/*-
 * ============LICENSE_START=======================================================
 *  Copyright (C) 2019 Nordix Foundation.
 * ================================================================================
 * 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.
 *
 * SPDX-License-Identifier: Apache-2.0
 * ============LICENSE_END=========================================================
 */

package org.onap.so.adapters.vnfmadapter.extclients.vnfm;

import static org.onap.so.client.RestTemplateConfig.CONFIGURABLE_REST_TEMPLATE;
import com.google.gson.Gson;
import java.io.IOException;
import java.security.KeyManagementException;
import java.security.KeyStore;
import java.security.KeyStoreException;
import java.security.NoSuchAlgorithmException;
import java.security.UnrecoverableKeyException;
import java.security.cert.CertificateException;
import java.util.Iterator;
import java.util.Map;
import java.util.UUID;
import java.util.concurrent.ConcurrentHashMap;
import javax.net.ssl.SSLContext;
import org.apache.commons.lang3.StringUtils;
import org.apache.http.client.HttpClient;
import org.apache.http.conn.ssl.SSLConnectionSocketFactory;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.ssl.SSLContextBuilder;
import org.onap.aai.domain.yang.EsrSystemInfo;
import org.onap.aai.domain.yang.EsrVnfm;
import org.onap.so.adapters.vnfmadapter.extclients.vnfm.lcn.JSON;
import org.onap.so.configuration.rest.BasicHttpHeadersProvider;
import org.onap.so.rest.service.HttpRestServiceProvider;
import org.onap.so.rest.service.HttpRestServiceProviderImpl;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.Resource;
import org.springframework.http.client.BufferingClientHttpRequestFactory;
import org.springframework.http.client.HttpComponentsClientHttpRequestFactory;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.http.converter.json.GsonHttpMessageConverter;
import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;
import org.springframework.security.oauth2.client.OAuth2RestTemplate;
import org.springframework.security.oauth2.client.token.grant.client.ClientCredentialsResourceDetails;
import org.springframework.web.client.RestTemplate;

/**
 * Configures the HttpRestServiceProvider for REST call to a VNFM.
 */
@Configuration
public class VnfmServiceProviderConfiguration {

    private static final Logger logger = LoggerFactory.getLogger(VnfmServiceProviderConfiguration.class);
    private Map<String, HttpRestServiceProvider> mapOfVnfmIdToHttpRestServiceProvider = new ConcurrentHashMap<>();

    @Value("${http.client.ssl.trust-store:#{null}}")
    private Resource trustStore;
    @Value("${http.client.ssl.trust-store-password:#{null}}")
    private String trustStorePassword;

    @Value("${server.ssl.key-store:#{null}}")
    private Resource keyStoreResource;
    @Value("${server.ssl.key--store-password:#{null}}")
    private String keyStorePassword;

    /**
     * This property is only intended to be temporary until the AAI schema is updated to support setting the endpoint
     */
    @Value("${vnfmadapter.temp.vnfm.oauth.endpoint:#{null}}")
    private String oauthEndpoint;

    @Qualifier(CONFIGURABLE_REST_TEMPLATE)
    @Autowired()
    private RestTemplate defaultRestTemplate;

    public HttpRestServiceProvider getHttpRestServiceProvider(final EsrVnfm vnfm) {
        if (!mapOfVnfmIdToHttpRestServiceProvider.containsKey(vnfm.getVnfmId())) {
            mapOfVnfmIdToHttpRestServiceProvider.put(vnfm.getVnfmId(), createHttpRestServiceProvider(vnfm));
        }
        return mapOfVnfmIdToHttpRestServiceProvider.get(vnfm.getVnfmId());
    }

    private HttpRestServiceProvider createHttpRestServiceProvider(final EsrVnfm vnfm) {
        final RestTemplate restTemplate = createRestTemplate(vnfm);
        setGsonMessageConverter(restTemplate);
        if (trustStore != null) {
            setTrustStore(restTemplate);
        }
        return new HttpRestServiceProviderImpl(restTemplate, new BasicHttpHeadersProvider());
    }

    private RestTemplate createRestTemplate(final EsrVnfm vnfm) {
        if (vnfm != null) {
            for (final EsrSystemInfo esrSystemInfo : vnfm.getEsrSystemInfoList().getEsrSystemInfo()) {
                if (!StringUtils.isEmpty(esrSystemInfo.getUserName())
                        && !StringUtils.isEmpty(esrSystemInfo.getPassword())) {
                    return createOAuth2RestTemplate(esrSystemInfo);
                }
            }
        }
        return defaultRestTemplate;
    }

    private OAuth2RestTemplate createOAuth2RestTemplate(final EsrSystemInfo esrSystemInfo) {
        logger.debug("Getting OAuth2RestTemplate ...");
        final ClientCredentialsResourceDetails resourceDetails = new ClientCredentialsResourceDetails();
        resourceDetails.setId(UUID.randomUUID().toString());
        resourceDetails.setClientId(esrSystemInfo.getUserName());
        resourceDetails.setClientSecret(esrSystemInfo.getPassword());
        resourceDetails.setAccessTokenUri(
                oauthEndpoint == null ? esrSystemInfo.getServiceUrl().replace("vnflcm/v1", "oauth/token")
                        : oauthEndpoint);
        resourceDetails.setGrantType("client_credentials");
        return new OAuth2RestTemplate(resourceDetails);
    }

    private void setGsonMessageConverter(final RestTemplate restTemplate) {
        final Iterator<HttpMessageConverter<?>> iterator = restTemplate.getMessageConverters().iterator();
        while (iterator.hasNext()) {
            if (iterator.next() instanceof MappingJackson2HttpMessageConverter) {
                iterator.remove();
            }
        }
        final Gson gson = new JSON().getGson();
        restTemplate.getMessageConverters().add(new GsonHttpMessageConverter(gson));
    }

    private void setTrustStore(final RestTemplate restTemplate) {
        SSLContext sslContext;
        try {
            if (keyStoreResource != null) {
                KeyStore keystore = KeyStore.getInstance("pkcs12");
                keystore.load(keyStoreResource.getInputStream(), keyStorePassword.toCharArray());
                sslContext =
                        new SSLContextBuilder().loadTrustMaterial(trustStore.getURL(), trustStorePassword.toCharArray())
                                .loadKeyMaterial(keystore, keyStorePassword.toCharArray()).build();
            } else {
                sslContext = new SSLContextBuilder()
                        .loadTrustMaterial(trustStore.getURL(), trustStorePassword.toCharArray()).build();
            }
            logger.info("Setting truststore: {}", trustStore.getURL());
            final SSLConnectionSocketFactory socketFactory = new SSLConnectionSocketFactory(sslContext);
            final HttpClient httpClient = HttpClients.custom().setSSLSocketFactory(socketFactory).build();
            final HttpComponentsClientHttpRequestFactory factory =
                    new HttpComponentsClientHttpRequestFactory(httpClient);
            restTemplate.setRequestFactory(new BufferingClientHttpRequestFactory(factory));
        } catch (KeyManagementException | NoSuchAlgorithmException | KeyStoreException | CertificateException
                | IOException | UnrecoverableKeyException exception) {
            logger.error("Error reading truststore, TLS connection to VNFM will fail.", exception);
        }
    }

}