package com.amazonwebservices.blogs.containers.sigv4.util;

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

import org.apache.logging.log4j.Logger;
import org.apache.logging.log4j.LogManager;

/**
 * Various Http helper routines
 */
public class HttpUtils {

	private static final Logger logger = LogManager.getLogger(HttpUtils.class);

    /**
     * Makes a http request to the specified endpoint
     */
    public static String invokeHttpRequest(URL endpointUrl,
                                         String httpMethod,
                                         Map<String, String> headers,
                                         String requestBody) {
        HttpURLConnection connection = createHttpConnection(endpointUrl, httpMethod, headers);
        try {
            if ( requestBody != null ) {
                DataOutputStream wr = new DataOutputStream(connection.getOutputStream());
                wr.writeBytes(requestBody);
                wr.flush();
                wr.close();
            }
        } catch (Exception e) {
            throw new RuntimeException("Request failed. " + e.getMessage(), e);
        }
        return executeHttpRequest(connection);
    }
    
    public static String executeHttpRequest(HttpURLConnection connection) {
        try {
            // Get Response
            InputStream is;
            try {
                is = connection.getInputStream();
            } catch (IOException e) {
                is = connection.getErrorStream();
            }
            
            BufferedReader rd = new BufferedReader(new InputStreamReader(is));
            String line;
            StringBuffer response = new StringBuffer();
            while ((line = rd.readLine()) != null) {
                response.append(line);
                response.append('\r');
            }
            rd.close();
            return response.toString();
        } catch (Exception e) {
            throw new RuntimeException("Request failed. " + e.getMessage(), e);
        } finally {
            if (connection != null) {
                connection.disconnect();
            }
        }
    }
    
    public static HttpURLConnection createHttpConnection(URL endpointUrl,
                                                         String httpMethod,
                                                         Map<String, String> headers) {
        try {
            HttpURLConnection connection = (HttpURLConnection) endpointUrl.openConnection();
            connection.setRequestMethod(httpMethod);
            
            if ( headers != null ) {
                logger.info("Request headers");
                for ( String headerKey : headers.keySet() ) {
                    logger.info(headerKey + ": " + headers.get(headerKey));
                    connection.setRequestProperty(headerKey, headers.get(headerKey));
                }
            }

            connection.setUseCaches(false);
            connection.setDoInput(true);
            connection.setDoOutput(true);
            return connection;
        } catch (Exception e) {
            throw new RuntimeException("Cannot create connection. " + e.getMessage(), e);
        }
    }
    
    public static String urlEncode(String url, boolean keepPathSlash) {
        String encoded;
        try {
            encoded = URLEncoder.encode(url, "UTF-8");
        } catch (UnsupportedEncodingException e) {
            throw new RuntimeException("UTF-8 encoding is not supported.", e);
        }
        if ( keepPathSlash ) {
            encoded = encoded.replace("%2F", "/");
        }
        return encoded;
    }
}