# Quick Reference: Tech Stack Decisions

**For comprehensive rationale, see [STACK.md](./STACK.md)**

## One-Page Summary

```
Bot Framework:      discord.py 2.6.4 (Python 3.10+)
Database:           SQLite (MVP) / PostgreSQL (production)
PluralKit:          pluralkit.py + webhook dispatch
Hosting:            Railway ($0-5/month) or Oracle Cloud (free)
Command Style:      Slash commands (/translate 🎭)
```

---

## Installation Checklist (Fresh Project)

```bash
# Create project
mkdir vivi-speech-translator
cd vivi-speech-translator
python -m venv venv
source venv/bin/activate  # or `venv\Scripts\activate` on Windows

# Core dependencies
pip install discord.py==2.6.4
pip install pluralkit==1.1.5
pip install aiosqlite==0.19.0  # MVP database
pip install aiohttp==3.9.0     # Webhook server
pip install emoji==2.11.0      # Emoji handling
pip install pydantic==2.5.0     # Data validation
pip install python-dotenv==1.0.0

# Optional (production)
pip install asyncpg==0.29.0    # PostgreSQL driver
pip install sentry-sdk==1.45.0 # Error tracking

# Testing
pip install pytest==7.4.0
pip install pytest-asyncio==0.23.0
```

---

## Database Quick Start

### MVP (SQLite)
```python
import aiosqlite

# Create database
async with aiosqlite.connect('emoji.db') as db:
    await db.execute('''
        CREATE TABLE IF NOT EXISTS emoji_mappings (
            id INTEGER PRIMARY KEY,
            emoji TEXT UNIQUE NOT NULL,
            meaning TEXT NOT NULL,
            created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
        )
    ''')
    await db.commit()

# Use in bot
async def learn_emoji(emoji_str, meaning):
    async with aiosqlite.connect('emoji.db') as db:
        await db.execute(
            'INSERT INTO emoji_mappings (emoji, meaning) VALUES (?, ?)',
            (emoji_str, meaning)
        )
        await db.commit()
```

### Production (PostgreSQL)
```python
import asyncpg

pool = await asyncpg.create_pool('postgresql://user:pwd@host/db')

async def learn_emoji(emoji_str, meaning):
    async with pool.acquire() as conn:
        await conn.execute(
            'INSERT INTO emoji_mappings (emoji, meaning) VALUES ($1, $2)',
            emoji_str, meaning
        )
```

---

## PluralKit Integration Checklist

- [ ] Get system token: Run `pk;token` in Discord with PluralKit bot
- [ ] Store token in `.env`: `PLURALKIT_TOKEN=pk_...`
- [ ] Create webhook endpoint in your bot
- [ ] Register webhook URL with PluralKit API
- [ ] Set up webhook signature verification (use nacl library)
- [ ] Cache member list in memory on startup
- [ ] Update cache on webhook events (CREATE_MEMBER, UPDATE_MEMBER, DELETE_MEMBER)

**Webhook Endpoint Example:**
```python
from aiohttp import web

async def handle_pk_webhook(request):
    body = await request.text()
    signature = request.headers.get('X-Signature-Ed25519')

    # Verify signature
    if not verify_signature(body, signature):
        return web.Response(status=401)

    data = await request.json()
    # Update emoji mappings based on member changes
    return web.Response(status=200)

# Add to bot setup
app.router.add_post('/webhooks/pluralkit', handle_pk_webhook)
```

---

## Slash Commands vs Prefix Commands

### ✅ Use Slash Commands (Recommended)
```python
@bot.slash_command(name="learn")
async def learn(ctx, emoji: str, meaning: str):
    """Learn what an emoji means"""
    await learn_emoji(emoji, meaning)
    await ctx.respond(f"Learned: {emoji} = {meaning}")

# No MessageContent intent needed!
# Users see autocomplete, clearer UI
```

### ❌ Don't Use Prefix Commands
```python
@bot.command(name="learn")
async def learn(ctx, emoji: str, meaning: str):
    """Learn what an emoji means"""
    # Requires MessageContent intent ❌
    # Harder to use, poor UX
```

---

## Environment Variables (.env)

```bash
# .env (DO NOT COMMIT - add to .gitignore)
DISCORD_TOKEN=your_bot_token_here
PLURALKIT_TOKEN=pk_your_system_token_here
DATABASE_URL=postgresql://user:password@localhost/emojidb
WEBHOOK_SECRET=your_webhook_secret_from_pk

# Optional
SENTRY_DSN=https://...@sentry.io/...
LOG_LEVEL=INFO
```

