/**
    * 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.configurable.mvc;
  
  import org.kuali.student.common.ui.client.configurable.mvc.binding.ModelWidgetBinding;
  import org.kuali.student.common.ui.client.configurable.mvc.binding.MultiplicityCompositeBinding;
  import org.kuali.student.common.ui.client.configurable.mvc.multiplicity.MultiplicityComposite;
  import org.kuali.student.common.ui.client.mvc.Callback;
  import org.kuali.student.common.ui.client.mvc.HasDataValue;
  import org.kuali.student.common.ui.client.widgets.KSCheckBox;
  import org.kuali.student.common.ui.client.widgets.KSTextBox;
  import org.kuali.student.common.ui.client.widgets.RichTextEditor;
  import org.kuali.student.common.ui.client.widgets.field.layout.element.FieldElement;
  import org.kuali.student.common.ui.client.widgets.field.layout.element.MessageKeyInfo;
  import org.kuali.student.common.ui.client.widgets.list.KSSelectItemWidgetAbstract;
  import org.kuali.student.core.assembly.data.Metadata;
  import org.kuali.student.core.assembly.data.MetadataInterrogator;
  
  import com.google.gwt.user.client.ui.HasText;
  import com.google.gwt.user.client.ui.HasValue;
  import com.google.gwt.user.client.ui.Widget;
  
  /**
   * This is a field descriptor that defines ui fields.
   * A field descriptor is defined by its fieldKey and its metadata, the field key is the key that is used
   * to identify it during validation and save processing and maps directly to a field which exists in the
   * model definition for the model it relates to.  The fieldKey must match something within the model to
   * be a valid field.  <br>The metadata is its piece of information in the model definition which is used to
   * generate the field's widget and determine what the validation on this field is (also if this field
   * is backed by a search it will use the lookup metadata defined in its metadata to generate the appropriate
   * search widget).  It also determines if a requiredness indicator appears (constraint minOccurs > 1).
   * <br><br>
   * A field descriptor can be fully customized to any need, the widget can be chosen to be
   * defined directly instead of using one that is auto generated by the metadata - if this is done make sure
   * the data type it is using works with what is in the metadata and that it implements one of these standard 
   * interfaces:<br>
   * HasText<br>
   * KSSelectItemWidgetAbstract<br>
   * HasDataValue<br>
   * HasValue<br>
   * or, you MUST override the ModelWidgetBinding by calling setModelWidgetBinding
   * <br>
   * Setting the ModelWidgetBinding allows you to manipulate the widget's data and model data as you see fit
   * before a save when model data is loaded into the widget.
   * <br>
   * <br>
   * General layout of a field generated by FieldDescriptor, all elements are conditional based on the field's
   * configuration: <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 a 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 message 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 FieldElement
   * @see Section
   * @see BaseSection
   * @see Configurer
   */
  public class FieldDescriptor {
      protected String fieldKey;
  	protected Metadata metadata;
      @SuppressWarnings("unchecked")
  	private ModelWidgetBinding modelWidgetBinding;
      private Callback<Boolean> validationRequestCallback;
      private boolean dirty = false;
      private boolean hasHadFocus = false;
      private final FieldElement fieldElement;
      private String modelId;
      private MessageKeyInfo messageKey;
      private boolean optional = false;
 
     /**
      * @param fieldKey - key for this field which matches a field in the overall model definition that this
      * field will be used for
      * @param messageKey - key object used for determing field labels
      * @param metadata - metadata used to determine requiredness, validation, and autogenerated widget
      */
     public FieldDescriptor(String fieldKey, MessageKeyInfo messageKey, Metadata metadata) {
     	this.fieldKey = fieldKey;
     	this.metadata = metadata;
     	if(messageKey == null){
     		messageKey = new MessageKeyInfo("");
     	}
     	setMessageKey(messageKey);
     	fieldElement = new FieldElement(fieldKey, messageKey, createFieldWidget());
     	setupField();
     }
 
