/*******************************************************************************
 * Copyright 2019 Graz University of Technology
 * MOA ZS has been developed in a cooperation between EGIZ
 * and Graz University of Technology.
 * Licensed under the EUPL, Version 1.2 or - as soon they will be approved by
 * the European Commission - subsequent versions of the EUPL (the "Licence");
 * You may not use this work except in compliance with the Licence.
 * You may obtain a copy of the Licence at:
 * https://joinup.ec.europa.eu/news/understanding-eupl-v12
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the Licence is distributed on an "AS IS" basis,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the Licence for the specific language governing permissions and
 * limitations under the Licence.
 *
 * This product combines work with different licenses. See the "NOTICE" text
 * file for details on the various modules and licenses.
 * The "NOTICE" text file is part of the distribution. Any derivative works
 * that you distribute must include a readable copy of the "NOTICE" text file.
 *******************************************************************************/
package at.gv.egiz.moazs.preprocess;

import at.gv.egiz.moazs.util.StringUtils;
import at.gv.zustellung.app2mzs.xsd.*;
import org.springframework.stereotype.Component;

import java.math.BigInteger;
import java.util.List;
import java.util.Map;
import java.util.stream.Stream;

import static at.gv.zustellung.app2mzs.xsd.ClientType.clientTypeBuilder;
import static at.gv.zustellung.app2mzs.xsd.ConfigType.configTypeBuilder;
import static at.gv.zustellung.app2mzs.xsd.CustomHTTPHeaderType.*;
import static at.gv.zustellung.app2mzs.xsd.ForwardResponseToServiceType.forwardResponseToServiceTypeBuilder;
import static at.gv.zustellung.app2mzs.xsd.KeyStoreType.keyStoreTypeBuilder;
import static at.gv.zustellung.app2mzs.xsd.MsgResponseSinksType.msgResponseSinksTypeBuilder;
import static at.gv.zustellung.app2mzs.xsd.SSLType.SSLTypeBuilder;
import static at.gv.zustellung.app2mzs.xsd.SaveResponseToFileType.saveResponseToFileTypeBuilder;
import static java.util.stream.Collectors.toList;
import static java.util.stream.Collectors.toMap;

/**
 * @author Christof Rabensteiner
 *
 */
@Component
public class ConfigUtil {

    public static final String TNVZ_REQUEST_KEY = "perform-query-person-request";
    public static final String MSG_CLIENT_KEY = "msg-client";
    public static final String TNVZ_CLIENT_KEY = "tnvz-client";
    public static final String URL_KEY = "url";
    public static final String SSL_KEY = "ssl";
    public static final String TRUST_ALL_KEY = "trust-all";
    public static final String LAX_HOSTNAME_VERIFICATION_KEY = "lax-hostname-verification";
    public static final String KEYSTORE_KEY = "keystore";
    public static final String TRUSTSTORE_KEY = "truststore";
    public static final String FILENAME_KEY = "filename";
    public static final String FILETYPE_KEY = "filetype";
    public static final String PASSWORD_KEY = "password";
    public static final String RECEIVE_TIMEOUT_KEY = "receive-timeout";
    public static final String CONNECTION_TIMEOUT_KEY = "connection-timeout";
    public static final String MSG_RESPONSE_SINKS_KEY = "msg-response-sinks";
    public static final String LOG_RESPONSE_KEY = "log-response";
    public static final String SAVE_RESPONSE_TO_FILE_KEY = "save-response-to-file";
    public static final String ACTIVE_KEY = "active";
    public static final String SAVE_RESPONSE_TO_FILE_PATH_KEY = "path";
    public static final String FORWARD_RESPONSE_TO_SERVICE_KEY = "forward-response-to-service";
    public static final String APP_CLIENT_KEY = "app-client";
    public static final String SERVICE_TIMEOUT_KEY = "service-timeout";
    public static final String CUSTOM_HTTP_HEADERS_KEY = "custom-http-headers";


