# Base de Dados — Firestore

## 🔐 Users

users/
  userId/
    email: string
    username: string
    themeMode: "system" | "light" | "dark"
    primaryColor: string (hex)
    language: "pt" | "en"
    favoriteGenres: [string]
    createdAt: timestamp

---

## 🎵 Songs

songs/
  songId/
    title: string
    artist: string
    url: string
    coverUrl: string
    userId: string
    genre: string
    mood: string
    duration: number
    createdAt: timestamp

---

## 📂 Playlists

playlists/
  playlistId/
    name: string
    userId: string
    songs: [songId]
    createdAt: timestamp

---

## 💬 Chats

chats/
  chatId/
    participants: [userId]
    lastMessage: string
    updatedAt: timestamp

---

## 📨 Messages

messages/
  messageId/
    chatId: string
    senderId: string
    text: string (optional)
    songId: string (optional)
    timestamp: timestamp

---

## ⚡ Regras importantes

- Nunca duplicar dados desnecessários
- Usar IDs para relações
- Otimizar leituras (Firestore billing)