A script which uses the Lichess API to listen for events, in order to detect any missed challenges

missed-challenges.jsh

if (! Files.exists(Path.of("chariot.jar"))) {
    Files.write(Path.of("chariot.jar"), URI.create(
        "https://repo1.maven.org/maven2/io/github/tors42/chariot/0.0.84/chariot-0.0.84.jar"
        ).toURL().openStream().readAllBytes());
}
/env --class-path chariot.jar

import java.time.LocalTime;
import java.util.prefs.Preferences;

import chariot.*;
import chariot.Client.*;
import chariot.model.*;
import chariot.model.ChallengeInfo.FromTo;
import chariot.model.Event.*;

void logMissedChallenges(ClientAuth client, String myId) {
    client.board().connect().stream().forEach(event -> { switch(event) {
        case GameStartEvent         start    -> {
        }
        case GameStopEvent          stop     -> {
        }
        case ChallengeCreatedEvent  created  -> {
        }
        case ChallengeDeclinedEvent declined -> {
        }
        case ChallengeCanceledEvent canceled -> {
            if (canceled.challenge().players() instanceof FromTo(var challenger, var challenged)
                && challenged.user().id().equals(myId)) {
                System.out.println(LocalTime.now().withNano(0) + " Missed challenge from " + challenger.user());
            }
        }
    }});
}

ClientAuth initializeClient() {
    return switch(Client.load(Preferences.userRoot().node("challenge-log"))) {
        case ClientAuth client when client.scopes().contains(Scope.challenge_read) -> client;
        case Client client -> switch(client.withPkce(
                    url -> System.out.println("Visit Lichess to grant access at,\n" + url),
                    pkce -> pkce.scope(Scope.challenge_read))) {
            case AuthOk(var ok) -> {
                ok.store(Preferences.userRoot().node("challenge-log"));
                yield ok;
            }
            case AuthFail(var msg) -> {
                System.out.println("Failed to authenticate: " + msg);
                yield null;
            }
        };
    };
}

if (initializeClient() instanceof ClientAuth client
    && client.account().profile() instanceof Entry(var user)) {

    System.out.println("Listening for missed challenges...");
    logMissedChallenges(client, user.id());

} else {
    System.out.println("Failed to listen for missed challenges.");
}

Uses Java (jshell), whcih can be downloaded from here for instance: https://jdk.java.net/21/

When running the script the first time,
it will ask for authorization to read challenges on Lichess.

Subsequent runs will reuse the received authorization token.
(The token can be revoked at any time at the Security page, https://lichess.org/account/security)

$ jshell missed-challenges.jsh
Listening for missed challenges...
16:56:05 Missed challenge from [BOT] charibot (charibot)
...

Here's a video showing it in action,
where my "tors42" account is listening for missed challenges,
and I use my bot account "charibot" to send and cancel a challenge to "tors42",
and the "missed-challenges.jsh" script shows a message about the missed challenge!

missed-challenges.webm