import java.util.Map;
import org.apache.axis2.client.Options;
import org.apache.axis2.client.ServiceClient;
import org.apache.axis2.context.ConfigurationContext;
import org.apache.axis2.context.ConfigurationContextFactory;
import org.apache.axis2.transport.http.HTTPConstants;
import org.apache.axis2.transport.http.HttpTransportProperties;
import org.apache.http.HttpHeaders;
import org.apache.synapse.ManagedLifecycle;
import org.apache.synapse.MessageContext;
import org.apache.synapse.core.SynapseEnvironment;
import org.apache.synapse.core.axis2.Axis2MessageContext;
import org.apache.synapse.rest.AbstractHandler;
import
org.wso2.carbon.identity.oauth2.stub.OAuth2TokenValidationServiceStub;
import
org.wso2.carbon.identity.oauth2.stub.dto.OAuth2TokenValidationRequestDTO;

public class SimpleOauthHandler extends AbstractHandler implements ManagedLifecycle {

private String securityHeader = HttpHeaders.AUTHORIZATION;
private String consumerKeyHeaderSegment = "Bearer";
private String oauthHeaderSplitter = ",";
private String consumerKeySegmentDelimiter = " ";
private String oauth2TokenValidationService = "oauth2TokenValidationService";
private String identityServerUserName = "identityServerUserName";
private String identityServerPw = "identityServerPw";


public boolean handleRequest(MessageContext messageContext) {
    try{
        ConfigurationContext configCtx = ConfigurationContextFactory.createConfigurationContextFromFileSystem(null, null);
        //Read parameters from axis2.xml
        String identityServerUrl = messageContext.getConfiguration().getAxisConfiguration().getParameter(oauth2TokenValidationService).getValue().toString();
        String username = messageContext.getConfiguration().getAxisConfiguration().getParameter(identityServerUserName).getValue().toString();
        String password = messageContext.getConfiguration().getAxisConfiguration().getParameter(identityServerPw).getValue().toString();

        OAuth2TokenValidationServiceStub stub = new OAuth2TokenValidationServiceStub(configCtx,identityServerUrl);
        ServiceClient client = stub._getServiceClient();
        Options options = client.getOptions();
        HttpTransportProperties.Authenticator authenticator = new HttpTransportProperties.Authenticator();
        authenticator.setUsername(username);
        authenticator.setPassword(password);
        authenticator.setPreemptiveAuthentication(true);

        options.setProperty(HTTPConstants.AUTHENTICATE, authenticator);
        client.setOptions(options);
        OAuth2TokenValidationRequestDTO dto = new OAuth2TokenValidationRequestDTO();
        dto.setTokenType("bearer");
        Map headers = (Map) ((Axis2MessageContext) messageContext).getAxis2MessageContext().
                getProperty(org.apache.axis2.context.MessageContext.TRANSPORT_HEADERS);
        String apiKey = null;
        if (headers != null) {
            apiKey = extractCustomerKeyFromAuthHeader(headers);
        }
        dto.setAccessToken(apiKey);
        //validate passed apiKey(token)
        if(stub.validate(dto).getValid()){
            return true;
        }else{
            return false;
        }
    }catch(Exception e){
        e.printStackTrace();
        return false;
    }
}

public String extractCustomerKeyFromAuthHeader(Map headersMap) {

    //From 1.0.7 version of this component onwards remove the OAuth authorization header from
    // the message is configurable. So we dont need to remove headers at this point.
    String authHeader = (String) headersMap.get(securityHeader);
    if (authHeader == null) {
        return null;
    }

    if (authHeader.startsWith("OAuth ") || authHeader.startsWith("oauth ")) {
        authHeader = authHeader.substring(authHeader.indexOf("o"));
    }

    String[] headers = authHeader.split(oauthHeaderSplitter);
    if (headers != null) {
        for (int i = 0; i < headers.length; i++) {
            String[] elements = headers[i].split(consumerKeySegmentDelimiter);
            if (elements != null && elements.length > 1) {
                int j = 0;
                boolean isConsumerKeyHeaderAvailable = false;
                for (String element : elements) {
                    if (!"".equals(element.trim())) {
                        if (consumerKeyHeaderSegment.equals(elements[j].trim())) {
                            isConsumerKeyHeaderAvailable = true;
                        } else if (isConsumerKeyHeaderAvailable) {
                            return removeLeadingAndTrailing(elements[j].trim());
                        }
                    }
                    j++;
                }
            }
        }
    }
    return null;
}

private String removeLeadingAndTrailing(String base) {
    String result = base;

    if (base.startsWith(""") || base.endsWith(""")) {
        result = base.replace(""", "");
    }
    return result.trim();
}


public boolean handleResponse(MessageContext messageContext) {
  return true;
}

public void init(SynapseEnvironment synapseEnvironment) {
    //To change body of implemented methods use File | Settings | File Templates.
}


public void destroy() {
    //To change body of implemented methods use File | Settings | File Templates.
}