/*-
 * ============LICENSE_START=======================================================
 * org.onap.dmaap
 * ================================================================================
 * Copyright (C) 2017 AT&T Intellectual Property. All rights reserved.
 * ================================================================================
 * 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.dmaap.dbcapi.service;

import static com.att.eelf.configuration.Configuration.MDC_BEGIN_TIMESTAMP;
import static com.att.eelf.configuration.Configuration.MDC_ELAPSED_TIME;
import static com.att.eelf.configuration.Configuration.MDC_END_TIMESTAMP;
import static com.att.eelf.configuration.Configuration.MDC_KEY_REQUEST_ID;
import static com.att.eelf.configuration.Configuration.MDC_PARTNER_NAME;
import static com.att.eelf.configuration.Configuration.MDC_RESPONSE_CODE;
import static com.att.eelf.configuration.Configuration.MDC_RESPONSE_DESC;
import static com.att.eelf.configuration.Configuration.MDC_SERVICE_NAME;
import static com.att.eelf.configuration.Configuration.MDC_STATUS_CODE;

import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.TimeZone;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import javax.ws.rs.core.Response;
import javax.ws.rs.core.Response.Status;
import javax.xml.bind.DatatypeConverter;

import org.onap.dmaap.dbcapi.aaf.DmaapPerm;
import org.onap.dmaap.dbcapi.aaf.authentication.ApiPolicy;
import org.onap.dmaap.dbcapi.aaf.authentication.AuthenticationErrorException;
import org.onap.dmaap.dbcapi.logging.BaseLoggingClass;
import org.onap.dmaap.dbcapi.model.ApiError;
import org.onap.dmaap.dbcapi.model.Dmaap;
import org.onap.dmaap.dbcapi.resources.RequiredFieldException;
import org.onap.dmaap.dbcapi.util.DmaapConfig;
import org.onap.dmaap.dbcapi.util.RandomString;
import org.slf4j.MDC;

public class ApiService extends BaseLoggingClass {
	private class StopWatch {
		private long clock = 0;
		private long elapsed = 0;
		

		
		public StopWatch() {
			clock = 0;
			elapsed = 0;
		}
		
		public void reset() {
			clock = System.currentTimeMillis();
			elapsed = 0;
		}
		public void stop() {
			Long stopTime = System.currentTimeMillis();
			elapsed +=  stopTime - clock;
			clock = 0;
			MDC.put( MDC_END_TIMESTAMP, isoFormatter.format(new Date(stopTime)));
			MDC.put( MDC_ELAPSED_TIME, String.valueOf(elapsed));
		}
		public void start() {
			if ( clock != 0 ) {
				//not stopped
				return;
			}
			clock = System.currentTimeMillis();	
			MDC.put( MDC_BEGIN_TIMESTAMP, isoFormatter.format(new Date(clock)));
		}
		private long getElapsed() {
			return elapsed;
		}
	}

	 private String apiNamespace;
	 private boolean usePE;
	 private String uri;
	 private String uriPath;
	 private String method;
	 private String authorization;
	 private String requestId;
	private ApiError err;
	private StopWatch stopwatch;
	private ApiPolicy apiPolicy;
	
	public static final String ISO_FORMAT = "yyyy-MM-dd'T'HH:mm:ss.SSSZ";
    public final static TimeZone utc = TimeZone.getTimeZone("UTC");
    public final static SimpleDateFormat isoFormatter = new SimpleDateFormat(ISO_FORMAT);
	
    static {
    	isoFormatter.setTimeZone(utc);
    }	
	public ApiService() {

		stopwatch = new StopWatch();
		stopwatch.start();
		err = new ApiError();
		requestId = (new RandomString(10)).nextString();
		
		if (apiNamespace == null) {
			DmaapConfig p = (DmaapConfig)DmaapConfig.getConfig();
			usePE = "true".equalsIgnoreCase(p.getProperty("UsePE", "false"));
			apiNamespace = p.getProperty("ApiNamespace", "org.openecomp.dmaapBC.api");
		}
		apiPolicy = new ApiPolicy();
		logger.info( "usePE=" + usePE + " apiNamespace=" + apiNamespace);	
	}

	public ApiService setAuth( String auth ) {
		this.authorization = auth;
		logger.info( "setAuth:  authorization={} ",  authorization);
		return this;
	}
	private void setServiceName(){
		String svcRequest = new String( this.method + " " + this.uriPath );
        MDC.put(MDC_SERVICE_NAME, svcRequest );
	}
	public ApiService setHttpMethod( String httpMethod ) {
		this.method = httpMethod;
		logger.info( "setHttpMethod: method={} ", method);
		setServiceName();
		return this;
	}
	public ApiService setUriPath( String uriPath ) {
		this.uriPath = uriPath;
		this.uri = setUriFromPath( uriPath );
		logger.info( "setUriPath: uriPath={} uri={}", uriPath, uri);
		setServiceName();
		return this;
	}
	private String setUriFromPath( String uriPath ) {
		int ch = uriPath.indexOf("/");
		if ( ch > 0 ) {
			return( (String) uriPath.subSequence(0, ch ) );
		} else {
			return uriPath;
		}
	}	
	
	public ApiError getErr() {
		return err;
	}


	public void setErr(ApiError err) {
		this.err = err;
	}


	// test for presence of a required field
	public void required( String name, Object val, String expr ) throws RequiredFieldException {
		if ( val == null  ) {
			err.setCode(Status.BAD_REQUEST.getStatusCode());
			err.setMessage("missing required field");
			err.setFields( name );	
			throw new RequiredFieldException();
		}
		if ( expr != null && ! expr.isEmpty() ) {
			Pattern pattern = Pattern.compile(expr);
			Matcher matcher = pattern.matcher((CharSequence) val);
			if ( ! matcher.find() ) {
				err.setCode(Status.BAD_REQUEST.getStatusCode());
				err.setMessage( "value '" + val + "' violates regexp check '" + expr + "'");
				err.setFields( name );
				throw new RequiredFieldException();
			}
		}
	}
	
