# Kifi Project Context

## Overview
Kifi is a financial and inventory management application designed to handle strict accounting principles along with inventory, vendor, and business operations.

### Components
- **kifi-app**: Flutter mobile frontend.
- **kifi-api**: Spring Boot WebFlux backend (reactive stack).
- **Infrastructure**: PostgreSQL database (accessed via R2DBC), MinIO for object storage (images/attachments), Redis, Docker registry (`hub.technobeesolutions.in`).

## Core Features & Architecture

### 1. Accounting System
- **Double-Entry Principle**: Strict double-entry accounting is mandated. Every financial entry must balance. 
  - *Example*: Interest/bank fees on a Credit Card are recorded as a transfer: `From: CC -> To: Expense (Bank Charges/Interest)`.
- **Entities**: The core entities are `Wallet` (which represents all forms of accounts/ledgers) and `Transaction`.
- **Account Types (Natures)**: Accounts are categorized by `nature` (e.g., SAVINGS, INCOME, EXPENSE, PAYABLES, INVESTMENTS) and further specialized by `sub_nature`.
- **Payables**: Specialized support for Credit Cards, Overdrafts (OD), EMIs, and Policy Premiums. Features configurable cycle dates, credit limits, and fixed amounts for recurring dues.
- **Dashboard**: Features an `UpcomingDuesWidget` that proactively calculates and displays urgent dues based on cycle dates and negative balances.

### 2. Inventory Management
- Supports Products, Categories, Unit of Measure (UOM), and Bills of Material (BOM).
- Product pricing can follow auto-calculated rules.
- Images are uploaded as Multipart form data, converted to Base64 in the backend, and sent to MinIO.

### 3. Vendor & Purchase Orders (Current Focus)
- Active development on Vendor Management, Purchase Orders, and Purchase Payments. 

## Important Technical Rules & Conventions
1. **R2DBC Limitations**: Because R2DBC is fully reactive, it does not automatically fetch relations (no lazy loading like Hibernate). Transient relational fields (e.g. `@Transient List<ProductImage> images` in `Product`) MUST be manually populated in the Service layers using `Mono.zip` or `flatMap` before returning to the controller.
2. **API Routing (kifi vs kifi-v2)**: The application is migrating to a new reactive backend. New endpoints are mapped under `/api/kifi-v2/` (e.g., `/api/kifi-v2/inventory/products`), while some legacy mobile integrations might still point to `/api/kifi/` (e.g., transactions). Pay close attention to Base URL configurations in `DioClient` vs hardcoded URLs in UI widgets.
3. **Payload Limits**: `spring.codec.max-in-memory-size` is set to `10MB` in `application.yml` to prevent `DataBufferLimitException` when handling large image uploads/downloads.
4. **Image/Attachment Loading**: The backend reads byte buffers from MinIO (Base64) and decodes them to byte arrays (`byte[]`) to serve over HTTP. Flutter uses `Image.network` (or `NetworkImage`) with Bearer tokens in headers to fetch these secured endpoints.