How to get previous 4 week sales at a level

I would like to find previous four week sales at a level in Python. Say for example

ID  Category    Date    Sales
1   AA  7/02/2022   1
1   AA  31/01/2022  3
1   AA  24/01/2022  5
1   AA  10/01/2022  7
1   AA  03/01/2022  9
2   BB  7/02/2022   2
2   BB  31/01/2022  4
2   BB  24/01/2022  6
2   BB  17/01/2022  8
2   BB  10/01/2022  10

For 1 AA 7/02/2022 sum of last four weeks will be 9 (as 17/01/2022 bales is not there and must include current row date)

You could set the date as index, groupby Category and take the sum of a 28-day rolling window of Sales:

import pandas as pd
import io

data = '''ID  Category    Date    Sales
1   AA  7/02/2022   1
1   AA  31/01/2022  3
1   AA  24/01/2022  5
1   AA  10/01/2022  7
1   AA  03/01/2022  9
2   BB  7/02/2022   2
2   BB  31/01/2022  4
2   BB  24/01/2022  6
2   BB  17/01/2022  8
2   BB  10/01/2022  10'''

df = pd.read_csv(io.StringIO(data), sep='\s+')
df['Date'] = pd.to_datetime(df['Date'], format='%d/%m/%Y')

result_df = df.set_index('Date').sort_index().groupby('Category')['Sales'].rolling("28D").sum().reset_index()

Output: