// Copyright (C) 2010-2012  The OpenTSDB Authors.

//

// This program is free software: you can redistribute it and/or modify it

// under the terms of the GNU Lesser General Public License as published by

// the Free Software Foundation, either version 2.1 of the License, or (at your

// option) any later version.  This program is distributed in the hope that it

// will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty

// of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser

// General Public License for more details.  You should have received a copy

// of the GNU Lesser General Public License along with this program.  If not,

// see <http://www.gnu.org/licenses/>.

* DISCLAIMER

* This my first GWT code ever, so it's most likely horribly wrong as I've had

* virtually no exposure to the technology except through the tutorial. --tsuna

*/

* Root class for the 'query UI'.

* Manages the entire UI, forms to query the TSDB and other misc panels.

*/

  // Some URLs we use to fetch data from the TSD.

  private static final String AGGREGATORS_URL = "/aggregators";

  private static final String LOGS_URL = "/logs?json";

  private static final String STATS_URL = "/stats?json";

  private static final String VERSION_URL = "/version?json";

  private static final DateTimeFormat FULLDATE =

    DateTimeFormat.getFormat("yyyy/MM/dd-HH:mm:ss");

  private final Label current_error = new Label();

  private final DateTimeBox start_datebox = new DateTimeBox();

  private final DateTimeBox end_datebox = new DateTimeBox();

  private final CheckBox autoreload = new CheckBox("Autoreload");

  private final ValidatedTextBox autoreoload_interval = new ValidatedTextBox();

  private Timer autoreoload_timer;

  private final ValidatedTextBox yrange = new ValidatedTextBox();

  private final ValidatedTextBox y2range = new ValidatedTextBox();

  private final CheckBox ylog = new CheckBox();

  private final CheckBox y2log = new CheckBox();

  private final TextBox ylabel = new TextBox();

  private final TextBox y2label = new TextBox();

  private final ValidatedTextBox yformat = new ValidatedTextBox();

  private final ValidatedTextBox y2format = new ValidatedTextBox();

  private final ValidatedTextBox wxh = new ValidatedTextBox();

  private String keypos = "";  // Position of the key on the graph.

  private final CheckBox horizontalkey = new CheckBox("Horizontal layout");

  private final CheckBox keybox = new CheckBox("Box");

  private final CheckBox nokey = new CheckBox("No key (overrides others)");

  // Styling options.

  private final CheckBox smooth = new CheckBox();

  /**

   * Handles every change to the query form and gets a new graph.

   * Whenever the user changes one of the parameters of the graph, we want

   * to automatically get a new graph.

   */

  private final EventsHandler refreshgraph = new EventsHandler() {

    protected <H extends EventHandler> void onEvent(final DomEvent<H> event) {

      refreshGraph();

    }

  };

  final MetricForm.MetricChangeHandler metric_change_handler =

    new MetricForm.MetricChangeHandler() {

      public void onMetricChange(final MetricForm metric) {

        final int index = metrics.getWidgetIndex(metric);

        metrics.getTabBar().setTabText(index, getTabTitle(metric));

      }

      private String getTabTitle(final MetricForm metric) {

        final String metrictext = metric.getMetric();

        final int last_period = metrictext.lastIndexOf('.');

        if (last_period < 0) {

          return metrictext;

        }

        return metrictext.substring(last_period + 1);

      }

    };

  final EventsHandler updatey2range = new EventsHandler() {

      protected <H extends EventHandler> void onEvent(final DomEvent<H> event) {

        for (final Widget metric : metrics) {

          if (!(metric instanceof MetricForm)) {

            continue;

          }

          if (((MetricForm) metric).x1y2().getValue()) {

            y2range.setEnabled(true);

            y2log.setEnabled(true);

            y2label.setEnabled(true);

            y2format.setEnabled(true);

            return;

          }

        }

        y2range.setEnabled(false);

        y2log.setEnabled(false);

        y2label.setEnabled(false);

        y2format.setEnabled(false);

      }

    };

  /** List of known aggregation functions.  Fetched once from the server. */

  private final ArrayList<String> aggregators = new ArrayList<String>();

  private final DecoratedTabPanel metrics = new DecoratedTabPanel();

  /** Panel to place generated graphs and a box for zoom highlighting. */

  private final AbsolutePanel graphbox = new AbsolutePanel();

  private final Image graph = new Image();

  private final ZoomBox zoom_box = new ZoomBox();

  private final Label graphstatus = new Label();

  /** Remember the last URI requested to avoid requesting twice the same. */

  private String lastgraphuri;

  /**

   * We only send one request at a time, how many have we not sent yet?.

