# Online Booking Application

## Cliff Hill's Coding Project

This is a full-stack application simulating an online booking system for conference rooms.

---

## Design Decisions

### React Contexts for State Management

- Global state for rooms, bookings, and users via context providers.
- Real-time updates using SSE in context.

### Modular Component Architecture

- Reusable, focused components (e.g., BookingForm, RoomList, RoomSelect, CalendarView).
- Shared UI logic abstracted into dedicated components.

### TypeScript for Safety and Documentation

- Strong typing for all props, state, and data models.
- Centralized type/interface definitions.

### Unified Color and Style Logic

- Room/event colors assigned by room id modulo, using CSS custom properties.
- Consistent visual theming across lists, dropdowns, and calendar.

### Separation of Concerns

- Business logic and API calls abstracted into helpers and service modules.
- Thin UI components focused on rendering and interaction.

### Robust Error Handling and Validation

- Field-level validation and user-friendly error messages in forms.
- Backend errors formatted for clarity.

### Centralized Logging

- Logging utility used throughout frontend and backend for analytics and debugging.
- Key actions and lifecycle events are logged.

### JSDoc and Docstrings for Documentation

- File-level and component-level documentation in both frontend and backend.
- TypeScript interfaces and Python models are documented.

### React Router for Navigation

- Page routing and programmatic navigation after booking actions.

### Accessibility and User Experience

- Disabled states, error messages, and skeleton loaders for better UX.
- Visual distinction for selected/unavailable rooms.

### FastAPI Backend with SQLAlchemy ORM

- Async API endpoints grouped by resource (rooms, bookings, users).
- Database models with relationships and constraints.

### Pydantic Schemas for Validation

- Separate schemas for create, update, and response objects.

### Service Layer Abstraction in Backend

- Business logic separated from HTTP routing.

### Testing and Code Quality

- Pytest, coverage, pre-commit hooks, and code style enforcement for backend
- Jest and React Testing Library, code style enforcement and additional pre-commit hooks for frontend
- All tests can be run from the`nox` command in the root directory

### Docker Compose for Orchestration

- Multi-service setup: backend (FastAPI), frontend (React), and Postgres database.
- Custom network, healthchecks, and persistent volumes.
- Environment variables managed via .env files.

### Extensibility and Maintainability

- Modular design for easy feature addition and refactoring.
- Generated from Hypermodern Python Cookiecutter for best practices.

### AI Use

I used AI to stub out a couple of files:

- The backend/Dockerfile and frontend/Dockerfile - to speed up the process of getting docker loaded efficiently for the project.
- The compose.yml file - getting the different images gathered together quickly.
- The compose.dev.yml file - used to get a further understanding of how to hook up an extension to the previous file.
- The mermaid diagrams used in this file.
- I have the CodeGPT plugin in VSCode, and it has helped with docstrings, logging messages, and sometimes reducing the time it takes me to write out the code.
- I used AI to rapidly set up tests for each users component (router, service), then adapted it to the others independently. I believe AI is great for getting reasonable tests written quickly, and then I simply refined it, and replicated the kinds of tests across the different components.
- I was experimenting with some AI edits for debugging the tests.
- My frontend skills are less polished than my backend skills. I've been using AI along the lines of how I would use StackOverflow, answering questions to help me get the code written.
- I used AI to help clean up and better structure the CSS for the frontend project, as well as get some code documentation in place.
- AI was used to refactor code a few times to make it cleaner and better organized.

---

## Development Environment Setup

Follow these steps to get your local development environment running:

### 1. Clone the repository

You can use either HTTPS or SSH:

**HTTPS:**

```bash
git clone https://github.com/xlorepdarkhelm/numinar-coding-project.git
cd numinar-coding-project
```

**SSH:**

```bash
git clone git@github.com:xlorepdarkhelm/numinar-coding-project.git
cd numinar-coding-project
```

### 2. Copy environment variables

```bash
cp .env.example .env
# Or, if present:
cp .env.sample .env
```

### 3. Install backend dependencies

```bash
cd backend
poetry install
```

### 4. Set up pre-commit hooks (recommended)

```bash
pre-commit install
```

### 5. Install frontend dependencies

```bash
cd ../frontend
yarn install
```

### 6. Start Docker Compose in development mode (in a separate terminal)

From the project root:

```bash
docker compose -f compose.dev.yml up
```

This will start the backend (port 8000), frontend (port 3000), and Postgres (port 5432) with hot-reload enabled for rapid development.

