# $swarms Token Subscription Payment System

## Overview

This documentation covers the implementation of subscription-based payments using $swarms tokens on the Solana blockchain.

## System Architecture

```mermaid
flowchart TB
    subgraph Frontend
        UI[User Interface]
        PM[Payment Manager]
    end

    subgraph Backend
        SM[Subscription Manager]
        DB[(Database)]
        Queue[Job Queue]
    end

    subgraph Blockchain
        SC[Smart Contract]
        Token[$swarms Token]
    end

    UI -->|Subscribe| PM
    PM -->|Create Subscription| SM
    SM -->|Store| DB
    SM -->|Schedule| Queue
    Queue -->|Execute Payment| SC
    SC -->|Transfer| Token
```

## Core Components

### 1. Subscription Smart Contract

```typescript
import { Program, web3 } from "@project-serum/anchor";
import { PublicKey, SystemProgram } from "@solana/web3.js";

interface SubscriptionAccount {
  subscriber: PublicKey;
  merchant: PublicKey;
  amount: number;
  interval: number;
  nextPaymentDate: number;
  active: boolean;
}

class SubscriptionContract {
  program: Program;

  constructor(program: Program) {
    this.program = program;
  }

  async createSubscription(
    subscriber: PublicKey,
    merchant: PublicKey,
    amount: number,
    interval: number
  ): Promise<string> {
    const subscription = web3.Keypair.generate();
    const currentTimestamp = Math.floor(Date.now() / 1000);

    await this.program.rpc.createSubscription(
      new BN(amount),
      new BN(interval),
      new BN(currentTimestamp + interval),
      {
        accounts: {
          subscription: subscription.publicKey,
          subscriber,
          merchant,
          systemProgram: SystemProgram.programId,
        },
        signers: [subscription],
      }
    );

    return subscription.publicKey.toString();
  }

  async processPayment(subscriptionAddress: string): Promise<string> {
    const subscription = await this.program.account.subscription.fetch(
      new PublicKey(subscriptionAddress)
    );

    // Transfer tokens
    const signature = await this.transferTokens(
      subscription.subscriber,
      subscription.merchant,
      subscription.amount
    );

    // Update next payment date
    await this.updateNextPaymentDate(
      subscriptionAddress,
      subscription.nextPaymentDate + subscription.interval
    );

    return signature;
  }
}
```

### 2. Subscription Manager Service

```typescript
class SubscriptionManager {
  private contract: SubscriptionContract;
  private db: Database;
  private queue: Queue;

  constructor(contract: SubscriptionContract, db: Database, queue: Queue) {
    this.contract = contract;
    this.db = db;
    this.queue = queue;
  }

  async createSubscription(
    subscriberAddress: string,
    merchantAddress: string,
    amount: number,
    interval: number,
    planDetails: SubscriptionPlan
  ): Promise<SubscriptionResponse> {
    // Create blockchain subscription
    const subscriptionAddress = await this.contract.createSubscription(
      new PublicKey(subscriberAddress),
      new PublicKey(merchantAddress),
      amount,
      interval
    );

    // Store subscription details
    const subscription = await this.db.subscriptions.create({
      address: subscriptionAddress,
      subscriber: subscriberAddress,
      merchant: merchantAddress,
      amount,
      interval,
      planDetails,
      status: "active",
      createdAt: new Date(),
    });

    // Schedule first payment
    await this.scheduleNextPayment(subscription);

    return {
      subscriptionId: subscription.id,
      address: subscriptionAddress,
      status: "active",
    };
  }

  async cancelSubscription(
    subscriptionId: string,
    reason?: string
  ): Promise<void> {
    // Update blockchain state
    await this.contract.deactivateSubscription(subscriptionId);

    // Update database
    await this.db.subscriptions.update({
      where: { id: subscriptionId },
      data: {
        status: "cancelled",
        cancelledAt: new Date(),
        cancelReason: reason,
      },
    });

    // Remove scheduled payments
    await this.queue.removeScheduledJobs(subscriptionId);
  }
}
```

### 3. Payment Processing System

```typescript
class PaymentProcessor {
  private connection: Connection;
  private subscriptionManager: SubscriptionManager;

  async processSubscriptionPayment(
    subscriptionId: string
  ): Promise<PaymentResult> {
    const subscription = await this.subscriptionManager.get(subscriptionId);

    try {
      // Create and send transaction
      const signature = await this.createAndExecutePayment(subscription);

      // Update payment history
      await this.recordPayment({
        subscriptionId,
        amount: subscription.amount,
        signature,
        status: "success",
      });

      // Schedule next payment
      await this.subscriptionManager.scheduleNextPayment(subscription);

      return { success: true, signature };
    } catch (error) {
      await this.handlePaymentFailure(subscription, error);
      return { success: false, error };
    }
  }

  private async createAndExecutePayment(
    subscription: Subscription
  ): Promise<string> {
    const transaction = await this.buildPaymentTransaction(subscription);
    return await this.sendAndConfirmTransaction(transaction);
  }
}
```

