/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * 
 */

package org.apache.jmeter.visualizers;

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Image;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.text.NumberFormat;

import javax.swing.BorderFactory;
import javax.swing.Box;
import javax.swing.JCheckBox;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextField;
import javax.swing.border.Border;
import javax.swing.border.EmptyBorder;

import org.apache.jmeter.gui.util.JMeterColor;
import org.apache.jmeter.samplers.Clearable;
import org.apache.jmeter.samplers.SampleResult;
import org.apache.jmeter.util.JMeterUtils;
import org.apache.jmeter.visualizers.gui.AbstractVisualizer;

/**
 * This class implements a statistical analyser that calculates both the average
 * and the standard deviation of the sampling process and outputs them as
 * autoscaling plots.
 * 
 * Created February 8, 2001
 * 
 */
public class GraphVisualizer extends AbstractVisualizer implements ImageVisualizer, ItemListener, Clearable {
    
	private static final String ZERO = "0";  //$NON-NLS-1$
	
	private NumberFormat nf = NumberFormat.getInstance(); // OK, because used in synchronised method

	private SamplingStatCalculator model;

	private JTextField maxYField = null;

	private JTextField minYField = null;

	private JTextField noSamplesField = null;

	private String minute = JMeterUtils.getResString("minute"); // $NON-NLS-1$

	private Graph graph;

	private JCheckBox data;

	private JCheckBox average;

	private JCheckBox deviation;

	private JCheckBox throughput;

	private JCheckBox median;

	private JTextField dataField;

	private JTextField averageField;

	private JTextField deviationField;

	private JTextField throughputField;

	private JTextField medianField;

	/**
	 * Constructor for the GraphVisualizer object.
	 */
	public GraphVisualizer() {
		model = new SamplingStatCalculator("Graph");
		graph = new Graph(model);
		init();
	}

	/**
	 * Gets the Image attribute of the GraphVisualizer object.
	 * 
	 * @return the Image value
	 */
	public Image getImage() {
		Image result = graph.createImage(graph.getWidth(), graph.getHeight());

		graph.paintComponent(result.getGraphics());

		return result;
	}

	public synchronized void updateGui(Sample s) {
		// We have received one more sample
		graph.updateGui(s);
		noSamplesField.setText(Long.toString(s.getCount()));
		dataField.setText(Long.toString(s.getData()));
		averageField.setText(Long.toString(s.getAverage()));
		deviationField.setText(Long.toString(s.getDeviation()));
		throughputField.setText(nf.format(60 * s.getThroughput()) + "/" + minute); // $NON-NLS-1$
		medianField.setText(Long.toString(s.getMedian()));
		updateYAxis();
	}

	public void add(SampleResult res) {
		updateGui(model.addSample(res));
	}

	public String getLabelResource() {
		return "graph_results_title"; // $NON-NLS-1$
	}

	public void itemStateChanged(ItemEvent e) {
		if (e.getItem() == data) {
			this.graph.enableData(e.getStateChange() == ItemEvent.SELECTED);
		} else if (e.getItem() == average) {
			this.graph.enableAverage(e.getStateChange() == ItemEvent.SELECTED);
		} else if (e.getItem() == deviation) {
			this.graph.enableDeviation(e.getStateChange() == ItemEvent.SELECTED);
		} else if (e.getItem() == throughput) {
			this.graph.enableThroughput(e.getStateChange() == ItemEvent.SELECTED);
		} else if (e.getItem() == median) {
			this.graph.enableMedian(e.getStateChange() == ItemEvent.SELECTED);
		}
		this.graph.repaint();
	}

	public void clearData() {
		graph.clearData();		
		model.clear();
		dataField.setText(ZERO);
		averageField.setText(ZERO);
		deviationField.setText(ZERO);
		throughputField.setText("0/" + minute); //$NON-NLS-1$
		medianField.setText(ZERO);
		noSamplesField.setText(ZERO);
		updateYAxis();
		repaint();
	}

	public String toString() {
		return "Show the samples analysis as dot plots";
	}

	/**
	 * Update the max and min value of the Y axis.
	 */
	private void updateYAxis() {
		maxYField.setText(Long.toString(graph.getGraphMax()));
		minYField.setText(ZERO);
	}

	/**
	 * Initialize the GUI.
	 */
	private void init() {
		this.setLayout(new BorderLayout());

		// MAIN PANEL
		Border margin = new EmptyBorder(10, 10, 5, 10);

		this.setBorder(margin);

		// Set up the graph with header, footer, Y axis and graph display
		JPanel graphPanel = new JPanel(new BorderLayout());
		graphPanel.add(createYAxis(), BorderLayout.WEST);
		graphPanel.add(createChoosePanel(), BorderLayout.NORTH);
		graphPanel.add(createGraphPanel(), BorderLayout.CENTER);
		graphPanel.add(createGraphInfoPanel(), BorderLayout.SOUTH);

		// Add the main panel and the graph
		this.add(makeTitlePanel(), BorderLayout.NORTH);
		this.add(graphPanel, BorderLayout.CENTER);
	}

