NFR Design Plan - Nokia Snake Game

Unit Context

Unit Name: Nokia Snake Game (Monolithic)
Type: Single monolithic web application
Scope: Complete Nokia Snake game implementation
Technology: Vanilla JavaScript, Vite, WebGL, localStorage

NFR Design Plan Steps

Step 1: Analyze NFR Requirements

• 1.1 Review NFR Requirements

  • Read aidlc-docs/construction/nokia-snake-game/nfr-requirements/nfr-requirements.md
  • Understand performance, security, mobile, and offline requirements
  • Identify key NFR priorities

• 1.2 Review Tech Stack Decisions

  • Read aidlc-docs/construction/nokia-snake-game/nfr-requirements/tech-stack-decisions.md
  • Understand technology choices and rationale
  • Identify implementation patterns needed

Step 2: Performance Design Patterns

• 2.1 Game Loop Optimization

  • Design fixed time step pattern for consistent gameplay
  • Design frame skipping strategy for performance
  • Design render optimization patterns

• 2.2 Memory Management Patterns

  • Design object pooling pattern for game entities
  • Design garbage collection minimization strategy
  • Design memory leak prevention patterns

• 2.3 Rendering Optimization

  • Design WebGL rendering pipeline
  • Design Canvas 2D fallback strategy
  • Design sprite batching and texture atlas patterns

Step 3: Security Design Patterns

• 3.1 Input Validation Pattern

  • Design comprehensive input validation architecture
  • Design whitelist-based validation strategy
  • Design input sanitization patterns

• 3.2 Exception Handling Pattern

  • Design global error boundary pattern
  • Design safe state fallback mechanism
  • Design error recovery strategy

• 3.3 Audit Logging Pattern

  • Design security event logging architecture
  • Design audit trail storage strategy
  • Design log rotation and retention patterns

Step 4: Mobile Optimization Patterns

• 4.1 Touch Input Pattern

  • Design touch gesture recognition system
  • Design swipe direction detection algorithm
  • Design touch feedback patterns

• 4.2 Responsive Design Pattern

  • Design canvas scaling strategy
  • Design viewport adaptation patterns
  • Design orientation change handling

• 4.3 Mobile Performance Pattern

  • Design battery optimization strategy
  • Design mobile-specific rendering optimizations
  • Design haptic feedback patterns

Step 5: Offline Functionality Patterns

• 5.1 Data Persistence Pattern

  • Design localStorage abstraction layer
  • Design data serialization/deserialization strategy
  • Design data validation and migration patterns

• 5.2 State Management Pattern

  • Design Redux-like store architecture
  • Design state update and notification patterns
  • Design state persistence triggers

• 5.3 Offline-First Pattern

  • Design zero-network-dependency architecture
  • Design asset bundling strategy
  • Design offline error handling

Step 6: Resilience Patterns

• 6.1 Error Recovery Pattern

  • Design automatic error recovery mechanism
  • Design graceful degradation strategy
  • Design user notification patterns

• 6.2 Data Integrity Pattern

  • Design data corruption detection
  • Design data validation on load
  • Design fallback to defaults strategy

Step 7: Accessibility Patterns

• 7.1 Keyboard Navigation Pattern

  • Design keyboard event handling architecture
  • Design focus management strategy
  • Design keyboard shortcuts system

• 7.2 Screen Reader Pattern

  • Design ARIA label strategy
  • Design live region announcement patterns
  • Design semantic HTML structure

Step 8: Logical Components Design

• 8.1 Core Game Components

  • Design Game Engine component architecture
  • Design Rendering Engine component
  • Design Input Manager component
  • Design State Manager component

• 8.2 Support Components

  • Design Security Logger component
  • Design Performance Monitor component
  • Design Storage Manager component
  • Design Error Handler component

• 8.3 Component Interactions

  • Design component communication patterns
  • Design event bus or pub/sub system
  • Design component lifecycle management

Questions for User Input

Question 1: Game Loop Implementation Strategy

How should the game loop handle performance variations across devices?

A) Fixed time step only - Consistent gameplay, may drop frames on slow devices
B) Variable time step - Smooth on all devices, gameplay speed varies
C) Fixed time step with frame skipping - Consistent gameplay, skip rendering if behind
D) Adaptive - Switch between fixed and variable based on performance

Question 2: Object Pooling Scope

Which game objects should use object pooling for memory optimization?

A) None - Simple allocation/deallocation sufficient
B) Food items only - Most frequently created/destroyed
C) Snake segments and food - Core game objects
D) All game objects - Maximum optimization

Question 3: Error Recovery Strategy Detail

When an unrecoverable error occurs, what should happen?

A) Silent recovery - Reset to main menu without notification
B) Brief notification - Show "An error occurred" for 2 seconds, then reset
C) Detailed error - Show error details with option to report
D) Save state - Attempt to save state, then show error and reset

Question 4: Audit Logging Storage Strategy

How should audit logs be stored and managed?

A) Console only - Log to console, no persistence
B) localStorage with rotation - Keep last 1000 entries
C) localStorage with export - Allow user to export logs
D) External service - Send logs to external logging service

Question 5: Touch Gesture Sensitivity

How sensitive should touch gesture detection be?

A) Low sensitivity - Require 50px+ swipe to register
B) Medium sensitivity - Require 30px swipe (recommended)
C) High sensitivity - Require 15px swipe
D) Adaptive - Adjust based on screen size

Question 6: Canvas Scaling Strategy

How should the game canvas scale on different screen sizes?

A) Fixed size - 800x600px, scroll if needed
B) Fit to container - Scale to fit, maintain aspect ratio
C) Fill container - Stretch to fill, ignore aspect ratio
D) Responsive grid - Adjust grid size based on screen

Question 7: State Persistence Trigger

When should game state be persisted to localStorage?

A) On every state change - Maximum data safety, performance impact
B) On game over only - Minimal persistence, risk of data loss
C) Periodic (every 30 seconds) - Balanced approach
D) On pause and game over - User-initiated saves only

Question 8: WebGL Fallback Detection

How should WebGL availability be detected and fallback handled?

A) Try WebGL, fallback immediately if unavailable
B) Feature detection before initialization
C) User preference - Let user choose renderer
D) Progressive enhancement - Start with Canvas 2D, upgrade to WebGL if available

Question 9: Performance Monitoring Scope

What performance metrics should be monitored during gameplay?

A) None - No performance monitoring needed
B) FPS only - Track frame rate
C) FPS and memory - Track frame rate and memory usage
D) Comprehensive - FPS, memory, render time, input latency

Question 10: Component Communication Pattern

How should components communicate with each other?

A) Direct method calls - Simple, tightly coupled
B) Event bus - Decoupled, flexible
C) State manager only - All communication through state
D) Hybrid - Direct calls for critical path, events for others

Step 9: Generate NFR Design Artifacts

• Generate nfr-design-patterns.md with detailed design patterns
• Generate logical-components.md with component architecture

Step 10: Validate NFR Design

• Validate design patterns completeness
• Validate logical components architecture
• Validate alignment with NFR requirements

Step 11: Security Compliance Check

• Verify SECURITY baseline compliance in design patterns
• Document security implementation patterns
• Validate audit logging and error handling design