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

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

# Imports
import boto3
import concurrent.futures
from openpyxl import load_workbook
from openpyxl.worksheet.worksheet import Worksheet


def getRegions(all_regions=False):
    ec2 = boto3.client('ec2')
    response = ec2.describe_regions(AllRegions=all_regions)
    return [region['RegionName'] for region in response['Regions']]

def getResources(region_name: str) -> list[list[str | int]]:
    return_data = []
    client = boto3.client('rds', region_name=region_name)
    response = client.describe_db_instances()
    for i in response['DBInstances']:
        return_data.append([i['DBInstanceIdentifier'], i['DBInstanceClass'], i['Engine'], i['EngineVersion'], i['MultiAZ'], region_name])
    return return_data

# Main function
def main() -> None:
    # Open spreadsheet and add a sheet
    wb = load_workbook('aws-inventory.xlsx')
    ws = wb.create_sheet("RDS")

    ws.append(["DBInstanceIdentifier", "DBInstanceClass", "Engine", "EngineVersion", "MultiAZ", "Region"])
    with concurrent.futures.ThreadPoolExecutor(max_workers=8) as executor:
        results = executor.map(getResources, getRegions())
        for region_rows in results:
            # append to worksheet only if resoruces are found in the region
            if region_rows:
                for row in region_rows:
                    ws.append(row)

    wb.save('aws-inventory.xlsx')

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