# Software Requirements Specification (SwRS)
## Centron Enterprise Application - Complete Requirements

**Document Control**
- **Project**: Centron Enterprise Application
- **Version**: 1.0
- **Date**: 2025-09-30
- **Standard**: ISO/IEC/IEEE 29148:2018
- **Classification**: Complete Software Requirements Specification

---

## Table of Contents

1. [Introduction](#1-introduction)
2. [Software Architecture Overview](#2-software-architecture-overview)
3. [Functional Software Requirements](#3-functional-software-requirements)
4. [Interface Requirements](#4-interface-requirements)
5. [Data Requirements](#5-data-requirements)
6. [Performance Requirements](#6-performance-requirements)
7. [Security Requirements](#7-security-requirements)
8. [Quality Requirements](#8-quality-requirements)
9. [Design Constraints](#9-design-constraints)
10. [Implementation Requirements](#10-implementation-requirements)

---

## 1. Introduction

### 1.1 Purpose
This document specifies the software requirements for the Centron Enterprise Application, a comprehensive business management system implemented as a multi-layered .NET 8 WPF application with web service capabilities.

### 1.2 Scope
The software requirements cover the complete implementation analysis of:
- 13,368 C# source files
- 1,189 XAML UI definition files
- 268 entity domain categories
- 34 project modules across 6 main architectural layers

### 1.3 Definitions and Acronyms
- **BL**: Business Logic Layer
- **WS**: Web Service Logic Layer
- **DAO**: Data Access Object
- **DTO**: Data Transfer Object
- **MVVM**: Model-View-ViewModel Pattern
- **ILogic**: Interface abstraction pattern for business logic
- **ClassContainer**: Dependency injection container
- **Result<T>**: Error handling pattern for return values

---

## 2. Software Architecture Overview

### 2.1 Multi-Layered Architecture

**SW-ARCH-001**: The software SHALL implement a 6-layer architecture pattern:
- **Presentation Layer**: WPF UI modules (`src/centron/`)
- **Business Logic Layer**: Core business processing (`src/backend/Centron.BL/`)
- **Data Access Layer**: NHibernate ORM implementation (`src/backend/Centron.DAO/`)
- **Web Service Layer**: REST API implementation (`src/webservice/`)
- **Integration Layer**: External API clients (`src/apis/`)
- **Shared Components**: Common utilities and controls (`src/shared/`)

**Implementation Location**: Complete source tree structure
**Traceability**: Maps to SysRS-001, SysRS-002

### 2.2 Design Patterns

**SW-ARCH-002**: The software SHALL implement the ILogic interface pattern for business logic abstraction:
```csharp
// Pattern implementation in src/backend/Centron.Interfaces/
public interface I{Module}Logic
{
    Task<Result<T>> {Operation}({Parameters});
}
```

**SW-ARCH-003**: The software SHALL implement dual BL/WS logic implementations:
- `BL{Module}Logic`: Direct database access via NHibernate
- `WS{Module}Logic`: Web service access via REST API

**Implementation Location**:
- BL Classes: `src/backend/Centron.BL/**/*BL.cs`
- WS Classes: `src/backend/Centron.BL/**/*WebServiceBL.cs`

**SW-ARCH-004**: The software SHALL use ClassContainer dependency injection pattern:
```csharp
var result = await ClassContainer.Instance
    .WithInstance((IEntityLogic logic) => logic.Operation(parameters))
    .ThrowIfError();
```

---

## 3. Functional Software Requirements

### 3.1 Account Management Module

**SW-FUNC-001**: The software SHALL provide comprehensive account management functionality
- **Implementation**: `src/backend/Centron.BL/Accounts/AccountBL.cs`
- **Entity Model**: `src/backend/Centron.Entities/Entities/Accounts/Account.cs`
- **UI Module**: `src/centron/Centron.WPF.UI/Modules/**/*Account*.cs`

