/**

  * Copyright 2010 The Kuali Foundation Licensed under the

  * Educational Community 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.osedu.org/licenses/ECL-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.kuali.student.common.ui.client.widgets.field.layout.element;

 import org.kuali.student.common.ui.client.application.Application;

 import org.kuali.student.common.ui.client.configurable.mvc.sections.ValidationMessagePanel;

 import org.kuali.student.common.ui.client.widgets.HasInputWidget;

 import org.kuali.student.common.ui.client.widgets.HasWatermark;

 import org.kuali.student.common.ui.client.widgets.KSLabel;

 import org.kuali.student.common.ui.client.widgets.KSTitleDescPanel;

 import org.kuali.student.common.ui.client.widgets.field.layout.element.AbbrButton.AbbrButtonType;

 import org.kuali.student.common.ui.client.widgets.field.layout.layouts.FieldLayoutComponent;

 import org.kuali.student.common.validation.dto.ValidationResultInfo;

 import org.kuali.student.common.validation.dto.ValidationResultInfo.ErrorLevel;

 import com.google.gwt.user.client.Element;

 import com.google.gwt.user.client.ui.Composite;

 import com.google.gwt.user.client.ui.FlowPanel;

 import com.google.gwt.user.client.ui.HTMLPanel;

 import com.google.gwt.user.client.ui.Panel;

 import com.google.gwt.user.client.ui.Widget;

 /**

  * A ui field element.  Areas which contain a field for user data entry should use

  * this class for visual and behavior consistency.  Used by FieldDescriptor for its layout.

  * 

  * General layout of a field element, all elements are conditional based on the field's

  * configuration through set methods on this class: <br>

  * <b>[label][requiredness indicator][help]<br>

  * [input widget]<br>

  * [constraint text]<br></b>

  * <br>

  * 

  * The messageKeyInfo passed in is used to generate the messages needed for a field these include:<br>

  * Field Label<br>

  * Help text<br>

  * Instructions<br>

  * Constraint text<br>

  * Watermark text - only if the widget one that accepts text input<br><br>

  * These are generated by the single key, the additional text is determined by special suffixes on keys within

  * the messages data - example - you pass in "sampleField" for the message key - it is automatically determined

  * that if there is a message in the messages data named "sampleField-instruct", instructions will be added to the field

  * in the appropriate location.<br>

  * List of the appended keys for use in messages data:<br>

  * "-help" for help text<br>

  * "-instruct" for instructions<br>

  * "-constraints" for constraint text<br>

  * "-watermark" for watermark text<br>

  * 

  * @author Kuali Student Team

  * @see FieldDescriptor

  * @see FieldLayout

  */

 public class FieldElement extends Composite implements FieldLayoutComponent{

         //Layout

         private KSTitleDescPanel titlePanel = new KSTitleDescPanel();

         private FlowPanel layout = new FlowPanel();

         private FieldTitle fieldTitle;

         private SpanPanel instructions = new SpanPanel();

         private SpanPanel constraints = new SpanPanel();

         private AbbrPanel required = new AbbrPanel("Required", "ks-form-module-elements-required", " * ");

         private AbbrButton help = new AbbrButton(AbbrButtonType.HELP);

         private Widget fieldWidget;

         private SpanPanel widgetSpan = new SpanPanel();

         private String fieldHTMLId;

         private LineNum margin;

         private String watermarkText = null;

         public static enum LineNum{SINGLE, DOUBLE, TRIPLE}

         private ValidationMessagePanel validationPanel;

         private String fieldKey;

         private boolean labelShown = true;

         private Panel parentPanel;

         private Element parentElement;

         /**

          * Sets this field's validation panel, note that this does not add it to the ui.  Attaching must be done

          * elsewhere.  Most FieldLayout implementations handle this attachment.

