# GUIDE
This document outlines the technical architecture and organization of the project. It details the high-level architectural design, the rationale behind the codebase structure, descriptions of key functional components, and illustrates primary data flows within the system. The aim is to provide a clear and comprehensive guide for developers and architects involved with the project.
# FORMAT
## Title: [Application/Website Name]
app_ver: [app_ver]
doc_ver: [doc_ver]
## 1. Architecture Overview
[Explanation of the overall architecture model (e.g., Microservices, Monolithic, Layered). Brief description of the main parts of the system and their high-level relationships. Can include a high-level architecture diagram (if available).]
## 2. Project Structure
[Brief overview of how the directory structure organizes the codebase and the reasoning behind this organization.]
### Directory Tree
A/
├── B/
│   ├── C/        # [Brief explanation]
│   │   ├── C1/   # [Brief explanation]
│   │   └── C2/   # [Brief explanation]
│   ├── D/        # [Brief explanation]
│   │   ├── D1/   # [Brief explanation]
### Structure Explanation
[More detailed explanation of the roles and responsibilities of the main layers and directories. Why this structure was chosen.]
## 3. Key Components
### [Numerical order]. [Component Name]
* **Description:** [Detailed description of the component's function and responsibilities.]
* **Location in Directory Tree (if relevant):** [Directory path]
* **Dependencies:** [List of components this component depends on]
* **Interactions with Other Components:** [Description of how this component interacts with other parts of the system.]
## 4. Main Data Flow
[Description of the most important data flows in the system, such as user creation flow, order processing flow. Can use a Mermaid diagram for visualization.]
```
[mermaid flow chart here]
```

---
# CONTENT

## Title: ZEE Quiz Application
app_ver: 1.0.0
doc_ver: A1

## 1. Architecture Overview

### 1.1. System Architecture

The ZEE Quiz Application follows a **modular monolith** architecture with **Domain-Driven Design (DDD)** principles. This approach provides the right balance between maintainability and development velocity while keeping the system simple to deploy and operate.

**Key Architectural Principles:**
- **Domain-Driven Design (DDD)** for clear domain boundaries
- **Clean Architecture** for separation of concerns
- **Container-First** design for cloud-native deployment

### 1.2. High-Level Architecture

```mermaid
graph TD
    Client[Web Client] --> HTTP[HTTP Transport Layer]
    HTTP --> Handler[Request Handlers]
    Handler --> Service[Business Services]
    
    subgraph Internal Resources
        Service --> User[User Resource]
        Service --> Role[Role Resource]
    end
    
    subgraph Infrastructure
        User --> DB[(PostgreSQL)]
        Role --> DB
        User --> Cache[(Redis)]
        Service --> Logger[Logger]
    end
    
    subgraph Helpers
        Handler --> Config[Config Helper]
        Service --> Feature[Feature Flags]
        DB --> DBUtil[Database Utils]
    end
```

**Component Responsibilities:**

1. **Transport Layer**
   - HTTP request/response handling
   - Route management
   - Middleware (auth, logging, etc.)
   - DTO validation

2. **Business Services**
   - Core business logic implementation
   - Transaction management
   - Resource coordination
   - Event handling

3. **Internal Resources**
   - User management
   - Role and permissions
   - Domain logic encapsulation

4. **Infrastructure**
   - PostgreSQL for persistent storage
   - Redis for caching
   - Structured logging

5. **Helper Utilities**
   - Configuration management
   - Database utilities
   - Feature flag management
   - Common helper functions

## 2. Project Structure

### 2.1. Directory Structure

```
zee/
├── cmd/                      # Application entry points
│   └── app/                  # Main application server
│
├── configs/                  # Configuration files
│
├── docs/                     # Documentation files
│
├── internal/                 # Private application code
│   ├── adapter/              # External adapters
│   │   └── postgres/         # PostgreSQL adapter
│   ├── helper/               # Helper utilities
│   │   ├── config/          # Configuration helpers
│   │   ├── database/        # Database utilities
│   │   ├── feature/         # Feature flags
│   │   └── logger/          # Logging utilities
│   ├── pkg/                  # Internal packages
│   │   └── lifecycle/       # Application lifecycle
│   ├── resource/             # Domain resources
│   │   ├── role/           # Role management
│   │   └── user/           # User management
│   ├── service/              # Business services
│   └── transport/            # Transport layer
│       └── http/            # HTTP handlers
│           ├── dto/        # Data transfer objects
│           ├── handler/    # Request handlers
│           └── middleware/ # HTTP middleware
│
├── migrations/              # Database migrations
│
└── templates/               # Template files
│   ├── interfaces/        # Interface adapters
│   │   ├── http/          # HTTP handlers
│   │   │   ├── v1/        # API v1 routes
│   │   │   └── middleware # HTTP middleware
│   │   └── repository/    # Repository implementations
│   │
│   └── pkg/              # Shared packages
│       ├── auth/          # Authentication
│       ├── logger/        # Logging
│       └── validator/     # Input validation
│
├── pkg/                   # Public packages
│   ├── errors/            # Common errors
│   └── uuid/              # UUID utilities
│
├── migrations/           # Database migrations
├── web/                   # Frontend assets
├── configs/               # Configuration files
├── scripts/               # Utility scripts
├── .github/               # GitHub workflows
├── docs/                  # Documentation
├── go.mod                 # Go module definition
└── Makefile               # Common tasks
```