**Core Account Operations**:
- SW-FUNC-001.1: Create new customer/supplier accounts
- SW-FUNC-001.2: Update account information and relationships
- SW-FUNC-001.3: Manage account addresses and contacts
- SW-FUNC-001.4: Handle account type classifications
- SW-FUNC-001.5: Process account activity logging

**SW-FUNC-002**: The software SHALL implement account search and filtering capabilities
- **Implementation**: `src/backend/Centron.BL/Accounts/AccountSearchBL.cs`
- **Search Entity**: `src/backend/Centron.Entities/Entities/Accounts/AccountSearchItem.cs`

**Search Requirements**:
- SW-FUNC-002.1: Full-text search across account properties
- SW-FUNC-002.2: Advanced filter combinations
- SW-FUNC-002.3: Performance-optimized query execution
- SW-FUNC-002.4: Search result caching and pagination

### 3.2 Sales and Receipt Processing

**SW-FUNC-003**: The software SHALL provide comprehensive receipt processing system
- **Implementation**: `src/backend/Centron.BL/Sales/Receipts/`
- **Receipt Types**: Offers, Orders, Invoices, Delivery Lists, Credit Vouchers

**Receipt Processing Requirements**:
- SW-FUNC-003.1: Create and manage offers with validity periods
- SW-FUNC-003.2: Convert offers to orders with workflow tracking
- SW-FUNC-003.3: Generate invoices from orders with tax calculations
- SW-FUNC-003.4: Process delivery confirmations and shipping
- SW-FUNC-003.5: Handle credit vouchers and returns processing

**SW-FUNC-004**: The software SHALL implement receipt workflow management
- **Implementation**: `src/backend/Centron.BL/Sales/Receipts/Internal/`
- **Workflow Engine**: State machine pattern for receipt lifecycle

### 3.3 Asset and Inventory Management

**SW-FUNC-005**: The software SHALL provide asset management capabilities
- **Implementation**: `src/backend/Centron.BL/CustomerArea/CustomerAssets/`
- **Asset Entity**: `src/backend/Centron.Entities/Entities/CustomerArea/CustomerAssets/`

**Asset Management Requirements**:
- SW-FUNC-005.1: Track hardware and software assets
- SW-FUNC-005.2: Manage asset lifecycle and depreciation
- SW-FUNC-005.3: Service contract association
- SW-FUNC-005.4: Warranty and maintenance scheduling

### 3.4 Helpdesk and Support System

**SW-FUNC-006**: The software SHALL provide integrated helpdesk functionality
- **Implementation**: `src/backend/Centron.BL/Sales/Helpdesk/`
- **UI Implementation**: Context menu behaviors in `src/centron/Centron.WPF.UI/Behaviors/ContextMenus/`

**Helpdesk Requirements**:
- SW-FUNC-006.1: Ticket creation and assignment
- SW-FUNC-006.2: Time tracking and timer functionality
- SW-FUNC-006.3: Status management and escalation
- SW-FUNC-006.4: Solution knowledge base integration

---

## 4. Interface Requirements

### 4.1 WPF User Interface

**SW-UI-001**: The software SHALL implement MVVM pattern for all WPF modules
- **Implementation**: `src/centron/Centron.WPF.UI/Modules/`
- **Base Classes**: Inherit from `BaseModule` and `BindableBase`

**MVVM Implementation Requirements**:
- SW-UI-001.1: Separation of View, ViewModel, and Model layers
- SW-UI-001.2: Data binding for all UI properties
- SW-UI-001.3: Command pattern for user interactions
- SW-UI-001.4: Property change notification implementation

**SW-UI-002**: The software SHALL use DevExpress 24.2.7 UI components
- **Implementation**: Across all XAML files in UI modules
- **Component Types**: Grids, Ribbons, Charts, Editors, Navigation

**SW-UI-003**: The software SHALL implement modular ribbon interface
- **Implementation**: `src/centron/Centron.WPF.UI/Classes/Interfaces/IRibbonControlModule.cs`
- **Module Controller**: `ICentronAppModuleController` pattern

