// License: GPL. Copyright 2007 by Immanuel Scholz and others
package org.openstreetmap.josm.io;

import static org.openstreetmap.josm.tools.I18n.tr;

import java.io.IOException;
import java.io.InputStream;
import java.net.URLConnection;

import org.openstreetmap.josm.gui.PleaseWaitDialog;

/**
 * Read from an other reader and increment an progress counter while on the way.
 * @author Imi
 */
public class ProgressInputStream extends InputStream {

    private final InputStream in;
    private int readSoFar = 0;
    private int lastDialogUpdate = 0;
    private final URLConnection connection;
    private PleaseWaitDialog pleaseWaitDlg;

    public class OsmServerException extends IOException {
        private OsmServerException(String e) {
            super(e);
        }
    }

    public ProgressInputStream(URLConnection con, PleaseWaitDialog pleaseWaitDlg) throws IOException, OsmServerException {
        this.connection = con;

        try {
            this.in = con.getInputStream();
        } catch (IOException e) {
            if (con.getHeaderField("Error") != null)
                throw new OsmServerException(tr(con.getHeaderField("Error")));
            throw e;
        }

        int contentLength = con.getContentLength();
        this.pleaseWaitDlg = pleaseWaitDlg;
        if (pleaseWaitDlg == null)
            return;
        if (contentLength > 0)
            pleaseWaitDlg.progress.setMaximum(contentLength);
        else
            pleaseWaitDlg.progress.setMaximum(0);
        pleaseWaitDlg.progress.setValue(0);
    }

    @Override public void close() throws IOException {
        in.close();
    }

    @Override public int read(byte[] b, int off, int len) throws IOException {
        int read = in.read(b, off, len);
        if (read != -1)
            advanceTicker(read);
        return read;
    }

    @Override public int read() throws IOException {
        int read = in.read();
        if (read != -1)
            advanceTicker(1);
        return read;
    }

    /**
     * Increase ticker (progress counter and displayed text) by the given amount.
     * @param amount
     */
    private void advanceTicker(int amount) {
        if (pleaseWaitDlg == null)
            return;

        if (pleaseWaitDlg.progress.getMaximum() == 0 && connection.getContentLength() != -1)
            pleaseWaitDlg.progress.setMaximum(connection.getContentLength());

        readSoFar += amount;

        if (readSoFar / 1024 != lastDialogUpdate) {
            lastDialogUpdate++;
            String progStr = " "+readSoFar/1024+"/";
            progStr += (pleaseWaitDlg.progress.getMaximum()==0) ? "??? KB" : (pleaseWaitDlg.progress.getMaximum()/1024)+" KB";
            pleaseWaitDlg.progress.setValue(readSoFar);

            String cur = pleaseWaitDlg.currentAction.getText();
            int i = cur.indexOf(' ');
            if (i != -1)
                cur = cur.substring(0, i) + progStr;
            else
                cur += progStr;
            pleaseWaitDlg.currentAction.setText(cur);
        }
    }
}