# CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

## Overview

Invoice Az is a Frappe application that integrates with Azerbaijan's e-taxes.gov.az system for:
- Downloading and importing purchase invoices from e-taxes
- Downloading and importing sales invoices from e-taxes
- Sending sales invoices to e-taxes with ASAN Imza signing
- Importing VAT Account operations and creating Journal Entries
- Managing authentication via ASAN Login with automatic token renewal

## Development Commands

### Linting and Code Quality
```bash
# Run ruff for Python linting
ruff check invoice_az/

# Run ruff format
ruff format invoice_az/

# Run pre-commit hooks (includes ruff, eslint, prettier, pyupgrade)
pre-commit run --all-files
```

### Testing
```bash
# Run unit tests for a specific doctype
bench run-tests --app invoice_az --doctype "E-Taxes Item"

# Run all tests for the app
bench run-tests --app invoice_az
```

### Development
```bash
# Clear cache after making changes
bench clear-cache

# Restart workers after API changes
bench restart

# Watch logs
bench --site [site-name] console
```

## Architecture

### Core Modules

1. **Authentication Module** (`invoice_az/auth.py`)
   - ASAN Login integration for Azerbaijan government authentication
   - Token management with automatic renewal every 4 minutes via cron job
   - Activity tracking to prevent unnecessary token renewals
   - Retry logic with exponential backoff for failed requests
   - Token validity checking and automatic refresh on 401 errors
   - Full authentication flow: start auth → poll status → get certificates → select taxpayer
   - Key functions: `renew_token()`, `get_auth_token()`, `check_auth_status()`, `get_certificates()`, `choose_taxpayer()`, `check_token_validity()`, `handle_unauthorized_request()`, `handle_authentication()`, `poll_auth_status()`, `select_certificate()`, `select_taxpayer()`

2. **Purchase API** (`invoice_az/api.py`)
   - Download and import purchase invoices from e-taxes
   - Party, item, and unit mapping system
   - Separate Customer and Supplier mapping systems
   - Create Purchase Orders and Purchase Invoices
   - E-Taxes Purchase tracking records
   - Reference data management (sync items, units, parties from e-taxes)
   - Batch invoice processing for loading reference data
   - Auto-matching for items, units, customers, suppliers by name similarity

3. **Sales Import API** (`invoice_az/sales_api.py`)
   - Download and import sales invoices from e-taxes outbox
   - Customer mapping system (separate from suppliers)
   - Create Sales Orders and Sales Invoices
   - E-Taxes Sales tracking records
   - Azerbaijani character normalization for matching

4. **Sales Send API** (`invoice_az/send_sales_api.py`)
   - Send Sales Invoices to e-taxes system
   - Two-step workflow: create draft, then sign with ASAN Imza
   - Generate serial numbers from e-taxes
   - Build invoice payload with product codes and VAT fields
   - E-Taxes Sales Outbox tracking
   - Cancel/remove draft invoices functionality
   - Retry signing for failed/pending invoices
   - Get customer objects by TIN for delivery address selection

5. **VAT Operations API** (`invoice_az/vat_api.py`)
   - Import VAT Account operations from e-taxes
   - Import all operations (both income and expense types)
   - Create Journal Entries with configurable account mappings
   - VAT Account Mappings by operation type and expense/income type (Sub uçot hesabı → Sub uçot hesabı, Sub uçot hesabı → Büdcə, etc.)
   - Classification Code support - allows specific account mappings per tax code with priority:
     - Priority 1: Mapping with matching operation_type + expense_income + classification_code
     - Priority 2: Default mapping with matching operation_type + expense_income (empty classification_code)
   - Required mapping configuration - operation fails with error if mapping not found
   - Smart party assignment: adds Customer/Supplier only for Receivable/Payable accounts
   - Customer lookup by TIN
   - E-Taxes VAT Operations tracking
   - Key functions: `get_accounts_for_operation_type()`, `find_account_by_number()`, `create_journal_entry_from_vat_operation()`, `map_operation_type()`

6. **VAT Operations Hooks** (`invoice_az/vat_operations.py`)
   - Delete related E-Taxes VAT Operations when Journal Entry is deleted/cancelled

### Document Integration (hooks.py)

**Extended Doctypes:**
- Purchase Order - import from e-taxes, delete hooks
- Purchase Invoice - import from e-taxes
- Sales Order - import from e-taxes, delete hooks
- Sales Invoice - send to e-taxes, delete hooks
- Journal Entry - import VAT operations, delete hooks
- E-Taxes Settings - on_update hook to sync mapped statuses

