/*
 * Copyright 2011 Vaadin Ltd.
 * 
 * Licensed 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 com.vaadin.terminal.gwt.client.ui;

import java.util.Set;

import com.google.gwt.event.dom.client.ChangeEvent;
import com.google.gwt.event.dom.client.ChangeHandler;
import com.google.gwt.event.dom.client.ClickEvent;
import com.google.gwt.event.dom.client.ClickHandler;
import com.google.gwt.event.dom.client.KeyCodes;
import com.google.gwt.event.dom.client.KeyPressEvent;
import com.google.gwt.event.dom.client.KeyPressHandler;
import com.google.gwt.user.client.ui.Composite;
import com.google.gwt.user.client.ui.FlowPanel;
import com.google.gwt.user.client.ui.Panel;
import com.google.gwt.user.client.ui.Widget;
import com.vaadin.terminal.gwt.client.ApplicationConnection;
import com.vaadin.terminal.gwt.client.Focusable;
import com.vaadin.terminal.gwt.client.Paintable;
import com.vaadin.terminal.gwt.client.UIDL;

abstract class VOptionGroupBase extends Composite implements Paintable, Field,
        ClickHandler, ChangeHandler, KeyPressHandler, Focusable {

    public static final String CLASSNAME_OPTION = "v-select-option";

    protected ApplicationConnection client;

    protected String id;

    protected Set<String> selectedKeys;

    private boolean immediate;

    private boolean multiselect;

    private boolean disabled;

    private boolean readonly;

    private int cols = 0;

    private int rows = 0;

    private boolean nullSelectionAllowed = true;

    private boolean nullSelectionItemAvailable = false;

    /**
     * Widget holding the different options (e.g. ListBox or Panel for radio
     * buttons) (optional, fallbacks to container Panel)
     */
    protected Widget optionsContainer;

    /**
     * Panel containing the component
     */
    private final Panel container;

    private VTextField newItemField;

    private VNativeButton newItemButton;

    public VOptionGroupBase(String classname) {
        container = new FlowPanel();
        initWidget(container);
        optionsContainer = container;
        container.setStyleName(classname);
        immediate = false;
        multiselect = false;
    }

    /*
     * Call this if you wish to specify your own container for the option
     * elements (e.g. SELECT)
     */
    public VOptionGroupBase(Widget w, String classname) {
        this(classname);
        optionsContainer = w;
        container.add(optionsContainer);
    }

    protected boolean isImmediate() {
        return immediate;
    }

    protected boolean isMultiselect() {
        return multiselect;
    }

    protected boolean isDisabled() {
        return disabled;
    }

    protected boolean isReadonly() {
        return readonly;
    }

    protected boolean isNullSelectionAllowed() {
        return nullSelectionAllowed;
    }

    protected boolean isNullSelectionItemAvailable() {
        return nullSelectionItemAvailable;
    }

    /**
     * @return "cols" specified in uidl, 0 if not specified
     */
    protected int getColumns() {
        return cols;
    }

    /**
     * @return "rows" specified in uidl, 0 if not specified
     */

    protected int getRows() {
        return rows;
    }

    public void updateFromUIDL(UIDL uidl, ApplicationConnection client) {
        this.client = client;
        id = uidl.getId();

        if (client.updateComponent(this, uidl, true)) {
            return;
        }

        selectedKeys = uidl.getStringArrayVariableAsSet("selected");

        readonly = uidl.getBooleanAttribute("readonly");
        disabled = uidl.getBooleanAttribute("disabled");
        multiselect = "multi".equals(uidl.getStringAttribute("selectmode"));
        immediate = uidl.getBooleanAttribute("immediate");
        nullSelectionAllowed = uidl.getBooleanAttribute("nullselect");
        nullSelectionItemAvailable = uidl.getBooleanAttribute("nullselectitem");

        if (uidl.hasAttribute("cols")) {
            cols = uidl.getIntAttribute("cols");
        }
        if (uidl.hasAttribute("rows")) {
            rows = uidl.getIntAttribute("rows");
        }

        final UIDL ops = uidl.getChildUIDL(0);

        if (getColumns() > 0) {
            container.setWidth(getColumns() + "em");
            if (container != optionsContainer) {
                optionsContainer.setWidth("100%");
            }
        }

        buildOptions(ops);

        if (uidl.getBooleanAttribute("allownewitem")) {
            if (newItemField == null) {
                newItemButton = new VNativeButton();
                newItemButton.setText("+");
                newItemButton.addClickHandler(this);
                newItemField = new VTextField();
                newItemField.addKeyPressHandler(this);
            }
            newItemField.setEnabled(!disabled && !readonly);
            newItemButton.setEnabled(!disabled && !readonly);

            if (newItemField == null || newItemField.getParent() != container) {
                container.add(newItemField);
                container.add(newItemButton);
                final int w = container.getOffsetWidth()
                        - newItemButton.getOffsetWidth();
                newItemField.setWidth(Math.max(w, 0) + "px");
            }
        } else if (newItemField != null) {
            container.remove(newItemField);
            container.remove(newItemButton);
        }

        setTabIndex(uidl.hasAttribute("tabindex") ? uidl
                .getIntAttribute("tabindex") : 0);

    }

    abstract protected void setTabIndex(int tabIndex);

    public void onClick(ClickEvent event) {
        if (event.getSource() == newItemButton
                && !newItemField.getText().equals("")) {
            client.updateVariable(id, "newitem", newItemField.getText(), true);
            newItemField.setText("");
        }
    }

    public void onChange(ChangeEvent event) {
        if (multiselect) {
            client.updateVariable(id, "selected", getSelectedItems(), immediate);
        } else {
            client.updateVariable(id, "selected", new String[] { ""
                    + getSelectedItem() }, immediate);
        }
    }

    public void onKeyPress(KeyPressEvent event) {
        if (event.getSource() == newItemField
                && event.getCharCode() == KeyCodes.KEY_ENTER) {
            newItemButton.click();
        }
    }

    protected abstract void buildOptions(UIDL uidl);

    protected abstract String[] getSelectedItems();

    protected String getSelectedItem() {
        final String[] sel = getSelectedItems();
        if (sel.length > 0) {
            return sel[0];
        } else {
            return null;
        }
    }

}