   * Note that we don't buffer pending requests.  When there are multiple

   * ones pending, we will only execute the last one and discard the other

   * intermediate ones, since the user is no longer interested in them.

   */

  private int pending_requests = 0;

  /** How many graph requests we make.  */

  private int nrequests = 0;

  // Other misc panels.

  private final FlexTable logs = new FlexTable();

  private final FlexTable stats_table = new FlexTable();

  private final HTML build_data = new HTML("Loading...");

  /**

   * This is the entry point method.

   */

  public void onModuleLoad() {

    asyncGetJson(AGGREGATORS_URL, new GotJsonCallback() {

      public void got(final JSONValue json) {

        // Do we need more manual type checking?  Not sure what will happen

        // in the browser if something other than an array is returned.

        final JSONArray aggs = json.isArray();

        for (int i = 0; i < aggs.size(); i++) {

          aggregators.add(aggs.get(i).isString().stringValue());

        }

        ((MetricForm) metrics.getWidget(0)).setAggregators(aggregators);

        refreshFromQueryString();

        refreshGraph();

      }

    });

    // All UI elements need to regenerate the graph when changed.

    {

      final ValueChangeHandler<Date> vch = new ValueChangeHandler<Date>() {

        public void onValueChange(final ValueChangeEvent<Date> event) {

          refreshGraph();

        }

      };

      TextBox tb = start_datebox.getTextBox();

      tb.addBlurHandler(refreshgraph);

      tb.addKeyPressHandler(refreshgraph);

      start_datebox.addValueChangeHandler(vch);

      tb = end_datebox.getTextBox();

      tb.addBlurHandler(refreshgraph);

      tb.addKeyPressHandler(refreshgraph);

      end_datebox.addValueChangeHandler(vch);

    }

    autoreoload_interval.addBlurHandler(refreshgraph);

    autoreoload_interval.addKeyPressHandler(refreshgraph);

    yrange.addBlurHandler(refreshgraph);

    yrange.addKeyPressHandler(refreshgraph);

    y2range.addBlurHandler(refreshgraph);

    y2range.addKeyPressHandler(refreshgraph);

    ylog.addClickHandler(new AdjustYRangeCheckOnClick(ylog, yrange));

    y2log.addClickHandler(new AdjustYRangeCheckOnClick(y2log, y2range));

    ylog.addClickHandler(refreshgraph);

    y2log.addClickHandler(refreshgraph);

    ylabel.addBlurHandler(refreshgraph);

    ylabel.addKeyPressHandler(refreshgraph);

    y2label.addBlurHandler(refreshgraph);

    y2label.addKeyPressHandler(refreshgraph);

    yformat.addBlurHandler(refreshgraph);

    yformat.addKeyPressHandler(refreshgraph);

    y2format.addBlurHandler(refreshgraph);

    y2format.addKeyPressHandler(refreshgraph);

    wxh.addBlurHandler(refreshgraph);

    wxh.addKeyPressHandler(refreshgraph);

    horizontalkey.addClickHandler(refreshgraph);

    keybox.addClickHandler(refreshgraph);

    nokey.addClickHandler(refreshgraph);

    smooth.addClickHandler(refreshgraph);

    yrange.setValidationRegexp("^("                            // Nothing or

                               + "|\\[([-+.0-9eE]+|\\*)?"      // "[start

                               + ":([-+.0-9eE]+|\\*)?\\])$");  //   :end]"

    yrange.setVisibleLength(5);

    yrange.setMaxLength(44);  // MAX=2^26=20 chars: "[-$MAX:$MAX]"

    yrange.setText("[0:]");

    y2range.setValidationRegexp("^("                            // Nothing or

                                + "|\\[([-+.0-9eE]+|\\*)?"      // "[start

                                + ":([-+.0-9eE]+|\\*)?\\])$");  //   :end]"

    y2range.setVisibleLength(5);

    y2range.setMaxLength(44);  // MAX=2^26=20 chars: "[-$MAX:$MAX]"

    y2range.setText("[0:]");

    y2range.setEnabled(false);

    y2log.setEnabled(false);

    ylabel.setVisibleLength(10);

    ylabel.setMaxLength(50);  // Arbitrary limit.

    y2label.setVisibleLength(10);

    y2label.setMaxLength(50);  // Arbitrary limit.

    y2label.setEnabled(false);

    yformat.setValidationRegexp("^(|.*%..*)$");  // Nothing or at least one %?

    yformat.setVisibleLength(10);

    yformat.setMaxLength(16);  // Arbitrary limit.

    y2format.setValidationRegexp("^(|.*%..*)$");  // Nothing or at least one %?

    y2format.setVisibleLength(10);

    y2format.setMaxLength(16);  // Arbitrary limit.

