POWR/docs/design/Analysis/OlasSocialFeed.md

After analyzing Olas's social feed implementation, I can provide you with valuable insights for building your workout-focused social feed using Nostr. Here's a breakdown of their implementation and how you can adapt it for POWR:

Key Components of Olas's Feed Implementation

1. Feed Architecture

• They use a main Feed component with two key parts:
  • useFeedEvents hook for managing feed data
  • useFeedMonitor hook for monitoring and updating feed entries

2. NDK Integration

import { 
    NDKEvent, 
    NDKFilter, 
    NDKKind, 
    NDKSubscription,
    useNDK 
} from "@nostr-dev-kit/ndk-mobile";

3. Event Filtering

• They filter events based on specific kinds:

switch (event.kind) {
    case NDKKind.VerticalVideo:
    case NDKKind.HorizontalVideo:
    case 30018:
    case 30402:
    case NDKKind.Text:
    case NDKKind.Media:
    case NDKKind.Image: 
        return handleContentEvent(eventId, event);

Implementing POWR's Workout Feed

For your workout app, here's how you can adapt their implementation:

1. Event Kind Definition

// Define workout event kind
const WORKOUT_EVENT_KIND = 30311; // Choose an appropriate kind number for workouts

2. Feed Filter Setup

const workoutFeedFilters: NDKFilter[] = [{
    kinds: [WORKOUT_EVENT_KIND],
    // Add any additional filters like tags
}];

3. Feed Component

import { NDKEvent, NDKFilter, useNDK } from "@nostr-dev-kit/ndk-mobile";

export function WorkoutFeed() {
    const { entries, newEntries, updateEntries } = useFeedEvents(
        workoutFeedFilters,
        { 
            subId: 'workout-feed',
            filterFn: (entry) => {
                // Add custom filtering for workout events
                return true;
            }
        }
    );

    return (
        <FlashList
            data={entries}
            renderItem={({ item }) => (
                <WorkoutPost 
                    event={item.event}
                    timestamp={item.timestamp}
                />
            )}
            estimatedItemSize={400}
        />
    );
}

4. Useful NDK Tools to Leverage

• Subscription Management

const subscription = ndk.subscribe(
    workoutFeedFilters,
    { 
        groupable: false,
        skipVerification: true,
        subId: 'workout-feed'
    }
);

subscription.on("event", handleWorkoutEvent);
subscription.once('eose', handleEose);

• Event Processing

const handleWorkoutEvent = (event: NDKEvent) => {
    // Process workout specific data
    const workout = {
        id: event.id,
        type: event.tagValue('workout-type'),
        duration: event.tagValue('duration'),
        // other workout specific fields
    };
    
    // Update feed
    updateEntry(event.id, (entry) => ({
        ...entry,
        event,
        workout,
        timestamp: event.created_at
    }));
};

5. Feed Entry Type

type WorkoutFeedEntry = {
    id: string;
    event?: NDKEvent;
    workout?: {
        type: string;
        duration: string;
        // other workout metadata
    };
    timestamp: number;
};

Key NDK Tools to Use

1. Event Subscription

• NDKSubscription for real-time workout updates
• NDKFilter for filtering workout-specific events

2. Event Processing

• NDKEvent for handling workout event data
• Event tags for workout metadata

3. Feed Management

• useFeedEvents hook pattern for managing workout feed state
• Entry caching and update mechanisms

Best Practices from Olas's Implementation

1. Performance Optimization

• Use of FlashList for efficient list rendering
• Implement entry caching
• Handle new entries efficiently

2. State Management

• Track active entries
• Manage subscription lifecycle
• Handle feed updates appropriately

3. User Experience

• Implement pull-to-refresh
• Show new entries notification
• Handle scrolling and viewing positions

Additional Recommendations for POWR

1. Workout-Specific Filters

• Add filters for workout types
• Filter by duration, intensity, etc.
• Use workout-specific tags

2. Data Structure

// Workout event structure
const workoutEvent = {
    kind: WORKOUT_EVENT_KIND,
    tags: [
        ['workout-type', 'strength'],
        ['duration', '45'],
        ['exercises', JSON.stringify(exercises)],
        // Additional metadata
    ],
    content: workoutDescription
};

3. Real-time Updates

• Implement real-time workout progress updates
• Show active workouts in progress
• Enable social interactions during workouts

This implementation will give you a solid foundation for building a workout-focused social feed using Nostr. The key is adapting Olas's efficient feed management system while customizing it for workout-specific content and interactions.