/*
 * Password Management Servlets (PWM)
 * http://www.pwm-project.org
 *
 * Copyright (c) 2006-2009 Novell, Inc.
 * Copyright (c) 2009-2018 The PWM Project
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

package password.pwm.http.servlet;

import com.novell.ldapchai.exception.ChaiUnavailableException;
import lombok.Data;
import password.pwm.AppProperty;
import password.pwm.Permission;
import password.pwm.PwmApplication;
import password.pwm.PwmApplicationMode;
import password.pwm.PwmConstants;
import password.pwm.config.Configuration;
import password.pwm.config.PwmSetting;
import password.pwm.config.option.SelectableContextMode;
import password.pwm.error.ErrorInformation;
import password.pwm.error.PwmError;
import password.pwm.error.PwmException;
import password.pwm.error.PwmUnrecoverableException;
import password.pwm.http.HttpHeader;
import password.pwm.http.HttpMethod;
import password.pwm.http.IdleTimeoutCalculator;
import password.pwm.http.ProcessStatus;
import password.pwm.http.PwmHttpRequestWrapper;
import password.pwm.http.PwmRequest;
import password.pwm.http.PwmSession;
import password.pwm.http.PwmURL;
import password.pwm.i18n.Display;
import password.pwm.svc.stats.EpsStatistic;
import password.pwm.svc.stats.Statistic;
import password.pwm.util.LocaleHelper;
import password.pwm.util.java.TimeDuration;
import password.pwm.util.logging.PwmLogger;
import password.pwm.util.macro.MacroMachine;
import password.pwm.util.secure.PwmHashAlgorithm;
import password.pwm.util.secure.SecureEngine;
import password.pwm.ws.server.RestResultBean;
import password.pwm.ws.server.rest.RestHealthServer;
import password.pwm.ws.server.rest.bean.HealthData;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.Serializable;
import java.net.URI;
import java.time.Instant;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.ResourceBundle;
import java.util.TreeMap;
import java.util.TreeSet;

@WebServlet(
        name = "ClientApiServlet",
        urlPatterns = {
                PwmConstants.URL_PREFIX_PUBLIC + "/api",
        }
)
public class ClientApiServlet extends ControlledPwmServlet
{

    private static final PwmLogger LOGGER = PwmLogger.forClass( ClientApiServlet.class );

    @Data
    public static class AppData implements Serializable
    {
        @SuppressWarnings( "checkstyle:MemberName" )
        public Map<String, Object> PWM_GLOBAL;
    }

    @Data
    public static class PingResponse implements Serializable
    {
        private Instant time;
        private String runtimeNonce;
    }

    public enum ClientApiAction implements AbstractPwmServlet.ProcessAction
    {
        clientData( HttpMethod.GET ),
        strings( HttpMethod.GET ),
        health( HttpMethod.GET ),
        ping( HttpMethod.GET ),;

        private final HttpMethod method;

        ClientApiAction( final HttpMethod method )
        {
            this.method = method;
        }

        public Collection<HttpMethod> permittedMethods( )
        {
            return Collections.singletonList( method );
        }
    }

    @Override
    public Class<? extends ProcessAction> getProcessActionsClass( )
    {
        return ClientApiServlet.ClientApiAction.class;
    }

    @Override
    protected void nextStep( final PwmRequest pwmRequest ) throws PwmUnrecoverableException, IOException, ChaiUnavailableException, ServletException
    {
        // no mvc pattern in this servlet
    }

    @Override
    public ProcessStatus preProcessCheck( final PwmRequest pwmRequest ) throws PwmUnrecoverableException, IOException, ServletException
    {
        return ProcessStatus.Continue;
    }


    @ActionHandler( action = "clientData" )
    public ProcessStatus processRestClientData( final PwmRequest pwmRequest )
            throws PwmUnrecoverableException, IOException, ChaiUnavailableException
    {
        final String pageUrl = pwmRequest.readParameterAsString( "pageUrl", PwmHttpRequestWrapper.Flag.BypassValidation );
        final String etagParam = pwmRequest.readParameterAsString( "etag", PwmHttpRequestWrapper.Flag.BypassValidation );

        final int maxCacheAgeSeconds = 60 * 5;

        final String eTagValue = makeClientEtag( pwmRequest.getPwmApplication(), pwmRequest.getPwmSession(), pwmRequest.getHttpServletRequest() );

