/*
 * Copyright 2005 JBoss Inc
 * 
 * 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 org.drools.process.core.datatype.impl.type;

import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
import java.lang.reflect.InvocationTargetException;
import java.util.HashMap;
import java.util.Map;

import org.drools.process.core.datatype.DataType;

/**
 * Representation of an Enum datatype.
 * 
 * @author <a href="mailto:kris_verlaenen@hotmail.com">Kris Verlaenen</a>
 */
public class EnumDataType implements DataType {

    private static final long serialVersionUID = 4L;

    private String className;
    private transient Map<String, Object> valueMap;
    
    public EnumDataType() {
    }

    public EnumDataType(String className) {
    	setClassName(className);
    }

    public String getClassName() {
        return className;
    }

    public void setClassName(String className) {
        this.className = className;
    }

    public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
    	className = (String) in.readObject();
    }

    public void writeExternal(ObjectOutput out) throws IOException {
    	out.writeObject(className);
    }

    public boolean verifyDataType(final Object value) {
    	if (value == null) {
        	return true;
        }
    	return getValueMap().containsValue(value);
    }
    
	public Object readValue(String value) {
		return getValueMap().get(value);
	}

	public String writeValue(Object value) {
		return value == null ? "" : value.toString();
	}

	public String getStringType() {
		return className == null ? "java.lang.Object" : className;
	}
	
	public Object[] getValues() {
		return getValueMap().values().toArray();
	}
	
	public String[] getValueNames() {
		return getValueMap().keySet().toArray(new String[0]);
	}
	
	public Map<String, Object> getValueMap() {
		if (this.valueMap == null) {
			try {
				this.valueMap = new HashMap<String, Object>();
				if (className == null) {
					return null;
				}
				Class<?> clazz = Class.forName(className);
		        if (!clazz.isEnum()) {
		        	return null;
		        }
		        Object[] values = (Object[]) clazz.getMethod("values", null).invoke(clazz, null);
		        for (Object value: values) {
		        	this.valueMap.put(value.toString(), value);
		        }
			} catch (ClassNotFoundException e) {
	            throw new IllegalArgumentException(
	                "Could not find data type " + className);
			} catch (IllegalAccessException e) {
	            throw new IllegalArgumentException(
	                "IllegalAccessException " + e);
			} catch (InvocationTargetException e) {
	            throw new IllegalArgumentException(
	                "InvocationTargetException " + e);
			} catch (NoSuchMethodException e) {
	            throw new IllegalArgumentException(
	                "NoSuchMethodException " + e);
			}
			
		}
		return this.valueMap;
	}
}