# Payments System

### Implementation: **BARK Payments System Components**

Components for both the backend and frontend systems of the BARK Payments System, including descriptions and implementation details.

***

#### **1. Backend Components**

**1.1 Authentication**

**Component:** `auth.ts`\
**Purpose:** Handles user authentication and authorization.

**Key Functions:**

* `generateToken(userId: string): string` - Generates a JWT token for the user.
* `verifyToken(token: string): any` - Verifies the JWT token.
* `hashPassword(password: string): Promise<string>` - Hashes the user password.
* `comparePassword(password: string, hash: string): Promise<boolean>` - Compares the plaintext password with the hashed password.

**Dependencies:** `jsonwebtoken`, `bcryptjs`, `dotenv`

***

**1.2 User Management**

**Component:** `user.ts`\
**Purpose:** Defines the User schema and model for MongoDB.

**Key Features:**

* User registration and profile management.
* Schema includes fields for username, password, and email.

**Dependencies:** `mongoose`

***

**1.3 Payment Handling**

**Component:** `payment.ts`\
**Purpose:** Manages payment processing for CNFTs and other transactions.

**Key Functions:**

* `createPayment(recipient: PublicKey, amount: number, token: string): Promise<{ paymentURL: string; qrCode: string }>` - Creates a payment URL and QR code.

**Dependencies:** `@solana/web3.js`, `QRCode`, `dotenv`

***

**1.4 Escrow Management**

**Component:** `escrow.ts`\
**Purpose:** Manages escrow accounts and transactions.

**Key Functions:**

* `createEscrow(payer: PublicKey, amount: number, releaseTime: number): Promise<PublicKey>` - Creates an escrow account.
* `releaseEscrowFunds(escrowAccount: PublicKey, recipient: PublicKey): Promise<string>` - Releases funds from the escrow account.
* `resolveDispute(escrowAccount: PublicKey, disputeData: any): Promise<void>` - Resolves disputes.

**Dependencies:** `@solana/web3.js`

***

**1.5 Utility Functions**

**Component:** `utils.ts`\
**Purpose:** Provides utility functions for QR code and payment URL generation.

**Key Functions:**

* `createQR(url: string): Promise<string>` - Generates a QR code for a given URL.
* `createPaymentURL(recipient: PublicKey, amount: number, token: string, network: string): Promise<string>` - Constructs a payment URL.

**Dependencies:** `QRCode`, `@solana/web3.js`

***

#### **2. Frontend Components**

**2.1 Authentication Hooks**

**Component:** `useAuth.ts`\
**Purpose:** Custom React hook for user authentication and profile management.

**Key Functions:**

* `login(username: string, password: string)` - Logs in the user and stores the JWT token.
* `fetchProfile()` - Retrieves user profile data.
* `logout()` - Logs out the user and clears local storage.

**Dependencies:** `axios`, `react`

***

**2.2 Login Component**

**Component:** `Login.tsx`\
**Purpose:** Provides a user interface for login.

**Key Features:**

* Input fields for username and password.
* Form submission handling to call `login()` function from `useAuth`.

**Dependencies:** `react`, `useAuth`

***

**2.3 Payment Component**

**Component:** `Payment.tsx`\
**Purpose:** Displays payment options and processes transactions.

**Key Features:**

* Options for BARK, SOL, and USDC payments.
* QR code and payment URL display.
* Integration with the backend `createPayment` function.

**Dependencies:** `react`, `axios`

***

**2.4 Profile Component**

**Component:** `Profile.tsx`\
**Purpose:** Displays user profile information.

**Key Features:**

* Shows user details fetched from the backend.
* Integration with `fetchProfile` from `useAuth`.

**Dependencies:** `react`, `useAuth`

***

#### **3. Integration with Vercel**

**Purpose:** Deploy and manage the application on Vercel.

**Key Steps:**

1. **Install Vercel CLI:**

   ```bash
   npm install -g vercel
   ```
2. **Deploy Backend:**

   Navigate to your backend directory and run:

   ```bash
   vercel
   ```
3. **Deploy Frontend:**

   Navigate to your frontend directory and run:

   ```bash
   vercel
   ```
4. **Set Environment Variables:**

   Configure environment variables through the Vercel dashboard or using the Vercel CLI.
5. **Monitor and Scale:**

   Use Vercel's monitoring tools to keep track of your deployment's performance and scale as necessary.

***

#### **4. Testing**

**Purpose:** Ensure that the application functions correctly under various conditions.

**Key Approaches:**

* **Unit Tests:** For individual functions and components.
* **Integration Tests:** To verify interactions between components and services.
* **End-to-End Tests:** To simulate real user interactions.

**Tools:**

* **Jest**: For unit and integration testing.
* **React Testing Library**: For testing React components.
* **Cypress**: For end-to-end testing.

***

#### **5. Monitoring**

**Purpose:** Track the health and performance of the application.

**Tools:**

* **Vercel Monitoring**: Built-in monitoring for serverless deployments.
* **Sentry**: For error tracking and performance monitoring.