    y2format.setEnabled(false);

    wxh.setValidationRegexp("^[1-9][0-9]{2,}x[1-9][0-9]{2,}$");  // 100x100

    wxh.setVisibleLength(9);

    wxh.setMaxLength(11);  // 99999x99999

    wxh.setText((Window.getClientWidth() - 20) + "x"

                + (Window.getClientHeight() * 4 / 5));

    final FlexTable table = new FlexTable();

    table.setText(0, 0, "From");

    {

      final HorizontalPanel hbox = new HorizontalPanel();

      hbox.add(new InlineLabel("To"));

      final Anchor now = new Anchor("(now)");

      now.addClickHandler(new ClickHandler() {

        public void onClick(final ClickEvent event) {

          end_datebox.setValue(new Date());

          refreshGraph();

        }

      });

      hbox.add(now);

      hbox.add(autoreload);

      hbox.setWidth("100%");

      table.setWidget(0, 1, hbox);

    }

    autoreload.addValueChangeHandler(new ValueChangeHandler<Boolean>() {

      @Override

      public void onValueChange(final ValueChangeEvent<Boolean> event) {

        if (autoreload.getValue()) {

          final HorizontalPanel hbox = new HorizontalPanel();

          hbox.setWidth("100%");

          hbox.add(new InlineLabel("Every:"));

          hbox.add(autoreoload_interval);

          hbox.add(new InlineLabel("seconds"));

          table.setWidget(1, 1, hbox);

          if (autoreoload_interval.getValue().isEmpty()) {

            autoreoload_interval.setValue("15");

          }

          autoreoload_interval.setFocus(true);

          lastgraphuri = "";  // Force refreshGraph.

          refreshGraph();     // Trigger the 1st auto-reload

        } else {

          table.setWidget(1, 1, end_datebox);

        }

      }

    });

    autoreoload_interval.setValidationRegexp("^([5-9]|[1-9][0-9]+)$");  // >=5s

    autoreoload_interval.setMaxLength(4);

    autoreoload_interval.setVisibleLength(8);

    table.setWidget(1, 0, start_datebox);

    table.setWidget(1, 1, end_datebox);

    {

      final HorizontalPanel hbox = new HorizontalPanel();

      hbox.add(new InlineLabel("WxH:"));

      hbox.add(wxh);

      table.setWidget(0, 3, hbox);

    }

    {

      addMetricForm("metric 1", 0);

      metrics.selectTab(0);

      metrics.add(new InlineLabel("Loading..."), "+");

      metrics.addBeforeSelectionHandler(new BeforeSelectionHandler<Integer>() {

        public void onBeforeSelection(final BeforeSelectionEvent<Integer> event) {

          final int item = event.getItem();

          final int nitems = metrics.getWidgetCount();

          if (item == nitems - 1) {  // Last item: the "+" was clicked.

            event.cancel();

            final MetricForm metric = addMetricForm("metric " + nitems, item);

            metrics.selectTab(item);

            metric.setFocus(true);

          }

        }

      });

      table.setWidget(2, 0, metrics);

    }

    table.getFlexCellFormatter().setColSpan(2, 0, 2);

    table.getFlexCellFormatter().setRowSpan(1, 3, 2);

    final DecoratedTabPanel optpanel = new DecoratedTabPanel();

    optpanel.add(makeAxesPanel(), "Axes");

    optpanel.add(makeKeyPanel(), "Key");

    optpanel.add(makeStylePanel(), "Style");

    optpanel.selectTab(0);

    table.setWidget(1, 3, optpanel);

    final DecoratorPanel decorator = new DecoratorPanel();

    decorator.setWidget(table);

    final VerticalPanel graphpanel = new VerticalPanel();

    graphpanel.add(decorator);

    {

      final VerticalPanel graphvbox = new VerticalPanel();

      graphvbox.add(graphstatus);

      graph.setVisible(false);

      // Put the graph image element and the zoombox elements inside the absolute panel

      graphbox.add(graph, 0, 0);

      zoom_box.setVisible(false);

      graphbox.add(zoom_box, 0, 0);

      graph.addMouseOverHandler(new MouseOverHandler() {

        public void onMouseOver(final MouseOverEvent event) {

          final Style style = graphbox.getElement().getStyle();

          style.setCursor(Cursor.CROSSHAIR);

        }

      });

      graph.addMouseOutHandler(new MouseOutHandler() {

        public void onMouseOut(final MouseOutEvent event) {

          final Style style = graphbox.getElement().getStyle();

          style.setCursor(Cursor.AUTO);

        }

      });

      graphvbox.add(graphbox);

      graph.addErrorHandler(new ErrorHandler() {

        public void onError(final ErrorEvent event) {

          graphstatus.setText("Oops, failed to load the graph.");

