firestore.rules

rules_version = '2';
service cloud.firestore {
  match /databases/{database}/documents {
    match /{documents=**} {
      allow read, write: if false;
    }

    function isRequester(uid) {
      return request.auth != null && request.auth.uid == uid;
    }

    match /profiles/{profileUid} {
      allow read;
      allow create: if
        'birthDate' in request.resource.data &&
        'bio' in request.resource.data &&
        'gender' in request.resource.data &&
        'name' in request.resource.data &&
        'language' in request.resource.data &&
        'fluency' in request.resource.data &&
        'username' in request.resource.data;
      allow update, delete: if isRequester(profileUid);
    }

    match /chats/{chatUid} {
      function inChat() {
        return request.auth != null && request.auth.uid in get(/databases/$(database)/documents/chats/$(chatUid)).data.members;
      }

      allow create;
      allow read: if inChat();

      match /messages/{messageUid} {
        allow read, create: if inChat();
        allow update, delete: if request.auth != null && resource.data.author == request.auth.uid;
      }

      match /readReceipts/{userUid} {
        allow read, write: if isRequester(userUid);
      }
    }
  }
}