package org.reprap.gui.steppertest;

import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.IOException;
import java.util.Timer;
import java.util.TimerTask;

import javax.swing.JButton;
import javax.swing.JCheckBox;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JSlider;
import javax.swing.SwingConstants;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;

import org.reprap.Preferences;
import org.reprap.comms.Communicator;
import org.reprap.comms.snap.SNAPAddress;
import org.reprap.devices.GenericStepperMotor;

/// TODO There is a bug in this app that can cause the stepper to skip some steps
/// and lose its place.  This can occur if you slowly drag the position slider.  Multiple
/// updates will be rapidly sent to the stepper telling it to change position. This
/// will actually cause it to perform a step immediately on each request so it
/// can cause steps to occur faster than they normally would.  If this happens
/// too quickly, it will be beyond the safe torque speed and it will skip.  This
/// should be resolved with a timer or something in the gui.  If an update just
/// occurred the new one should not be sent immedidately.  Instead the event
/// should be queued up and only send after a safe amount of time has elapsed.
/// This would also allow multiple movement events to be coallesced into a single
/// request if they occur very quickly.  It still has to be sent eventually
/// or else the motor will not go to the correct location represented in the gui.
/// One way to avoid this is for the short term to use keys instead of the mouse
/// (eg pgup, pgdown) and don't press too quickly.  This problem has no
/// consequences for normal software driven operation, just interactive use.

public class StepperPanel extends JPanel implements ChangeListener {

	private static final long serialVersionUID = 6262697694879478425L;

	private JSlider externalSpeedSlider;  // Externally maintained speed slider
	private JSlider positionRequest;      // Slider to control position
	private JSlider positionActual;       // Slider to indicate position
	
	private JCheckBox torque;            // If motor is driving or not
	
	private JLabel rangeLabel;
	
	private GenericStepperMotor motor; 
	private boolean moving = false;   // True if (as far as we know) the motor is seeking
	private boolean waiting = false;  // True if already waiting for a timer to complete (so we don't start another one)

	private Timer updateTimer;
	
	private int minValue = 0;
	private int maxValue = 30000;
	private int startingPosition = 5000;
	
	private boolean monitoring = false;
	
	public StepperPanel(String name, int motorId, JSlider externalSpeedSlider, Communicator communicator) throws IOException {
		super();
		

		String axis;
		switch(motorId)
		{
		case 1:
			axis = "X";
			break;
		case 2:
			axis = "Y";
			break;
		case 3:
			axis = "Z";
			break;
		default:
			axis = "X";
			System.err.println("StepperPanel - dud axis id: " + motorId);
				
		}
		int address = Preferences.loadGlobalInt(axis + "Axis" + "Address");
		
		double stepsPerMM = Preferences.loadGlobalDouble(axis + "AxisScale(steps/mm)");
		double axisLength = Preferences.loadGlobalDouble("Working" + axis + "(mm)");
		maxValue = (int)Math.round(stepsPerMM*axisLength);
		startingPosition = maxValue/6;
		
		updateTimer = new Timer();
		
		motor = new GenericStepperMotor(communicator, new SNAPAddress(address), Preferences.getGlobalPreferences(), motorId);
		
		this.externalSpeedSlider = externalSpeedSlider;
		
		setLayout(new GridBagLayout());
		GridBagConstraints c = new GridBagConstraints();
		
		c.insets.bottom = c.insets.top = 0;
		c.ipady = 0;
		c.gridx = 0;
		c.gridy = 0;
		
		add(new JLabel("Set " + name + " axis position"), c);
		positionRequest = new JSlider(SwingConstants.HORIZONTAL, minValue, maxValue, 0);
		positionRequest.setValue(startingPosition);
		positionRequest.addChangeListener(this);
		c.gridy = 1;
		add(positionRequest, c);
		
		c.gridy = 2;
		add(new JLabel("Actual " + name + " axis position"), c);
		positionActual = new JSlider(SwingConstants.HORIZONTAL, minValue, maxValue, 0);
		positionActual.setValue(startingPosition);
		positionActual.setEnabled(false);
		c.gridy = 3;
		add(positionActual, c);
		
		c.gridx = 1;
		c.gridy = 0;
		rangeLabel = new JLabel();
		updateRange();
		add(rangeLabel, c);
		
		c.gridy = 1;
		JButton calibrate = new JButton("Calibrate");
		calibrate.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent evt) {
				onCalibrate();
			}
		});
		add(calibrate, c);
		
		c.gridx = 2;
		JButton home = new JButton("Home");
		home.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent evt) {
				onHomeReset();
			}
		});
		add(home, c);
		
		c.gridx = 3;
		JButton stepForward = new JButton("Step +");
		stepForward.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent evt) {
				onOneStep(true);
			}
		});
		add(stepForward, c);
		
		c.gridx = 4;
		JButton stepBackward = new JButton("Step -");
		stepBackward.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent evt) {
				onOneStep(false);
			}
		});
		add(stepBackward, c);
		
		c.gridx = 1;
		c.gridy = 2;
		torque = new JCheckBox("Torque");
		torque.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent evt) {
				onTorqueUpdate();
        	}
        });
        add(torque, c);
        
		try {
			motor.setPosition(startingPosition);
		} catch (Exception ex) {
			motor.dispose();
			motor = null;
			positionRequest.setEnabled(false);
			calibrate.setEnabled(false);
			torque.setEnabled(false);
			home.setEnabled(false);
			stepForward.setEnabled(false);
			stepBackward.setEnabled(false);
			return;
		}