        }

      });

      graph.addLoadHandler(new LoadHandler() {

        public void onLoad(final LoadEvent event) {

          graphbox.setWidth(graph.getWidth() + "px");

          graphbox.setHeight(graph.getHeight() + "px");

        }

      });

      graphpanel.add(graphvbox);

    }

    final DecoratedTabPanel mainpanel = new DecoratedTabPanel();

    mainpanel.setWidth("100%");

    mainpanel.add(graphpanel, "Graph");

    mainpanel.add(stats_table, "Stats");

    mainpanel.add(logs, "Logs");

    mainpanel.add(build_data, "Version");

    mainpanel.selectTab(0);

    mainpanel.addBeforeSelectionHandler(new BeforeSelectionHandler<Integer>() {

      public void onBeforeSelection(final BeforeSelectionEvent<Integer> event) {

        clearError();

        final int item = event.getItem();

        switch (item) {

          case 1: refreshStats(); return;

          case 2: refreshLogs(); return;

          case 3: refreshVersion(); return;

        }

      }

    });

    final VerticalPanel root = new VerticalPanel();

    root.setWidth("100%");

    root.add(current_error);

    current_error.setVisible(false);

    current_error.addStyleName("dateBoxFormatError");

    root.add(mainpanel);

    RootPanel.get("queryuimain").add(root);

    // Must be done at the end, once all the widgets are attached.

    ensureSameWidgetSize(optpanel);

    History.addHistoryListener(this);

  }

  @Override

  public void onHistoryChanged(String historyToken) {

    refreshFromQueryString();

    refreshGraph();

  }

  /** Additional styling options.  */

  private Grid makeStylePanel() {

    final Grid grid = new Grid(5, 3);

    grid.setText(0, 1, "Smooth");

    grid.setWidget(0, 2, smooth);

    return grid;

  }

  /**

   * Builds the panel containing customizations for the axes of the graph.

   */

  private Grid makeAxesPanel() {

    final Grid grid = new Grid(5, 3);

    grid.setText(0, 1, "Y");

    grid.setText(0, 2, "Y2");

    setTextAlignCenter(grid.getRowFormatter().getElement(0));

    grid.setText(1, 0, "Label");

    grid.setWidget(1, 1, ylabel);

    grid.setWidget(1, 2, y2label);

    grid.setText(2, 0, "Format");

    grid.setWidget(2, 1, yformat);

    grid.setWidget(2, 2, y2format);

    grid.setText(3, 0, "Range");

    grid.setWidget(3, 1, yrange);

    grid.setWidget(3, 2, y2range);

    grid.setText(4, 0, "Log scale");

    grid.setWidget(4, 1, ylog);

    grid.setWidget(4, 2, y2log);

    setTextAlignCenter(grid.getCellFormatter().getElement(4, 1));

    setTextAlignCenter(grid.getCellFormatter().getElement(4, 2));

    return grid;

  }

  private MetricForm addMetricForm(final String label, final int item) {

    final MetricForm metric = new MetricForm(refreshgraph);

    metric.x1y2().addClickHandler(updatey2range);

    metric.setMetricChangeHandler(metric_change_handler);

    metric.setAggregators(aggregators);

    metrics.insert(metric, label, item);

    return metric;

  }

  private final HashMap<String, RadioButton> keypos_map =

    new HashMap<String, RadioButton>(17);

  /**

   * Small helper to build a radio button used to change the position of the

   * key of the graph.

   */

  private RadioButton addKeyRadioButton(final Grid grid,

                                        final int row, final int col,

                                        final String pos) {

    final RadioButton rb = new RadioButton("keypos");

    rb.addClickHandler(new ClickHandler() {

      public void onClick(final ClickEvent event) {

        keypos = pos;

      }

    });

    rb.addClickHandler(refreshgraph);

    grid.setWidget(row, col, rb);

    keypos_map.put(pos, rb);

    return rb;

  }

  /**

   * Builds the panel containing the customizations for the key of the graph.

