/*
@VaadinApache2LicenseForJavaFiles@
 */

package com.vaadin.ui;

import java.io.IOException;
import java.io.Serializable;
import java.lang.reflect.Method;
import java.util.Map;

import com.vaadin.event.Action;
import com.vaadin.event.FieldEvents;
import com.vaadin.event.FieldEvents.BlurEvent;
import com.vaadin.event.FieldEvents.BlurListener;
import com.vaadin.event.FieldEvents.FocusEvent;
import com.vaadin.event.FieldEvents.FocusListener;
import com.vaadin.event.ShortcutAction;
import com.vaadin.event.ShortcutAction.KeyCode;
import com.vaadin.event.ShortcutAction.ModifierKey;
import com.vaadin.event.ShortcutListener;
import com.vaadin.terminal.PaintException;
import com.vaadin.terminal.PaintTarget;
import com.vaadin.terminal.gwt.client.MouseEventDetails;
import com.vaadin.terminal.gwt.client.ui.VButton;
import com.vaadin.terminal.gwt.client.ui.VButton.ButtonClientToServerRpc;
import com.vaadin.terminal.gwt.client.ui.VButtonPaintable;
import com.vaadin.terminal.gwt.server.RpcTarget;
import com.vaadin.tools.ReflectTools;
import com.vaadin.ui.ClientWidget.LoadStyle;
import com.vaadin.ui.Component.Focusable;

/**
 * A generic button component.
 * 
 * @author Vaadin Ltd.
 * @version
 * @VERSION@
 * @since 3.0
 */
@SuppressWarnings("serial")
@ClientWidget(value = VButtonPaintable.class, loadStyle = LoadStyle.EAGER)
public class Button extends AbstractComponent implements
        FieldEvents.BlurNotifier, FieldEvents.FocusNotifier, Focusable,
        Action.ShortcutNotifier, RpcTarget {

    /* Private members */

    boolean disableOnClick = false;

    /**
     * Creates a new push button.
     */
    public Button() {
        // TODO take the implementation out of an anonymous class?
        registerRpcImplementation(new ButtonClientToServerRpc() {
            public void click(String mouseEventDetails) {
                fireClick(MouseEventDetails.deSerialize(mouseEventDetails));
            }

            public void disableOnClick() {
                // Could be optimized so the button is not repainted because of
                // this (client side has already disabled the button)
                setEnabled(false);
            }
        }, ButtonClientToServerRpc.class);
    }

    /**
     * Creates a new push button with the given caption.
     * 
     * @param caption
     *            the Button caption.
     */
    public Button(String caption) {
        this();
        setCaption(caption);
    }

    /**
     * Creates a new push button with a click listener.
     * 
     * @param caption
     *            the Button caption.
     * @param listener
     *            the Button click listener.
     */
    public Button(String caption, ClickListener listener) {
        this(caption);
        addListener(listener);
    }

    /**
     * Paints the content of this component.
     * 
     * @param event
     *            the PaintEvent.
     * @throws IOException
     *             if the writing failed due to input/output error.
     * @throws PaintException
     *             if the paint operation failed.
     */
    @Override
    public void paintContent(PaintTarget target) throws PaintException {
        super.paintContent(target);

        if (isDisableOnClick()) {
            target.addAttribute(VButton.ATTR_DISABLE_ON_CLICK, true);
        }
        if (clickShortcut != null) {
            target.addAttribute("keycode", clickShortcut.getKeyCode());
        }
    }

    /**
     * Invoked when the value of a variable has changed. Button listeners are
     * notified if the button is clicked.
     * 
     * @param source
     * @param variables
     */
    @Override
    public void changeVariables(Object source, Map<String, Object> variables) {
        super.changeVariables(source, variables);

        if (variables.containsKey(FocusEvent.EVENT_ID)) {
            fireEvent(new FocusEvent(this));
        }
        if (variables.containsKey(BlurEvent.EVENT_ID)) {
            fireEvent(new BlurEvent(this));
        }
    }

    /**
     * Click event. This event is thrown, when the button is clicked.
     * 
     * @author Vaadin Ltd.
     * @version
     * @VERSION@
     * @since 3.0
     */
    public class ClickEvent extends Component.Event {

        private final MouseEventDetails details;

        /**
         * New instance of text change event.
         * 
         * @param source
         *            the Source of the event.
         */
        public ClickEvent(Component source) {
            super(source);
            details = null;
        }