	}

	/**
	 * Utility function to update the range display and 
	 * slider end points
	 */
	private void updateRange() {
		rangeLabel.setText(minValue + " to " + maxValue);
		
		positionRequest.setMinimum(minValue);
		positionRequest.setMaximum(maxValue);
		positionActual.setMinimum(minValue);
		positionActual.setMaximum(maxValue);
		
        int range = maxValue - minValue;
        positionRequest.setMajorTickSpacing(range/8);  // Ten circles
        positionRequest.setMinorTickSpacing(range/80);   // A full circle
        positionRequest.setPaintTicks(true);
	}

	/**
	 * Calibrate button handler
	 */
	protected void onCalibrate() {
		try {
			GenericStepperMotor.Range range = motor.getRange(externalSpeedSlider.getValue());
			minValue = range.minimum;
			maxValue = range.maximum;
			// We could re-request current position, but for now we know
			// that we're at the max position, so update to reflect this
			moving = false;
			updateRange();
			positionRequest.setValue(maxValue);
		} catch (Exception ex) {
			JOptionPane.showMessageDialog(null, "Problem during calibration: " + ex);
		}
	}

	/**
	 * Callback when the torque checkbox is clicked
	 */
	protected void onTorqueUpdate()
	{
		try {
			if (torque.isSelected()) {
				// You can't currently do this
				torque.setSelected(false);
			} else {
				motor.setIdle();
				moving = false;
			}
		} catch (Exception ex) {
			JOptionPane.showMessageDialog(null, "Could not idle motor: " + ex);
		}
			
	}
	
	/**
	 * Callback when the Home button is clicked
	 */
	protected void onHomeReset()
	{
		try {
			motor.homeReset(externalSpeedSlider.getValue());
			positionRequest.setValue(0);
			positionActual.setValue(0);
			torque.setSelected(true);
		} catch (Exception ex) {
			JOptionPane.showMessageDialog(null, "Could not home motor: " + ex);
		}
	}
	
	/**
	 * Callback when the Step + button is clicked
	 */
	protected void onOneStep(boolean forward)
	{
		try {
			if(forward)
				motor.stepForward();
			else
				motor.stepBackward();
			setDisplayPosition();
			torque.setSelected(true);
		} catch (Exception ex) {
			JOptionPane.showMessageDialog(null, "Could not step motor: " + ex);
		}
	}

	/**
	 * Callback when a slider is changed
	 */
	public void stateChanged(ChangeEvent evt) {
		try {
			Object srcObj = evt.getSource();
			
			if (srcObj instanceof JSlider) {
				JSlider src = (JSlider)srcObj;
				if (src == positionRequest)
					seekToSelectedPosition();
			}
		} catch (Exception ex) {
    		JOptionPane.showMessageDialog(null, "Update exception: " + ex);
		} 
	}

	/**
	 * Queue a timer event for the near future
	 */
	private void startUpdates() {
		if (!waiting && (moving || monitoring)) {    // If there is already one, don't create another
			waiting = true;
			TimerTask task = new TimerTask() {
				public void run() {
					Thread.currentThread().setName("Stepper position poll");
					waiting = false;
					updatePosition();
				}			
			};
			updateTimer.schedule(task, 200);
		}
	}

	/**
	 * Request the current position and display it
	 */
	private void setDisplayPosition() throws IOException {
		int position = motor.getPosition();
		if (monitoring)
			positionRequest.setValue(position);
		positionActual.setValue(position);
		if (position == positionRequest.getValue())
			moving = false;
	}	

	/**
	 * Called when the slider is moved to seek the motor
	 * @throws IOException
	 */
	private void seekToSelectedPosition() throws IOException {
		motor.seek(externalSpeedSlider.getValue(), positionRequest.getValue());
		torque.setSelected(true);
		moving = true;
		startUpdates();
	}

	/**
	 * Called when the speed slider is changed
	 * @throws IOException
	 */
	public void updateSpeed() throws IOException {
		// If we're not moving, changing the speed does nothing.
		// Otherwise, we just re-seek to the current position
		// with the new speed for it to take effect.
		if (moving)
			seekToSelectedPosition();
	}

	/**
	 * This method is called on the timer event to get the current
	 * position and display it.
	 */
	protected void updatePosition()
	{
		try {
			setDisplayPosition();
			if (moving || monitoring)  // If we're moving, start another timer
				startUpdates();
		} catch (IOException ex) {
			// Ignore these if they happen
			System.out.println("Ignored IO exception in position update: " + ex);
		}
	}

	/**
	 * @return Returns the motor.
	 */
	public GenericStepperMotor getMotor() {
		return motor;
	}

	public void monitor(boolean enable) {
		monitoring = enable;
		if (monitoring)
			startUpdates();
			
	}
	
	public void setMoved() {
		torque.setSelected(true);
	}

	public void loadPosition() throws IOException {
		monitor(false);
		positionActual.setValue(motor.getPosition());
		positionRequest.setValue(motor.getPosition());
		torque.setSelected(true);
	}
	
	public void dispose() {
		if (motor != null)
			motor.dispose();
		updateTimer.cancel();
	}
}