     /**
      * @param fieldKey - key for this field which matches a field in the overall model definition that this
      * field will be used for
      * @param messageKey - key object used for determing field labels
      * @param metadata - metadata used to determine requiredness and validation
      * @param fieldWidget - widget to use instead of an automatically determined one
      */
     public FieldDescriptor(String fieldKey, MessageKeyInfo messageKey, Metadata metadata, Widget fieldWidget){
     	this.fieldKey = fieldKey;
     	this.metadata = metadata;
     	if(messageKey == null){
     		messageKey = new MessageKeyInfo("");
     	}
         setMessageKey(messageKey);
     	addStyleToWidget(fieldWidget);
     	fieldElement = new FieldElement(fieldKey, messageKey, fieldWidget);
     	setupField();
     }
 
     protected void addStyleToWidget(Widget w){
     	if(fieldKey != null && !fieldKey.isEmpty() && w != null){
     		String style = this.fieldKey.replaceAll("/", "-");
     		w.addStyleName(style);
     	}
     }
 
     protected void setupField() {
     	if(metadata != null){
     		if(MetadataInterrogator.isRequired(metadata)){
     			fieldElement.setRequiredString("requiredMarker", "ks-form-module-elements-required");
     		}
     		else if(MetadataInterrogator.isRequiredForNextState(metadata)){
     			String nextState = MetadataInterrogator.getNextState(metadata);
     			if(nextState != null){
     				if(nextState.equalsIgnoreCase("SUBMITTED")){
     					fieldElement.setRequiredString("requiredOnSubmit", "ks-form-required-for-submit");
     				}
     				else if(nextState.equalsIgnoreCase("APPROVED")){
     					fieldElement.setRequiredString("reqApproval", "ks-form-required-for-submit");
     				}
 					else if(nextState.equalsIgnoreCase("ACTIVE")){
 						fieldElement.setRequiredString("reqActivate", "ks-form-required-for-submit");
     				}
 					else if(nextState.equalsIgnoreCase("INACTIVE") ||
 							nextState.equalsIgnoreCase("RETIRED")){
 						fieldElement.setRequiredString("reqDeactivate", "ks-form-required-for-submit");
 					}
 					else {
 						fieldElement.setRequiredString("requiredOnSubmit", "ks-form-required-for-submit");
 					}
 
     			}
     		} else{
                 fieldElement.clearRequiredText();
             }
     	}
     }
 
     /**
      * @see FieldElement#hideLabel()
      */
     public void hideLabel(){
     	fieldElement.hideLabel();
     }
 
     public boolean isLabelShown(){
     	return fieldElement.isLabelShown();
     }
 
     public FieldElement getFieldElement(){
     	return fieldElement;
     }
 
 	public String getFieldKey() {
         return fieldKey;
     }
 
     public void setFieldKey(String fieldKey) {
 		this.fieldKey = fieldKey;
 	}
 
     public String getFieldLabel() {
         return fieldElement.getFieldName();
     }
 
     public Widget getFieldWidget(){
         if (fieldElement.getFieldWidget() == null){
             Widget w = createFieldWidget();
             fieldElement.setWidget(w);
         }
         return fieldElement.getFieldWidget();
     }
 
     protected Widget createFieldWidget() {
     	if (metadata == null) {
     		// backwards compatibility for old ModelDTO code
 	    	// for now, default to textbox if not specified
 	    	Widget result = new KSTextBox();
 	    	addStyleToWidget(result);
 	    	return result;
     	} else {
     		Widget result = DefaultWidgetFactory.getInstance().getWidget(this);
     		addStyleToWidget(result);
     		return result;
     	}
     }
 
