/*--

 * Copyright 2012 René M. de Bloois

 *

 * 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 solidstack.template.groovy;



import groovy.lang.Closure;

import groovy.lang.GString;



import java.io.IOException;



import org.codehaus.groovy.runtime.InvokerHelper;



import solidstack.template.ConvertingWriter;

import solidstack.template.EncodingWriter;

import solidstack.template.TemplateException;





/**

 * A ConvertingWriter that converts Groovy specific data types to Java data types.

 *

 * @author René de Bloois

 */

public class GroovyConvertingWriter implements ConvertingWriter

{

	/**

	 * The EncodingWriter to write to.

	 */

	protected EncodingWriter writer;



	/**

	 * Constructor.

	 *

	 * @param writer The EncodingWriter to write to.

	 */

	public GroovyConvertingWriter( EncodingWriter writer )

	{

		this.writer = writer;

	}



	public void write( Object o ) throws IOException

	{

		if( o == null )

			this.writer.write( null );

		else if( o instanceof String )

			this.writer.write( (String)o );

		else if( o instanceof GString )

		{

			GString gString = (GString)o;

			String[] strings = gString.getStrings();

			Object[] values = gString.getValues();

			if( !( strings.length == values.length + 1 ) )

				throw new IllegalStateException();



			for( int i = 0; i < values.length; i++ )

			{

				this.writer.write( strings[ i ] );

				writeEncoded( values[ i ] );

			}

			this.writer.write( strings[ values.length ] );

		}

		else if( o instanceof Closure )

		{

			Closure c = (Closure)o;

			int pars = c.getMaximumNumberOfParameters();

			if( pars > 0 )

				throw new TemplateException( "Closures with parameters are not supported in expressions." );

			write( c.call() ); // May be recursive

		}

		else

			this.writer.write( (String)InvokerHelper.invokeMethod( o, "asType", String.class ) );

	}



	public void writeEncoded( Object o ) throws IOException

	{

		if( o == null )

			this.writer.writeEncoded( null );

		else if( o instanceof String )

			this.writer.writeEncoded( o );

		else if( o instanceof GString )

			this.writer.writeEncoded( o.toString() );

		else if( o instanceof Closure )

		{

			Closure c = (Closure)o;

			int pars = c.getMaximumNumberOfParameters();

			if( pars > 0 )

				throw new TemplateException( "Closures with parameters are not supported in expressions." );

			writeEncoded( c.call() ); // May be recursive

		}

		else

		{

			if( this.writer.stringsOnly() )

				this.writer.writeEncoded( InvokerHelper.invokeMethod( o, "asType", String.class ) );

			else

				this.writer.writeEncoded( o );

		}

	}



	public void flush() throws IOException

	{

		this.writer.flush();

	}

}