   */

  private Widget makeKeyPanel() {

    final Grid grid = new Grid(5, 5);

    addKeyRadioButton(grid, 0, 0, "out left top");

    addKeyRadioButton(grid, 0, 2, "out center top");

    addKeyRadioButton(grid, 0, 4, "out right top");

    addKeyRadioButton(grid, 1, 1, "top left");

    addKeyRadioButton(grid, 1, 2, "top center");

    addKeyRadioButton(grid, 1, 3, "top right").setValue(true);

    addKeyRadioButton(grid, 2, 0, "out center left");

    addKeyRadioButton(grid, 2, 1, "center left");

    addKeyRadioButton(grid, 2, 2, "center");

    addKeyRadioButton(grid, 2, 3, "center right");

    addKeyRadioButton(grid, 2, 4, "out center right");

    addKeyRadioButton(grid, 3, 1, "bottom left");

    addKeyRadioButton(grid, 3, 2, "bottom center");

    addKeyRadioButton(grid, 3, 3, "bottom right");

    addKeyRadioButton(grid, 4, 0, "out bottom left");

    addKeyRadioButton(grid, 4, 2, "out bottom center");

    addKeyRadioButton(grid, 4, 4, "out bottom right");

    final Grid.CellFormatter cf = grid.getCellFormatter();

    cf.getElement(1, 1).getStyle().setProperty("borderLeft", "1px solid #000");

    cf.getElement(1, 1).getStyle().setProperty("borderTop", "1px solid #000");

    cf.getElement(1, 2).getStyle().setProperty("borderTop", "1px solid #000");

    cf.getElement(1, 3).getStyle().setProperty("borderTop", "1px solid #000");

    cf.getElement(1, 3).getStyle().setProperty("borderRight", "1px solid #000");

    cf.getElement(2, 1).getStyle().setProperty("borderLeft", "1px solid #000");

    cf.getElement(2, 3).getStyle().setProperty("borderRight", "1px solid #000");

    cf.getElement(3, 1).getStyle().setProperty("borderLeft", "1px solid #000");

    cf.getElement(3, 1).getStyle().setProperty("borderBottom", "1px solid #000");

    cf.getElement(3, 2).getStyle().setProperty("borderBottom", "1px solid #000");

    cf.getElement(3, 3).getStyle().setProperty("borderBottom", "1px solid #000");

    cf.getElement(3, 3).getStyle().setProperty("borderRight", "1px solid #000");

    final VerticalPanel vbox = new VerticalPanel();

    vbox.add(new InlineLabel("Key location:"));

    vbox.add(grid);

    vbox.add(horizontalkey);

    keybox.setValue(true);

    vbox.add(keybox);

    vbox.add(nokey);

    return vbox;

  }

  private void refreshStats() {

    asyncGetJson(STATS_URL, new GotJsonCallback() {

      public void got(final JSONValue json) {

        final JSONArray stats = json.isArray();

        final int nstats = stats.size();

        for (int i = 0; i < nstats; i++) {

          final String stat = stats.get(i).isString().stringValue();

          String part = stat.substring(0, stat.indexOf(' '));

          stats_table.setText(i, 0, part);  // metric

          int pos = part.length() + 1;

          part = stat.substring(pos, stat.indexOf(' ', pos));

          stats_table.setText(i, 1, part);  // timestamp

          pos += part.length() + 1;

          part = stat.substring(pos, stat.indexOf(' ', pos));

          stats_table.setText(i, 2, part);  // value

          pos += part.length() + 1;

          stats_table.setText(i, 3, stat.substring(pos));  // tags

        }

      }

    });

  }

  private void refreshVersion() {

    asyncGetJson(VERSION_URL, new GotJsonCallback() {

      public void got(final JSONValue json) {

        final JSONObject bd = json.isObject();

        final JSONString shortrev = bd.get("short_revision").isString();

        final JSONString status = bd.get("repo_status").isString();

        final JSONString stamp = bd.get("timestamp").isString();

        final JSONString user = bd.get("user").isString();

        final JSONString host = bd.get("host").isString();

        final JSONString repo = bd.get("repo").isString();

        final JSONString version = bd.get("version").isString();

        build_data.setHTML(

          "OpenTSDB version [" + version.stringValue() + "] built from revision "

          + shortrev.stringValue()

          + " in a " + status.stringValue() + " state<br/>"

          + "Built on " + new Date((Long.parseLong(stamp.stringValue()) * 1000))

          + " by " + user.stringValue() + '@' + host.stringValue()

          + ':' + repo.stringValue());

      }

    });

  }

  private void refreshLogs() {

    asyncGetJson(LOGS_URL, new GotJsonCallback() {

      public void got(final JSONValue json) {

        final JSONArray logmsgs = json.isArray();

        final int nmsgs = logmsgs.size();

        final FlexTable.FlexCellFormatter fcf = logs.getFlexCellFormatter();

        final FlexTable.RowFormatter rf = logs.getRowFormatter();

        for (int i = 0; i < nmsgs; i++) {

          final String msg = logmsgs.get(i).isString().stringValue();

          String part = msg.substring(0, msg.indexOf('\t'));

          logs.setText(i * 2, 0,

                       new Date(Integer.valueOf(part) * 1000L).toString());

          logs.setText(i * 2 + 1, 0, "");  // So we can change the style ahead.