        // check the incoming header;
        final String ifNoneMatchValue = pwmRequest.readHeaderValueAsString( "If-None-Match" );

        if ( ifNoneMatchValue != null && ifNoneMatchValue.equals( eTagValue ) && eTagValue.equals( etagParam ) )
        {
            pwmRequest.getPwmResponse().setStatus( 304 );
            return ProcessStatus.Halt;
        }

        pwmRequest.getPwmResponse().setHeader( HttpHeader.ETag, eTagValue );
        pwmRequest.getPwmResponse().setHeader( HttpHeader.Expires, String.valueOf( System.currentTimeMillis() + ( maxCacheAgeSeconds * 1000 ) ) );
        pwmRequest.getPwmResponse().setHeader( HttpHeader.CacheControl, "public, max-age=" + maxCacheAgeSeconds );

        final AppData appData = makeAppData(
                pwmRequest.getPwmApplication(),
                pwmRequest.getPwmSession(),
                pwmRequest.getHttpServletRequest(),
                pwmRequest.getPwmResponse().getHttpServletResponse(),
                pageUrl
        );
        final RestResultBean restResultBean = RestResultBean.withData( appData );
        pwmRequest.outputJsonResult( restResultBean );
        return ProcessStatus.Halt;
    }

    @ActionHandler( action = "strings" )
    public ProcessStatus doGetStringsData( final PwmRequest pwmRequest
    )
            throws PwmUnrecoverableException, IOException, ChaiUnavailableException, ServletException
    {
        final String bundleName = pwmRequest.readParameterAsString( "bundle" );
        final int maxCacheAgeSeconds = 60 * 5;

        final String eTagValue = makeClientEtag( pwmRequest.getPwmApplication(), pwmRequest.getPwmSession(), pwmRequest.getHttpServletRequest() );

        pwmRequest.getPwmResponse().setHeader( HttpHeader.ETag, eTagValue );
        pwmRequest.getPwmResponse().setHeader( HttpHeader.Expires, String.valueOf( System.currentTimeMillis() + ( maxCacheAgeSeconds * 1000 ) ) );
        pwmRequest.getPwmResponse().setHeader( HttpHeader.CacheControl, "public, max-age=" + maxCacheAgeSeconds );

        try
        {
            final LinkedHashMap<String, String> displayData = new LinkedHashMap<>( makeDisplayData( pwmRequest.getPwmApplication(),
                    pwmRequest.getPwmSession(), bundleName ) );
            final RestResultBean restResultBean = RestResultBean.withData( displayData );
            pwmRequest.outputJsonResult( restResultBean );
        }
        catch ( Exception e )
        {
            final String errorMSg = "error during rest /strings call for bundle " + bundleName + ", error: " + e.getMessage();
            final ErrorInformation errorInformation = new ErrorInformation( PwmError.ERROR_UNKNOWN, errorMSg );
            LOGGER.debug( pwmRequest, errorInformation );
            pwmRequest.respondWithError( errorInformation );
        }
        return ProcessStatus.Halt;
    }

    @ActionHandler( action = "health" )
    public ProcessStatus restHealthProcessor( final PwmRequest pwmRequest )
            throws IOException, ServletException, PwmUnrecoverableException
    {
        if ( pwmRequest.getPwmApplication().getApplicationMode() == PwmApplicationMode.RUNNING )
        {

            if ( !pwmRequest.isAuthenticated() )
            {
                final ErrorInformation errorInformation = new ErrorInformation( PwmError.ERROR_AUTHENTICATION_REQUIRED );
                LOGGER.debug( pwmRequest, errorInformation );
                pwmRequest.respondWithError( errorInformation );
                return ProcessStatus.Halt;
            }

