/*
 * Copyright 2013-2017 Amazon.com, Inc. or its affiliates.
 * 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.
 */

package com.amazonaws.mobileconnectors.cognitoauth.util;

import com.amazonaws.http.TLS12SocketFactory;
import com.amazonaws.mobileconnectors.cognitoauth.exceptions.AuthClientException;
import com.amazonaws.mobileconnectors.cognitoauth.exceptions.AuthServiceException;

import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;
import java.util.List;
import java.util.Map;

import javax.net.ssl.HttpsURLConnection;

/**
 * Local http client.
 */

public final class AuthHttpClient {

	public String httpPost(final URL uri, final Map<String, String> headerParams, final Map<String, String> bodyParams) throws Exception {
		if (uri == null || bodyParams == null || bodyParams.size() < 1 ) {
			throw new AuthClientException("Invalid http request parameters");
		}

		final HttpsURLConnection httpsURLConnection = (HttpsURLConnection) uri.openConnection();
		TLS12SocketFactory.fixTLSPre21(httpsURLConnection);
		DataOutputStream httpOutputStream = null;
		BufferedReader br = null;
		try {
			// Request header
			httpsURLConnection.setRequestMethod(ClientConstants.HTTP_REQUEST_TYPE_POST);
			httpsURLConnection.setDoOutput(true);
			for (Map.Entry<String, String> param: headerParams.entrySet()) {
				httpsURLConnection.addRequestProperty(param.getKey(), param.getValue());
			}

			// Request body
			StringBuilder reqBuilder = new StringBuilder();
			int index = bodyParams.size();
			for (Map.Entry<String, String> param: bodyParams.entrySet()) {
				reqBuilder.append(URLEncoder.encode(param.getKey(), "UTF-8")).append('=').append(URLEncoder.encode(param.getValue(), "UTF-8"));
				if(index-- > 1){
					reqBuilder.append('&');
				}
			}
			String requestBody = reqBuilder.toString();

			httpOutputStream = new DataOutputStream(httpsURLConnection.getOutputStream());

			httpOutputStream.writeBytes(requestBody);
			httpOutputStream.flush();

			// Parse response
			Map<String, List<String>> respHeaders =  httpsURLConnection.getHeaderFields();

			int responseCode = httpsURLConnection.getResponseCode();

			if (responseCode >= HttpURLConnection.HTTP_OK &&
					responseCode < HttpURLConnection.HTTP_INTERNAL_ERROR) {

				// Return response from the http call
				InputStream httpDataStream;
				if (responseCode < HttpURLConnection.HTTP_BAD_REQUEST) {
					httpDataStream = httpsURLConnection.getInputStream();
				} else {
					httpDataStream = httpsURLConnection.getErrorStream();
				}
				br = new BufferedReader(new InputStreamReader(httpDataStream));

				String line = "";
				StringBuilder responseOutput = new StringBuilder();
				while ((line = br.readLine()) != null) {
					responseOutput.append(line);
				}

				return responseOutput.toString();
			} else {
				// Throw a Cognito Client Exception
				throw new AuthServiceException(httpsURLConnection.getResponseMessage());
			}

		} catch (final Exception e) {
			throw e;
		} finally {
			if (httpOutputStream != null) {
				httpOutputStream.close();
			}
			if (br != null) {
				br.close();
			}
		}
	}
}