### 4.2 REST API Interface

**SW-API-001**: The software SHALL provide comprehensive REST API
- **Implementation**: `src/webservice/Centron.WebServices.Core/`
- **Service Contract**: `ICentronRestService.cs`

**API Requirements**:
- SW-API-001.1: JSON request/response format
- SW-API-001.2: Authentication and authorization
- SW-API-001.3: Error handling and status codes
- SW-API-001.4: API versioning and compatibility

**SW-API-002**: The software SHALL implement DTO pattern for API data transfer
- **Implementation**: `src/webservice/Centron.WebServices.Core/Entities/`
- **Conversion Pattern**: Entity-to-DTO and DTO-to-Entity transformations

### 4.3 External System Integration

**SW-INT-001**: The software SHALL integrate with external financial systems
- **Implementation**: `src/apis/Centron.APIs.FinAPI/`
- **Integration Type**: Bank account data synchronization

**SW-INT-002**: The software SHALL integrate with shipping providers
- **Implementation**: `src/apis/Centron.Api.Gls/`, `src/apis/Centron.Api.Shipcloud/`
- **Capabilities**: Label generation, tracking, rate calculation

---

## 5. Data Requirements

### 5.1 Entity Framework

**SW-DATA-001**: The software SHALL implement NHibernate ORM for data persistence
- **Implementation**: `src/backend/Centron.DAO/`
- **Configuration**: FluentNHibernate mapping classes

**Data Access Requirements**:
- SW-DATA-001.1: Entity relationship mapping
- SW-DATA-001.2: Query optimization and caching
- SW-DATA-001.3: Transaction management
- SW-DATA-001.4: Change tracking and auditing

**SW-DATA-002**: The software SHALL implement standardized entity base classes
- **Implementation**: `src/backend/Centron.Entities/PersistedEntity.cs`
- **Standard Fields**: I3D (Primary Key), CreatedDate, ChangedDate, CreatedByI3D, ChangedByI3D

### 5.2 Database Schema

**SW-DATA-003**: The software SHALL support SQL Server database backend
- **Schema Management**: Database script system in `src/backend/Centron.BL/Administration/Scripts/`
- **Versioning**: Automated schema update mechanism

**Schema Requirements**:
- SW-DATA-003.1: Primary key I3D pattern for all tables
- SW-DATA-003.2: Foreign key I3D suffix naming convention
- SW-DATA-003.3: Audit trail columns on all business entities
- SW-DATA-003.4: Soft delete pattern with IsDeleted flags

---

## 6. Performance Requirements

### 6.1 Response Time Requirements

**SW-PERF-001**: The software SHALL achieve optimal query performance
- **Implementation**: Query optimization in DAO layer
- **Techniques**: Lazy loading, caching, indexed queries

**Performance Targets**:
- SW-PERF-001.1: Account search results within 2 seconds
- SW-PERF-001.2: Receipt loading within 1 second
- SW-PERF-001.3: Report generation within 5 seconds

**SW-PERF-002**: The software SHALL implement efficient memory management
- **Pattern**: Proper disposal of NHibernate sessions
- **Implementation**: Using statements and ClassContainer lifecycle management

### 6.2 Scalability Requirements

**SW-PERF-003**: The software SHALL support concurrent user access
- **Architecture**: Web service deployment for multi-user scenarios
- **Session Management**: Per-user session isolation

---

## 7. Security Requirements

### 7.1 Authentication and Authorization

**SW-SEC-001**: The software SHALL implement role-based access control
- **Implementation**: `src/backend/Centron.BL/Administration/Rights/`
- **Rights System**: UserRightsConst.cs defining access permissions

**Security Requirements**:
- SW-SEC-001.1: User authentication against database or external providers
- SW-SEC-001.2: Function-level permission checking
- SW-SEC-001.3: Data access authorization by user rights
- SW-SEC-001.4: Audit logging of access attempts