            if ( !pwmRequest.getPwmSession().getSessionManager().checkPermission( pwmRequest.getPwmApplication(), Permission.PWMADMIN ) )
            {
                final ErrorInformation errorInformation = new ErrorInformation( PwmError.ERROR_UNAUTHORIZED, "admin privileges required" );
                LOGGER.debug( pwmRequest, errorInformation );
                pwmRequest.respondWithError( errorInformation );
                return ProcessStatus.Halt;
            }
        }

        try
        {
            final HealthData jsonOutput = RestHealthServer.processGetHealthCheckData(
                    pwmRequest.getPwmApplication(),
                    pwmRequest.getLocale(),
                    false );
            final RestResultBean restResultBean = RestResultBean.withData( jsonOutput );
            pwmRequest.outputJsonResult( restResultBean );
        }
        catch ( PwmException e )
        {
            final ErrorInformation errorInformation = e.getErrorInformation();
            LOGGER.debug( pwmRequest, errorInformation );
            pwmRequest.respondWithError( errorInformation );
        }
        catch ( Exception e )
        {
            final String errorMessage = "unexpected error executing web service: " + e.getMessage();
            final ErrorInformation errorInformation = new ErrorInformation( PwmError.ERROR_UNKNOWN, errorMessage );
            LOGGER.debug( pwmRequest, errorInformation );
            pwmRequest.respondWithError( errorInformation );
        }
        return ProcessStatus.Halt;
    }

    @ActionHandler( action = "ping" )
    public ProcessStatus processPingRequest( final PwmRequest pwmRequest )
            throws IOException
    {
        final PingResponse pingResponse = new PingResponse();
        pingResponse.setTime( Instant.now() );
        pingResponse.setRuntimeNonce( pwmRequest.getPwmApplication().getRuntimeNonce() );
        pwmRequest.outputJsonResult( RestResultBean.withData( pingResponse ) );
        return ProcessStatus.Halt;
    }

    public static String makeClientEtag( final PwmRequest pwmRequest )
            throws PwmUnrecoverableException
    {
        return makeClientEtag( pwmRequest.getPwmApplication(), pwmRequest.getPwmSession(), pwmRequest.getHttpServletRequest() );
    }

    public static String makeClientEtag(
            final PwmApplication pwmApplication,
            final PwmSession pwmSession,
            final HttpServletRequest httpServletRequest
    )
            throws PwmUnrecoverableException
    {
        final StringBuilder inputString = new StringBuilder();
        inputString.append( PwmConstants.BUILD_NUMBER );
        inputString.append( pwmApplication.getStartupTime().toEpochMilli() );
        inputString.append( httpServletRequest.getSession().getMaxInactiveInterval() );
        inputString.append( pwmApplication.getRuntimeNonce() );

        if ( pwmSession.getSessionStateBean().getLocale() != null )
        {
            inputString.append( pwmSession.getSessionStateBean().getLocale() );
        }

        inputString.append( pwmSession.getSessionStateBean().getSessionID() );
        if ( pwmSession.isAuthenticated() )
        {
            inputString.append( pwmSession.getUserInfo().getUserGuid() );
            inputString.append( pwmSession.getLoginInfoBean().getAuthTime() );
        }

        return SecureEngine.hash( inputString.toString(), PwmHashAlgorithm.SHA1 ).toLowerCase();
    }

    private AppData makeAppData(
            final PwmApplication pwmApplication,
            final PwmSession pwmSession,
            final HttpServletRequest request,
            final HttpServletResponse response,
            final String pageUrl
    )
            throws ChaiUnavailableException, PwmUnrecoverableException
    {
        final AppData appData = new AppData();
        appData.PWM_GLOBAL = makeClientData( pwmApplication, pwmSession, request, response, pageUrl );
        return appData;
    }

    private static Map<String, Object> makeClientData(
            final PwmApplication pwmApplication,
            final PwmSession pwmSession,
            final HttpServletRequest request,
            final HttpServletResponse response,
            final String pageUrl
    )
            throws ChaiUnavailableException, PwmUnrecoverableException
    {
        final Locale userLocale = pwmSession.getSessionStateBean().getLocale();

