4])
    create_validation_image(page_number, fields_json_path, input_image_path, output_image_path)