/**
The contents of this file are subject to the Mozilla Public License Version 1.1 
(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.mozilla.org/MPL/ 
Software distributed under the License is distributed on an "AS IS" basis, 
WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for the 
specific language governing rights and limitations under the License. 

The Original Code is "Varies.java".  Description: 
"Varies is a Type used as a placeholder for another Type in cases where 
  the appropriate Type is not known until run-time (e.g" 

The Initial Developer of the Original Code is University Health Network. Copyright (C) 
2001.  All Rights Reserved. 

Contributor(s): ______________________________________. 

Alternatively, the contents of this file may be used under the terms of the 
GNU General Public License (the  "GPL"), in which case the provisions of the GPL are 
applicable instead of those above.  If you wish to allow use of your version of this 
file only under the terms of the GPL and not to allow others to use your version 
of this file under the MPL, indicate your decision by deleting  the provisions above 
and replace  them with the notice and other provisions required by the GPL License.  
If you do not delete the provisions above, a recipient may use your version of 
this file under either the MPL or the GPL. 

*/

package ca.uhn.hl7v2.model;

import ca.uhn.hl7v2.HL7Exception;
import ca.uhn.hl7v2.parser.EncodingCharacters;
import ca.uhn.hl7v2.parser.ModelClassFactory;
import ca.uhn.log.HapiLog;
import ca.uhn.log.HapiLogFactory;

/**
 * <p>Varies is a Type used as a placeholder for another Type in cases where 
 * the appropriate Type is not known until run-time (e.g. OBX-5).  
 * Parsers and validators may have logic that enforces restrictions on the 
 * Type based on other features of a segment.</p>  
 * <p>If you want to set both the type and the values of a Varies object, you should
 * set the type first by calling setData(Type t), keeping a reference to your Type, 
 * and then set values by calling methods on the Type.  Here is an example:</p>
 * <p><code>CN cn = new CN();<br>
 * variesObject.setData(cn);<br>
 * cn.getIDNumber().setValue("foo");</code></p>
 * 
 * @author Bryan Tripp (bryan_tripp@users.sourceforge.net)
 * @author Andy Pardue 
 * 
 */
public class Varies implements Type {

	/** 
	 * System property key. The value may be set to provide a default
	 * datatype ("ST", "NM", etc) for an OBX segment with a missing
	 * OBX-2 value.
	 */	
	public static final String DEFAULT_OBX2_TYPE_PROP = "ca.uhn.hl7v2.model.varies.default_obx2_type";

	private static final HapiLog log = HapiLogFactory.getHapiLog(Varies.class);

    private Type data;
    private Message message;

    /** 
     * Creates new Varies. 
     *  
     * @param message message to which this type belongs
     */
    public Varies(Message message) {
        data = new GenericPrimitive(message);
        this.message = message;
    }

    /**
     * Returns the data contained by this instance of Varies.  Returns a GenericPrimitive unless 
     * setData() has been called. 
     */
    public Type getData() {
        return this.data;
    }

    /** @see Type#getName */
    public String getName() {
        String name = "*";
        if (this.data != null) {
            name = this.data.getName();
        }
        return name;
    }

    /**
     * Sets the data contained by this instance of Varies.  If a data object already exists, 
     * then its values are copied to the incoming data object before the old one is replaced.  
     * For example, if getData() returns an ST with the value "19901012" and you call 
     * setData(new DT()), then subsequent calls to getData() will return the same DT, with the value 
     * set to "19901012".   
     */
    public void setData(Type data) throws DataTypeException {
        if (this.data != null) {
            if (!(this.data instanceof Primitive) || ((Primitive) this.data).getValue() != null) {
                ca.uhn.hl7v2.util.DeepCopy.copy(this.data, data);
            }
        }
        this.data = data;
    }
    
    /** Returns extra components from the underlying Type */
    public ExtraComponents getExtraComponents() {
        return this.data.getExtraComponents();
    }
    
    /**
     * @return the message to which this Type belongs
     */
    public Message getMessage() {
        return message;
    }    

    /** 
     * Sets the data type of field 5 in the given OBX segment to the value of OBX-2.  The argument 
     * is a Segment as opposed to a particular OBX because it is meant to work with any version.  
     */
    public static void fixOBX5(Segment segment, ModelClassFactory factory) throws HL7Exception {
        try {
            //get unqualified class name
            Primitive obx2 = (Primitive) segment.getField(2, 0);
            Type[] reps = segment.getField(5);
            for (int i = 0; i < reps.length; i++) {
                Varies v = (Varies)reps[i];

                // If we don't have a value for OBX-2, a default
                // can be supplied via a System property
                if (obx2.getValue() == null) {
	                String defaultOBX2Type = System.getProperty(DEFAULT_OBX2_TYPE_PROP);
					if (defaultOBX2Type != null) {
	                    log.debug("setting default obx2 type to " + defaultOBX2Type);
	                    obx2.setValue(defaultOBX2Type);
	                }
                } // if
                
                if (obx2.getValue() == null) {
                    if (v.getData() != null) {
                        if (!(v.getData() instanceof Primitive) || ((Primitive) v.getData()).getValue() != null) {
                            throw new HL7Exception(
                                "OBX-5 is valued, but OBX-2 is not.  A datatype for OBX-5 must be specified using OBX-2.",
                                HL7Exception.REQUIRED_FIELD_MISSING);
                        }
                    }
                }
                else {
                    //set class
                    String version = segment.getMessage().getVersion();
					String obx2Value = obx2.getValue();
					Class<? extends Type> c = factory.getTypeClass(obx2Value, version);
//                    Class c = ca.uhn.hl7v2.parser.Parser.findClass(obx2.getValue(), 
//                                                    segment.getMessage().getVersion(), 
//                                                    "datatype");
                    if (c == null) {
                    	Primitive obx1 = (Primitive) segment.getField(1, 0);
                    	HL7Exception h = new HL7Exception("\'" +
                    		obx2.getValue() + "\' in record " +
                    		obx1.getValue() + " is invalid for version " + version,
                    		HL7Exception.DATA_TYPE_ERROR);
                    	h.setSegmentName("OBX");
                    	h.setFieldPosition(2);
                    	throw h;
                    }

                    Type newTypeInstance;
                    try {
                        newTypeInstance = (Type) c.getConstructor(new Class[]{Message.class}).newInstance(new Object[]{v.getMessage()});
                    } catch (NoSuchMethodException e) {
                        newTypeInstance = (Type) c.getConstructor(new Class[]{Message.class, Integer.class}).newInstance(new Object[]{v.getMessage(), 0});
                    }
                    v.setData(newTypeInstance);
                }
                
            } // for reps
            
        }
        catch (HL7Exception e) {
            throw e;
        }
        catch (Exception e) {
            throw new HL7Exception(
                e.getClass().getName() + " trying to set data type of OBX-5",
                HL7Exception.APPLICATION_INTERNAL_ERROR,
                e);
        }
    }


    /**
     * {@inheritDoc }
     */
    public void parse(String string) throws HL7Exception {
        getMessage().getParser().parse(this, string, EncodingCharacters.getInstance(getMessage()));
    }


    /**
     * {@inheritDoc }
     */
    public String encode() throws HL7Exception {
        return getMessage().getParser().doEncode(this, EncodingCharacters.getInstance(getMessage()));
    }


	/**
	 * {@inheritDoc }
	 */
	public void clear() {
		data.clear();
	}

}