/**
 * MailArchiver is an application that provides services for storing and managing e-mail messages through a Web Services SOAP interface.
 * Copyright (C) 2012  Marcio Andre Scholl Levien and Fernando Alberto Reuter Wendt and Jose Ronaldo Nogueira Fonseca Junior
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/******************************************************************************\
*
*  This product was developed by
*
*        SERVIÇO FEDERAL DE PROCESSAMENTO DE DADOS (SERPRO),
*
*  a government company established under Brazilian law (5.615/70),
*  at Department of Development of Porto Alegre.
*
\******************************************************************************/

package serpro.mailarchiver.util;

import com.sun.jna.Platform;
import com.sun.jna.platform.win32.Advapi32;
import com.sun.jna.platform.win32.Kernel32;
import com.sun.jna.platform.win32.W32Errors;
import com.sun.jna.platform.win32.WinBase;
import com.sun.jna.platform.win32.WinNT.HANDLE;
import com.sun.jna.platform.win32.WinNT.HANDLEByReference;

import org.jvnet.libpam.PAM;
import org.jvnet.libpam.PAMException;
import org.jvnet.libpam.UnixUser;

public class SystemAuthenticator {

    private static final Logger log = Logger.getLocalLogger();

    public SystemAccount authenticate(String username, String password) {
        return authenticate(username, password, null);
    }

    public SystemAccount authenticate(String username, String password, String domain) {

        if(username == null) {
            return null;
        }
    	if(password == null) {
            password = "";
        }
    	if(domain == null) {
            //domain = "";
            domain = ""; // "." significa usar a estação local
        }

        if(Platform.isWindows()) {

            HANDLE token = null;

            try {
                HANDLEByReference tokenRef = new HANDLEByReference();

                boolean success = Advapi32.INSTANCE.LogonUser(
                        username, domain, password,

                        //Logon types e desc -> http://msdn.microsoft.com/en-us/library/windows/desktop/aa378184%28v=vs.85%29.aspx
                        //WinBase.LOGON32_LOGON_BATCH,
                        //WinBase.LOGON32_LOGON_NETWORK,
                        //WinBase.LOGON32_LOGON_SERVICE,
                        //WinBase.LOGON32_LOGON_INTERACTIVE,
                        WinBase.LOGON32_LOGON_NETWORK_CLEARTEXT,
                        WinBase.LOGON32_PROVIDER_DEFAULT,
                        tokenRef);

                if(success) {
                    token = tokenRef.getValue();
                    return new SystemAccount(token);
                }
                else {
                    int error = Kernel32.INSTANCE.GetLastError();
                    String errorDesc;
                    switch(error) {
                        case W32Errors.ERROR_LOGON_FAILURE:
                            errorDesc = "logon failure";
                            break;

                        case W32Errors.ERROR_INVALID_PARAMETER:
                            errorDesc = "invalid parameter";
                            break;

                        case W32Errors.ERROR_INVALID_PASSWORD:
                            errorDesc = "invalid password";
                            break;

                        case W32Errors.ERROR_LOGON_NOT_GRANTED:
                            errorDesc = "logon not granted";
                            break;

                        case W32Errors.ERROR_LOGON_TYPE_NOT_GRANTED:
                            errorDesc = "logon type not granted";
                            break;

                        case W32Errors.ERROR_ACCOUNT_RESTRICTION:
                            errorDesc = "account restriction";
                            break;

                        default:
                            errorDesc = "" + error;
                    }
                    log.error("System authentication error: %s", errorDesc);
                }
            }
            finally {
                if(token != null) {
                    Kernel32.INSTANCE.CloseHandle(token);
                }
            }
        }
        else {

            PAM pam = null;

            try {
                pam = new PAM("common-auth");
                UnixUser unixUser = pam.authenticate(username, password);
                return new SystemAccount(unixUser);
            }
            catch(PAMException ex) {
                log.error("System authentication error: %s" + ex.getMessage());
            }
            finally {
                if(pam != null) {
                    pam.dispose();
                }
            }
        }
        return null;
    }
}