	// Methods used in creating the GUI

	/**
	 * Creates the panel containing the graph's Y axis labels.
	 * 
	 * @return the Y axis panel
	 */
	private JPanel createYAxis() {
		JPanel graphYAxisPanel = new JPanel();

		graphYAxisPanel.setLayout(new BorderLayout());

		maxYField = createYAxisField(5);
		minYField = createYAxisField(3);

		graphYAxisPanel.add(createYAxisPanel("graph_results_ms", maxYField), BorderLayout.NORTH); // $NON-NLS-1$
		graphYAxisPanel.add(createYAxisPanel("graph_results_ms", minYField), BorderLayout.SOUTH); // $NON-NLS-1$

		return graphYAxisPanel;
	}

	/**
	 * Creates a text field to be used for the value of a Y axis label. These
	 * fields hold the minimum and maximum values for the graph. The units are
	 * kept in a separate label outside of this field.
	 * 
	 * @param length
	 *            the number of characters which the field will use to calculate
	 *            its preferred width. This should be set to the maximum number
	 *            of digits that are expected to be necessary to hold the label
	 *            value.
	 * 
	 * @see #createYAxisPanel(String, JTextField)
	 * 
	 * @return a text field configured to be used in the Y axis
	 */
	private JTextField createYAxisField(int length) {
		JTextField field = new JTextField(length);
		field.setBorder(BorderFactory.createEmptyBorder(0, 10, 0, 0));
		field.setEditable(false);
		field.setForeground(Color.black);
		field.setBackground(getBackground());
		field.setHorizontalAlignment(JTextField.RIGHT);
		return field;
	}

	/**
	 * Creates a panel for an entire Y axis label. This includes the dynamic
	 * value as well as the unit label.
	 * 
	 * @param labelResourceName
	 *            the name of the label resource. This is used to look up the
	 *            label text using {@link JMeterUtils#getResString(String)}.
	 * 
	 * @return a panel containing both the dynamic and static parts of a Y axis
	 *         label
	 */
	private JPanel createYAxisPanel(String labelResourceName, JTextField field) {
		JPanel panel = new JPanel(new FlowLayout());
		JLabel label = new JLabel(JMeterUtils.getResString(labelResourceName));

		panel.add(field);
		panel.add(label);
		return panel;
	}

	/**
	 * Creates a panel which allows the user to choose which graphs to display.
	 * This panel consists of a check box for each type of graph (current
	 * sample, average, deviation, and throughput).
	 * 
	 * @return a panel allowing the user to choose which graphs to display
	 */
	private JPanel createChoosePanel() {
		JPanel chooseGraphsPanel = new JPanel();

		chooseGraphsPanel.setLayout(new FlowLayout());
		JLabel selectGraphsLabel = new JLabel(JMeterUtils.getResString("graph_choose_graphs")); //$NON-NLS-1$
		data = createChooseCheckBox("graph_results_data", Color.black); // $NON-NLS-1$
		average = createChooseCheckBox("graph_results_average", Color.blue); // $NON-NLS-1$
		deviation = createChooseCheckBox("graph_results_deviation", Color.red); // $NON-NLS-1$
		throughput = createChooseCheckBox("graph_results_throughput", JMeterColor.dark_green); // $NON-NLS-1$
		median = createChooseCheckBox("graph_results_median", JMeterColor.purple); // $NON-NLS-1$

		chooseGraphsPanel.add(selectGraphsLabel);
		chooseGraphsPanel.add(data);
		chooseGraphsPanel.add(average);
		chooseGraphsPanel.add(median);
		chooseGraphsPanel.add(deviation);
		chooseGraphsPanel.add(throughput);
		return chooseGraphsPanel;
	}

	/**
	 * Creates a check box configured to be used to in the choose panel allowing
	 * the user to select whether or not a particular kind of graph data will be
	 * displayed.
	 * 
	 * @param labelResourceName
	 *            the name of the label resource. This is used to look up the
	 *            label text using {@link JMeterUtils#getResString(String)}.
	 * @param color
	 *            the color used for the checkbox text. By convention this is
	 *            the same color that is used to draw the graph and for the
	 *            corresponding info field.
	 * 
	 * @return a checkbox allowing the user to select whether or not a kind of
	 *         graph data will be displayed
	 */
	private JCheckBox createChooseCheckBox(String labelResourceName, Color color) {
		JCheckBox checkBox = new JCheckBox(JMeterUtils.getResString(labelResourceName));
		checkBox.setSelected(true);
		checkBox.addItemListener(this);
		checkBox.setForeground(color);
		return checkBox;
	}