	// utility to serialize ApiErr object
	public String toString() {
		return String.format( "code=%d msg=%s fields=%s", err.getCode(), err.getMessage(), err.getFields() );
	}


	public void setCode(int statusCode) {
		err.setCode(statusCode);	
	}


	public void setMessage(String string) {
		err.setMessage(string);
	}


	public void setFields(String string) {
		err.setFields(string);
	}

	private Response  buildResponse( Object obj ) {
		stopwatch.stop();
		MDC.put( MDC_RESPONSE_CODE, String.valueOf(err.getCode()) );
		
		auditLogger.auditEvent( "" );
		return Response.status( err.getCode())
				.entity(obj)
				.build();
	}
	private Response  buildSuccessResponse(Object d) {
		MDC.put( MDC_STATUS_CODE,  "COMPLETE");
		MDC.put( MDC_RESPONSE_DESC, "");
		return buildResponse( d );
	}
	private Response  buildErrResponse() {
	
		MDC.put( MDC_STATUS_CODE,  "ERROR");
		MDC.put( MDC_RESPONSE_DESC, err.getMessage());
		
		return buildResponse(getErr());
	}
	public Response success( Object d ) {
		err.setCode(Status.OK.getStatusCode());
		return buildSuccessResponse(d);
				
	}
	public Response success( int code, Object d ) {
		err.setCode(code);
		return buildSuccessResponse(d);
	}

	public Response unauthorized( String msg ) {
		err.setCode(Status.UNAUTHORIZED.getStatusCode());
		err.setFields( "Authorization");
		err.setMessage( msg );
		return buildErrResponse();
	}
	public Response unauthorized() {
		err.setCode(Status.UNAUTHORIZED.getStatusCode());
		err.setFields( "Authorization");
		err.setMessage( "User credentials in HTTP Header field Authorization are not authorized for the requested action");
		return buildErrResponse();
	}
	public Response unavailable() {
		err.setCode(Status.SERVICE_UNAVAILABLE.getStatusCode());
		err.setMessage( "Request is unavailable due to unexpected condition");
		return buildErrResponse();
	}
	public Response notFound() {
		err.setCode(Status.NOT_FOUND.getStatusCode());
		err.setMessage( "Requested object not found");
		return buildErrResponse();
	}
	public Response error() {
		return buildErrResponse();
	}
	
	public void checkAuthorization( String auth, String uriPath, String httpMethod ) throws AuthenticationErrorException, Exception {
		authorization = auth;
		setUriFromPath( uriPath );
		method = httpMethod;
		
		checkAuthorization();
	}

	
	public void checkAuthorization() throws AuthenticationErrorException, Exception {

		MDC.put(MDC_KEY_REQUEST_ID, requestId); 
	
		logger.info("request: uri={} method={} auth={}", uri, method, authorization );

		if ( uri == null || uri.isEmpty()) {
			String errmsg = "No URI value provided ";
			err.setMessage(errmsg);
			logger.info( errmsg );
			throw new AuthenticationErrorException( );			
		}
		if ( method == null || method.isEmpty()) {
			String errmsg = "No method value provided ";
			err.setMessage(errmsg);
			logger.info( errmsg );
			throw new AuthenticationErrorException( );			
		}
		DmaapService dmaapService = new DmaapService();
		Dmaap dmaap = dmaapService.getDmaap();
		String env = 		dmaap.getDmaapName();
		
		// special case during bootstrap of app when DMaaP environment may not be set.
		// this allows us to authorize certain APIs used for initialization during this window.
		if ( env == null || env.isEmpty() ) {
			env = "boot";
		}
		if ( ! usePE ) return;  // skip authorization if not enabled
		if ( authorization == null || authorization.isEmpty()) {
			String errmsg = "No basic authorization value provided ";
			err.setMessage(errmsg);
			logger.info( errmsg );
			throw new AuthenticationErrorException( );
		}
		String credentials = authorization.substring("Basic".length()).trim();
        byte[] decoded = DatatypeConverter.parseBase64Binary(credentials);
        String decodedString = new String(decoded);
        String[] actualCredentials = decodedString.split(":");
        String ID = actualCredentials[0];
        String Password = actualCredentials[1];
        MDC.put(MDC_PARTNER_NAME, ID);
		try {
			
			DmaapPerm p = new DmaapPerm( apiNamespace + "." + uri, env, method );
			apiPolicy.check( ID, Password, p);
		} catch ( AuthenticationErrorException ae ) {
			String errmsg =  "User " + ID + " failed authentication/authorization for " + apiNamespace + "." + uriPath + " " + env + " " + method;
			logger.info( errmsg );
			err.setMessage(errmsg);
			throw ae;

		} 
		

	}
	public String getRequestId() {
		return requestId;
	}
	public ApiService setRequestId(String requestId) {
		if ( requestId == null || requestId.isEmpty()) {	
			this.requestId = (new RandomString(10)).nextString();
			logger.warn( "X-ECOMP-RequestID not set in HTTP Header.  Setting RequestId value to: " + this.requestId );
		} else {
			this.requestId = requestId;
		}
		MDC.put(MDC_KEY_REQUEST_ID, this.requestId); 
		return this;
	}
}