# Podcast Architecture & Implementation Plan

## Overview
Convert Daily Digest blog posts into a podcast format with automated TTS generation, RSS feed for distribution, and Supabase Storage for audio file hosting.

## Architecture

### 1. Database Schema Updates
Add `audio_url` and `audio_duration` fields to the `blog_messages` table.

### 2. TTS Generation
**Option A: Piper TTS (Recommended - Free)**
- Local execution, no API costs
- High quality neural voices
- Fast processing
- No rate limits

**Option B: OpenAI TTS (Paid)**
- Premium quality voices
- Simple API integration
- ~$2-4/month for daily 5-min content

### 3. Audio Storage
- **Provider**: Supabase Storage
- **Bucket**: `podcast-audio`
- **Cost**: Free tier includes 1GB storage
- **Access**: Public read via signed URLs

### 4. RSS Feed Generation
- **Endpoint**: `/api/podcast/rss`
- **Format**: RSS 2.0 with iTunes extensions
- **Compatible with**: Apple Podcasts, Spotify, Google Podcasts
- **Auto-updates**: Pulls from blog_messages table

### 5. Integration Points
1. **Daily Digest Workflow** (`/api/digest` POST):
   - After saving post, trigger async TTS generation
   - Upload audio to Supabase Storage
   - Update database with audio_url

2. **RSS Feed** (`/api/podcast/rss`):
   - Returns XML RSS feed
   - Includes all posts with audio_url

3. **Podcast Page** (`/podcast`):
   - Web player for each episode
   - Subscribe links
   - Episode list

## Implementation Steps

### Phase 1: Database & Storage Setup
1. Create `podcast-audio` bucket in Supabase
2. Add columns to blog_messages table

### Phase 2: TTS Service
1. Create `src/lib/tts.ts` - TTS abstraction
2. Create `src/lib/storage.ts` - Supabase storage helpers
3. Create `src/scripts/generate-tts.ts` - TTS generation script

### Phase 3: API Endpoints
1. Create `src/app/api/podcast/rss/route.ts` - RSS feed
2. Update `src/app/api/digest/route.ts` - Add TTS trigger

### Phase 4: UI
1. Create `src/app/podcast/page.tsx` - Podcast page
2. Update post display to show audio player

### Phase 5: Documentation
1. Create `PODCAST_SETUP.md` - Setup instructions
2. Update README with podcast features

## Cost Estimate
- **Piper TTS**: $0 (local processing)
- **OpenAI TTS**: ~$2-4/month
- **Supabase Storage**: $0 (within free tier 1GB)
- **RSS Hosting**: $0 (generated by Next.js API)
- **Total**: $0 (Piper) or $2-4/month (OpenAI)

## File Structure
```
src/
├── app/
│   ├── api/
│   │   ├── digest/route.ts (updated)
│   │   └── podcast/
│   │       └── rss/route.ts (new)
│   ├── podcast/
│   │   └── page.tsx (new)
│   └── page.tsx (updated - add audio player)
├── lib/
│   ├── tts.ts (new)
│   ├── storage.ts (new)
│   └── podcast.ts (new)
└── scripts/
    └── generate-tts.ts (new)
```