        /**
         * Constructor with mouse details
         * 
         * @param source
         *            The source where the click took place
         * @param details
         *            Details about the mouse click
         */
        public ClickEvent(Component source, MouseEventDetails details) {
            super(source);
            this.details = details;
        }

        /**
         * Gets the Button where the event occurred.
         * 
         * @return the Source of the event.
         */
        public Button getButton() {
            return (Button) getSource();
        }

        /**
         * Returns the mouse position (x coordinate) when the click took place.
         * The position is relative to the browser client area.
         * 
         * @return The mouse cursor x position or -1 if unknown
         */
        public int getClientX() {
            if (null != details) {
                return details.getClientX();
            } else {
                return -1;
            }
        }

        /**
         * Returns the mouse position (y coordinate) when the click took place.
         * The position is relative to the browser client area.
         * 
         * @return The mouse cursor y position or -1 if unknown
         */
        public int getClientY() {
            if (null != details) {
                return details.getClientY();
            } else {
                return -1;
            }
        }

        /**
         * Returns the relative mouse position (x coordinate) when the click
         * took place. The position is relative to the clicked component.
         * 
         * @return The mouse cursor x position relative to the clicked layout
         *         component or -1 if no x coordinate available
         */
        public int getRelativeX() {
            if (null != details) {
                return details.getRelativeX();
            } else {
                return -1;
            }
        }

        /**
         * Returns the relative mouse position (y coordinate) when the click
         * took place. The position is relative to the clicked component.
         * 
         * @return The mouse cursor y position relative to the clicked layout
         *         component or -1 if no y coordinate available
         */
        public int getRelativeY() {
            if (null != details) {
                return details.getRelativeY();
            } else {
                return -1;
            }
        }

        /**
         * Checks if the Alt key was down when the mouse event took place.
         * 
         * @return true if Alt was down when the event occured, false otherwise
         *         or if unknown
         */
        public boolean isAltKey() {
            if (null != details) {
                return details.isAltKey();
            } else {
                return false;
            }
        }

        /**
         * Checks if the Ctrl key was down when the mouse event took place.
         * 
         * @return true if Ctrl was pressed when the event occured, false
         *         otherwise or if unknown
         */
        public boolean isCtrlKey() {
            if (null != details) {
                return details.isCtrlKey();
            } else {
                return false;
            }
        }

        /**
         * Checks if the Meta key was down when the mouse event took place.
         * 
         * @return true if Meta was pressed when the event occured, false
         *         otherwise or if unknown
         */
        public boolean isMetaKey() {
            if (null != details) {
                return details.isMetaKey();
            } else {
                return false;
            }
        }

        /**
         * Checks if the Shift key was down when the mouse event took place.
         * 
         * @return true if Shift was pressed when the event occured, false
         *         otherwise or if unknown
         */
        public boolean isShiftKey() {
            if (null != details) {
                return details.isShiftKey();
            } else {
                return false;
            }
        }
    }

    /**
     * Interface for listening for a {@link ClickEvent} fired by a
     * {@link Component}.
     * 
     * @author Vaadin Ltd.
     * @version
     * @VERSION@
     * @since 3.0
     */
    public interface ClickListener extends Serializable {

        public static final Method BUTTON_CLICK_METHOD = ReflectTools
                .findMethod(ClickListener.class, "buttonClick",
                        ClickEvent.class);

        /**
         * Called when a {@link Button} has been clicked. A reference to the
         * button is given by {@link ClickEvent#getButton()}.
         * 
         * @param event
         *            An event containing information about the click.
         */
        public void buttonClick(ClickEvent event);

    }

    /**
     * Adds the button click listener.
     * 
     * @param listener
     *            the Listener to be added.
     */
    public void addListener(ClickListener listener) {
        addListener(ClickEvent.class, listener,
                ClickListener.BUTTON_CLICK_METHOD);
    }

    /**
     * Removes the button click listener.
     * 
     * @param listener
     *            the Listener to be removed.
     */
    public void removeListener(ClickListener listener) {
        removeListener(ClickEvent.class, listener,
                ClickListener.BUTTON_CLICK_METHOD);
    }

    /**
     * Fires a click event to all listeners without any event details.
     * 
     * In subclasses, override {@link #fireClick(MouseEventDetails)} instead of
     * this method.
     */
    protected void fireClick() {
        fireEvent(new Button.ClickEvent(this));
    }

