Power BI Solution: Dynamic Stock Aging Report from Item Ledger Transactions

Note: If this task is successfully completed, there may be additional related projects. Successful completion could lead to an ongoing freelancing opportunity with us.
FYI to all - We have a working solution already developed in Power BI using M Code and DAX. This is a part of the assessment to check your skills on the requirements understanding and technical proficiency, to hire you for a long term BI engagement.

We have an item ledger entry table containing item number, batch number, transaction date, and transaction type (purchase, sales, adjustments, etc.). This table logs all inventory transactions but does not hold current stock balances directly.

Requirement:
We need a Power BI solution - using Power Query, DAX, or a combination - that will:
• Calculate the aging of stock as of any user-selected date (dynamic, not only the current date).
• Show the stock position (inventory on hand) as of the chosen date.
• For each item/batch in stock as of that date, display aging details (number of days held, ideally grouped by aging buckets).
• Accurately account for all transaction types through the selected date.
• Support historical analysis (e.g., view aging as of previous week, end of month, or any specific date).

Deliverables:
• A complete Power BI report (PBIX file) that implements the above logic.
• All transformation and aging logic should be done in Power Query, DAX, or a combination.
• Documentation or comments explaining the logic.
• Walkthrough or demo of the solution.

Skills Required:
• Power BI development (Power Query and DAX)
• Data modeling and stock ledger/aging calculation expertise

Additional Notes:
• Please provide examples of similar Power BI work or briefly describe your approach.
• The report should be efficient and handle large data volumes.
• Visual presentation of the aging report is a plus.