package de.bahntechnik.dd.util.eclipse.emf.databinding;

import org.eclipse.core.databinding.conversion.Converter;
import org.eclipse.core.databinding.conversion.IConverter;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Status;
import org.eclipse.emf.databinding.EMFUpdateValueStrategy;
import org.eclipse.emf.ecore.EAttribute;
import org.eclipse.emf.ecore.EObject;
import org.eclipse.emf.edit.command.SetCommand;

public class EMFUpdateValueStrategyUnsettable extends 
EMFUpdateValueStrategy {

	private IConverter mSuperConverter = null;
	private String mUnsetDisplay = "";
	private EObject mEObj = null;

	public EMFUpdateValueStrategyUnsettable(EObject pEObj) {
		this(pEObj, "");
	}

	public EMFUpdateValueStrategyUnsettable(EObject pEObj, String 
pUnsetDisplay) {
		super();
		mEObj = pEObj;
		mUnsetDisplay = pUnsetDisplay;
	}

	@Override
	public IStatus validateAfterConvert(Object value) {
		return SetCommand.UNSET_VALUE.equals(value) ? Status.OK_STATUS : 
super.validateAfterConvert(value);
	}

	@Override
	public IStatus validateBeforeSet(Object value) {
		return SetCommand.UNSET_VALUE.equals(value) ? Status.OK_STATUS : 
super.validateBeforeSet(value);
	}

	@Override
	protected IConverter createConverter(Object fromType, Object toType) {
		mSuperConverter = super.createConverter(fromType, toType);

		if (fromType == String.class) {
			if (toType instanceof EAttribute) {
				final EAttribute eAttribute = (EAttribute) toType;
				if (eAttribute.isUnsettable()) {
					return new Converter(fromType, toType) {
						public Object convert(Object fromObject) {
							Object lRet = null;
							String value = fromObject == null ? null : fromObject.toString();
							if (value != null && value.isEmpty()) {
								lRet = SetCommand.UNSET_VALUE;
								// System.out.println("String2Attribute Unset: " + fromObject + 
": " + eAttribute);
							} else {
								lRet = mSuperConverter.convert(fromObject);
								// System.out.println("String2Attribute Set__: " + fromObject + 
": " + eAttribute);
							}
							return lRet;
						}
					};
				}
				return mSuperConverter;
			}
		} else if (toType == String.class) {
			if (fromType instanceof EAttribute) {
				final EAttribute eAttribute = (EAttribute) fromType;
				if (eAttribute.isUnsettable()) {
					return new Converter(fromType, toType) {
						public Object convert(Object fromObject) {
							Object lRet = null;
							if (false == mEObj.eIsSet(eAttribute)) {
								lRet = mUnsetDisplay;
								// System.out.println("Attribute2String Unset: " + fromObject + 
": " + eAttribute);
							} else {
								// System.out.println("Attribute2String Set__: " + fromObject + 
": " + eAttribute);
								lRet = mSuperConverter.convert(fromObject);
							}
							return lRet;
						}
					};
				}

				return mSuperConverter;
			}
		}
		return mSuperConverter;
	}
}