jshell script to backup studies into a single file

backup-studies.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/0.0.82/chariot-0.0.82.jar"
        ).toURL().openStream().readAllBytes());
}
/env --class-path chariot.jar

import chariot.*;
import chariot.Client.*;
import chariot.model.*;

void exportStudiesWithClientForUserId(Client client, String userId) throws Exception {
    System.out.println("Downloading studies for " + userId);
    var studies = client.studies().exportStudiesByUserId(userId, p -> p.source()).stream().map(Pgn::toString).toList();
    if (studies.isEmpty()) {
        System.out.println("No studies found by " + userId);
        return;
    }
    var outputFile = Path.of(userId+".studies.pgn");
    Files.write(outputFile, studies);
    System.out.println("Wrote " + studies.size() + " studies to " + outputFile);
}

String userId = System.getProperty("user");

if (userId != null) {
    exportStudiesWithClientForUserId(Client.basic(), userId);
} else {
    var loginResult = Client.auth(uri -> {
            if (java.awt.Desktop.isDesktopSupported()) {
                var desktop = java.awt.Desktop.getDesktop();
                if (desktop.isSupported(java.awt.Desktop.Action.BROWSE)) {
                    try {
                        System.out.println("Opening desktop browser");
                        desktop.browse(uri);
                        return;
                    } catch(Exception e) {
                        System.out.println("Failed to open browser");
                        e.printStackTrace();
                    }
                }
            }
            System.out.println("Visit following Lichess URL to grant this script permission to export private studies:");
            System.out.println(uri);
        },
        pkce -> pkce.scope(Scope.study_read));

    if (loginResult instanceof AuthOk ok) {
        System.out.println("Successfully logged in");
        var profileResult = ok.client().account().profile();
        if (profileResult instanceof Entry<UserAuth> profile) {
            exportStudiesWithClientForUserId(ok.client(), profile.entry().id());
        } else {
            System.err.println("Failed to lookup profile " + profileResult);
        }
        System.out.println("Revoking token (Logging out)");
        ok.client().revokeToken();
    } else {
        System.err.println("Failed to login " + loginResult);
    }
}

/exit

Runs with jshell from Java 17 or newer (https://jdk.java.net/21/)

Example without logging in, (if wanting to backup only public studies),

$ jshell -R-Duser=tors42 backup-studies.jsh
Downloading studies for tors42
Wrote 1 studies to tors42.studies.pgn

Example with logging in (if wanting to backup also private studies),

$ jshell backup-studies.jsh
Opening desktop browser

Now the Web Browser opens a Lichess web page, asking to authorize the script to read studies.
If clicking Authorize,

Successfully logged in
Downloading studies for tors42
Wrote 72 studies to tors42.studies.pgn
Revoking token (Logging out)