    /**
     * Convert a map into a Config object.
     *
     * @param values: Map with well-defined indexes and values
     * @return Config
     */
    public ConfigType convert(Map<String, String> values) {
        Boolean performQueryPersonRequest = booleanOrNull(values.get(TNVZ_REQUEST_KEY));

        var msgClientParams = filterMapByPrefix(values, MSG_CLIENT_KEY);
        ClientType msgClient = msgClientParams.isEmpty()
                ? null : buildClient(msgClientParams);

        var tnvzClientParams = filterMapByPrefix(values, TNVZ_CLIENT_KEY);
        ClientType tnvzClient = tnvzClientParams.isEmpty()
                ? null : buildClient(tnvzClientParams);

        var msgResponseSinksParams = filterMapByPrefix(values, MSG_RESPONSE_SINKS_KEY);
        MsgResponseSinksType sinks = msgResponseSinksParams.isEmpty()
                ? null : buildMsgResponseSinks(msgResponseSinksParams);

        var serviceTimeout = bigIntOrNull(values.get(SERVICE_TIMEOUT_KEY));

        return ConfigType.configTypeBuilder()
                .withPerformQueryPersonRequest(performQueryPersonRequest)
                .withMSGClient(msgClient)
                .withTNVZClient(tnvzClient)
                .withMsgResponseSinks(sinks)
                .withServiceTimeout(serviceTimeout)
                .build();
    }

    private Map<String, String> filterMapByPrefix(Map<String, String> values, String prefix) {
        return values.entrySet().stream()
                .filter(entry -> entry.getKey().startsWith(prefix))
                .collect(toMap(e -> StringUtils.removePrefix(e.getKey()), Map.Entry::getValue));
    }


    private ClientType buildClient(Map<String, String> clientParams) {

        var url = clientParams.get(URL_KEY);

        var connectionTimeout = bigIntOrNull(clientParams.get(CONNECTION_TIMEOUT_KEY));

        var receiveTimeout = bigIntOrNull(clientParams.get(RECEIVE_TIMEOUT_KEY));

        var sslParams = filterMapByPrefix(clientParams, SSL_KEY);
        SSLType ssl = sslParams.isEmpty()
                ? null : buildSSL(sslParams);

        var customHeaderParams = filterMapByPrefix(clientParams, CUSTOM_HTTP_HEADERS_KEY);
        var customHeaders = customHeaderParams.isEmpty()
                ? null : convertMapToHeaders(customHeaderParams);

        return clientTypeBuilder()
                .withURL(url)
                .withSSL(ssl)
                .withConnectionTimeout(connectionTimeout)
                .withReceiveTimeout(receiveTimeout)
                .withCustomHTTPHeader(customHeaders)
                .build();

    }

    private SSLType buildSSL(Map<String, String> sslParams) {

        var keyStoreParams = filterMapByPrefix(sslParams, KEYSTORE_KEY);
        KeyStoreType keyStore = keyStoreParams.isEmpty()
                ? null : buildKeyStore(keyStoreParams);

        var trustStoreParams = filterMapByPrefix(sslParams, TRUSTSTORE_KEY);
        KeyStoreType trustStore = trustStoreParams.isEmpty()
                ? null : buildKeyStore(trustStoreParams);

        var trustAll = booleanOrNull(sslParams.get(TRUST_ALL_KEY));
        var laxHostNameVerification = booleanOrNull(sslParams.get(LAX_HOSTNAME_VERIFICATION_KEY));

        return SSLTypeBuilder()
                .withKeyStore(keyStore)
                .withTrustStore(trustStore)
                .withTrustAll(trustAll)
                .withLaxHostNameVerification(laxHostNameVerification)
                .build();