        final Configuration config = pwmApplication.getConfig();
        final TreeMap<String, Object> settingMap = new TreeMap<>();

        settingMap.put( "client.ajaxTypingTimeout", Integer.parseInt( config.readAppProperty( AppProperty.CLIENT_AJAX_TYPING_TIMEOUT ) ) );
        settingMap.put( "client.ajaxTypingWait", Integer.parseInt( config.readAppProperty( AppProperty.CLIENT_AJAX_TYPING_WAIT ) ) );
        settingMap.put( "client.activityMaxEpsRate", Integer.parseInt( config.readAppProperty( AppProperty.CLIENT_ACTIVITY_MAX_EPS_RATE ) ) );
        settingMap.put( "client.js.enableHtml5Dialog", Boolean.parseBoolean( config.readAppProperty( AppProperty.CLIENT_JS_ENABLE_HTML5DIALOG ) ) );
        settingMap.put( "client.locale", LocaleHelper.getBrowserLocaleString( pwmSession.getSessionStateBean().getLocale() ) );
        settingMap.put( "client.pwShowRevertTimeout", Integer.parseInt( config.readAppProperty( AppProperty.CLIENT_PW_SHOW_REVERT_TIMEOUT ) ) );
        settingMap.put( "enableIdleTimeout", config.readSettingAsBoolean( PwmSetting.DISPLAY_IDLE_TIMEOUT ) );
        settingMap.put( "pageLeaveNotice", config.readSettingAsLong( PwmSetting.SECURITY_PAGE_LEAVE_NOTICE_TIMEOUT ) );
        settingMap.put( "setting-showHidePasswordFields", pwmApplication.getConfig().readSettingAsBoolean( password.pwm.config.PwmSetting.DISPLAY_SHOW_HIDE_PASSWORD_FIELDS ) );
        settingMap.put( "setting-displayEula", PwmConstants.ENABLE_EULA_DISPLAY );
        settingMap.put( "setting-showStrengthMeter", config.readSettingAsBoolean( PwmSetting.PASSWORD_SHOW_STRENGTH_METER ) );

        {
            long idleSeconds = config.readSettingAsLong( PwmSetting.IDLE_TIMEOUT_SECONDS );
            if ( pageUrl == null || pageUrl.isEmpty() )
            {
                LOGGER.warn( pwmSession, "request to /client data did not include pageUrl" );
            }
            else
            {
                try
                {
                    final PwmURL pwmURL = new PwmURL( new URI( pageUrl ), request.getContextPath() );
                    final TimeDuration maxIdleTime = IdleTimeoutCalculator.idleTimeoutForRequest( pwmURL, pwmApplication, pwmSession );
                    idleSeconds = maxIdleTime.as( TimeDuration.Unit.SECONDS );
                }
                catch ( Exception e )
                {
                    LOGGER.error( pwmSession, "error determining idle timeout time for request: " + e.getMessage() );
                }
            }
            settingMap.put( "MaxInactiveInterval", idleSeconds );
        }
        settingMap.put( "paramName.locale", config.readAppProperty( AppProperty.HTTP_PARAM_NAME_LOCALE ) );
        settingMap.put( "runtimeNonce", pwmApplication.getRuntimeNonce() );
        settingMap.put( "applicationMode", pwmApplication.getApplicationMode() );

        final String contextPath = request.getContextPath();
        settingMap.put( "url-context", contextPath );
        settingMap.put( "url-logout", contextPath + PwmServletDefinition.Logout.servletUrl() );
        settingMap.put( "url-command", contextPath + PwmServletDefinition.PublicCommand.servletUrl() );
        settingMap.put( "url-resources", contextPath + "/public/resources" + pwmApplication.getResourceServletService().getResourceNonce() );
        settingMap.put( "url-restservice", contextPath + "/public/rest" );

