DeclarationTVA/PLANNING.md

DeclarationTVA - French CA-3 VAT Declaration Module

Project Overview

This Dolibarr module creates the French VAT declaration CA-3 (Déclaration de TVA CA3) with PCG account mapping functionality. The module allows users to configure PCG (Plan Comptable Général) accounts for each CA-3 box and generates the appropriate VAT declaration.

Architecture

Core Components

• Module Class: modDeclarationTVA.class.php - Main module descriptor
• Setup Interface: admin/setup.php - Configuration page for PCG account mapping
• Database Schema: sql/dolibarr_allversions.sql - Database structure
• Language Support: Bilingual (French/English) interface
• Main Interface: declarationtvaindex.php - Main module page

CA-3 Box Structure

The module handles the following CA-3 boxes:

Box	Label	Description	PCG Accounts
01	Livraisons de biens et prestations de services imposables en France	Domestic sales at 20% (or reduced rates)	7xxxx (Sales) → 44571x (TVA collectée à 20%), 44572x (10%), 44573x (5,5%), 44574x (2,1%)
02	Autres opérations imposables	Other taxable domestic operations	Same 4457xx depending on rate
03	Acquisitions intracommunautaires	Intra-EU purchases (autoliquidation)	Base: 6xxxx purchases / 2xxxx immobilisations. VAT due: 4452xxx (TVA due intracom)
05	Importations	Imports from outside EU	4452xxx (TVA due sur importations)
08	Autres opérations imposables	Specific operations (reverse charge on services, etc.)	4452xxx

Technical Requirements

Database Structure

• Main table: llx_declarationtva_config - Stores PCG account mappings
• Declaration table: llx_declarationtva_declarations - Stores generated declarations
• Period table: llx_declarationtva_periods - Manages declaration periods

Key Features

1. PCG Account Configuration: Setup page to map PCG accounts to CA-3 boxes
2. Period Management: Handle quarterly/monthly declaration periods
3. Data Extraction: Query Dolibarr accounting data based on PCG mappings
4. Declaration Generation: Create CA-3 format declarations
5. Export Functionality: Export to various formats (PDF, XML, CSV)
6. Bilingual Interface: French and English language support

File Structure

declarationtva/
├── admin/
│   ├── setup.php (Enhanced with PCG configuration)
│   └── about.php
├── core/
│   ├── modules/modDeclarationTVA.class.php
│   └── class/
│       ├── declarationtva.class.php
│       ├── declarationtva_config.class.php
│       └── declarationtva_period.class.php
├── lib/
│   └── declarationtva.lib.php
├── langs/
│   ├── en_US/declarationtva.lang
│   └── fr_FR/declarationtva.lang
├── sql/
│   └── dolibarr_allversions.sql
├── templates/
│   └── declarationtva/
│       ├── ca3_form.tpl
│       └── ca3_pdf.tpl
└── declarationtvaindex.php

Development Phases

Phase 1: Foundation (Week 1-2)

• Database schema design and implementation
• Core class structure
• Basic module setup and configuration

Phase 2: Configuration Interface (Week 3-4)

• PCG account mapping interface
• Period management
• User permissions and access control

Phase 3: Data Processing (Week 5-6)

• Accounting data extraction
• CA-3 calculation logic
• Data validation and error handling

Phase 4: User Interface (Week 7-8)

• Main declaration interface
• Period selection and management
• Declaration preview and editing

Phase 5: Export and Reporting (Week 9-10)

• PDF generation
• XML export for tax authorities
• CSV export for analysis

Phase 6: Testing and Documentation (Week 11-12)

• Unit testing
• Integration testing
• User documentation
• French tax compliance validation

Success Criteria

1. Functional Requirements

   • Complete CA-3 form generation
   • Accurate PCG account mapping
   • Proper period management
   • Export functionality

2. Technical Requirements

   • Dolibarr compatibility (v19+)
   • Bilingual interface (FR/EN)
   • Database integrity
   • Performance optimization

3. Compliance Requirements

   • French tax authority format compliance
   • Data accuracy and validation
   • Audit trail maintenance

Risk Mitigation

1. Tax Compliance: Regular validation with French tax requirements
2. Data Accuracy: Comprehensive testing with real accounting data
3. Performance: Optimization for large datasets
4. User Experience: Intuitive interface for non-technical users

Future Enhancements

1. Automated Submission: Direct submission to tax authorities
2. Advanced Analytics: VAT analysis and reporting
3. Multi-Entity Support: Support for multiple companies
4. Integration: Enhanced integration with other Dolibarr modules