          int pos = part.length() + 1;

          part = msg.substring(pos, msg.indexOf('\t', pos));

          if ("WARN".equals(part)) {

            rf.getElement(i * 2).getStyle().setBackgroundColor("#FCC");

            rf.getElement(i * 2 + 1).getStyle().setBackgroundColor("#FCC");

          } else if ("ERROR".equals(part)) {

            rf.getElement(i * 2).getStyle().setBackgroundColor("#F99");

            rf.getElement(i * 2 + 1).getStyle().setBackgroundColor("#F99");

          } else {

            rf.getElement(i * 2).getStyle().clearBackgroundColor();

            rf.getElement(i * 2 + 1).getStyle().clearBackgroundColor();

            if ((i % 2) == 0) {

              rf.addStyleName(i * 2, "subg");

              rf.addStyleName(i * 2 + 1, "subg");

            }

          }

          pos += part.length() + 1;

          logs.setText(i * 2, 1, part); // level

          part = msg.substring(pos, msg.indexOf('\t', pos));

          pos += part.length() + 1;

          logs.setText(i * 2, 2, part); // thread

          part = msg.substring(pos, msg.indexOf('\t', pos));

          pos += part.length() + 1;

          if (part.startsWith("net.opentsdb.")) {

            part = part.substring(13);

          } else if (part.startsWith("org.hbase.")) {

            part = part.substring(10);

          }

          logs.setText(i * 2, 3, part); // logger

          logs.setText(i * 2 + 1, 0, msg.substring(pos)); // message

          fcf.setColSpan(i * 2 + 1, 0, 4);

          rf.addStyleName(i * 2, "fwf");

          rf.addStyleName(i * 2 + 1, "fwf");

        }

      }

    });

  }

  private void addLabels(final StringBuilder url) {

    final String ylabel = this.ylabel.getText();

    if (!ylabel.isEmpty()) {

      url.append("&ylabel=").append(ylabel);

    }

    if (y2label.isEnabled()) {

      final String y2label = this.y2label.getText();

      if (!y2label.isEmpty()) {

        url.append("&y2label=").append(y2label);

      }

    }

  }

  private void addFormats(final StringBuilder url) {

    final String yformat = this.yformat.getText();

    if (!yformat.isEmpty()) {

      url.append("&yformat=").append(yformat);

    }

    if (y2format.isEnabled()) {

      final String y2format = this.y2format.getText();

      if (!y2format.isEmpty()) {

        url.append("&y2format=").append(y2format);

      }

    }

  }

  private void addYRanges(final StringBuilder url) {

    final String yrange = this.yrange.getText();

    if (!yrange.isEmpty()) {

      url.append("&yrange=").append(yrange);

    }

    if (y2range.isEnabled()) {

      final String y2range = this.y2range.getText();

      if (!y2range.isEmpty()) {

        url.append("&y2range=").append(y2range);

      }

    }

  }

  private void addLogscales(final StringBuilder url) {

    if (ylog.getValue()) {

      url.append("&ylog");

    }

    if (y2log.isEnabled() && y2log.getValue()) {

      url.append("&y2log");

    }

  }

  /**

   * Maybe sets the text of a {@link TextBox} from a query string parameter.

   * @param qs A parsed query string.

   * @param key Name of the query string parameter.

   * If this parameter wasn't passed, the {@link TextBox} will be emptied.

   * @param tb The {@link TextBox} to change.

   */

  private static void maybeSetTextbox(final QueryString qs,

                                      final String key,

                                      final TextBox tb) {

    final ArrayList<String> values = qs.get(key);

    if (values == null) {

      tb.setText("");

      return;

    }

    tb.setText(values.get(0));

  }

  /**

   * Sets the text of a {@link TextBox} from a query string parameter.

   * @param qs A parsed query string.

   * @param key Name of the query string parameter.

   * @param tb The {@link TextBox} to change.

   */

  private static void setTextbox(final QueryString qs,

                                 final String key,

                                 final TextBox tb) {

    final ArrayList<String> values = qs.get(key);

    if (values != null) {

      tb.setText(values.get(0));

    }

  }

  private static QueryString getQueryString(final String qs) {

    return qs.isEmpty() ? new QueryString() : QueryString.decode(qs);

  }

  private void refreshFromQueryString() {

    final QueryString qs = getQueryString(History.getToken());

    maybeSetTextbox(qs, "start", start_datebox.getTextBox());

    maybeSetTextbox(qs, "end", end_datebox.getTextBox());

    setTextbox(qs, "wxh", wxh);

    autoreload.setValue(qs.containsKey("autoreload"), true);

    maybeSetTextbox(qs, "autoreload", autoreoload_interval);

    final ArrayList<String> newmetrics = qs.get("m");

    if (newmetrics == null) {  // Clear all metric forms.

      final int toremove = metrics.getWidgetCount() - 1;

      addMetricForm("metric 1", 0);

      metrics.selectTab(0);

      for (int i = 0; i < toremove; i++) {

        metrics.remove(1);

      }

      return;

    }

    final int n = newmetrics.size();  // We want this many metrics.

