Design Document

Technical architecture and design specifications for the NFT Music Player

Architecture

Design Document

Overview

The NFT Music Player is a Progressive Web App built with Next.js that combines traditional music playback with immersive Three.js visualizations and XRP Ledger NFT integration. The application follows a modular architecture to support future React Native expansion while providing a rich, responsive user experience across devices.

Architecture

High-Level Architecture

graph TB
    UI[UI Layer - Next.js/React] --> Audio[Audio Engine]
    UI --> Visual[Visualization Engine - Three.js]
    UI --> Storage[Storage Layer]
    UI --> NFT[NFT Integration Layer]
    
    Audio --> WebAudio[Web Audio API]
    Visual --> ThreeJS[Three.js Scene]
    Storage --> LocalStorage[localStorage]
    Storage --> Cache[PWA Cache]
    NFT --> XRPL[XRP Ledger API]
    
    WebAudio --> Analyzer[Audio Analyzer]
    Analyzer --> Visual
    
    XRPL --> Metadata[NFT Metadata Parser]
    Metadata --> Visual

Core Layers

  1. Presentation Layer: Next.js React components with responsive PWA interface
  2. Audio Engine: Web Audio API abstraction for playback and analysis
  3. Visualization Engine: Three.js-based audio-reactive graphics system
  4. Storage Layer: localStorage and PWA caching for offline functionality
  5. NFT Integration: XRP Ledger connectivity and metadata processing
  6. Service Worker: PWA functionality and background processing

Components and Interfaces

Audio System Components

AudioEngine

interface AudioEngine {
  loadTrack(source: AudioSource): Promise<void>
  play(): void
  pause(): void
  stop(): void
  setVolume(level: number): void
  seek(position: number): void
  getAnalyzerData(): Uint8Array
  getCurrentTime(): number
  getDuration(): number
}

interface AudioSource {
  type: 'local' | 'nft'
  url: string
  metadata?: TrackMetadata
}

AudioAnalyzer

interface AudioAnalyzer {
  getFrequencyData(): Uint8Array
  getTimeDomainData(): Uint8Array
  getAverageFrequency(): number
  getBassLevel(): number
  getTrebleLevel(): number
}

Visualization System Components

VisualizationEngine

interface VisualizationEngine {
  initialize(canvas: HTMLCanvasElement): void
  setVisualizationMode(mode: VisualizationMode): void
  updateWithAudioData(audioData: AudioAnalyzerData): void
  loadNFTAssets(assets: NFTVisualAssets): void
  render(): void
  resize(width: number, height: number): void
}

type VisualizationMode = 'spectrum' | 'waveform' | 'particles' | 'nft-enhanced' | 'album-art'

interface NFTVisualAssets {
  textures?: string[]
  colors?: string[]
  animations?: AnimationData[]
  staticImage?: string
}

NFT Integration Components

XRPLConnector

interface XRPLConnector {
  connect(walletAddress?: string): Promise<void>
  disconnect(): void
  getNFTCollection(): Promise<NFTItem[]>
  getMusicNFTs(): Promise<MusicNFT[]>
  getNFTMetadata(nftId: string): Promise<NFTMetadata>
}

interface MusicNFT {
  id: string
  name: string
  audioUrl: string
  videoUrl?: string
  visualAssets: NFTVisualAssets
  metadata: NFTMetadata
}

Storage Components

MusicLibrary

interface MusicLibrary {
  addLocalTrack(file: File): Promise<Track>
  addNFTTrack(nft: MusicNFT): Promise<Track>
  getTracks(): Track[]
  getTrack(id: string): Track | null
  removeTrack(id: string): void
  createPlaylist(name: string, trackIds: string[]): Playlist
}

interface Track {
  id: string
  title: string
  artist?: string
  duration: number
  source: AudioSource
  visualAssets?: NFTVisualAssets
  albumArt?: string
}

Data Models

Core Data Models

Track Model

interface Track {
  id: string
  title: string
  artist?: string
  album?: string
  duration: number
  source: AudioSource
  visualAssets?: NFTVisualAssets
  albumArt?: string
  addedAt: Date
  playCount: number
}

