/**
 * ============LICENSE_START=======================================================
 * org.onap.aai
 * ================================================================================
 * Copyright © 2017-2019 AT&T Intellectual Property. All rights reserved.
 * ================================================================================
 * Modifications Copyright © 2018 IBM.
 * ================================================================================
 * 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.aai.restclient;

import java.net.URI;
import java.net.URISyntaxException;
import java.util.Map;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.core.io.Resource;
import org.springframework.http.HttpEntity;
import org.springframework.http.HttpMethod;
import org.springframework.http.ResponseEntity;
import org.springframework.util.MultiValueMap;
import org.springframework.web.client.RestClientException;
import org.springframework.web.client.RestTemplate;

public abstract class RestClient {

    private static Logger log = LoggerFactory.getLogger(RestClient.class);
    @Value("${spring.application.name}")
    protected String appName;

    /**
     * Execute the given http method against the uri with passed headers
     *
     * @param uri properly encoded, can include query params also properly encoded
     * @param method http method of the request
     * @param headers headers for the request
     * @param body body of the request
     * @return response of request
     * @throws RestClientException on internal rest template exception or invalid url
     */
    public ResponseEntity<String> execute(String uri, HttpMethod method, Map<String, String> headers, String body)
            throws RestClientException {

        HttpEntity<String> httpEntity;
        log.debug("Request Headers: {}", headers);
        if (body == null) {
            httpEntity = new HttpEntity<>(getHeaders(headers));
        } else {
            httpEntity = new HttpEntity<>(body, getHeaders(headers));
        }

        // verify that either the base url ends with '/' or uri starts with '/', adjust uri accordingly.
        if (getBaseUrl().endsWith("/") && uri.startsWith("/")) {
            uri = uri.replaceFirst("/", "");
        } else if (!getBaseUrl().endsWith("/") && !uri.startsWith("/")) {
            uri = "/" + uri;
        }

        URI url;
        try {
            url = new URI(getBaseUrl() + uri);
        } catch (URISyntaxException e) {
            log.error("URL syntax error with url {}{}", getBaseUrl(), uri);
            throw new RestClientException(e.getMessage());
        }
        log.debug("METHOD={}, URL={}, BODY={}", method, url, httpEntity.getBody());
        ResponseEntity<String> responseEntity = getRestTemplate().exchange(url, method, httpEntity, String.class);
        log.trace("RESPONSE={}", responseEntity);
        return responseEntity;
    }

    /**
     * Execute the given http method against the uri with passed headers
     *
     * @param uri properly encoded, can include query params also properly encoded
     * @param method http method of the request
     * @param headers headers for the request
     * @param body body of the request
     * @return response of request
     * @throws RestClientException on internal rest template exception or invalid url
     */
    public ResponseEntity<String> execute(String uri, String method, Map<String, String> headers, String body)
            throws RestClientException {
        return execute(uri, HttpMethod.valueOf(method), headers, body);
    }

    /**
     * Execute the given http method against the uri with passed headers
     *
     * @param uri properly encoded, can include query params also properly encoded
     * @param method http method of the request
     * @param headers headers for the request
     * @return response of request
     * @throws RestClientException on internal rest template exception or invalid url
     */
    public ResponseEntity<String> execute(String uri, HttpMethod method, Map<String, String> headers)
            throws RestClientException {
        return execute(uri, method, headers, null);
    }

    /**
     * Execute the given http method against the uri with passed headers
     *
     * @param uri properly encoded, can include query params also properly encoded
     * @param method http method of the request
     * @param headers headers for the request
     * @return response of request
     * @throws RestClientException on internal rest template exception or invalid url
     */
    public ResponseEntity<String> execute(String uri, String method, Map<String, String> headers)
            throws RestClientException {
        return execute(uri, HttpMethod.valueOf(method), headers, null);
    }

    public ResponseEntity<Resource> executeResource(String uri, HttpMethod method, Map<String, String> headers,
            String body) throws RestClientException {

        HttpEntity<String> httpEntity;
        log.debug("Headers: " + headers.toString());
        if (body == null) {
            httpEntity = new HttpEntity(getHeaders(headers));
        } else {
            httpEntity = new HttpEntity(body, getHeaders(headers));
        }
        String url = getBaseUrl() + uri;
        return getRestTemplate().exchange(url, method, httpEntity, Resource.class);
    }

    public ResponseEntity<String> getGetRequest(String content, String uri, Map<String, String> headersMap) {
        return this.execute(uri, HttpMethod.GET, headersMap, content);

    }

    public ResponseEntity<Resource> getGetResource(String content, String uri, Map<String, String> headersMap) {
        return this.executeResource(uri, HttpMethod.GET, headersMap, content);

    }

    public abstract RestTemplate getRestTemplate();

    public abstract String getBaseUrl();

    protected abstract MultiValueMap<String, String> getHeaders(Map<String, String> headers);

}