# Fixed FBA Inventory Sync & Credential Refactor

**Date:** 2026-02-23
**Author:** Jules (Agent)
**Status:** Success (Backend Verified)

## Overview
The primary goal was to resolve the "No active inventory found" error when syncing FBA inventory from Amazon. The investigation revealed that the previously used SP-API report type was returning `FATAL` errors for FBA accounts, and the credential management system was brittle, relying on environment variables that didn't scale for multi-user support.

## Challenges
1.  **FBA Report Failure:** The report `GET_FBA_MYI_UNSUPPRESSED_INVENTORY_DATA` consistently returned a `FATAL` status or empty results for the user's FBA account.
2.  **Incomplete Inventory Definition:** The initial logic only counted `afn-fulfillable-quantity`, ignoring stock that was `Inbound` (Working, Shipped, Receiving). This led to "Zero Active Inventory" even when thousands of units were on their way to Amazon.
3.  **Credential Dependency:** Diagnostic scripts and backend tasks crashed because they strictly expected `SP_API_SELLER_ID` and `SP_API_REFRESH_TOKEN` in the `.env` file. This violated the multi-user architecture where credentials must be loaded from the database (`user_credentials` table).
4.  **Sandbox Misconfiguration:** The system occasionally defaulted to the SP-API Sandbox URL, which contains no real inventory data.

## Solutions Implemented

### 1. FBA Report Switch
*   **Action:** Switched the FBA report type in `keepa_deals/inventory_import.py` from `GET_FBA_MYI_UNSUPPRESSED_INVENTORY_DATA` to `GET_FBA_MYI_ALL_INVENTORY_DATA`.
*   **Result:** Verified via `Diagnostics/test_fba_reports.py` that the new report type returns HTTP 202 (Accepted) and valid content, unlike the legacy one.

### 2. Comprehensive Inventory Counting
*   **Action:** Updated parsing logic to define "Active FBA Inventory" as:
    ```python
    qty = fulfillable + inbound_working + inbound_shipped + inbound_receiving
    ```
*   **Result:** Ensures inventory is tracked throughout the entire supply chain, not just when it lands on the shelf.

### 3. Credential Refactoring (DB-First)
*   **Action:** Refactored `keepa_deals/inventory_import.py` and `Diagnostics/check_inventory_permissions.py` to prioritize loading credentials from the SQLite database (`deals.db`).
*   **Action:** Created `Diagnostics/inject_credentials.py` to allow manual population of the DB via CLI args (`python3 inject_credentials.py <SELLER_ID> <TOKEN>`), removing the need to edit `.env` files for user-specific data.

### 4. Safety & Hardening
*   **Action:** Hardcoded the Amazon **Production URL** (`https://sellingpartnerapi-na.amazon.com`) as the default in `amazon_sp_api.py` and `inventory_import.py` to prevent accidental Sandbox connections.
*   **Action:** Added `tests/test_inventory_parsing.py` to unit-test the parsing logic against sample FBA report data.

## Verification Results
*   **Tests:** Full test suite passed, including the new inventory parsing tests.
*   **Diagnostics:** `check_inventory_permissions.py` successfully retrieves credentials from the DB and generates the Merchant report. `test_fba_reports.py` confirmed `GET_FBA_MYI_ALL_INVENTORY_DATA` is the working report type.

## Next Steps (Handover)
The backend logic is solid. The next agent should:
1.  **UI Verification:** Manually confirm that the "Sync from Amazon" button in the frontend correctly updates the UI table.
2.  **Visual Polish:** Ensure the "Inbound" vs "Fulfillable" breakdown is communicated clearly if the UI supports it (currently it sums them).