Chess Game Design

Design a chess game that supports the following features: Users can initiate a match request to a friend. During the game, if the opponent has not made the next move, the user can choose to undo the last move. Additionally, the game should have a leaderboard to display the score ranking of all users at any time. Functional Requirements: Users can send game invitations and compete with friends. Users can undo the last move if the opponent has not made their next move. A leaderboard should be maintained, displaying the ranking based on players' win-loss records. Constraints: Support at least 1000 concurrent online users. Each user has a historical match record of no more than 1000 games on the platform.