/*
 * ============LICENSE_START=======================================================
 * PROJECT
 * ================================================================================
 * Copyright (C) 2017 AT&T Intellectual Property. All rights reserved.
 * Copyright (C) 2018 - 2020 Nokia. All rights reserved.s
 * ================================================================================
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * ============LICENSE_END=========================================================
 */

package org.onap.dcae;

import static java.lang.String.format;

import com.google.common.annotations.VisibleForTesting;
import com.google.common.reflect.TypeToken;
import com.google.gson.Gson;
import com.networknt.schema.JsonSchema;
import io.vavr.Function1;
import io.vavr.collection.HashMap;
import io.vavr.collection.Map;
import java.io.FileReader;
import java.io.IOException;
import java.lang.reflect.Type;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.List;
import javax.annotation.Nullable;
import org.apache.commons.configuration.ConfigurationException;
import org.apache.commons.configuration.PropertiesConfiguration;
import org.onap.dcae.common.EventTransformation;
import org.onap.dcae.common.configuration.AuthMethodType;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Abstraction over application configuration.
 * Its job is to provide easily discoverable (by method names lookup) and type safe access to configuration properties.
 */
public class ApplicationSettings {

    private static final String EVENT_TRANSFORM_FILE_PATH = "./etc/eventTransform.json";
    private static final String COULD_NOT_FIND_FILE = "Couldn't find file " + EVENT_TRANSFORM_FILE_PATH;

    private static final Logger log = LoggerFactory.getLogger(ApplicationSettings.class);
    private static final String FALLBACK_VES_VERSION = "v5";
    private static final int DISABLED = -1;
    private static final int ENABLED = 1;
    private final String appInvocationDir;
    private final String configurationFileLocation;
    private final PropertiesConfiguration properties = new PropertiesConfiguration();
    private final Map<String, JsonSchema> loadedJsonSchemas;
    private final List<EventTransformation> eventTransformations;

    public ApplicationSettings(String[] args, Function1<String[], Map<String, String>> argsParser) {
        this(args, argsParser, System.getProperty("user.dir"));
    }

    public ApplicationSettings(String[] args, Function1<String[], Map<String, String>> argsParser, String appInvocationDir) {
        this.appInvocationDir = appInvocationDir;
        properties.setDelimiterParsingDisabled(true);
        Map<String, String> parsedArgs = argsParser.apply(args);
        configurationFileLocation = findOutConfigurationFileLocation(parsedArgs);
        loadPropertiesFromFile();
        parsedArgs.filterKeys(k -> !"c".equals(k)).forEach(this::addOrUpdate);
        String collectorSchemaFile = properties.getString("collector.schema.file",
                format("{\"%s\":\"etc/CommonEventFormat_28.4.1.json\"}", FALLBACK_VES_VERSION));
        loadedJsonSchemas = new JSonSchemasSupplier().loadJsonSchemas(collectorSchemaFile);
        eventTransformations = loadEventTransformations();
    }

    public void reloadProperties() {
        try {
            properties.load(configurationFileLocation);
            properties.refresh();
        } catch (ConfigurationException ex) {
            log.error("Cannot load properties cause:", ex);
            throw new ApplicationException(ex);
        }
    }

    public Map<String, String> validAuthorizationCredentials() {
        return prepareUsersMap(properties.getString("header.authlist", null));
    }
    public Path configurationFileLocation() {
        return Paths.get(configurationFileLocation);
    }

    public boolean eventSchemaValidationEnabled() {
        return properties.getInt("collector.schema.checkflag", DISABLED) > 0;
    }

    public JsonSchema jsonSchema(String version) {
        return loadedJsonSchemas.get(version)
            .orElse(loadedJsonSchemas.get(FALLBACK_VES_VERSION))
            .getOrElseThrow(() -> new IllegalStateException("No fallback schema present in application."));
    }

    public boolean isVersionSupported(String version){
       return loadedJsonSchemas.containsKey(version);
    }

    public int httpPort() {
        return properties.getInt("collector.service.port", 8080);
    }

    public int httpsPort() {
        return properties.getInt("collector.service.secure.port", 8443);
    }

    public int configurationUpdateFrequency() {
        return properties.getInt("collector.dynamic.config.update.frequency", 5);
    }

    public boolean httpsEnabled() {
        return httpsPort() > 0;
    }

    public boolean eventTransformingEnabled() {
        return properties.getInt("event.transform.flag", ENABLED) > 0;
    }

    public String keystorePasswordFileLocation() {
        return prependWithUserDirOnRelative(properties.getString("collector.keystore.passwordfile", "etc/passwordfile"));
    }

    public String keystoreFileLocation() {
        return prependWithUserDirOnRelative(properties.getString("collector.keystore.file.location", "etc/keystore"));
    }