	/**
	 * Creates a scroll pane containing the actual graph of the results.
	 * 
	 * @return a scroll pane containing the graph
	 */
	private Component createGraphPanel() {
		JScrollPane graphScrollPanel = makeScrollPane(graph, JScrollPane.VERTICAL_SCROLLBAR_NEVER,
				JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
		graphScrollPanel.setViewportBorder(BorderFactory.createEmptyBorder(2, 2, 2, 2));
		graphScrollPanel.setPreferredSize(graphScrollPanel.getMinimumSize());

		return graphScrollPanel;
	}

	/**
	 * Creates a panel which numerically displays the current graph values.
	 * 
	 * @return a panel showing the current graph values
	 */
	private Box createGraphInfoPanel() {
		Box graphInfoPanel = Box.createHorizontalBox();

		noSamplesField = createInfoField(Color.black, 6);
		dataField = createInfoField(Color.black, 5);
		averageField = createInfoField(Color.blue, 5);
		deviationField = createInfoField(Color.red, 5);
		throughputField = createInfoField(JMeterColor.dark_green, 15);
		medianField = createInfoField(JMeterColor.purple, 5);

		graphInfoPanel.add(createInfoColumn(createInfoLabel("graph_results_no_samples", noSamplesField), // $NON-NLS-1$
				noSamplesField, createInfoLabel("graph_results_deviation", deviationField), deviationField)); // $NON-NLS-1$
		graphInfoPanel.add(Box.createHorizontalGlue());

		graphInfoPanel.add(createInfoColumn(createInfoLabel("graph_results_latest_sample", dataField), dataField, // $NON-NLS-1$
				createInfoLabel("graph_results_throughput", throughputField), throughputField)); // $NON-NLS-1$
		graphInfoPanel.add(Box.createHorizontalGlue());

		graphInfoPanel.add(createInfoColumn(createInfoLabel("graph_results_average", averageField), averageField, // $NON-NLS-1$
				createInfoLabel("graph_results_median", medianField), medianField)); // $NON-NLS-1$
		graphInfoPanel.add(Box.createHorizontalGlue());
		return graphInfoPanel;
	}

	/**
	 * Creates one of the fields used to display the graph's current values.
	 * 
	 * @param color
	 *            the color used to draw the value. By convention this is the
	 *            same color that is used to draw the graph for this value and
	 *            in the choose panel.
	 * @param length
	 *            the number of digits which the field should be able to display
	 * 
	 * @return a text field configured to display one of the current graph
	 *         values
	 */
	private JTextField createInfoField(Color color, int length) {
		JTextField field = new JTextField(length);
		field.setBorder(BorderFactory.createEmptyBorder(0, 0, 0, 0));
		field.setEditable(false);
		field.setForeground(color);
		field.setBackground(getBackground());

		// The text field should expand horizontally, but have
		// a fixed height
		field.setMaximumSize(new Dimension(field.getMaximumSize().width, field.getPreferredSize().height));
		return field;
	}

	/**
	 * Creates a label for one of the fields used to display the graph's current
	 * values. Neither the label created by this method or the
	 * <code>field</code> passed as a parameter is added to the GUI here.
	 * 
	 * @param labelResourceName
	 *            the name of the label resource. This is used to look up the
	 *            label text using {@link JMeterUtils#getResString(String)}.
	 * @param field
	 *            the field this label is being created for.
	 */
	private JLabel createInfoLabel(String labelResourceName, JTextField field) {
		JLabel label = new JLabel(JMeterUtils.getResString(labelResourceName));
		label.setForeground(field.getForeground());
		label.setLabelFor(field);
		return label;
	}

	/**
	 * Creates a panel containing two pairs of labels and fields for displaying
	 * the current graph values. This method exists to help with laying out the
	 * fields in columns. If one or more components are null then these
	 * components will be represented by blank space.
	 * 
	 * @param label1
	 *            the label for the first field. This label will be placed in
	 *            the upper left section of the panel. If this parameter is
	 *            null, this section of the panel will be left blank.
	 * @param field1
	 *            the field corresponding to the first label. This field will be
	 *            placed in the upper right section of the panel. If this
	 *            parameter is null, this section of the panel will be left
	 *            blank.
	 * @param label2
	 *            the label for the second field. This label will be placed in
	 *            the lower left section of the panel. If this parameter is
	 *            null, this section of the panel will be left blank.
	 * @param field2
	 *            the field corresponding to the second label. This field will
	 *            be placed in the lower right section of the panel. If this
	 *            parameter is null, this section of the panel will be left
	 *            blank.
	 */
	private Box createInfoColumn(JLabel label1, JTextField field1, JLabel label2, JTextField field2) {
		// This column actually consists of a row with two sub-columns
		// The first column contains the labels, and the second
		// column contains the fields.
		Box row = Box.createHorizontalBox();
		Box col = Box.createVerticalBox();
		col.add(label1 != null ? label1 : Box.createVerticalGlue());
		col.add(label2 != null ? label2 : Box.createVerticalGlue());
		row.add(col);

		row.add(Box.createHorizontalStrut(5));

		col = Box.createVerticalBox();
		col.add(field1 != null ? field1 : Box.createVerticalGlue());
		col.add(field2 != null ? field2 : Box.createVerticalGlue());
		row.add(col);

		row.add(Box.createHorizontalStrut(5));

		return row;
	}

}
