package dalclient;

import edu.jhu.pha.ivoa.*;
import java.io.*;
import java.net.*;
import java.util.*;


/**
 * DAL Query.  Provides methods to build up and execute a query against a
 * predefined service connection context.
 */
public
class DALQuery {
    LinkedHashMap params = new LinkedHashMap();
    DALConnection connection;
    String queryURL;

    DALQuery(DALConnection conn) {
	connection = conn;
    }

    /* Add a query parameter=value pair. */
    public void addParameter(String name, String value) {
	params.put(name, value);
    }

    /* Execute query and write to stdout in CSV format.  */
    public void executeCSV() throws Exception {
	executeCSV(System.out);
    }

    /* Execute query and write to the named file in CSV format.  */
    public void executeCSV(String fname) throws Exception {
	OutputStream ostream = new FileOutputStream(fname);
	executeCSV(new PrintStream(ostream));
    }

    /* Execute query and write to the given output stream in CSV format.
     * At this level we do not support queries to multiple services as
     * the tables returned may differ.
     */
    public void executeCSV(PrintStream out) throws Exception {
	VOTWrap.VOTable vot = this.executeVOTable();
	VOTWrap.Resource r = vot.getResource(0);
        VOTWrap.Table table = r.getTable(0);

	// Output the table header in CSV.
	for (int i=0;  i < table.getFieldCount();  i++) {
	    String colname;

	    VOTWrap.Field field = table.getField(i);
	    if ((colname = field.getUCD()) == null)
		colname = "";

	    if (i > 0)
		System.out.print(",");
	    out.print(colname);
	}
	out.println("");

	// Output the table data.
	int TRCount = table.getTableData().getTRCount();
	for (int j=0;  j < TRCount;  j++) {
	    VOTWrap.TR row = table.getTableData().getTR(j);
	    for (int i=0;  i < table.getFieldCount();  i++) {
		String s = row.getTD(i).getPCDATA();

		if (i > 0)
		    out.print(",");
		out.print(s.replace(',', ' '));
	    }
	    out.println("");
	}
    }

    /* Execute query and return a VOTable.  */
    public VOTWrap.VOTable executeVOTable() throws Exception {
	return (executeVOTable(0));
    }

    /* Query the specified service. */
    public VOTWrap.VOTable executeVOTable(int serviceIndex) throws Exception {
	return (VOTWrap.createVOTable(executeRaw(serviceIndex)));
    }

    /* Execute query and return a binary input stream to read raw results.
     * Note: multiple service connections are not supported at this level.
     * By default only the first service specified is queried.
     */
    public InputStream executeRaw() throws Exception {
	return (executeRaw(0));
    }

    /* Query the specified service. */
    public InputStream executeRaw(int serviceIndex) throws Exception {
	String url = getQueryString(serviceIndex);
	URL http = new URL(queryURL = url);
	return (http.openStream());
    }

    /* Get the current query URL as a string for the given service.
     */
    public String getQueryString(int serviceIndex) {
	Set s = params.entrySet();
	String url;

	// Get service baseURL.
	ArrayList services = connection.services;
	if (services.size() < serviceIndex)
	    return (null);
	String baseURL = (String) services.get(serviceIndex);
	url = baseURL;

	// Try to ensure that the service URL is properly terminated.
	char lastch = url.charAt(url.length() - 1);
	if (lastch != '?' && lastch != '&')
	    url += (url.indexOf('?') > 0) ? '&' : '?';

	// Add query parameters.
	int arg = 0;
	for (Iterator i = s.iterator();  i.hasNext();  arg++) {
	    Map.Entry me = (Map.Entry) i.next();
	    String name = (String) me.getKey();
	    String value = (String) me.getValue();

	    if (arg > 0)
		url += "&";
	    url += name + "=" + value;
	}

	return (url);
    }
}