# System Architecture Documentation (C4 Model)

_This document follows the C4 model for software architecture documentation, focusing on Context, Container, and Component levels._

## 1. System Context (C4 Level 1)

### System Overview

<!-- Brief description of what the system does and its primary purpose -->

### Users and Personas

<!-- Who uses this system? -->

- **[User Type 1]**: Description of user type and their needs
- **[User Type 2]**: Description of user type and their needs

### External Systems

<!-- What external systems does this system interact with? -->

- **[External System 1]**: Purpose and interaction type
- **[External System 2]**: Purpose and interaction type

### System Boundaries

<!-- What is inside vs outside the system boundary? -->

- **Inside the system**:
- **Outside the system**:

### Context Diagram

<!-- Describe or reference a C4 Context diagram showing the system and its environment -->

## 2. Container Architecture (C4 Level 2)

### Container Overview

<!-- High-level containers that make up the system -->

#### [Container Name 1]

- **Technology**:
- **Responsibilities**:
- **Interfaces**:
- **Data Storage**:

#### [Container Name 2]

- **Technology**:
- **Responsibilities**:
- **Interfaces**:
- **Data Storage**:

### Container Interactions

<!-- How do containers communicate with each other? -->

- **[Container A] → [Container B]**: Communication method and purpose
- **[Container B] → [External System]**: Communication method and purpose

### Deployment Architecture

<!-- How are containers deployed? -->

- **Environment**:
- **Infrastructure**:
- **Scaling**:

### Container Diagram

<!-- Describe or reference a C4 Container diagram showing the containers and their relationships -->

## 3. Component Architecture (C4 Level 3)

### Component Analysis by Container

#### [Container Name 1] Components

##### [Component Name 1]

- **Responsibilities**:
- **Interfaces**:
- **Dependencies**:
- **Design Patterns**:

##### [Component Name 2]

- **Responsibilities**:
- **Interfaces**:
- **Dependencies**:
- **Design Patterns**:

#### [Container Name 2] Components

##### [Component Name 3]

- **Responsibilities**:
- **Interfaces**:
- **Dependencies**:
- **Design Patterns**:

### Component Interactions

<!-- How do components within containers interact? -->

- **[Component A] → [Component B]**: Interaction type and purpose
- **[Component C] → [External Interface]**: Interaction type and purpose

### Component Diagrams

<!-- Describe or reference C4 Component diagrams for each significant container -->

## 4. Architecture Decisions

### Key Architectural Decisions

<!-- Important architectural decisions made during analysis -->

#### Decision 1: [Decision Title]

- **Context**:
- **Decision**:
- **Rationale**:
- **Consequences**:

#### Decision 2: [Decision Title]

- **Context**:
- **Decision**:
- **Rationale**:
- **Consequences**:

### Technology Choices

<!-- Why were specific technologies chosen? -->

- **[Technology 1]**: Rationale for choice
- **[Technology 2]**: Rationale for choice

## 5. Quality Attributes

### Performance Characteristics

<!-- How does the system perform? -->

- **Response Times**:
- **Throughput**:
- **Scalability**:

### Security Considerations

<!-- What security measures are in place? -->

- **Authentication**:
- **Authorization**:
- **Data Protection**:

### Reliability and Availability

<!-- How reliable is the system? -->

- **Uptime Requirements**:
- **Error Handling**:
- **Recovery Mechanisms**:

## 6. Enhancement Recommendations

### Modernization Opportunities

<!-- Based on the analysis, what modernization opportunities exist? -->

- **[Opportunity 1]**: Description and benefits
- **[Opportunity 2]**: Description and benefits

### Technical Debt

<!-- What technical debt was identified? -->

- **[Debt Item 1]**: Impact and recommended resolution
- **[Debt Item 2]**: Impact and recommended resolution

### API Testing Strategy

<!-- Recommendations for end-to-end API testing -->

- **External APIs**: Testing approach for external interfaces
- **Internal APIs**: Testing approach for internal interfaces
- **Test Data**: Strategy for test data management

### Enhancement Readiness

<!-- How ready is the system for enhancements? -->

- **Documentation Quality**:
- **Code Quality**:
- **Test Coverage**:
- **Development Environment**:

## 7. References and Resources

### Discovery Notes

- Reference to DISCOVERY.md file with detailed analysis notes

### Existing Documentation

<!-- Links to any existing documentation that was found -->

- **[Document 1]**: Description and relevance
- **[Document 2]**: Description and relevance

### Analysis Artifacts

<!-- Other artifacts created during the analysis -->

- **Component Analysis**: Detailed component analysis notes
- **Interface Documentation**: API and interface specifications
- **Data Flow Diagrams**: Data flow analysis results

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_This architecture documentation was created through systematic legacy system analysis using the C4 methodology. It provides the foundation for coherent system enhancements and modernization efforts._