**Add to .gitignore:**
```
.env
*.db
*.sqlite3
__pycache__/
venv/
```

---

## Bot Intents Configuration

```python
intents = discord.Intents.default()
intents.guilds = True              # Required
intents.members = True             # For member info
intents.message_content = False    # NOT needed (use slash commands)

bot = discord.Bot(intents=intents)
```

**Don't enable message_content unless you parse raw text messages.**

---

## Permissions URL

```
https://discord.com/oauth2/authorize
  ?client_id=YOUR_CLIENT_ID
  &scope=bot
  &permissions=536996928
```

**Permissions included:**
- Read Messages/View Channels (1024)
- Send Messages (2048)
- Embed Links (16384)
- Read Message History (65536)

---

## Hosting Setup

### Railway (Recommended)
```bash
# Install Railway CLI
curl -fsSL https://railway.app/install.sh | bash

# Initialize
railway init

# Deploy from GitHub
# (auto-deploys when you push to main)

# View logs
railway logs

# Set environment variables
railway variables set DISCORD_TOKEN=...
```

### Cost
- First $5/month free credit
- $5 for 1GB RAM for bot
- $15 for PostgreSQL (or get free tier)
- **Total: $0-20/month for small bot**

### Oracle Cloud (Free Alternative)
- 4 CPU, 24GB RAM, 200GB storage VM (always free)
- Run bot + PostgreSQL on same VM
- Note: May delete instances after 60 days inactivity
- Requires Linux/Docker knowledge

---

## Common Commands During Development

```bash
# Run locally
python main.py

# Run tests
pytest

# Format code
black .

# Check types
mypy .

# View database (SQLite)
sqlite3 emoji.db
> SELECT * FROM emoji_mappings;

# View logs on Railway
railway logs -f

# Deploy to Railway
git push origin main  # auto-deploys
```

---

## Anti-Patterns to Avoid

❌ Using Pycord (py-cord) - unmaintained since 2023
❌ Storing bot token in code - use `.env`
❌ Requesting MessageContent intent for slash commands
❌ Polling PluralKit API - use webhooks instead
❌ Synchronous database calls - use async/await
❌ Custom webhook signature verification - use nacl library
❌ Unbounded emoji history table - set expiry policies

---

## Testing Emoji Detection

```python
# test_emoji.py
import pytest
import emoji

def test_emoji_detection():
    test_emoji = "😊"
    assert emoji.is_emoji(test_emoji)

    demojized = emoji.demojize(test_emoji)
    assert demojized == ":smiling_face_with_smiling_eyes:"

@pytest.mark.asyncio
async def test_learn_emoji():
    await learn_emoji("🎭", "happy performance")
    meanings = await get_emoji_meanings("🎭")
    assert "happy performance" in meanings
```

---

## Monitoring in Production

**Recommended additions after MVP:**

1. **Error Tracking:** Sentry for automatic error alerts
2. **Logging:** Structured logging to file or cloud
3. **Metrics:** Track command usage, emoji diversity, member growth
4. **Health Checks:** Endpoint that Railway monitors (`GET /health`)

```python
# Simple health check
@app.route('/health')
async def health(request):
    return web.Response(text='OK', status=200)
```

---

## Troubleshooting Quick Fixes

| Problem | Solution |
|---------|----------|
| Bot doesn't start | Check DISCORD_TOKEN in .env |
| Slash commands not appearing | Call `await bot.sync_commands()` |
| Database locked error (SQLite) | Only one writer at a time - use PostgreSQL for scaling |
| PluralKit webhook not received | Check public URL is reachable, signature verification |
| Slow emoji lookups | Add database indices, implement Redis cache |
| Bot unresponsive | Check for sync calls blocking event loop |

---

## Next Steps

1. **Read full research:** [STACK.md](./STACK.md)
2. **Setup development environment** using checklist above
3. **Start with MVP:** SQLite, slash commands, Vivi user detection
4. **Implement PluralKit:** Webhook dispatch, member caching
5. **Test locally:** Private Discord server for development
6. **Deploy to Railway:** Connect GitHub, set environment variables
7. **Monitor in production:** Sentry, logs, metrics
8. **Iterate:** Gather feedback, add features

---

## Resources

- [discord.py Docs](https://discordpy.readthedocs.io/)
- [PluralKit API](https://pluralkit.me/api/)
- [Railway Getting Started](https://docs.railway.app/)
- [Pydantic Validation](https://docs.pydantic.dev/)
- [emoji Library](https://carpedm20.github.io/emoji/)