Firestore security rule

sample.rule

service cloud.firestore {
  match /databases/{database}/documents {
    function isOwn() {
      return request.resource.userId == request.auth.uid;
    }
    function hasTimestamp() {
      return request.resource.data.timestamp == request.time;
    }
    function isCalm() {
      return request.time > resource.data.timestamp + duration.value(5, 's');
    }
    function isBlackListed() {
      return exists(/databases/$(database)/documents/blacklist/$(request.auth.uid))
    }
    match /histories/{history} {
      allow create: if isOwn() && hasTimestamp() && !isBlackListed();
      allow update: if isOwn() && hasTimestamp() && isCalm() && !isBlackListed();
    }
  }
}