    }

    private KeyStoreType buildKeyStore(Map<String, String> params) {

        return keyStoreTypeBuilder()
                .withFileName(params.get(FILENAME_KEY))
                .withFileType(params.get(FILETYPE_KEY))
                .withPassword(params.get(PASSWORD_KEY))
                .build();
    }

    private MsgResponseSinksType buildMsgResponseSinks(Map<String, String> params) {

        var logResponse  = booleanOrNull(params.get(LOG_RESPONSE_KEY));

        var saveResponse = buildSaveResponse(filterMapByPrefix(params, SAVE_RESPONSE_TO_FILE_KEY));

        var forwardResponse = buildForwardResponse(filterMapByPrefix(params, FORWARD_RESPONSE_TO_SERVICE_KEY));

        return msgResponseSinksTypeBuilder()
                .withLogResponse(logResponse)
                .withSaveResponseToFile(saveResponse)
                .withForwardResponseToService(forwardResponse)
                .build();
    }

    private SaveResponseToFileType buildSaveResponse(Map<String, String> params) {

        var isActive = booleanOrNull(params.get(ACTIVE_KEY));
        var path = params.get(SAVE_RESPONSE_TO_FILE_PATH_KEY);

        return saveResponseToFileTypeBuilder()
                .withActive(isActive)
                .withPath(path)
                .build();
    }

    private ForwardResponseToServiceType buildForwardResponse(Map<String, String> params) {

        var isActive = booleanOrNull(params.get(ACTIVE_KEY));
        var appClientParams = filterMapByPrefix(params, APP_CLIENT_KEY);
        ClientType appClient = appClientParams.isEmpty()
                ? null : buildClient(appClientParams);

        return forwardResponseToServiceTypeBuilder()
                .withActive(isActive)
                .withAppClient(appClient)
                .build();
    }


    private Boolean booleanOrNull(String value) {
        return value == null ? null : Boolean.valueOf(value);
    }

    private BigInteger bigIntOrNull(String value) {
        return value == null
                ? null
                : new BigInteger(value);
    }

    /**
     * Combine properties of two Configs; {@code primary} overrides {@code fallback}.
     *
     * @param primary
     * @param fallback
     * @return Merged Config
     */
    public ConfigType merge(ConfigType primary, ConfigType fallback) {

        var builder = configTypeBuilder(fallback);

        if (primary.isPerformQueryPersonRequest() != null) {
            builder.withPerformQueryPersonRequest(primary.isPerformQueryPersonRequest());
        }

        if (primary.getMSGClient() != null) {
            builder.withMSGClient(merge(primary.getMSGClient(), fallback.getMSGClient()));
        }

        if (primary.getTNVZClient() != null) {
            builder.withTNVZClient(merge(primary.getTNVZClient(), fallback.getTNVZClient()));
        }

        if (primary.getMsgResponseSinks() != null) {
            builder.withMsgResponseSinks(merge(primary.getMsgResponseSinks(), fallback.getMsgResponseSinks()));
        }

        if (primary.getServiceTimeout() != null) {
            builder.withServiceTimeout(primary.getServiceTimeout());
        }

        return builder.build();
    }

    private ClientType merge(ClientType primary, ClientType fallback) {

        if (fallback == null) {
            return primary;
        }

        var builder = clientTypeBuilder(fallback);

        if (primary.getURL() != null) {
            builder.withURL(primary.getURL());
        }

        if (primary.getSSL() != null) {
            builder.withSSL(merge(primary.getSSL(), fallback.getSSL()));
        }

        if (primary.getConnectionTimeout() != null) {
            builder.withConnectionTimeout(primary.getConnectionTimeout());
        }

        if (primary.getReceiveTimeout() != null) {
            builder.withReceiveTimeout(primary.getReceiveTimeout());
        }

        if (primary.getCustomHTTPHeader() != null) {
            builder.withCustomHTTPHeader(merge(primary.getCustomHTTPHeader(), fallback.getCustomHTTPHeader()));
        }

        return builder.build();
    }

    private SSLType merge(SSLType primary, SSLType fallback) {

        if (fallback == null) {
            return primary;
        }

        var builder = SSLTypeBuilder(fallback);

        if (primary.getKeyStore() != null) {
            builder.withKeyStore(merge(primary.getKeyStore(), fallback.getKeyStore()));
        }