## Subscription Plans and Pricing

```mermaid
classDiagram
    class SubscriptionPlan {
        +string id
        +string name
        +number amount
        +number interval
        +Feature[] features
        +boolean isActive
        +create(PlanData) Plan
        +update(string, PlanData) Plan
        +delete(string) void
    }

    class Feature {
        +string id
        +string name
        +string description
        +boolean isEnabled
    }

    class PricingTier {
        +string id
        +string name
        +number amount
        +Discount[] discounts
    }

    class Discount {
        +string id
        +number percentage
        +number duration
    }

    SubscriptionPlan "1" -- "*" Feature
    SubscriptionPlan "1" -- "1" PricingTier
    PricingTier "1" -- "*" Discount
```

### Implementation Example

```typescript
interface SubscriptionPlan {
  id: string;
  name: string;
  amount: number;
  interval: number;
  features: Feature[];
  isActive: boolean;
}

class PlanManager {
  async createPlan(planData: CreatePlanDTO): Promise<SubscriptionPlan> {
    // Validate plan data
    this.validatePlanData(planData);

    // Create plan in database
    const plan = await this.db.plans.create({
      data: {
        ...planData,
        isActive: true,
        createdAt: new Date(),
      },
    });

    // Create on-chain representation
    await this.contract.registerPlan(plan.id, plan.amount, plan.interval);

    return plan;
  }

  async updatePlan(
    planId: string,
    updates: UpdatePlanDTO
  ): Promise<SubscriptionPlan> {
    // Validate updates
    this.validatePlanUpdates(updates);

    // Update in database
    const updatedPlan = await this.db.plans.update({
      where: { id: planId },
      data: updates,
    });

    // Update on-chain if necessary
    if (updates.amount || updates.interval) {
      await this.contract.updatePlan(planId, updates.amount, updates.interval);
    }

    return updatedPlan;
  }
}
```

## Payment Flow

```mermaid
sequenceDiagram
    participant User
    participant UI
    participant Backend
    participant Blockchain
    participant Wallet

    User->>UI: Select Subscription Plan
    UI->>Backend: Create Subscription Request
    Backend->>Blockchain: Deploy Subscription Contract
    Blockchain-->>Backend: Contract Address
    Backend->>UI: Subscription Details
    UI->>Wallet: Request Approval
    Wallet->>User: Confirm Transaction
    User->>Wallet: Approve
    Wallet->>Blockchain: Submit Transaction
    Blockchain-->>Backend: Confirmation
    Backend->>UI: Success Response
    UI->>User: Show Confirmation
```

## Error Handling and Recovery

```typescript
class SubscriptionErrorHandler {
  async handlePaymentFailure(
    subscription: Subscription,
    error: Error
  ): Promise<void> {
    // Log error
    await this.logError({
      subscriptionId: subscription.id,
      error,
      timestamp: new Date(),
    });

    // Determine retry strategy
    const retryStrategy = this.determineRetryStrategy(subscription, error);

    if (retryStrategy.shouldRetry) {
      await this.scheduleRetry(subscription, retryStrategy.retryAfter);
    } else {
      await this.handleSubscriptionFailure(subscription);
    }

    // Notify relevant parties
    await this.sendNotifications(subscription, error);
  }

  private async handleSubscriptionFailure(
    subscription: Subscription
  ): Promise<void> {
    // Update subscription status
    await this.subscriptionManager.updateStatus(subscription.id, "failed");

    // Notify merchant
    await this.notifyMerchant(subscription);

    // Create recovery task
    await this.createRecoveryTask(subscription);
  }
}
```

## Analytics and Reporting

```typescript
class SubscriptionAnalytics {
  async generateMetrics(timeframe: TimeFrame): Promise<SubscriptionMetrics> {
    const metrics = {
      activeSubscriptions: await this.countActiveSubscriptions(),
      recurringRevenue: await this.calculateMRR(),
      churnRate: await this.calculateChurnRate(timeframe),
      lifetimeValue: await this.calculateLTV(),
      conversionRate: await this.calculateConversionRate(),
    };

    return metrics;
  }

  async generateReport(options: ReportOptions): Promise<SubscriptionReport> {
    const report = {
      metrics: await this.generateMetrics(options.timeframe),
      subscriptionsByPlan: await this.aggregateByPlan(),
      revenueProjection: await this.projectRevenue(options.months),
      churnAnalysis: await this.analyzeChurn(),
    };

    return report;
  }
}
```