**Client-side Scripts (`invoice_az/client/`):**
- `purchase_order.js` - E-taxes import buttons and dialogs
- `purchase_invoice.js` - E-taxes import functionality
- `sales_order.js` - E-taxes import buttons and dialogs
- `sales_invoice.js` - Send to e-taxes, sign document, retry signing, cancel buttons
- `journal_entry.js` - VAT operations import functionality with operation type display
- `e_taxes_items_list.js` - Sync items from e-taxes
- `e_taxes_suppliers_list.js` - Sync suppliers from e-taxes
- `e_taxes_customers_list.js` - Sync customers from e-taxes
- `e_taxes_unit_list.js` - Sync units from e-taxes
- `etaxes_common.js` - Shared utilities

### Database Schema

**Authentication:**
- **Asan Login** - Stores ASAN credentials, tokens, certificates, auth status

**Settings:**
- **E-Taxes Settings** - Global settings, status mappings, item/party/customer/supplier/VAT account mappings

**E-Taxes Entities (cached from e-taxes):**
- **E-Taxes Item** - Products/services from e-taxes with EQM codes
- **E-Taxes Parties** - All parties (legacy, for purchases)
- **E-Taxes Suppliers** - Supplier companies for purchases
- **E-Taxes Customers** - Customer companies for sales
- **E-Taxes Unit** - Units of measurement
- **E-Taxes Item Group** - Product group codes (fixtures)
- **Classification code** - Tax classification codes from e-taxes (code and description)

**Mapping Tables:**
- **E-Taxes Item Mapping** - Links ERPNext Items to e-taxes items
- **E-Taxes Party Mapping** - Links ERPNext parties to e-taxes parties (legacy)
- **E-Taxes Supplier Mappings** - Links ERPNext Suppliers to e-taxes suppliers
- **E-Taxes Customer Mappings** - Links ERPNext Customers to e-taxes customers
- **E-Taxes Unit Mapping** - Links ERPNext UOM to e-taxes units
- **E-Taxes VAT Account Mapping** - Maps VAT operation types to Chart of Accounts (debit/credit), with expense/income type and optional classification code filtering

**Tracking Records:**
- **E-Taxes Purchase** - Tracks imported purchase documents
- **E-Taxes Sales** - Tracks imported sales documents (from e-taxes)
- **E-Taxes Sales Outbox** - Tracks sent sales invoices (to e-taxes)
- **E-Taxes VAT Operations** - Tracks imported VAT operations

### Key Features

- **Token Renewal**: Automatic token renewal via scheduler (every 4 minutes) with activity check
- **Token Validity Check**: Verify token validity before API calls, auto-refresh on 401 errors
- **Activity Tracking**: Records user activity to optimize token renewals
- **Entity Mapping**: Maps ERPNext items, parties, suppliers, customers, and units to e-taxes equivalents
- **Auto-Matching**: Automatic matching of items, units, customers, suppliers by name similarity
- **Bulk Operations**: Support for syncing multiple entities at once
- **Batch Processing**: Load reference data from invoices in batches
- **Error Handling**: Comprehensive error logging and user-friendly error messages
- **Azerbaijani Support**: Character normalization for Ə, Ü, Ö, Ğ, İ, Ç, Ş characters
- **Two-step Signing**: Create draft invoice, then sign with ASAN Imza
- **Retry Signing**: Retry signing for failed/pending invoices
- **VAT Import**: Import VAT account operations as Journal Entries with configurable account mappings
- **VAT Account Mappings**: Configure debit/credit accounts by operation type and expense/income type (Sub uçot hesabı → Sub uçot hesabı, Sub uçot hesabı → Büdcə, etc.)
- **Smart Party Assignment**: Automatically adds party (Customer/Supplier) only for Receivable/Payable accounts

### API Endpoints (E-Taxes)

**Base URL:** `https://new.e-taxes.gov.az`

- `/api/po/auth/public/v1/*` - Authentication endpoints
- `/api/po/invoice/public/v2/invoice/find.inbox` - Purchase invoices
- `/api/po/invoice/public/v2/invoice/find.outbox` - Sales invoices (sent)
- `/api/po/invoice/public/v2/invoice` - Create invoice
- `/api/po/invoice/public/v1/invoice/sign/withAsanImza` - Sign invoice
- `/api/po/invoice/public/v1/generateSerialNumber/defaultInvoice` - Generate serial
- `/api/po/invoice/public/v1/common/removeDrafts` - Remove draft invoices
- `/api/po/vatacc/public/v1/operation/find.outbox` - VAT operations
- `/api/po/profile/public/v1/taxpayer/{tin}/object/find` - Customer objects
- `/api/po/dictionary/public/v1/productGroups/find` - Product groups dictionary

### Fixtures

- **E-Taxes Item Group** - Pre-populated product group codes

### Install Hooks

- `after_install` and `after_migrate` both call `setup_token_renewal()` to ensure scheduler is configured

### Security Considerations

- All API endpoints are whitelisted with `@frappe.whitelist()`
- Token storage uses Frappe's password field type
- Activity tracking prevents unnecessary API calls
- Retry logic includes exponential backoff to prevent API flooding
- Automatic token refresh on 401 errors