    public String truststorePasswordFileLocation() {
        return prependWithUserDirOnRelative(properties.getString("collector.truststore.passwordfile", "etc/trustpasswordfile"));
    }

    public String truststoreFileLocation() {
        return prependWithUserDirOnRelative(properties.getString("collector.truststore.file.location", "etc/truststore"));
    }

    public String exceptionConfigFileLocation() {
        return properties.getString("exceptionConfig", null);
    }

    public String dMaaPConfigurationFileLocation() {
        return prependWithUserDirOnRelative(properties.getString("collector.dmaapfile", "etc/DmaapConfig.json"));
    }

    public String certSubjectMatcher(){
        return prependWithUserDirOnRelative(properties.getString("collector.cert.subject.matcher", "etc/certSubjectMatcher.properties"));
    }

    public String authMethod(){
        return properties.getString("auth.method", AuthMethodType.NO_AUTH.value());
    }

    public Map<String, String[]> getDmaapStreamIds() {
        String streamIdsProperty = properties.getString("collector.dmaap.streamid", null);
        if (streamIdsProperty == null) {
            return HashMap.empty();
        } else {
            return convertDMaaPStreamsPropertyToMap(streamIdsProperty);
        }
    }

    public boolean getExternalSchemaValidationCheckflag() {
        return properties.getInt("collector.externalSchema.checkflag", DISABLED) > 0;
    }

    public String getExternalSchemaSchemasLocation() {
        return properties.getString("collector.externalSchema.schemasLocation", "./etc/externalRepo");
    }

    public String getExternalSchemaMappingFileLocation() {
        return properties.getString("collector.externalSchema.mappingFileLocation", "./etc/externalRepo/schema-map.json");
    }

    public String getExternalSchemaSchemaRefPath() {
        return properties.getString("event.externalSchema.schemaRefPath", "/event/stndDefinedFields/schemaReference");
    }

    public String getExternalSchemaStndDefinedDataPath() {
        return properties.getString("event.externalSchema.stndDefinedDataPath", "/event/stndDefinedFields/data");
    }

    public List<EventTransformation> getEventTransformations() {
        return eventTransformations;
    }

    public String getApiVersionDescriptionFilepath() {
        return properties.getString("collector.description.api.version.location", "etc/api_version_description.json");
    }

    private void loadPropertiesFromFile() {
        try {
            properties.load(configurationFileLocation);
        } catch (ConfigurationException ex) {
            log.error("Cannot load properties cause:", ex);
            throw new ApplicationException(ex);
        }
    }

    private void addOrUpdate(String key, String value) {
        if (properties.containsKey(key)) {
            properties.setProperty(key, value);
        } else {
            properties.addProperty(key, value);
        }
    }

    private String findOutConfigurationFileLocation(Map<String, String> parsedArgs) {
        return prependWithUserDirOnRelative(parsedArgs.get("c").getOrElse("etc/collector.properties"));
    }

    private Map<String, String> prepareUsersMap(@Nullable String allowedUsers) {
        return allowedUsers == null ? HashMap.empty()
            : io.vavr.collection.List.of(allowedUsers.split("\\|"))
                .map(t->t.split(","))
                .toMap(t-> t[0].trim(), t -> t[1].trim());
    }

    private Map<String, String[]> convertDMaaPStreamsPropertyToMap(String streamIdsProperty) {
        java.util.HashMap<String, String[]> domainToStreamIdsMapping = new java.util.HashMap<>();
        String[] topics = streamIdsProperty.split("\\|");
        for (String t : topics) {
            String domain = t.split("=")[0];
            String[] streamIds = t.split("=")[1].split(",");
            domainToStreamIdsMapping.put(domain, streamIds);
        }
        return HashMap.ofAll(domainToStreamIdsMapping);
    }

    private String prependWithUserDirOnRelative(String filePath) {
        if (!Paths.get(filePath).isAbsolute()) {
            filePath = Paths.get(appInvocationDir, filePath).toString();
        }
        return filePath;
    }

    private List<EventTransformation> loadEventTransformations() {
        Type EVENT_TRANSFORM_LIST_TYPE = new TypeToken<List<EventTransformation>>() {}.getType();

        try (FileReader fr = new FileReader(EVENT_TRANSFORM_FILE_PATH)) {
            log.info("parse " + EVENT_TRANSFORM_FILE_PATH + " file");
            return new Gson().fromJson(fr, EVENT_TRANSFORM_LIST_TYPE);
        } catch (IOException e) {
            log.error(COULD_NOT_FIND_FILE, e);
            throw new ApplicationException(COULD_NOT_FIND_FILE, e);
        }
    }

    @VisibleForTesting
    String getStringDirectly(String key) {
        return properties.getString(key);
    }
}