## Security Measures

```typescript
class SubscriptionSecurity {
  validateSubscription(subscription: Subscription): boolean {
    return (
      this.validateSignature(subscription.signature) &&
      this.validatePermissions(subscription.subscriber) &&
      this.validateLimits(subscription.amount)
    );
  }

  async monitorTransactions(): Promise<void> {
    // Monitor for suspicious activity
    const transactions = await this.getRecentTransactions();

    for (const tx of transactions) {
      if (this.isAnomalous(tx)) {
        await this.flagTransaction(tx);
        await this.notifyAdmin(tx);
      }
    }
  }
}
```

## Testing Framework

```typescript
describe("Subscription System", () => {
  let subscriptionManager: SubscriptionManager;
  let paymentProcessor: PaymentProcessor;

  beforeEach(async () => {
    // Setup test environment
    subscriptionManager = new SubscriptionManager(
      mockContract,
      mockDb,
      mockQueue
    );

    paymentProcessor = new PaymentProcessor(
      mockConnection,
      subscriptionManager
    );
  });

  describe("Subscription Creation", () => {
    it("should create a new subscription", async () => {
      const subscription = await subscriptionManager.createSubscription(
        testData.subscriber,
        testData.merchant,
        testData.amount,
        testData.interval,
        testData.plan
      );

      expect(subscription).to.have.property("id");
      expect(subscription.status).to.equal("active");
    });
  });

  describe("Payment Processing", () => {
    it("should process recurring payments", async () => {
      const result = await paymentProcessor.processSubscriptionPayment(
        testData.subscriptionId
      );

      expect(result.success).to.be.true;
      expect(result).to.have.property("signature");
    });
  });
});
```

## Migration and Upgrades

```typescript
class SubscriptionMigrationManager {
  async migrateSubscriptions(
    fromVersion: string,
    toVersion: string
  ): Promise<MigrationResult> {
    const subscriptions = await this.getSubscriptionsForMigration(fromVersion);

    const results = await Promise.allSettled(
      subscriptions.map((sub) => this.migrateSubscription(sub, toVersion))
    );

    return this.generateMigrationReport(results);
  }

  private async migrateSubscription(
    subscription: Subscription,
    newVersion: string
  ): Promise<void> {
    // Create new subscription with updated structure
    const newSubscription = await this.createNewVersionSubscription(
      subscription,
      newVersion
    );

    // Migrate payment history
    await this.migratePaymentHistory(subscription.id, newSubscription.id);

    // Update references
    await this.updateSubscriptionReferences(
      subscription.id,
      newSubscription.id
    );

    // Archive old subscription
    await this.archiveSubscription(subscription.id);
  }
}
```

## Compliance and Audit

```typescript
class SubscriptionAuditor {
  async auditSubscription(subscriptionId: string): Promise<AuditReport> {
    const subscription = await this.getSubscription(subscriptionId);
    const payments = await this.getPaymentHistory(subscriptionId);

    return {
      subscription: this.validateSubscriptionData(subscription),
      payments: this.validatePayments(payments),
      compliance: await this.checkCompliance(subscription),
      recommendations: this.generateRecommendations(subscription),
    };
  }

  async generateComplianceReport(): Promise<ComplianceReport> {
    return {
      totalSubscriptions: await this.countSubscriptions(),
      activeSubscriptions: await this.countActiveSubscriptions(),
      riskAssessment: await this.assessRisk(),
      complianceStatus: await this.checkComplianceStatus(),
      regulatoryRequirements: await this.checkRegulatory(),
    };
  }
}
```

## Performance Optimization

```typescript
class SubscriptionOptimizer {
  async optimizePerformance(): Promise<OptimizationResult> {
    const metrics = await this.gatherPerformanceMetrics();
    const bottlenecks = this.identifyBottlenecks(metrics);

    // Optimize database queries
    await this.optimizeDatabaseQueries();

    // Optimize blockchain interactions
    await this.optimizeBlockchainCalls();

    // Cache frequently accessed data
    await this.setupCaching();

    return {
      beforeMetrics: metrics,
      afterMetrics: await this.gatherPerformanceMetrics(),
      improvements: this.calculateImprovements(),
      recommendations: this.generateOptimizationRecommendations(),
    };
  }

  private async optimizeDatabaseQueries(): Promise<void> {
    await this.createIndexes();
    await this.optimizeJoins();
    await this.implementQueryCaching();
  }

  private async optimizeBlockchainCalls(): Promise<void> {
    await this.implementBatchProcessing();
    await this.setupWebSocketConnections();
    await this.cacheBlockchainState();
  }
}
```

