/**
 * @author urbain, hornick
 * 
 * Retrieve stock quotes using YQL
 * http://developer.yahoo.com/yql
 * 
 */
package stokequote;

import java.net.URL;
import java.net.URLEncoder;
import java.util.ArrayList;
import java.util.List;

import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
import org.json.simple.parser.JSONParser;

import com.google.api.client.http.GenericUrl;
import com.google.api.client.http.HttpRequest;
import com.google.api.client.http.HttpRequestFactory;
import com.google.api.client.http.HttpResponse;
import com.google.api.client.http.HttpTransport;
import com.google.api.client.http.javanet.NetHttpTransport;


public class StockQuoter {

	//"http://query.yahooapis.com/v1/public/yql?q=select%20*%20from%20yahoo.finance.quotes%20where%20symbol%20in%20(%22YHOO%22%2C%22AAPL%22%2C%22GOOG%22%2C%22MSFT%22)&format=json&diagnostics=true&env=http%3A%2F%2Fdatatables.org%2Falltables.env&callback=cbfunc"

	/**
	 * @author urbain, hornick
	 * Retrieve stock quotes using YQL
	 * @param symbol the stock ticker symbol; eg: GOOG, AAPL, or QCOM
	 * @returns JSON string of stock information
	 */
	public static String getStockQuote(String symbol) throws Exception {

		// Sanity check
		if( symbol == null || symbol.isEmpty() ) {
			throw new Exception("null or empty symbol");
		}
		
		// Formulate the YQL query string incorporating the ticker symbol
		String stockString = "\""+symbol.toUpperCase()+"\"";
		String yql = "http://query.yahooapis.com/v1/public/yql?q=select%20*%20from%20yahoo.finance.quotes%20where%20symbol%20in%20(" + 
				URLEncoder.encode(stockString, "UTF-8") + 
				")&format=json&diagnostics=true&env=http%3A%2F%2Fdatatables.org%2Falltables.env";

		// Form the HTTP request to Yahoo
		HttpTransport httpTransport = new NetHttpTransport();
		HttpRequestFactory requestFactory = httpTransport.createRequestFactory();
		JSONParser parser = new JSONParser();
		GenericUrl url = new GenericUrl( yql );
		HttpRequest request = requestFactory.buildGetRequest(url);
		HttpResponse httpResponse = request.execute();
		String httpResponseString = httpResponse.parseAsString();
		//System.out.println( "HTTP Response String: " + httpResponseString );

		JSONObject jsonObject = (JSONObject)parser.parse( httpResponseString );
		//System.out.println("JSON Object: " + jsonObject);

		JSONObject query = (JSONObject) jsonObject.get("query");
		//System.out.println("Query: " + query);
		JSONObject results = (JSONObject) query.get("results");
		//System.out.println("Results: " + results);

		return results.toJSONString();
	}

	/**
	 * This is a very simple test harness for calling the above method
	 * @param args
	 */
	public static void main(String[] args) throws Exception {
		String quote = StockQuoter.getStockQuote("GOOG");
		System.out.println("Quote: " + quote );
	}

}