          * @param validationPanel

          */

         public void setValidationPanel(ValidationMessagePanel validationPanel) {

                 this.validationPanel = validationPanel;

         }

         public Panel getParentPanel() {

                 return parentPanel;

         }

         public void setParentPanel(Panel parentPanel) {

                 this.parentPanel = parentPanel;

                 this.parentElement = parentPanel.getElement();

         }

         public void setParentElement(Element element){

                 parentElement = element;

         }

         private String fieldName;

         private String instructionText;

     public String getInstructionText() {

                 return instructionText;

         }

         public FieldElement(String title, Widget widget) {

             generateLayout(title, title, null, null, null, widget);

     }

     public FieldElement(String key, String title, Widget widget){

             generateLayout(key, title, null, null, null, widget);

     }

     /**

      * Standard constructor for FieldElement

      * @param key unique key to identify this field

      * @param info key for the messages used in this field element - see class description

      */

     public FieldElement(String key, MessageKeyInfo info){

             init(key, info, null);

     }

     /**

      * Standard constructor for FieldElement

      * @param key unique key to identify this field

      * @param info key for the messages used in this field element - see class description

      * @param widget widget used for input/display on this field

      */

     public FieldElement(String key, MessageKeyInfo info, Widget widget){

             init(key, info, widget);

     }

     private void init(String key, MessageKeyInfo info, Widget widget){

             String title = Application.getApplicationContext().getUILabel(info.getGroup(), info.getType(), info.getState(), info.getId());

             String help = Application.getApplicationContext().getUILabel(info.getGroup(), info.getType(), info.getState(),

                             info.getId() + HELP_MESSAGE_KEY);

             if(help.equals(info.getId() + HELP_MESSAGE_KEY)){

                     help = null;

             }

             String instructions = Application.getApplicationContext().getUILabel(info.getGroup(), info.getType(), info.getState(),

                             info.getId() + INSTRUCT_MESSAGE_KEY);

             if(instructions.equals(info.getId() + INSTRUCT_MESSAGE_KEY)){

                     instructions = null;

             }

             String constraints = Application.getApplicationContext().getUILabel(info.getGroup(), info.getType(), info.getState(),

                             info.getId() + CONSTRAINT_MESSAGE_KEY);

             if(constraints.equals(info.getId() + CONSTRAINT_MESSAGE_KEY)){

                     constraints = null;

             }

             watermarkText = Application.getApplicationContext().getUILabel(info.getGroup(), info.getType(), info.getState(),

                             info.getId() + WATERMARK_MESSAGE_KEY);

             if(watermarkText.equals(info.getId() + WATERMARK_MESSAGE_KEY)){

                     watermarkText = null;

             }

             generateLayout(key, title, help, instructions, constraints, widget);

     }

     private void generateLayout(String key, String title, String helpText, String instructText, String constraintText, Widget widget){

             this.setKey(key);

                 fieldName = title;

                 fieldHTMLId = HTMLPanel.createUniqueId();

                 fieldTitle = new LabelPanel(title, fieldHTMLId);

                 required.setVisible(false);

                 fieldTitle.add(required);

                 if(helpText != null){

                         this.setHelp(helpText);

                 }

                 else{

                         help.setVisible(false);

                 }

                 fieldTitle.add(help);

                 layout.add(fieldTitle);

                 if(instructText != null){

                         this.setInstructions(instructText);

                 }

                 else{

                         instructions.setVisible(false);

                 }

                 if(constraintText != null){

                         this.setConstraintText(constraintText);

                 }

                 else{

                         constraints.setVisible(false);

                 }

                 instructions.setStyleName("ks-form-module-elements-instruction");

                 layout.add(instructions);

                 layout.add(widgetSpan);

                 if(widget != null){

                         this.setWidget(widget);

                 }

                 constraints.setStyleName("ks-form-module-elements-help-text");

                 layout.add(constraints);

         initWidget(layout);

         layout.addStyleName("ks-form-module-elements");

         layout.addStyleName("ks-form-module-single-line-margin");

     }

     /**

      * Sets the widget for this field, automatically adds an id which will match this field's label-for tag in

      * its label

      * @see com.google.gwt.user.client.ui.Composite#setWidget(com.google.gwt.user.client.ui.Widget)

