firestore.rules

rules_version = '2';
service cloud.firestore {
  match /databases/{database}/documents {
    match /rooms/{room} { 
      function isValidRoom(){
        let hasExactAmountOfProperties = request.resource.data.size() == 2;
        let isCorrectVersion = request.resource.data.version == 1;
        let hasSameNameAsDocumentId = request.resource.data.name == room;
        return hasExactAmountOfProperties && isCorrectVersion && hasSameNameAsDocumentId;
      }

      allow get: if true;
      allow create, update: if isValidRoom();
      allow delete, list: if false;
    }
    match /timers/{timer} {
      function isValidTimer(){
        let hasExactAmountOfProperties = request.resource.data.size() == 4;
        let isCorrectVersion = request.resource.data.version == 1;
        let endTimeIsValid = request.resource.data.endTime != null;
        let typeIsValid = request.resource.data.type == "Work" || request.resource.data.type == "Break" ;
        let durationSecondsIsValid = request.resource.data.durationSeconds > 0;
        return hasExactAmountOfProperties && isCorrectVersion && endTimeIsValid && typeIsValid && durationSecondsIsValid;
      }
      function roomExist(){
        return exists(/databases/$(database)/documents/rooms/$(timer)) == true
      }
      allow read: if true;
      allow create, update: if roomExist() && isValidTimer();
      allow delete, list: if false;
    }
  }
}