## Webhook Integration

```typescript
class SubscriptionWebhooks {
  private endpoints: Map<string, WebhookEndpoint>;

  async registerWebhook(
    event: WebhookEvent,
    endpoint: string,
    secret: string
  ): Promise<string> {
    const webhookId = generateUniqueId();

    await this.db.webhooks.create({
      id: webhookId,
      event,
      endpoint,
      secret,
      status: "active",
    });

    return webhookId;
  }

  async triggerWebhook(event: WebhookEvent, data: any): Promise<void> {
    const webhooks = await this.getWebhooksForEvent(event);

    for (const webhook of webhooks) {
      try {
        const payload = this.createWebhookPayload(event, data);
        const signature = this.signPayload(payload, webhook.secret);

        await this.sendWebhookRequest(webhook.endpoint, payload, signature);
      } catch (error) {
        await this.handleWebhookError(webhook, error);
      }
    }
  }
}
```

## Notification System

```mermaid
flowchart TB
    subgraph NotificationSystem
        E[Event Handler]
        T[Template Engine]
        Q[Queue Manager]
        D[Delivery Service]
    end

    subgraph Channels
        Email[Email Service]
        SMS[SMS Service]
        Push[Push Notifications]
        Web[Web Hooks]
    end

    E -->|Event| T
    T -->|Formatted| Q
    Q -->|Queued| D
    D -->|Send| Email
    D -->|Send| SMS
    D -->|Send| Push
    D -->|Send| Web
```

```typescript
class SubscriptionNotifier {
  async notify(
    event: SubscriptionEvent,
    subscription: Subscription
  ): Promise<void> {
    const template = await this.getNotificationTemplate(event);
    const recipients = await this.getRecipients(subscription);

    const notifications = recipients.map((recipient) =>
      this.createNotification(template, recipient, subscription)
    );

    await this.queueNotifications(notifications);
  }

  private async createNotification(
    template: Template,
    recipient: Recipient,
    subscription: Subscription
  ): Promise<Notification> {
    return {
      recipient,
      content: this.renderTemplate(template, {
        subscription,
        recipient,
      }),
      channel: recipient.preferredChannel,
      priority: this.determinePriority(template.event),
    };
  }
}
```

## Usage Analytics Dashboard

```typescript
interface SubscriptionAnalytics {
  totalRevenue: number;
  activeSubscriptions: number;
  churnRate: number;
  averageLifetime: number;
  topPlans: PlanAnalytics[];
}

class AnalyticsDashboard {
  async generateDashboardData(timeframe: TimeFrame): Promise<DashboardData> {
    return {
      overview: await this.generateOverview(timeframe),
      trends: await this.analyzeTrends(timeframe),
      forecasts: await this.generateForecasts(),
      recommendations: await this.generateRecommendations(),
    };
  }

  private async generateOverview(timeframe: TimeFrame): Promise<Overview> {
    return {
      totalRevenue: await this.calculateRevenue(timeframe),
      activeSubscriptions: await this.countActiveSubscriptions(),
      growthRate: await this.calculateGrowthRate(timeframe),
      churnMetrics: await this.analyzeChurn(timeframe),
    };
  }
}
```

## Rate Limiting and Throttling

```typescript
class RateLimiter {
  private readonly redis: Redis;
  private readonly limits: Map<string, RateLimit>;

  async checkLimit(key: string, operation: string): Promise<boolean> {
    const limit = this.limits.get(operation);
    if (!limit) return true;

    const current = await this.redis.incr(key);
    if (current === 1) {
      await this.redis.expire(key, limit.windowSeconds);
    }

    return current <= limit.maxRequests;
  }

  async handleRateLimit(
    subscription: Subscription,
    operation: string
  ): Promise<void> {
    const key = `${subscription.id}:${operation}`;

    if (!(await this.checkLimit(key, operation))) {
      throw new RateLimitError(`Rate limit exceeded for ${operation}`);
    }
  }
}
```