    /**
     * Fires a click event to all listeners.
     * 
     * @param details
     *            MouseEventDetails from which keyboard modifiers and other
     *            information about the mouse click can be obtained. If the
     *            button was clicked by a keyboard event, some of the fields may
     *            be empty/undefined.
     */
    protected void fireClick(MouseEventDetails details) {
        fireEvent(new Button.ClickEvent(this, details));
    }

    public void addListener(BlurListener listener) {
        addListener(BlurEvent.EVENT_ID, BlurEvent.class, listener,
                BlurListener.blurMethod);
    }

    public void removeListener(BlurListener listener) {
        removeListener(BlurEvent.EVENT_ID, BlurEvent.class, listener);
    }

    public void addListener(FocusListener listener) {
        addListener(FocusEvent.EVENT_ID, FocusEvent.class, listener,
                FocusListener.focusMethod);
    }

    public void removeListener(FocusListener listener) {
        removeListener(FocusEvent.EVENT_ID, FocusEvent.class, listener);

    }

    /*
     * Actions
     */

    protected ClickShortcut clickShortcut;

    private int tabIndex = 0;

    /**
     * Makes it possible to invoke a click on this button by pressing the given
     * {@link KeyCode} and (optional) {@link ModifierKey}s.<br/>
     * The shortcut is global (bound to the containing Window).
     * 
     * @param keyCode
     *            the keycode for invoking the shortcut
     * @param modifiers
     *            the (optional) modifiers for invoking the shortcut, null for
     *            none
     */
    public void setClickShortcut(int keyCode, int... modifiers) {
        if (clickShortcut != null) {
            removeShortcutListener(clickShortcut);
        }
        clickShortcut = new ClickShortcut(this, keyCode, modifiers);
        addShortcutListener(clickShortcut);
    }

    /**
     * Removes the keyboard shortcut previously set with
     * {@link #setClickShortcut(int, int...)}.
     */
    public void removeClickShortcut() {
        if (clickShortcut != null) {
            removeShortcutListener(clickShortcut);
            clickShortcut = null;
        }
    }

    /**
     * A {@link ShortcutListener} specifically made to define a keyboard
     * shortcut that invokes a click on the given button.
     * 
     */
    public static class ClickShortcut extends ShortcutListener {
        protected Button button;

        /**
         * Creates a keyboard shortcut for clicking the given button using the
         * shorthand notation defined in {@link ShortcutAction}.
         * 
         * @param button
         *            to be clicked when the shortcut is invoked
         * @param shorthandCaption
         *            the caption with shortcut keycode and modifiers indicated
         */
        public ClickShortcut(Button button, String shorthandCaption) {
            super(shorthandCaption);
            this.button = button;
        }

        /**
         * Creates a keyboard shortcut for clicking the given button using the
         * given {@link KeyCode} and {@link ModifierKey}s.
         * 
         * @param button
         *            to be clicked when the shortcut is invoked
         * @param keyCode
         *            KeyCode to react to
         * @param modifiers
         *            optional modifiers for shortcut
         */
        public ClickShortcut(Button button, int keyCode, int... modifiers) {
            super(null, keyCode, modifiers);
            this.button = button;
        }

        /**
         * Creates a keyboard shortcut for clicking the given button using the
         * given {@link KeyCode}.
         * 
         * @param button
         *            to be clicked when the shortcut is invoked
         * @param keyCode
         *            KeyCode to react to
         */
        public ClickShortcut(Button button, int keyCode) {
            this(button, keyCode, null);
        }

        @Override
        public void handleAction(Object sender, Object target) {
            if (button.isEnabled() && !button.isReadOnly()) {
                button.fireClick();
            }
        }
    }

    /**
     * Determines if a button is automatically disabled when clicked. See
     * {@link #setDisableOnClick(boolean)} for details.
     * 
     * @return true if the button is disabled when clicked, false otherwise
     */
    public boolean isDisableOnClick() {
        return disableOnClick;
    }

    /**
     * Determines if a button is automatically disabled when clicked. If this is
     * set to true the button will be automatically disabled when clicked,
     * typically to prevent (accidental) extra clicks on a button.
     * 
     * @param disableOnClick
     *            true to disable button when it is clicked, false otherwise
     */
    public void setDisableOnClick(boolean disableOnClick) {
        this.disableOnClick = disableOnClick;
        requestRepaint();
    }

    public int getTabIndex() {
        return tabIndex;
    }

    public void setTabIndex(int tabIndex) {
        this.tabIndex = tabIndex;

    }

    @Override
    public void focus() {
        // Overridden only to make public
        super.focus();
    }
}