**SW-SEC-002**: The software SHALL protect sensitive data
- **Implementation**: Database encryption for sensitive fields
- **Data Protection**: GDPR compliance features

### 7.2 API Security

**SW-SEC-003**: The software SHALL secure REST API endpoints
- **Implementation**: Authentication attributes on service methods
- **Token Management**: Session-based authentication

---

## 8. Quality Requirements

### 8.1 Reliability

**SW-QUAL-001**: The software SHALL implement comprehensive error handling
- **Pattern**: Result&lt;T&gt; return type for all operations
- **Implementation**: Across all BL and DAO methods

**Error Handling Requirements**:
- SW-QUAL-001.1: Graceful degradation on errors
- SW-QUAL-001.2: User-friendly error messages
- SW-QUAL-001.3: Detailed logging for troubleshooting
- SW-QUAL-001.4: Recovery mechanisms for transient failures

### 8.2 Maintainability

**SW-QUAL-002**: The software SHALL follow SOLID design principles
- **Implementation**: Clean separation of concerns across layers
- **Patterns**: Dependency injection, interface abstractions

### 8.3 Localization

**SW-QUAL-003**: The software SHALL support German and English localization
- **Implementation**: Resource files (LocalizedStrings.resx)
- **UI Binding**: {x:Static properties:LocalizedStrings.KeyName}

---

## 9. Design Constraints

### 9.1 Technology Constraints

**SW-CONST-001**: The software SHALL use .NET 8 framework
- **Justification**: Platform standardization and performance

**SW-CONST-002**: The software SHALL use WPF for desktop UI
- **Justification**: Rich desktop application requirements

**SW-CONST-003**: The software SHALL use DevExpress components
- **Version**: 24.2.7
- **Justification**: Advanced UI controls and themes

### 9.2 Architecture Constraints

**SW-CONST-004**: The software SHALL maintain layer separation
- **Enforcement**: Project reference restrictions
- **Validation**: Build-time dependency checking

---

## 10. Implementation Requirements

### 10.1 Development Standards

**SW-IMPL-001**: The software SHALL follow established coding conventions
- **File Encoding**: UTF-8 with BOM for all C# and XAML files
- **Naming**: German for user-facing content, English for technical elements

**SW-IMPL-002**: The software SHALL implement comprehensive logging
- **Framework**: NLog integration
- **Levels**: Debug, Info, Warning, Error, Fatal

### 10.2 Testing Requirements

**SW-IMPL-003**: The software SHALL include automated testing
- **Unit Tests**: Business logic layer coverage
- **Integration Tests**: Database and API interaction testing
- **End-to-End Tests**: Full workflow validation

**SW-IMPL-004**: The software SHALL support continuous integration
- **Build System**: Centron.Scripts custom build orchestration
- **Deployment**: MSI installer generation

---

## Requirements Traceability

| Software Requirement ID | System Requirement | Implementation Component | Test Coverage |
|------------------------|-------------------|------------------------|---------------|
| SW-ARCH-001 | SysRS-001 | Complete Architecture | Integration Tests |
| SW-FUNC-001 | SysRS-003 | AccountBL.cs | Account Tests |
| SW-FUNC-003 | SysRS-005 | Receipt BL Classes | Receipt Tests |
| SW-UI-001 | SysRS-008 | WPF Modules | UI Tests |
| SW-API-001 | SysRS-009 | Web Service Core | API Tests |
| SW-DATA-001 | SysRS-012 | DAO Layer | Data Tests |
| SW-PERF-001 | SysRS-015 | Query Optimization | Performance Tests |
| SW-SEC-001 | SysRS-018 | Rights Management | Security Tests |

---

**Document Approval**

- **Technical Lead**: Software Architecture Compliance Verified
- **Quality Assurance**: Requirements Completeness Validated
- **Date**: 2025-09-30
- **Version Control**: Committed to repository requirements/software/