## Disaster Recovery

```typescript
class DisasterRecovery {
  async backupData(): Promise<BackupResult> {
    const backup = {
      subscriptions: await this.backupSubscriptions(),
      payments: await this.backupPayments(),
      metadata: await this.backupMetadata(),
    };

    await this.storeBackup(backup);
    return backup;
  }

  async restore(
    backupId: string,
    options: RestoreOptions
  ): Promise<RestoreResult> {
    const backup = await this.loadBackup(backupId);

    // Validate backup integrity
    this.validateBackup(backup);

    // Perform restoration
    const result = await this.performRestore(backup, options);

    // Verify restoration
    await this.verifyRestoration(result);

    return result;
  }
}
```

## Subscription Lifecycle Events

```mermaid
stateDiagram-v2
    [*] --> Created
    Created --> Active: Payment Successful
    Active --> Suspended: Payment Failed
    Active --> Cancelled: User Cancellation
    Active --> Expired: Term Ended
    Suspended --> Active: Payment Resumed
    Suspended --> Cancelled: Grace Period Ended
    Cancelled --> [*]
    Expired --> [*]
```

## Future Enhancements

1. Smart Contract Upgrades

```typescript
class ContractUpgrader {
  async upgradeContract(newVersion: string): Promise<UpgradeResult> {
    // Validate new version
    await this.validateNewVersion(newVersion);

    // Deploy new contract
    const newContract = await this.deployNewVersion(newVersion);

    // Migrate state
    await this.migrateState(newContract);

    // Switch over
    await this.switchToNewContract(newContract);

    return {
      newContractAddress: newContract.address,
      migrationStatus: "success",
    };
  }
}
```

2. Multi-Token Support

```typescript
interface TokenConfig {
  address: string;
  decimals: number;
  symbol: string;
}

class MultiTokenSubscription {
  private supportedTokens: Map<string, TokenConfig>;

  async addToken(config: TokenConfig): Promise<void> {
    await this.validateToken(config);
    this.supportedTokens.set(config.symbol, config);
  }

  async createMultiTokenSubscription(
    subscriber: string,
    token: string,
    amount: number
  ): Promise<string> {
    const config = this.supportedTokens.get(token);
    if (!config) throw new Error("Unsupported token");

    return await this.createSubscription(subscriber, config, amount);
  }
}
```

## API Documentation

### REST Endpoints

```typescript
interface SubscriptionAPI {
  // Subscription Management
  "POST /subscriptions": {
    body: CreateSubscriptionDTO;
    response: SubscriptionResponse;
  };

  "GET /subscriptions/:id": {
    params: { id: string };
    response: SubscriptionDetails;
  };

  "PATCH /subscriptions/:id": {
    params: { id: string };
    body: UpdateSubscriptionDTO;
    response: SubscriptionResponse;
  };

  "DELETE /subscriptions/:id": {
    params: { id: string };
    response: void;
  };

  // Payment Management
  "GET /subscriptions/:id/payments": {
    params: { id: string };
    query: PaymentQueryParams;
    response: PaymentHistory;
  };

  // Analytics
  "GET /subscriptions/analytics": {
    query: AnalyticsParams;
    response: AnalyticsResponse;
  };
}
```

## Complete Implementation Checklist

1. Core Infrastructure
   - [ ] Smart Contract Development
   - [ ] Database Schema Design
   - [ ] API Layer Implementation
   - [ ] Payment Processing System
2. Security Measures
   - [ ] Authentication System
   - [ ] Authorization Rules
   - [ ] Rate Limiting
   - [ ] Input Validation
3. Integration Features
   - [ ] Webhook System
   - [ ] Notification Service
   - [ ] Analytics Dashboard
   - [ ] Reporting System
4. Maintenance Tools
   - [ ] Monitoring System
   - [ ] Backup Solution
   - [ ] Migration Tools
   - [ ] Testing Framework

## Deployment Guide

```mermaid
flowchart TB
    subgraph Preparation
        Config[Configuration]
        Deps[Dependencies]
        Env[Environment Setup]
    end

    subgraph Deployment
        Contract[Deploy Contract]
        Backend[Deploy Backend]
        Frontend[Deploy Frontend]
    end

    subgraph Verification
        Test[Testing]
        Monitor[Monitoring]
        Backup[Backup]
    end

    Preparation --> Deployment
    Deployment --> Verification
```

## Support and Resources

### Support Channels

- Technical Support: support@swarms.world
- Developer Discord: discord.gg/swarms
- Documentation Site: docs.swarms.world

## Version History

- v1.0.0: Initial Release
- v1.1.0: Added Multi-Token Support
- v1.2.0: Enhanced Analytics
- v1.3.0: Improved Error Handling
