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

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

# Imports
import boto3
from datetime import datetime, timedelta
from dateutil.relativedelta import relativedelta
import humanize

# Main function
def main() -> None:
    # get distributions
    cw = boto3.client('cloudwatch', region_name='us-east-1')
    cf = boto3.client('cloudfront', region_name='us-east-1')
    distros = cf.list_distributions()['DistributionList']['Items']
    dist_ids = [d['Id'] for d in distros if d['Status'] == 'Deployed']

    for dist_id in dist_ids:
        for month_offset in range(-3, 0):  # Past 3 months
            now = datetime.now()
            first_of_current_month = now.replace(day=1)
            start = (first_of_current_month + relativedelta(months=month_offset)).replace(day=1)
            end = (start + relativedelta(months=1)) - relativedelta(seconds=1)  # Last day

            # BytesDownloaded
            bytes_resp = cw.get_metric_statistics(
                Namespace='AWS/CloudFront', MetricName='BytesDownloaded',
                Dimensions=[{'Name': 'DistributionId', 'Value': dist_id}, {'Name': 'Region', 'Value': 'Global'}],
                StartTime=start, EndTime=end, Period=2678400, Statistics=['Sum']
            )
            bytes_total = bytes_resp['Datapoints'][0]['Sum'] if bytes_resp['Datapoints'] else 0

            # Requests
            reqs_resp = cw.get_metric_statistics(
                Namespace='AWS/CloudFront', MetricName='Requests',
                Dimensions=[{'Name': 'DistributionId', 'Value': dist_id}, {'Name': 'Region', 'Value': 'Global'}],
                StartTime=start, EndTime=end, Period=2678400, Statistics=['Sum']
            )
            reqs_total = reqs_resp['Datapoints'][0]['Sum'] if reqs_resp['Datapoints'] else 0

            # only interested in distro with high traffic (>10G)
            if bytes_total > 10 * 1024 ** 3:
                print(f"{dist_id}: {start:%Y-%b} Requests: {reqs_total:,.0f} BytesDownloaded: {humanize.naturalsize(bytes_total)}")


# Call main function
if __name__ == '__main__':
    main()