### Important Files

- `invoice_az/hooks.py` - App configuration, event hooks, scheduler setup, and fixtures (~310 lines)
- `invoice_az/auth.py` - Authentication and token management (~970 lines)
- `invoice_az/api.py` - Purchase invoice API and reference data management (~4460 lines)
- `invoice_az/sales_api.py` - Sales invoice import API (~890 lines)
- `invoice_az/send_sales_api.py` - Sales invoice send API (~1060 lines)
- `invoice_az/vat_api.py` - VAT operations import API (~620 lines)
- `invoice_az/vat_operations.py` - VAT operations hooks (~40 lines)
- `invoice_az/client/*.js` - Client-side functionality for UI enhancements
- `invoice_az/invoice_az/doctype/*/` - Custom doctype definitions
- `invoice_az/fixtures/e_taxes_item_group.json` - Item group fixtures

### Workflow: Importing Purchases

1. User opens Purchase Order/Invoice list
2. Clicks "Import from E-Taxes" button
3. System fetches invoices from e-taxes inbox
4. User selects invoice to import
5. System validates mappings (items, suppliers, units)
6. Creates Purchase Order with items
7. Creates E-Taxes Purchase tracking record

### Workflow: Importing Sales (from E-Taxes)

1. User opens Sales Order list
2. Clicks "Import from E-Taxes" button
3. System fetches invoices from e-taxes outbox
4. User selects invoice to import
5. System validates mappings (items, customers, units)
6. Creates Sales Order and Sales Invoice
7. Creates E-Taxes Sales tracking record

### Workflow: Sending Sales Invoice to E-Taxes

1. User creates and submits Sales Invoice
2. Fills customer_object_name field (required for delivery address)
3. Clicks "Send to E-Taxes" button
4. System generates serial number
5. Creates draft invoice on e-taxes
6. User clicks "Sign Document" button
7. System signs with ASAN Imza
8. E-Taxes Sales Outbox record updated

**Retry/Cancel:**
- If signing fails, user can click "Retry Signing" button
- User can cancel draft invoice using "Cancel on E-Taxes" button

### Workflow: Importing VAT Operations

1. User opens Journal Entry list
2. Clicks "Import VAT from E-Taxes" button
3. Selects date range
4. System fetches all VAT operations (both income and expense types)
5. System shows operation selection dialog with columns:
   - Date, TIN, Name, Operation Type, Classification Code, Amount
6. Creates Journal Entries using account mappings:
   - API returns technical operation types (SUB_TO_SUB, etc.) which are mapped to Azerbaijani names
   - API returns taxCodeInfo with code (e.g., "114117") and description
   - Looks up mapping in E-Taxes Settings with priority:
     - First: operation_type + classification_code (if taxCodeInfo.code exists)
     - Second: operation_type + empty classification_code (default mapping)
   - If mapping not found, operation fails with error (shown in error log)
   - Automatically adds party (Customer) only if account type is Receivable/Payable
   - Supports different debit/credit accounts for different operation types and classification codes
7. Creates E-Taxes VAT Operations tracking records

**VAT Account Mapping Configuration:**
- Configure in E-Taxes Settings > VAT Account Mappings tab
- Each mapping specifies: operation type, expense/income type (required), classification code (optional), debit account, credit account
- Expense/Income field: Select "Expense" or "Income" to distinguish between expense and income operations
- Classification Code field links to Classification code doctype
- Uniqueness: Each combination of operation_type + expense_income + classification_code must be unique
- Priority logic:
  - System determines expense/income type from API data (income > 0 → Income, expense > 0 → Expense)
  - If classification_code is set: mapping applies only to operations with matching taxCodeInfo.code
  - If classification_code is empty: mapping is default for this operation type
  - System searches with priority: specific classification_code first, then default (empty)
  - All searches include expense_income filter
- Supported operation types:
  - Sub uçot hesabı → Sub uçot hesabı (SUB_TO_SUB in API)
  - Naməlum → digər Sub hesab (UNKNOWN_TO_OTHER_SUB in API)
  - Cari → Sub uçot hesabı (CURRENT_TO_SUB in API)
  - Cari → Naməlum (CURRENT_TO_UNKNOWN in API)
  - Sub uçot hesabı → İdxal (SUB_TO_IMPORT in API)
  - Naməlum → İdxal (UNKNOWN_TO_IMPORT in API)
  - Sub uçot hesabı → Büdcə (SUB_TO_BUDGET and AUTO in API)
  - Naməlum → Büdcə (UNKNOWN_TO_BUDGET in API)

**Note:** AUTO operation types from API are automatically mapped to "Sub uçot hesabı → Büdcə" (SUB_TO_BUDGET).