from itertools import islice
import time

import pymysql.cursors

import config


def main():
    db_connection = pymysql.connect(
        host=config.DATABASE_HOST,
        user=config.DATABASE_USERNAME,
        password=config.DATABASE_PASSWORD,
        database='direct_delivery',
        cursorclass=pymysql.cursors.DictCursor
    )
    sql_get_assets_to_be_picked_up = 'SELECT id FROM temp_asset_received_queue_backfill WHERE processed = 0;'
    with db_connection:
        cursor = db_connection.cursor()
        cursor.execute(sql_get_assets_to_be_picked_up)
        assets_to_be_picked_up = cursor.fetchall()
        asset_iterator = iter(assets_to_be_picked_up)
        while list_of_50_assets := list(islice(asset_iterator, 50)):
            processed = False
            while not processed:
                sql_get_asset_received_queue_depth = f"""SELECT count(*) FROM asset_received_queue WHERE picked_up = 'N';"""
                cursor = db_connection.cursor()
                cursor.execute(sql_get_asset_received_queue_depth)
                db_connection.commit()
                asset_received_queue_depth = cursor.fetchone()['count(*)']
                print('Asset received queue depth is ' + str(asset_received_queue_depth))

                if asset_received_queue_depth < config.ASSET_RECEIVED_QUEUE_DEPTH_CEILING:
                    asset_list = ','.join([str(asset['id']) for asset in list_of_50_assets])
                    print(f'Assets to be picked up: {asset_list}')
                    sql_update_asset_records = f"""update asset_received_queue arq
                                                    inner join temp_asset_received_queue_backfill tarq on arq.id = tarq.id
                                                    set arq.picked_up = 'N', arq.priority = 3, tarq.processed = 1
                                                    where arq.id in ({str(asset_list)});"""
                    cursor = db_connection.cursor()
                    sql_update_asset_result = cursor.execute(sql_update_asset_records)
                    db_connection.commit()
                    print(f'Update asset result: changed row count is {str(sql_update_asset_result)}')
                    processed = True
                else:
                    print('Queue is too high')
                    time.sleep(5)

if __name__ == '__main__':
    print('Running update assets script')
    main()