firestore.rules

rules_version = '2';
service cloud.firestore {
  match /databases/{database}/documents {
    function isSignedIn() {
      return request.auth.uid != null;
    }
    function isSnippetOwner() {
      return resource.data.owner == request.auth.uid;
    }
    function isPublic() {
      return resource.data.visibility == 'public';
    }
    function isUnlisted() {
      return resource.data.visibility == 'unlisted';
    }
    function isLiker() {
      return resource.data.userID == request.auth.uid;
    }

    match /users/{user} {
      allow read, write: if isSignedIn() && user == request.auth.uid;
    }

    match /snippets/{snippet} {
      allow read: if isPublic() || isUnlisted() || (isSignedIn() && isSnippetOwner());
      allow create: if true;
      allow update, delete: if isSignedIn() && isSnippetOwner();
    }

    match /likes/{like} {
      // Likes are public info
      allow read: if true;
      allow create: if isSignedIn();
      allow update, delete: if isLiker();
    }
  }
}