      */

     public void setWidget(Widget w){

             if(fieldWidget != null){

                     widgetSpan.remove(fieldWidget);

             }

             fieldWidget = w;

             //TODO Do a check here to change the type of label based on widget type eventually

             if(fieldWidget != null){

                     //Checks for input widgets that may be incased in a more complex widget layout

                     if(fieldWidget instanceof HasInputWidget){

                             Widget input = ((HasInputWidget)fieldWidget).getInputWidget();

                             if(input != null){

                                     if(input instanceof HasWatermark && watermarkText != null){

                                             ((HasWatermark)input).setWatermarkText(watermarkText);

                                     }

                                     input.getElement().setAttribute("id", fieldHTMLId);

                             }

                             else{

                                     fieldWidget.getElement().setAttribute("id", fieldHTMLId);

                             }

                     }

                     else{

                         if(fieldWidget instanceof HasWatermark && watermarkText != null){

                                 ((HasWatermark)fieldWidget).setWatermarkText(watermarkText);

                         }

                             fieldWidget.getElement().setAttribute("id", fieldHTMLId);

                     }

                     widgetSpan.add(fieldWidget);

             }

     }

     /**

      * Sets the required string key to be used for when a field is required.  For example, in most cases this

      * key maps to a "*"

      * 

      * @param requiredKey

      */

     public void setRequiredString(String requiredKey){

             String requiredText = Application.getApplicationContext().getMessage(requiredKey);

             required.setText(requiredText);

             required.setVisible(true);

     }

     public void setRequiredString(String requiredKey, String style){

             String requiredText = Application.getApplicationContext().getMessage(requiredKey);

             required.setText(requiredText);

             required.setStyleName(style);

             required.setVisible(true);

     }

     public AbbrPanel getRequiredPanel(){

             return required;

     }

     public void clearRequiredText(){

         required.setText("");

     }

     public Widget getFieldWidget(){

             return fieldWidget;

     }

     public FlowPanel getFieldDetailsLayout(){

             FlowPanel div = new FlowPanel();

                 div.add(fieldTitle);

                 div.add(instructions);

                 div.addStyleName("ks-form-module-elements");

                 return div;

     }

     public FlowPanel getFieldWidgetAreaLayout(){

             FlowPanel div = new FlowPanel();

             div.add(fieldWidget);

             div.add(constraints);

             div.addStyleName("ks-form-module-elements");

             return div;

     }

     public boolean isRequired() {

         return required.isVisible();

     }

     public void setRequired(boolean isRequired){

             required.setVisible(isRequired);

     }

     public void setInstructions(String text){

             instructionText = text;

             if(instructionText != null && !instructionText.trim().equals("")){

                     instructions.setHTML(text);

                     instructions.setVisible(true);

             }

     }

     public void setConstraintText(String text){

             if(text != null && !text.trim().equals("")){

                     constraints.setHTML(text);

                     constraints.setVisible(true);

             }

     }

     public void setHelp(final String html){

             if(html != null && !html.trim().equals("")){

                     help.setVisible(true);

                     help.setHoverHTML(html);

                     /*help.addClickHandler(new ClickHandler(){

                                 @Override

                                 public void onClick(ClickEvent event) {

                                         //TODO show actual help window

                                         Window.alert(html);

                                 }

                         });*/

             }

             else{

                     help.setVisible(false);

             }

     }

         public Widget getTitleWidget() {

             return titlePanel.getTitleWidget();

         }

         public ValidationMessagePanel getValidationPanel() {

                 return validationPanel;

         }

         public Panel getEncapsulatingPanel() {

                 return parentPanel;

         }

         public String getFieldName() {

                 return fieldName;

         }

         public void setErrorState(boolean error){

                 if(error){

                         fieldTitle.addStyleName("invalid");

                         if(parentPanel != null){

                                 parentPanel.addStyleName("error");

                         }

                         else if(parentElement != null){

                                 parentElement.setClassName("error");

                         }

                 }

                 else{

                         fieldTitle.removeStyleName("invalid");

                         if(parentPanel != null){

                                 parentPanel.removeStyleName("error");

