#!/usr/bin/python3
r"""
Documentation

License: This program is released under the MIT License
"""

# Imports
import boto3
import pickle
import os


PICKLE_FILE = 'cache.pkl'

def getRegions(all_regions=False) -> list[str]:
    """
    Returns all aws regions, cached in pickle file to avoid repeated AWS calls.

    :param all_regions:
    :return:
    """
    cache_key = "aws_regions"

    if os.path.exists(PICKLE_FILE):
        with open(PICKLE_FILE, 'rb') as f:
            cache = pickle.load(f)
            if cache_key in cache:
                return cache[cache_key]

    # Fetch from AWS and cache it
    ec2 = boto3.client('ec2', region_name='us-east-1')
    response = ec2.describe_regions(AllRegions=all_regions)
    regions = [region['RegionName'] for region in response['Regions']]

    cache = {cache_key: regions}
    with open(PICKLE_FILE, 'wb') as f:
        pickle.dump(cache, f)

    return regions