    ArrayList<String> options = qs.get("o");

    if (options == null) {

      options = new ArrayList<String>(n);

    }

    for (int i = options.size(); i < n; i++) {  // Make both arrays equal size.

      options.add("");  // Add missing o's.

    }

    for (int i = 0; i < newmetrics.size(); ++i) {

      if (i == metrics.getWidgetCount() - 1) {

        addMetricForm("", i);

      }

      final MetricForm metric = (MetricForm) metrics.getWidget(i);

      metric.updateFromQueryString(newmetrics.get(i), options.get(i));

    }

    // Remove extra metric forms.

    final int m = metrics.getWidgetCount() - 1; // We have this many metrics.

    int showing = metrics.getTabBar().getSelectedTab();  // Currently selected.

    for (int i = m - 1; i >= n; i--) {

      if (showing == i) {  // If we're about to remove the currently selected,

        metrics.selectTab(--showing);  // fix focus to not wind up nowhere.

      }

      metrics.remove(i);

    }

    updatey2range.onEvent(null);

    maybeSetTextbox(qs, "ylabel", ylabel);

    maybeSetTextbox(qs, "y2label", y2label);

    maybeSetTextbox(qs, "yformat", yformat);

    maybeSetTextbox(qs, "y2format", y2format);

    maybeSetTextbox(qs, "yrange", yrange);

    maybeSetTextbox(qs, "y2range", y2range);

    ylog.setValue(qs.containsKey("ylog"));

    y2log.setValue(qs.containsKey("y2log"));

    if (qs.containsKey("key")) {

      final String key = qs.getFirst("key");

      keybox.setValue(key.contains(" box"));

      horizontalkey.setValue(key.contains(" horiz"));

      keypos = key.replaceAll(" (box|horiz\\w*)", "");

      keypos_map.get(keypos).setChecked(true);

    } else {

      keybox.setValue(false);

      horizontalkey.setValue(false);

      keypos_map.get("top right").setChecked(true);

      keypos = "";

    }

    nokey.setValue(qs.containsKey("nokey"));

    smooth.setValue(qs.containsKey("smooth"));

  }

  private void refreshGraph() {

    final Date start = start_datebox.getValue();

    if (start == null) {

      graphstatus.setText("Please specify a start time.");

      return;

    }

    final Date end = end_datebox.getValue();

    if (end != null && !autoreload.getValue()) {

      if (end.getTime() <= start.getTime()) {

        end_datebox.addStyleName("dateBoxFormatError");

        graphstatus.setText("End time must be after start time!");

        return;

      }

    }

    final StringBuilder url = new StringBuilder();

    url.append("/q?start=");

    final String start_text = start_datebox.getTextBox().getText();

    if (start_text.endsWith(" ago") || start_text.endsWith("-ago")) {

      url.append(start_text);

    } else {

      url.append(FULLDATE.format(start));

    }

    if (end != null && !autoreload.getValue()) {

      url.append("&end=");

      final String end_text = end_datebox.getTextBox().getText();

      if (end_text.endsWith(" ago") || end_text.endsWith("-ago")) {

        url.append(end_text);

      } else {

        url.append(FULLDATE.format(end));

      }

    } else {

      // If there's no end-time, the graph may change while the URL remains

      // the same.  No browser seems to re-fetch an image once it's been

      // fetched, even if we destroy the DOM object and re-created it with the

      // same src attribute.  This has nothing to do with caching headers sent

      // by the server.  The browsers simply won't retrieve the same URL again

      // through JavaScript manipulations, period.  So as a workaround, we add

      // a special parameter that the server will delete from the query.

      url.append("&ignore=" + nrequests++);

    }

    if (!addAllMetrics(url)) {

      return;

    }

    addLabels(url);

    addFormats(url);

    addYRanges(url);

    addLogscales(url);

    if (nokey.getValue()) {

      url.append("&nokey");

    } else if (!keypos.isEmpty() || horizontalkey.getValue()) {

      url.append("&key=");

      if (!keypos.isEmpty()) {

        url.append(keypos);

      }

      if (horizontalkey.getValue()) {

        url.append(" horiz");

      }

      if (keybox.getValue()) {

        url.append(" box");

      }

    }

    url.append("&wxh=").append(wxh.getText());

    if (smooth.getValue()) {

      url.append("&smooth=csplines");

    }

    final String unencodedUri = url.toString();

    final String uri = URL.encode(unencodedUri);

    if (uri.equals(lastgraphuri)) {

      return;  // Don't re-request the same graph.

