firestore.rules

rules_version = '2';
service cloud.firestore {
  match /databases/{database}/documents {
    match /users/{userId} {
      allow read: if request.auth != null;
      allow create: if request.auth != null && request.auth.uid == userId;
      allow update: if request.auth != null && request.auth.uid == userId;

     
      function isValidUser() {
        let user = request.resource.data;
        return user.displayName is string
          && user.email is string
          && (user.photoURL is string || user.photoURL == null)
          && user.credits is number
          && (user.friends is list || user.friends == null)
          && (('friendRequests' in user && user.friendRequests.sent is list && user.friendRequests.received is list) 
              || !('friendRequests' in user));
      }
    }

    match /chats/{chatId} {
      allow read, write: if request.auth != null;
    }

    match /messages/{messageId} {
      allow read, write: if request.auth != null;
    }
  }
}