signal-cli/src/main/java/org/asamk/signal/dbus/DbusCommandHandler.java

package org.asamk.signal.dbus;

import org.asamk.Signal;
import org.asamk.SignalControl;
import org.asamk.signal.DbusConfig;
import org.asamk.signal.commands.Command;
import org.asamk.signal.commands.CommandHandler;
import org.asamk.signal.commands.LocalCommand;
import org.asamk.signal.commands.MultiLocalCommand;
import org.asamk.signal.commands.ProvisioningCommand;
import org.asamk.signal.commands.RegistrationCommand;
import org.asamk.signal.commands.exceptions.CommandException;
import org.asamk.signal.commands.exceptions.UnexpectedErrorException;
import org.asamk.signal.commands.exceptions.UserErrorException;
import org.freedesktop.dbus.connections.impl.DBusConnection;
import org.freedesktop.dbus.connections.impl.DBusConnectionBuilder;
import org.freedesktop.dbus.errors.ServiceUnknown;
import org.freedesktop.dbus.errors.UnknownMethod;
import org.freedesktop.dbus.exceptions.DBusException;
import org.freedesktop.dbus.exceptions.DBusExecutionException;

import java.io.IOException;

public class DbusCommandHandler {

    public static void initDbusClient(
            final Command command,
            final String account,
            final boolean systemBus,
            final String busname,
            final CommandHandler commandHandler
    ) throws CommandException {
        try {
            final var busType = systemBus ? DBusConnection.DBusBusType.SYSTEM : DBusConnection.DBusBusType.SESSION;
            try (var dBusConn = DBusConnectionBuilder.forType(busType).build()) {
                handleCommand(command, account, dBusConn, busname, commandHandler);
            }
        } catch (ServiceUnknown e) {
            throw new UserErrorException("signal-cli DBus daemon not running on "
                    + (systemBus ? "system" : "session")
                    + " bus: "
                    + e.getMessage(), e);
        } catch (DBusExecutionException | DBusException | IOException e) {
            throw new UnexpectedErrorException("Dbus client failed: " + e.getMessage(), e);
        }
    }

    public static void handleCommand(
            final Command command,
            final String account,
            final DBusConnection dBusConn,
            final String busname,
            final CommandHandler commandHandler
    ) throws CommandException, DBusException {
        try {
            if (command instanceof ProvisioningCommand c) {
                if (account != null) {
                    throw new UserErrorException("You cannot specify an account when linking");
                }

                handleProvisioningCommand(c, dBusConn, busname, commandHandler);
                return;
            }

            if (account == null && command instanceof MultiLocalCommand c) {
                handleMultiLocalCommand(c, dBusConn, busname, commandHandler);
                return;
            }
            if (account != null && command instanceof RegistrationCommand c) {
                handleRegistrationCommand(c, account, dBusConn, busname, commandHandler);
                return;
            }
            if (!(command instanceof LocalCommand localCommand)) {
                throw new UserErrorException("Command only works in multi-account mode");
            }

            var accountObjectPath = account == null
                    ? tryGetSingleAccountObjectPath(dBusConn, busname)
                    : getAccountObjectPath(account, dBusConn, busname);
            if (accountObjectPath == null) {
                accountObjectPath = DbusConfig.getObjectPath(account);
            }
            handleLocalCommand(localCommand, accountObjectPath, dBusConn, busname, commandHandler);
        } catch (UnsupportedOperationException e) {
            throw new UserErrorException("Command is not yet implemented via dbus", e);
        } catch (DBusExecutionException e) {
            throw new UnexpectedErrorException(e.getMessage(), e);
        }
    }

    private static String getAccountObjectPath(
            final String account,
            final DBusConnection dBusConn,
            final String busname
    ) throws DBusException, CommandException {
        final var control = dBusConn.getRemoteObject(busname, DbusConfig.getObjectPath(), SignalControl.class);
        try {
            return control.getAccount(account).getPath();
        } catch (UnknownMethod e) {
            // A single-account daemon exports Signal directly at the base path.
            final var signal = dBusConn.getRemoteObject(busname, DbusConfig.getObjectPath(), Signal.class);
            if (!account.equals(signal.getSelfNumber()) && !account.equals(signal.getSelfACI())) {
                throw new UserErrorException("Unknown account: " + account);
            }
            return DbusConfig.getObjectPath();
        }
    }

    private static String tryGetSingleAccountObjectPath(
            final DBusConnection dBusConn,
            final String busname
    ) throws DBusException, CommandException {
        var control = dBusConn.getRemoteObject(busname, DbusConfig.getObjectPath(), SignalControl.class);
        try {
            final var accounts = control.listAccounts();
            if (accounts.isEmpty()) {
                throw new UserErrorException("No local users found, you first need to register or link an account");
            } else if (accounts.size() > 1) {
                throw new UserErrorException(
                        "Multiple users found, you need to specify an account (phone number or ACI) with -a");
            }

            return accounts.getFirst().getPath();
        } catch (UnknownMethod e) {
            // dbus daemon not running in multi-account mode
            return null;
        }
    }

    private static void handleMultiLocalCommand(
            final MultiLocalCommand c,
            final DBusConnection dBusConn,
            final String busname,
            final CommandHandler commandHandler
    ) throws CommandException, DBusException {
        final var signalControl = dBusConn.getRemoteObject(busname, DbusConfig.getObjectPath(), SignalControl.class);
        try (final var multiAccountManager = new DbusMultiAccountManagerImpl(signalControl, dBusConn, busname)) {
            commandHandler.handleMultiLocalCommand(c, multiAccountManager);
        }
    }

    private static void handleLocalCommand(
            final LocalCommand c,
            String accountObjectPath,
            final DBusConnection dBusConn,
            final String busname,
            final CommandHandler commandHandler
    ) throws CommandException, DBusException {
        var signal = dBusConn.getRemoteObject(busname, accountObjectPath, Signal.class);
        try (final var manager = new DbusManagerImpl(signal, dBusConn, busname)) {
            commandHandler.handleLocalCommand(c, manager);
        }
    }

    private static void handleRegistrationCommand(
            final RegistrationCommand c,
            String account,
            final DBusConnection dBusConn,
            final String busname,
            final CommandHandler commandHandler

    ) throws CommandException, DBusException {
        final var signalControl = dBusConn.getRemoteObject(busname, DbusConfig.getObjectPath(), SignalControl.class);
        try (final var registrationManager = new DbusRegistrationManagerImpl(account, signalControl, dBusConn)) {
            commandHandler.handleRegistrationCommand(c, registrationManager);
        }
    }

    private static void handleProvisioningCommand(
            final ProvisioningCommand c,
            final DBusConnection dBusConn,
            final String busname,
            final CommandHandler commandHandler

    ) throws CommandException, DBusException {
        final var signalControl = dBusConn.getRemoteObject(busname, DbusConfig.getObjectPath(), SignalControl.class);
        final var provisioningManager = new DbusProvisioningManagerImpl(signalControl, dBusConn);
        commandHandler.handleProvisioningCommand(c, provisioningManager);
    }
}