/*
 * Copyright (C) 2014 Civilian Framework.
 *
 * Licensed under the Civilian License (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.civilian-framework.org/license.txt
 *
 * 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.civilian.tool.csp;


import org.civilian.util.Scanner;


/**
 * CompilerExceptions are used by TemplateCompiler
 * to indicate errors when compiling a Template.
 */
public class CspException extends RuntimeException
{
	private static final long serialVersionUID = 1L; 

	
	private static String buildMessage(String msg, Throwable cause, Scanner scanner)
	{
		if ((msg == null) && (cause != null))
		{
			msg = cause.getMessage();
			if (msg == null)
				msg = cause.toString();
		}
		if (msg == null)
			msg = "error";
		
		if (scanner != null)
		{
			String source = scanner.getSource();
			int lineIndex = scanner.getLineIndex();
			if ((source != null) || (lineIndex >= 0))
			{
				msg += " (";
				if (source != null)
					msg += source;
				if ((source != null) && (lineIndex >= 0))
					msg += ":"; 
				if (lineIndex >= 0)
					msg += (lineIndex + 1);
				msg += ")";
			}
			String line = scanner.getLine();
			if ((line != null) && (line.length() > 0))
			{
				String s = line.length() > 20 ? line.substring(0, 20) + "..." : line;
				msg += ": \"" + s + '"';
			}
		}
		
		return msg;
	}

	
	/**
	 * Creates a new CompilerException.
	 * @param msg an error message.
	 */
	public CspException(String msg)
	{
		super(msg);
	}

	
	/**
	 * Creates a new CompilerException.
	 * @param msg an error message.
	 * @param cause the original error cause
	 */
	public CspException(String msg, Throwable cause)
	{
		super(msg, cause);
	}

	
	/**
	 * Creates a new CompilerException.
	 * @param msg an error message.
	 * @param scanner the used scanner, providing context information about the compiled input
	 */
	public CspException(String msg, Scanner scanner)
	{
		this(msg, null, scanner);
	}
	
	
	/**
	 * Creates a new CompilerException.
	 * @param msg an error message.
	 * @param cause the original error cause
	 * @param scanner the used scanner, providing context information about the compiled input
	 */
	public CspException(String msg, Throwable cause, Scanner scanner)
	{
		super(buildMessage(msg, cause, scanner), cause);
		if (scanner != null)
		{
			lineIndex_		= scanner.getLineIndex();
			line_			= scanner.getLine();
			templateFile_	= scanner.getSource();
		}
	}

	
	/**
	 * Returns the line index of the error causing line, or -1 if not known.
	 */
	public int getLineIndex()
	{
		return lineIndex_;
	}
	

	/**
	 * Returns the line that caused the error, or null if not known.
	 */
	public String getLine()
	{
		return line_;
	}
	

	/**
	 * Returns the template  file, or null if not known. 
	 */
	public String getTemplateFile()
	{
		return templateFile_;
	}

	
	private String templateFile_;
	private String line_;
	private int lineIndex_ = -1;
}