import json
import os
import time
import urllib.request as ureq

def download_image_with_retries(url, output_file, max_retries=3, backoff_factor=1):
    """Attempt to download an image with retries upon failure.

    Args:
        url (str): The URL of the image to download.
        output_file (str): The local file path to save the downloaded image.
        max_retries (int): The maximum number of retry attempts.
        backoff_factor (float): The factor to calculate the delay between retries.
    """
    attempt = 0
    while attempt < max_retries:
        try:
            ureq.urlretrieve(url, output_file)
            print(f"Successfully downloaded: {output_file}")
            return True
        except Exception as e:
            print(f"Attempt {attempt + 1} failed for {url}: {e}")
            time.sleep(backoff_factor * (2 ** attempt))
            attempt += 1
    print(f"Failed to download {url} after {max_retries} attempts.")
    return False

def verify_and_download_images(data):
    """Verify if images are downloaded; if not, download them.

    Args:
        data (dict): The dataset containing image URLs and additional information.
    """
    images_directory = './images'
    os.makedirs(images_directory, exist_ok=True)

    for key, value in data.items():
        image_url = value['imageURL']
        ext = os.path.splitext(image_url)[1]
        output_file = f'{images_directory}/{key}{ext}'

        if not os.path.exists(output_file):
            print(f"Image {key}{ext} not found, attempting to download...")
            if not download_image_with_retries(image_url, output_file):
                print(f"Warning: Could not download image {image_url}")
        

# Load the dataset JSON file
with open('dataset.json', 'r') as fp:
    data = json.load(fp)

# Check and download images as necessary
verify_and_download_images(data)