        {
            String passwordGuideText = pwmApplication.getConfig().readSettingAsLocalizedString(
                    PwmSetting.DISPLAY_PASSWORD_GUIDE_TEXT,
                    pwmSession.getSessionStateBean().getLocale()
            );
            final MacroMachine macroMachine = pwmSession.getSessionManager().getMacroMachine( pwmApplication );
            passwordGuideText = macroMachine.expandMacros( passwordGuideText );
            settingMap.put( "passwordGuideText", passwordGuideText );
        }

        {
            final List<String> epsTypes = new ArrayList<>();
            for ( final EpsStatistic loopEpsType : EpsStatistic.values() )
            {
                epsTypes.add( loopEpsType.toString() );
            }
            settingMap.put( "epsTypes", epsTypes );
        }

        {
            final List<String> epsDurations = new ArrayList<>();
            for ( final Statistic.EpsDuration loopEpsDuration : Statistic.EpsDuration.values() )
            {
                epsDurations.add( loopEpsDuration.toString() );
            }
            settingMap.put( "epsDurations", epsDurations );
        }

        {
            final Map<String, String> localeInfo = new LinkedHashMap<>();
            final Map<String, String> localeDisplayNames = new LinkedHashMap<>();
            final Map<String, String> localeFlags = new LinkedHashMap<>();

            final List<Locale> knownLocales = new ArrayList<>( pwmApplication.getConfig().getKnownLocales() );
            knownLocales.sort( LocaleHelper.localeComparator( PwmConstants.DEFAULT_LOCALE ) );

            for ( final Locale locale : knownLocales )
            {
                final String flagCode = pwmApplication.getConfig().getKnownLocaleFlagMap().get( locale );
                localeFlags.put( locale.toString(), flagCode );
                localeInfo.put( locale.toString(), locale.getDisplayName( PwmConstants.DEFAULT_LOCALE ) + " - " + locale.getDisplayLanguage( userLocale ) );
                localeDisplayNames.put( locale.toString(), locale.getDisplayLanguage() );
            }

            settingMap.put( "localeInfo", localeInfo );
            settingMap.put( "localeDisplayNames", localeDisplayNames );
            settingMap.put( "localeFlags", localeFlags );
            settingMap.put( "defaultLocale", PwmConstants.DEFAULT_LOCALE.toString() );
        }

        if ( pwmApplication.getConfig().readSettingAsEnum( PwmSetting.LDAP_SELECTABLE_CONTEXT_MODE, SelectableContextMode.class ) != SelectableContextMode.NONE )
        {
            final Map<String, Map<String, String>> ldapProfiles = new LinkedHashMap<>();
            for ( final String ldapProfile : pwmApplication.getConfig().getLdapProfiles().keySet() )
            {
                final Map<String, String> contexts = pwmApplication.getConfig().getLdapProfiles().get( ldapProfile ).getSelectableContexts( pwmApplication );
                ldapProfiles.put( ldapProfile, contexts );
            }
            settingMap.put( "ldapProfiles", ldapProfiles );
        }

        return settingMap;
    }


    private Map<String, String> makeDisplayData(
            final PwmApplication pwmApplication,
            final PwmSession pwmSession,
            final String bundleName
    )
    {
        Class displayClass = LocaleHelper.classForShortName( bundleName );
        displayClass = displayClass == null ? Display.class : displayClass;

        final Locale userLocale = pwmSession.getSessionStateBean().getLocale();
        final Configuration config = pwmApplication.getConfig();
        final TreeMap<String, String> displayStrings = new TreeMap<>();
        final ResourceBundle bundle = ResourceBundle.getBundle( displayClass.getName() );
        try
        {
            final MacroMachine macroMachine = pwmSession.getSessionManager().getMacroMachine( pwmApplication );
            for ( final String key : new TreeSet<>( Collections.list( bundle.getKeys() ) ) )
            {
                String displayValue = LocaleHelper.getLocalizedMessage( userLocale, key, config, displayClass );
                displayValue = macroMachine.expandMacros( displayValue );
                displayStrings.put( key, displayValue );
            }
        }
        catch ( Exception e )
        {
            LOGGER.error( pwmSession, "error expanding macro display value: " + e.getMessage() );
        }
        return displayStrings;
    }

}