### 2.2. Structure Explanation

- **cmd/api**: Contains the application's entry point and server setup
- **internal/domain**: Core domain models and business logic (DDD)
- **internal/application**: Application services and use cases
- **internal/interfaces**: Adapters for external communication (HTTP, repositories)
- **internal/pkg**: Shared infrastructure code
- **pkg**: Public reusable packages
- **migrations**: Database schema migrations
- **web**: Frontend assets and templates
- **configs**: Configuration files for different environments

## 3. Key Components

### 3.1. API Gateway
* **Description**: Single entry point for all client requests
* **Location**: `internal/interfaces/http`
* **Dependencies**: Application services, Authentication, Rate limiting
* **Responsibilities**:
  - Request/response handling
  - Authentication & Authorization
  - Request validation
  - Rate limiting
  - CORS handling

### 3.2. User Management
* **Description**: Handles user registration, authentication, and profile management
* **Location**: `internal/domain/user`, `internal/application/commands/user`
* **Dependencies**: JWT, Password hashing, Email service
* **Key Features**:
  - User registration with email verification
  - JWT-based authentication
  - Profile management
  - Role-based access control

### 3.3. Quiz Engine
* **Description**: Core quiz functionality
* **Location**: `internal/domain/quiz`, `internal/application/commands/quiz`
* **Dependencies**: Question repository, User repository
* **Features**:
  - Question management
  - Quiz session handling
  - Timer management
  - Answer validation

### 3.4. Result Processing
* **Description**: Handles quiz results and scoring
* **Location**: `internal/domain/result`, `internal/application/queries/result`
* **Dependencies**: Quiz repository, User repository
* **Features**:
  - Score calculation
  - Leaderboard generation
  - Result caching
  - Analytics

## 4. Main Data Flows

### 4.1. User Registration Flow

```mermaid
sequenceDiagram
    participant C as Client
    participant A as API Gateway
    participant U as User Service
    participant D as Database
    participant E as Email Service

    C->>A: POST /api/v1/register
    A->>U: RegisterUserCommand
    U->>D: Begin Transaction
    U->>D: Check if email exists
    U->>D: Create user
    U->>E: Send verification email
    U->>D: Commit Transaction
    U-->>A: User created
    A-->>C: 201 Created
```

### 4.2. Quiz Submission Flow

```mermaid
sequenceDiagram
    participant C as Client
    participant A as API Gateway
    participant Q as Quiz Service
    participant R as Result Service
    participant D as Database
    participant K as Cache (Redis)

    C->>A: POST /api/v1/quizzes/submit
    A->>Q: SubmitQuizCommand
    Q->>D: Load quiz session
    Q->>Q: Validate answers
    Q->>R: CalculateScoreCommand
    R->>D: Save results
    R->>K: Update leaderboard
    R-->>Q: Score calculated
    Q-->>A: Quiz result
    A-->>C: 200 OK with result
```

## 5. Technology Stack

### 5.1. Backend
- **Language**: Go 1.24.3
- **Web Framework**: Gin-Gonic Router
- **ORM**: GORM
- **Migrations**: GORM Migrate
- **Validation**: go-playground/validator
- **Logging**: zap
- **Configuration**: viper
- **Testing**: testify, gomock

### 5.2. Frontend
- **HTMX** for dynamic UI updates
- **TailwindCSS** for styling
- **Alpine.js** for client-side interactions
- **HTMX Extensions** for advanced functionality

### 5.3. Infrastructure
- **Containerization**: Docker
- **Orchestration**: Docker Compose (local), Kubernetes (production)
- **Database**: PostgreSQL 14
- **Caching**: Redis
- **Storage**: AWS S3
- **CI/CD**: Gitea Actions
- **Monitoring**: Prometheus, Grafana
- **Logging**: ELK Stack

## 6. Deployment Architecture

### 6.1. Development Environment
- Local Docker Compose setup
- Hot-reload for development
- Development database with sample data

### 6.2. Production Environment
- Container orchestration with Kubernetes
- Auto-scaling based on load
- Multi-AZ deployment for high availability
- Automated backups and disaster recovery

## 7. Security Considerations

### 7.1. Authentication & Authorization
- JWT-based authentication
- Role-based access control (RBAC)
- Secure password hashing (bcrypt)
- Rate limiting
- CORS policy

### 7.2. Data Protection
- TLS 1.3 for all communications
- Sensitive data encryption at rest
- Regular security audits
- GDPR compliance

## 8. Performance Considerations

### 8.1. Caching Strategy
- Redis for frequently accessed data
- HTTP caching headers
- Database query result caching

### 8.2. Database Optimization
- Proper indexing
- Query optimization
- Connection pooling
- Read replicas for scaling reads

## 9. Monitoring & Observability

### 9.1. Metrics
- Request/response times
- Error rates
- Database query performance
- System resource usage

### 9.2. Logging
- Structured logging with correlation IDs
- Log levels (debug, info, warn, error)
- Centralized log management

### 9.3. Alerting
- Error rate thresholds
- Response time thresholds
- System resource alerts
- Business metrics alerts

## 10. Future Considerations

### 10.1. Scalability
- Sharding for database scaling
- Event sourcing for audit trail
- CQRS for read/write scaling

### 10.2. Features
- Real-time leaderboard updates
- Social sharing
- Offline quiz support
- Mobile app integration

---

*Last Updated: 2025-06-06*
*Document Version: A1*