authorization-client/src/main/java/org/gcube/common/authorization/client/proxy/DefaultAuthorizationProxy.java

package org.gcube.common.authorization.client.proxy;

import static org.gcube.common.authorization.client.Constants.CONTEXT_PARAM;

import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;

import org.gcube.common.authorization.client.Binder;
import org.gcube.common.authorization.client.Constants;
import org.gcube.common.authorization.client.exceptions.ObjectNotFound;
import org.gcube.common.authorization.library.AuthorizationEntry;
import org.gcube.common.authorization.library.Policies;
import org.gcube.common.authorization.library.enpoints.AuthorizationEndpoint;
import org.gcube.common.authorization.library.enpoints.AuthorizationEndpointScanner;
import org.gcube.common.authorization.library.policies.Policy;
import org.gcube.common.authorization.library.provider.ClientInfo;
import org.gcube.common.authorization.library.provider.ServiceInfo;
import org.gcube.common.authorization.library.provider.UserInfo;
import org.gcube.common.encryption.StringEncrypter;
import org.gcube.common.scope.api.ScopeProvider;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class DefaultAuthorizationProxy implements AuthorizationProxy {

	private static Logger log = LoggerFactory.getLogger(AuthorizationProxy.class);
	
	private static Map<String, AuthorizationEntryCache> cache = new HashMap<String, AuthorizationEntryCache>();

	private static JAXBContext jaxbContext;
	
	private List<AuthorizationEndpoint> endpoints;

	public DefaultAuthorizationProxy() {
		try {
			jaxbContext = JAXBContext.newInstance(ClientInfo.class, UserInfo.class, ServiceInfo.class, Policies.class);
		} catch (JAXBException e) {
			log.error("error creating jaxb context",e);
			throw new RuntimeException(e);
		}
		endpoints = AuthorizationEndpointScanner.endpoints();
		this.setEndpoint(endpoints.get(0));
	}

	private String getInternalEnpoint(){
		StringBuilder endpoint = new StringBuilder("http://").append(getEndpoint().getHost()).append(":")
				.append(getEndpoint().getPort()).append("/authorization-service/gcube/service");
		return endpoint.toString();

	}
	
	@Override
	public String generateToken(ClientInfo client, String context) throws Exception {
		
		String methodPath = "/generate/"; 
		
		if (client instanceof UserInfo)
			methodPath+="user";
		else methodPath+="service";
				
		StringBuilder callUrl = new StringBuilder(getInternalEnpoint()).append(methodPath).append("?")
				.append(CONTEXT_PARAM).append("=").append(context);
					
		URL url = new URL(callUrl.toString());
		HttpURLConnection connection = (HttpURLConnection)url.openConnection();
		connection.setRequestMethod("PUT");
		connection.setDoOutput(true);
		
		try(OutputStream os = new BufferedOutputStream(connection.getOutputStream())){
			jaxbContext.createMarshaller().marshal(client, os);
		}

		if (connection.getResponseCode()!=200) throw new Exception("error contacting authorization service");
		String encryptedToken= "";
		try(BufferedReader reader = new BufferedReader(new InputStreamReader((InputStream)connection.getContent()))){
			StringBuilder result = new StringBuilder();
			String line;
			while((line = reader.readLine()) != null) 
				result.append(line);
			encryptedToken =  result.toString();
		}

		return StringEncrypter.getEncrypter().decrypt(encryptedToken, context);
	}
		
	@Override
	public AuthorizationEntry get(String token) throws ObjectNotFound, Exception{
		final String methodPath = "/retrieve/"; 

		StringBuilder callUrl = new StringBuilder(getInternalEnpoint()).append(methodPath).append(token);
		
		URL url = new URL(callUrl.toString());
		HttpURLConnection connection = makeRequest(url, "GET");
		connection.setDoInput(true);
		if (connection.getResponseCode()==404) throw new ObjectNotFound("token "+token+" not found");
		if (connection.getResponseCode()!=200) throw new Exception("error contacting authorization service");
		if (connection.getContentLengthLong()<=0) return null;

		try(InputStream stream = (InputStream)connection.getContent();){
			AuthorizationEntry entry = (AuthorizationEntry)Binder.getContext().createUnmarshaller().unmarshal(stream);
			cache.put(token, new AuthorizationEntryCache(entry));
			return entry;
		}

	}
	
	@Override
	public void addPolicies(List<Policy> policies) throws Exception {
		final String methodPath = "/policyManager"; 

		StringBuilder callUrl = new StringBuilder(getInternalEnpoint()).append(methodPath);
		
		URL url = new URL(callUrl.toString());
		HttpURLConnection connection = makeRequest(url, "POST");
		connection.setDoOutput(true);
		
		try(OutputStream os = new BufferedOutputStream(connection.getOutputStream())){
			jaxbContext.createMarshaller().marshal(new Policies(policies), os);
		}
		
		if (connection.getResponseCode()!=200) throw new Exception("error adding policies");
				
	}

	@Override
	public void removePolicies(long... ids) throws Exception {
		final String methodPath = "/policyManager/"; 
		StringBuilder callUrl = new StringBuilder(getInternalEnpoint()).append(methodPath);
		List<Long> errorIds = new ArrayList<Long>();
		for (long id: ids){
			URL url = new URL(callUrl.toString()+id);
			HttpURLConnection connection = makeRequest(url, "DELETE");
			if (connection.getResponseCode()!=200) errorIds.add(id);
		}
		if (!errorIds.isEmpty())
			throw new Exception("error removing policies with ids: "+errorIds);
	}

	@Override
	public List<Policy> getPolicies(String context) throws Exception{
		final String methodPath = "/policyManager/"; 

		StringBuilder callUrl = new StringBuilder(getInternalEnpoint()).append(methodPath).append("?").append(CONTEXT_PARAM).append("=").append(context);
		
		URL url = new URL(callUrl.toString());
		HttpURLConnection connection = makeRequest(url, "GET");
				
		if (connection.getResponseCode()!=200) throw new Exception("error retrieving policies");
		if (connection.getContentLengthLong()<=0) return null;

		try(InputStream stream = (InputStream)connection.getContent()){
			Policies policies = (Policies)Binder.getContext().createUnmarshaller().unmarshal(stream);
			return policies.getPolicies();
		}
	}
	


	private HttpURLConnection makeRequest(URL url, String method) throws Exception{
		HttpURLConnection connection = (HttpURLConnection)url.openConnection();
		connection.setRequestProperty(Constants.SCOPE_HEADER_ENTRY, ScopeProvider.instance.get());
		connection.setRequestMethod(method);
		return connection;
	}

	@Override
	public AuthorizationEndpoint getEndpoint() {
		return this.endpoints.get(0);
	}

	@Override
	public void setEndpoint(AuthorizationEndpoint authEndpoint) {
		this.endpoints = Collections.singletonList(authEndpoint);		
	}


}