     public ModelWidgetBinding<?> getModelWidgetBinding() {
         if(modelWidgetBinding == null){
             if(fieldElement.getFieldWidget() instanceof RichTextEditor){
             	modelWidgetBinding = org.kuali.student.common.ui.client.configurable.mvc.binding.RichTextBinding.INSTANCE;
             } else if (fieldElement.getFieldWidget() instanceof KSCheckBox){
             	modelWidgetBinding = org.kuali.student.common.ui.client.configurable.mvc.binding.HasValueBinding.INSTANCE;
             } else if(fieldElement.getFieldWidget() instanceof MultiplicityComposite){
         		modelWidgetBinding = MultiplicityCompositeBinding.INSTANCE;
         	} else if (fieldElement.getFieldWidget()instanceof HasText) {
         	    modelWidgetBinding = org.kuali.student.common.ui.client.configurable.mvc.binding.HasTextBinding.INSTANCE;
             } else if (fieldElement.getFieldWidget() instanceof KSSelectItemWidgetAbstract){
                 modelWidgetBinding = org.kuali.student.common.ui.client.configurable.mvc.binding.SelectItemWidgetBinding.INSTANCE;
             } else if (fieldElement.getFieldWidget() instanceof HasDataValue){
             	modelWidgetBinding = org.kuali.student.common.ui.client.configurable.mvc.binding.HasDataValueBinding.INSTANCE;
             } else if (fieldElement.getFieldWidget() instanceof HasValue){
             	modelWidgetBinding = org.kuali.student.common.ui.client.configurable.mvc.binding.HasValueBinding.INSTANCE;
             }
         }
         return modelWidgetBinding;
     }
 
     /**
      * Allows additional processing to happen when a validation check is being processed when the input
      * widget loses focus defined in the callback
      * @param callback
      */
     public void setValidationCallBack(Callback<Boolean> callback){
         validationRequestCallback = callback;
     }
 
     public Callback<Boolean> getValidationRequestCallback(){
         return validationRequestCallback;
     }
 
 	/**
 	 * Returns true if this field is marked as dirty.  In KS, dirty is when the field has been changed
 	 * in some way - however not completely accurate
 	 * @return
 	 */
 	public boolean isDirty() {
 		return dirty;
 	}
 
 	public void setDirty(boolean dirty) {
 		this.dirty = dirty;
 	}
 
 	/**
 	 * Return true if the field has been touched by the user in some fashion, this is set by the field's section
 	 * @return
 	 */
 	public boolean hasHadFocus() {
 		return hasHadFocus;
 	}
 
 	public void setHasHadFocus(boolean hasHadFocus) {
 		this.hasHadFocus = hasHadFocus;
 	}
 
     public Metadata getMetadata() {
 		return metadata;
 	}
 
     public void setMetadata(Metadata metadata) {
 		this.metadata = metadata;
         setupField();
 	}
 
     public void setFieldWidget(Widget fieldWidget) {
 		this.fieldElement.setWidget(fieldWidget);
 	}
 
 	public String getModelId() {
 		return modelId;
 	}
 
 	public void setModelId(String modelId) {
 		this.modelId = modelId;
 	}
 
     /**
      * Sets the ModelWidgetBinding for this field.  Changing this changes the way data from the server and
      * passed to the server is processed with the widget.  Set this when some special processing or handling
      * has to happen with the data in either phase.
      * @param widgetBinding
      */
     public void setWidgetBinding(ModelWidgetBinding widgetBinding) {
         this.modelWidgetBinding = widgetBinding;
     }
 
     public MessageKeyInfo getMessageKey() {
         return messageKey;
     }
 
     public void setMessageKey(MessageKeyInfo messageKey) {
         this.messageKey = messageKey;
     }
 
 	/**
 	 * Sets the optional flag
 	 * Fields that are optional should not be displayed if there is no data in some cases,
 	 * it is up to the section implementation whether or not to honor this flag
 	 * @param optional
 	 */
 	public void setOptional(boolean optional){
 		this.optional = optional;
 	}
 
 	/**
 	 * Fields that are optional should not be displayed if there is no data in some cases,
 	 * it is up to the section implementation whether or not to honor this flag
 	 */
 	public boolean isOptional(){
 		return optional;
 	}
 
 	/**
 	 * @return true if this field is visible to the user
 	 */
 	public boolean isVisible() {
 		if (metadata != null){
 			return metadata.isCanView();
 		} else {
 			return true;
 		}
 	}
 
 }