                         }

                         else if(parentElement != null){

                                 parentElement.setClassName("");

                         }

                 }

         }

         /**

          * Processes a validation result and adds an appropriate message, if needed

          * @param vr

          * @return

          */

         public ErrorLevel processValidationResult(ValidationResultInfo vr) {

                 ErrorLevel status = ErrorLevel.OK;

                 if(vr.getLevel() == ErrorLevel.ERROR){

                         String message = Application.getApplicationContext().getUILabel("validation", vr.getMessage());

                         this.addValidationErrorMessage(message);

                         if(status.getLevel() < ErrorLevel.ERROR.getLevel()){

                                 status = vr.getLevel();

                         }

                 }

                 else if(vr.getLevel() == ErrorLevel.WARN){

                         if(status.getLevel() < ErrorLevel.WARN.getLevel()){

                                 status = vr.getLevel();

                         }

                         //TODO does nothing on warn, warn is not currently used

                 }

                 else{

                         //TODO does nothing on ok, ok is not currently used

                 }

                 return status;

         }

         /**

          * Add a validation message to this fields validation panel as defined by setValidationPanel.

          * @param text

          */

         public void addValidationErrorMessage(String text){

                 if(validationPanel != null){

                         KSLabel message;

                         if(fieldName != null && !fieldName.trim().equals("")){

                                 message = new KSLabel(fieldName + " - " + text);

                         }

                         else{

                                 message = new KSLabel(text);

                         }

                         message.setStyleName("ks-form-validation-label");

                         this.setErrorState(true);

                         this.validationPanel.addMessage(message);

                 }

         }

         public void clearValidationPanel(){

                 this.setErrorState(false);

                 if(validationPanel != null){

                         this.validationPanel.clear();

                 }

         }

         @Override

         public String getKey() {

                 return fieldKey;

         }

         @Override

         public void setKey(String key) {

             if(key == null){

                         //TODO better way to generate unique id here?

                         key = HTMLPanel.createUniqueId();

                 }

                 this.fieldKey = key;

         }

         /**

          * Sets the expected number of lines needed to space the vertical height of this field consistently

          * with fields next to it horizontally

          * @param margin

          */

         public void setTitleDescLineHeight(LineNum margin) {

                 layout.removeStyleName("ks-form-module-single-line-margin");

                 switch(margin){

                         case TRIPLE:

                                 if(firstLineExists() && secondLineExists()){

                                         layout.addStyleName("ks-form-module-single-line-margin");

                                 }

                                 else if((firstLineExists() || secondLineExists())){

                                         layout.addStyleName("ks-form-module-double-line-margin");

                                 }

                                 else{

                                         layout.addStyleName("ks-form-module-triple-line-margin");

                                 }

                                 break;

                         case DOUBLE:

                                 if((firstLineExists() || secondLineExists())){

                                         layout.addStyleName("ks-form-module-single-line-margin");

                                 }

                                 else{

                                         layout.addStyleName("ks-form-module-double-line-margin");

                                 }

                                 break;

                         case SINGLE:

                                 layout.addStyleName("ks-form-module-single-line-margin");

                                 break;

                 }

         }

         private boolean firstLineExists(){

                 boolean exists = false;

                 if((fieldName != null && !fieldName.equals("")) || required.isVisible() || help.isVisible()){

                         exists = true;

                 }

                 return exists;

         }

         private boolean secondLineExists(){

                 boolean exists = false;

                 if(instructions.isVisible()){

                         exists = true;

                 }

                 return exists;

         }

         /**

          * Hides the label of this field visually, but screen readers can still read it for accessibility

          */

         public void hideLabel() {

                 layout.removeStyleName("ks-form-module-double-line-margin");

                 layout.removeStyleName("ks-form-module-triple-line-margin");

                 layout.addStyleName("ks-form-module-single-line-margin");

                 fieldTitle.setStyleName("accessibility-hidden");

                 instructions.setVisible(false);

                 labelShown = false;

         }

         public boolean isLabelShown(){

                 return labelShown;

         }

 }