        if (primary.getTrustStore() != null) {
            builder.withTrustStore(merge(primary.getTrustStore(), fallback.getTrustStore()));
        }

        if (primary.isLaxHostNameVerification() != null) {
            builder.withLaxHostNameVerification(primary.isLaxHostNameVerification());
        }

        if (primary.isTrustAll() != null) {
            builder.withTrustAll(primary.isTrustAll());
        }

        return builder.build();
    }

    private KeyStoreType merge(KeyStoreType primary, KeyStoreType fallback) {

        if (primary.getFileName() != null && primary.getFileType() != null && primary.getPassword() != null)
            return primary;

        return fallback;

    }

    private List<CustomHTTPHeaderType> merge(List<CustomHTTPHeaderType> primary, List<CustomHTTPHeaderType> fallback) {

        if (fallback == null) return primary;

        var primaryMap = convertHeadersToMap(primary);
        var fallbackMap = convertHeadersToMap(fallback);

        Map<String, String> mergedMap = Stream.of(fallbackMap, primaryMap)
                .flatMap(map -> map.entrySet().stream())
                .collect(toMap(
                        Map.Entry::getKey,
                        entry -> entry.getValue().get(0),
                        (v1, v2) -> v2
                ));

        return convertMapToHeaders(mergedMap);

    }


    private MsgResponseSinksType merge(MsgResponseSinksType primary, MsgResponseSinksType fallback) {

        if (fallback == null) {
            return primary;
        }

        var builder = msgResponseSinksTypeBuilder(fallback);

        if (primary.isLogResponse() != null) {
            builder.withLogResponse(primary.isLogResponse());
        }

        if (primary.getSaveResponseToFile() != null) {
            builder.withSaveResponseToFile(merge(primary.getSaveResponseToFile(), fallback.getSaveResponseToFile()));
        }

        if (primary.getForwardResponseToService() != null) {
            builder.withForwardResponseToService(merge(primary.getForwardResponseToService(), fallback.getForwardResponseToService()));
        }

        return builder.build();
    }

    private SaveResponseToFileType merge(SaveResponseToFileType primary, SaveResponseToFileType fallback) {

        if (fallback == null) return primary;

        var builder = saveResponseToFileTypeBuilder(fallback);

        if (primary.isActive() != null) {
            builder.withActive(primary.isActive());
        }

        if (primary.getPath() != null) {
            builder.withPath(primary.getPath());
        }

        return builder.build();
    }

    private ForwardResponseToServiceType merge(ForwardResponseToServiceType primary, ForwardResponseToServiceType fallback) {

        if (fallback == null) return primary;

        var builder = forwardResponseToServiceTypeBuilder(fallback);

        if (primary.isActive() != null) {
            builder.withActive(primary.isActive());
        }

        if (primary.getAppClient() != null) {
            builder.withAppClient(merge(primary.getAppClient(), fallback.getAppClient()));
        }

        return builder.build();

    }

    /**
     * Convert a Map that is indexed by header names into a List of CustomHTTPHeaders.
     * @param customHeaderMap map of headers, indexed by header names.
     * @return List of CustomHTTPHeaders
     */
    public List<CustomHTTPHeaderType> convertMapToHeaders(Map<String, String> customHeaderMap) {
        return customHeaderMap.entrySet().stream()
                .map(e -> customHTTPHeaderTypeBuilder()
                        .withName(e.getKey())
                        .withValue(e.getValue())
                        .build())
                .collect(toList());
    }


    /**
     * Convert a List of CustomHTTPHeaders into a Map that is indexed by the header names. Values are wrapped in Lists.
     * @param customHeaders List of CustomHTTPHeaders
     * @return Map of headers, indexed by header names.
     */
    public Map<String, List<String>> convertHeadersToMap(List<CustomHTTPHeaderType> customHeaders) {
        return customHeaders
                .stream()
                .collect(toMap(
                        CustomHTTPHeaderType::getName,
                        h -> List.of(h.getValue())));
    }

}