Playlist Model

interface Playlist {
  id: string
  name: string
  tracks: string[] // Track IDs
  createdAt: Date
  updatedAt: Date
  isDefault: boolean
}

User Preferences Model

interface UserPreferences {
  volume: number
  visualizationMode: VisualizationMode
  autoPlay: boolean
  shuffleMode: boolean
  repeatMode: 'none' | 'one' | 'all'
  xrplWalletAddress?: string
  theme: 'light' | 'dark' | 'auto'
}

NFT-Specific Models

NFT Metadata Model

interface NFTMetadata {
  name: string
  description?: string
  image?: string
  animation_url?: string
  attributes: NFTAttribute[]
  properties?: Record<string, any>
}

interface NFTAttribute {
  trait_type: string
  value: string | number
}

Error Handling

Error Categories

  1. Audio Errors: Playback failures, unsupported formats, network issues
  2. Visualization Errors: WebGL context loss, shader compilation failures
  3. Storage Errors: localStorage quota exceeded, cache failures
  4. NFT Integration Errors: Network connectivity, authentication failures, metadata parsing
  5. PWA Errors: Service worker registration, update failures

Error Handling Strategy

interface ErrorHandler {
  handleAudioError(error: AudioError): void
  handleVisualizationError(error: VisualizationError): void
  handleStorageError(error: StorageError): void
  handleNFTError(error: NFTError): void
  showUserNotification(message: string, type: 'error' | 'warning' | 'info'): void
}

// Graceful degradation for visualization errors
const fallbackVisualization = () => {
  // Simple canvas-based visualization when WebGL fails
  // Static album art display when all visualizations fail
}

Testing Strategy

Unit Testing

  • Audio engine components with mock Web Audio API
  • Visualization engine with headless WebGL context
  • Storage layer with mock localStorage
  • NFT integration with mock XRP Ledger responses

Integration Testing

  • End-to-end audio playback workflows
  • Visualization synchronization with audio
  • PWA installation and offline functionality
  • NFT loading and metadata parsing

Performance Testing

  • Audio latency and buffer management
  • Visualization frame rate optimization
  • Memory usage with large music libraries
  • Network efficiency for NFT metadata loading

Cross-Platform Testing

  • Desktop browsers (Chrome, Firefox, Safari, Edge)
  • Mobile browsers (iOS Safari, Android Chrome)
  • PWA installation across platforms
  • Touch interface responsiveness

PWA Implementation Details

Service Worker Strategy

  • Cache-first for static assets (JS, CSS, images)
  • Network-first for NFT metadata and audio streams
  • Offline fallback for core functionality
  • Background sync for NFT collection updates

Manifest Configuration

{
  "name": "NFT Music Player",
  "short_name": "NFT Player",
  "description": "Music player with Three.js visualizations and XRP Ledger NFT support",
  "start_url": "/",
  "display": "standalone",
  "background_color": "#000000",
  "theme_color": "#6366f1",
  "icons": [
    {
      "src": "/icons/icon-192.png",
      "sizes": "192x192",
      "type": "image/png"
    },
    {
      "src": "/icons/icon-512.png",
      "sizes": "512x512",
      "type": "image/png"
    }
  ]
}

Offline Functionality

  • Cached music files remain playable offline
  • Basic visualizations work without network
  • NFT metadata cached after first load
  • Graceful degradation when network unavailable

Performance Considerations

Audio Performance

  • Use Web Audio API for low-latency playback
  • Implement audio buffer management for large files
  • Optimize analyzer data processing for real-time visualization

Visualization Performance

  • Use requestAnimationFrame for smooth animations
  • Implement LOD (Level of Detail) for complex visualizations
  • GPU-based particle systems for better performance
  • Texture atlasing for NFT visual assets

Storage Optimization

  • Compress audio metadata in localStorage
  • Implement LRU cache for NFT assets
  • Progressive loading for large music libraries
  • Efficient serialization of user preferences

Network Optimization

  • Lazy loading of NFT metadata
  • Image optimization for album art and NFT assets
  • Connection pooling for XRP Ledger requests
  • Retry mechanisms with exponential backoff
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