package ca.uhn.fhir.rest.client.apache;

/*
 * #%L
 * HAPI FHIR - Core Library
 * %%
 * Copyright (C) 2014 - 2017 University Health Network
 * %%
 * 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.
 * #L%
 */

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.io.StringReader;
import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.commons.io.IOUtils;
import org.apache.http.Header;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.entity.ContentType;

import ca.uhn.fhir.rest.client.api.IHttpResponse;
import ca.uhn.fhir.rest.server.Constants;
import ca.uhn.fhir.rest.server.exceptions.InternalErrorException;

/**
 * A Http Response based on Apache. This is an adapter around the class
 * {@link org.apache.http.HttpResponse HttpResponse}
 * 
 * @author Peter Van Houte | peter.vanhoute@agfa.com | Agfa Healthcare
 */
public class ApacheHttpResponse implements IHttpResponse {

        private static final org.slf4j.Logger ourLog = org.slf4j.LoggerFactory.getLogger(ApacheHttpResponse.class);

        private boolean myEntityBuffered = false;
        private byte[] myEntityBytes;
        private final HttpResponse myResponse;

        public ApacheHttpResponse(HttpResponse theResponse) {
                this.myResponse = theResponse;
        }

        @Deprecated // override deprecated method
        @Override
        public void bufferEntitity() throws IOException {
                bufferEntity();
        }

        @Override
        public void bufferEntity() throws IOException {
                if (myEntityBuffered) {
                        return;
                }
                InputStream respEntity = readEntity();
                if (respEntity != null) {
                        this.myEntityBuffered = true;
                        try {
                                this.myEntityBytes = IOUtils.toByteArray(respEntity);
                        } catch (IllegalStateException e) {
                                // FIXME resouce leak
                                throw new InternalErrorException(e);
                        }
                }
        }

        @Override
        public void close() {
                if (myResponse instanceof CloseableHttpResponse) {
                        try {
                                ((CloseableHttpResponse) myResponse).close();
                        } catch (IOException e) {
                                ourLog.debug("Failed to close response", e);
                        }
                }
        }

        @Override
        public Reader createReader() throws IOException {
                HttpEntity entity = myResponse.getEntity();
                if (entity == null) {
                        return new StringReader("");
                }
                Charset charset = null;
                if (entity.getContentType() != null && entity.getContentType().getElements() != null
                                && entity.getContentType().getElements().length > 0) {
                        ContentType ct = ContentType.get(entity);
                        charset = ct.getCharset();
                }
                if (charset == null) {
                        if (Constants.STATUS_HTTP_204_NO_CONTENT != myResponse.getStatusLine().getStatusCode()) {
                                ourLog.warn("Response did not specify a charset.");
                        }
                        charset = Charset.forName("UTF-8");
                }

                Reader reader = new InputStreamReader(readEntity(), charset);
                return reader;
        }

        @Override
        public Map<String, List<String>> getAllHeaders() {
                Map<String, List<String>> headers = new HashMap<String, List<String>>();
                if (myResponse.getAllHeaders() != null) {
                        for (Header next : myResponse.getAllHeaders()) {
                                String name = next.getName().toLowerCase();
                                List<String> list = headers.get(name);
                                if (list == null) {
                                        list = new ArrayList<String>();
                                        headers.put(name, list);
                                }
                                list.add(next.getValue());
                        }

                }
                return headers;
        }

        @Override
        public List<String> getHeaders(String theName) {
                Header[] headers = myResponse.getHeaders(theName);
                if (headers == null) {
                        headers = new Header[0];
                }
                List<String> retVal = new ArrayList<String>();
                for (Header next : headers) {
                        retVal.add(next.getValue());
                }
                return retVal;
        }

        @Override
        public String getMimeType() {
                ContentType ct = ContentType.get(myResponse.getEntity());
                return ct != null ? ct.getMimeType() : null;
        }

        @Override
        public HttpResponse getResponse() {
                return myResponse;
        }

        @Override
        public int getStatus() {
                return myResponse.getStatusLine().getStatusCode();
        }

        @Override
        public String getStatusInfo() {
                return myResponse.getStatusLine().getReasonPhrase();
        }

        @Override
        public InputStream readEntity() throws IOException {
                if (this.myEntityBuffered) {
                        return new ByteArrayInputStream(myEntityBytes);
                } else if (myResponse.getEntity() != null) {
                        return myResponse.getEntity().getContent();
                } else {
                        return null;
                }
        }
}