    } else if (pending_requests++ > 0) {

      return;

    }

    lastgraphuri = uri;

    graphstatus.setText("Loading graph...");

    asyncGetJson(uri + "&json", new GotJsonCallback() {

      public void got(final JSONValue json) {

        if (autoreoload_timer != null) {

          autoreoload_timer.cancel();

          autoreoload_timer = null;

        }

        final JSONObject result = json.isObject();

        final JSONValue err = result.get("err");

        String msg = "";

        if (err != null) {

          displayError("An error occurred while generating the graph: "

                       + err.isString().stringValue());

          graphstatus.setText("Please correct the error above.");

        } else {

          clearError();

          String history = unencodedUri.substring(3)      // Remove "/q?".

            .replaceFirst("ignore=[^&]*&", "");  // Unnecessary cruft.

          if (autoreload.getValue()) {

            history += "&autoreload=" + autoreoload_interval.getText();

          }

          if (!history.equals(History.getToken())) {

            History.newItem(history, false);

          }

          final JSONValue nplotted = result.get("plotted");

          final JSONValue cachehit = result.get("cachehit");

          if (cachehit != null) {

            msg += "Cache hit (" + cachehit.isString().stringValue() + "). ";

          }

          if (nplotted != null && nplotted.isNumber().doubleValue() > 0) {

            graph.setUrl(uri + "&png");

            graph.setVisible(true);

            msg += result.get("points").isNumber() + " points retrieved, "

              + nplotted + " points plotted";

          } else {

            graph.setVisible(false);

            msg += "Your query didn't return anything";

          }

          final JSONValue timing = result.get("timing");

          if (timing != null) {

            msg += " in " + timing + "ms.";

          } else {

            msg += '.';

          }

        }

        final JSONValue info = result.get("info");

        if (info != null) {

          if (!msg.isEmpty()) {

            msg += ' ';

          }

          msg += info.isString().stringValue();

        }

        graphstatus.setText(msg);

        if (result.get("etags") != null) {

          final JSONArray etags = result.get("etags").isArray();

          final int netags = etags.size();

          for (int i = 0; i < netags; i++) {

            if (i >= metrics.getWidgetCount()) {

              break;

            }

            final Widget widget = metrics.getWidget(i);

            if (!(widget instanceof MetricForm)) {

              break;

            }

            final MetricForm metric = (MetricForm) widget;

            final JSONArray tags = etags.get(i).isArray();

            final int ntags = tags.size();

            for (int j = 0; j < ntags; j++) {

              metric.autoSuggestTag(tags.get(j).isString().stringValue());

            }

          }

        }

        if (autoreload.getValue()) {

          final int reload_in = Integer.parseInt(autoreoload_interval.getValue());

          if (reload_in >= 5) {

            autoreoload_timer = new Timer() {

              public void run() {

                // Verify that we still want auto reload and that the graph

                // hasn't been updated in the mean time.

                if (autoreload.getValue() && lastgraphuri == uri) {

                  // Force refreshGraph to believe that we want a new graph.

                  lastgraphuri = "";

                  refreshGraph();

                }

              }

            };

            autoreoload_timer.schedule(reload_in * 1000);

          }

        }

        if (--pending_requests > 0) {

          pending_requests = 0;

          refreshGraph();

        }

      }

    });

  }

  private boolean addAllMetrics(final StringBuilder url) {

    boolean found_metric = false;

    for (final Widget widget : metrics) {

      if (!(widget instanceof MetricForm)) {

        continue;

      }

      final MetricForm metric = (MetricForm) widget;

      found_metric |= metric.buildQueryString(url);

    }

    if (!found_metric) {

      graphstatus.setText("Please specify a metric.");

    }

    return found_metric;

  }

  private void asyncGetJson(final String url, final GotJsonCallback callback) {

    final RequestBuilder builder = new RequestBuilder(RequestBuilder.GET, url);

    try {

      builder.sendRequest(null, new RequestCallback() {

        public void onError(final Request request, final Throwable e) {

          displayError("Failed to get " + url + ": " + e.getMessage());

          // Since we don't call the callback we've been given, reset this

          // bit of state as we're not going to retry anything right now.

          pending_requests = 0;

        }

        public void onResponseReceived(final Request request,

                                       final Response response) {

          final int code = response.getStatusCode();

          if (code == Response.SC_OK) {

            clearError();

            callback.got(JSONParser.parse(response.getText()));