### 7. Run tests (backend & frontend)

#### Backend tests

```bash
cd backend
nox           # Run all tests and checks (also builds API docs)
# or run only unit tests:
nox --session=tests
```

##### API Documentation

- The `nox` command above will also build the backend API documentation.
- **View the API docs in development mode:** Open [http://localhost:8000/docs](http://localhost:8000/docs) in
  your browser (when running dev Docker Compose).
- **Generated static docs (after running nox):** See `backend/docs/build/index.html` relative to the project
  root.

#### Frontend tests

```bash
cd frontend
nox
# or run only nox tests:
nox --session=jest
```

#### All tests

from the project root

```bash
nox
```

Note - you can use any of the sessions from frontend or backend here to isolate just that test.

#### Further improvements

Integration testing, and end-to-end tests really would make this robust. Having all of the tests run in CICD before allowing code to be merged/commited to the main branch would be a mechanism to help ensure code quality. I would have set up the github project to have "feature branches" be made, to add whatever feature that a work item/issue had, and then Peer Reviews - typically set up with 2 peers reviewing 1 PR and approving it, aswell as all CICD checks/tests needing to pass before allowing the branch to be merged.

I would have templates in place for creating a PR, with a set of instructions that would give the "definition of done" - a checklist that would need to be completed before the issue could be marked as completed and a PR could then be reviewed.

Further kinds of tests can be added for the frontend through the frontend's noxfile.

## Diagrams

### Docker Compose Components

```mermaid
graph TD
  subgraph Docker_Network
    B[Frontend]
    C[Backend]
    D[PostgreSQL]
    C -- "SQL: 5432" --> D
  end
  Client[Client] -- "HTTP: 3000" --> B
  Client -- "HTTP/REST: 8000" --> C
```

---

### Database Schema Diagram

```mermaid
classDiagram
  class User {
    string email
    string name
  }
  class Room {
    int id
    string name
    string location
    string equipment
    int capacity
  }
  class Booking {
    int id
    int room_id
    datetime start_time
    datetime end_time
    string title
  }
  class Invitee {
    int id
    int booking_id
    string user_email
  }

  User "1" <|-- "*" Invitee : user_email
  Room "1" <|-- "*" Booking : room_id
  Booking "1" <|-- "*" Invitee : booking_id
```

---

### Component Diagram

```mermaid
graph TD
    subgraph Frontend
        F1[Pages] --> F2[Components]
        F2 --> F3[API Calls]
    end
    subgraph Backend
        B1[FastAPI Routers] --> B2[Pydantic Schemas]
        B1 --> B3[Service Layer]
        B3 --> B4[SQLAlchemy Models]
        B4 --> B5[PostgreSQL]
    end
    F3 -->|REST| B1
```

---

### Backend Request Data Path

```mermaid
sequenceDiagram
  participant Frontend
  participant FastAPI_Router as FastAPI Router
  participant API_Endpoint as API Endpoint
  participant Pydantic_Schema as Pydantic Schema
  participant Service_Layer as Service Layer
  participant DB_Model as DB Model
  participant Database

  Frontend->>FastAPI_Router: HTTP Request (REST)
  FastAPI_Router->>API_Endpoint: Route Match
  API_Endpoint->>Pydantic_Schema: Validate & Parse Input
  Pydantic_Schema-->>API_Endpoint: Validated Data
  API_Endpoint->>Service_Layer: Pass Data
  Service_Layer->>DB_Model: Business Logic
  DB_Model->>Database: DB Query/Update
  Database-->>DB_Model: Query Result
  DB_Model-->>Service_Layer: Data
  Service_Layer-->>API_Endpoint: Response Data
  API_Endpoint-->>Frontend: HTTP Response (JSON)
```

---

### SSE Update Flow (Real-Time Room Availability)

```mermaid
sequenceDiagram
  participant Frontend
  participant FastAPI_Router as FastAPI Router
  participant SSE_Endpoint as SSE Endpoint
  participant Event_Generator as Event Generator
  participant Publisher as Publisher

  Frontend->>SSE_Endpoint: Open EventSource /availability/stream
  SSE_Endpoint->>Event_Generator: Start Async Event Loop
  loop While Connected
    Event_Generator->>Publisher: Wait for Event or Timeout
    Publisher-->>Event_Generator: Room Availability Event | Keep-Alive
    Event_Generator-->>Frontend: Send SSE Event (data: ...)
  end
  Frontend-->>SSE_Endpoint: Disconnect (close EventSource)
  SSE_Endpoint-->>Event_Generator: Cleanup Subscriber
```