Simple example implemented using YouTrack .NET client library
Sample .NET client application that interacts with YouTrack via REST API
Basic workflow shown is as follows :
1. Ask user for project ID
2. Ask user for search string
2a. If search string is NOT empty - search for issues in the project which contain search string. If list is not empty - print all issues, and select the most recent one (by update date).
2b. If search string is empty - then CREATE new issue with issue title = search string.
3. As the result of item (2) we have a NON-EMPTY issue variable, so:
3a. Add a comment - "test"
3b. Set priority to MAJOR; state to OPEN;
3c. Assign the issue to ## SOME VALID USER ID ##
4. If issue was created in (2) - delete it, otherwise do nothing.