package org.json.simple.parser;

/**
 * ParseException explains why and where the error occurs in source JSON text.
 * 
 * @author FangYidong<fangyidong@yahoo.com.cn>
 * 
 */
public class ParseException extends Exception {
	private static final long serialVersionUID = -7880698968187728547L;

	public static final int ERROR_UNEXPECTED_CHAR = 0;
	public static final int ERROR_UNEXPECTED_TOKEN = 1;
	public static final int ERROR_UNEXPECTED_EXCEPTION = 2;

	private int errorType;
	private Object unexpectedObject;
	private int position;

	public ParseException(final int errorType) {
		this(-1, errorType, null);
	}

	public ParseException(final int errorType, final Object unexpectedObject) {
		this(-1, errorType, unexpectedObject);
	}

	public ParseException(final int position, final int errorType, final Object unexpectedObject) {
		this.position = position;
		this.errorType = errorType;
		this.unexpectedObject = unexpectedObject;
	}

	public int getErrorType() {
		return this.errorType;
	}

	public void setErrorType(final int errorType) {
		this.errorType = errorType;
	}

	/**
	 * @see org.json.simple.parser.JSONParser#getPosition()
	 * 
	 * @return The character position (starting with 0) of the input where the
	 *         error occurs.
	 */
	public int getPosition() {
		return this.position;
	}

	public void setPosition(final int position) {
		this.position = position;
	}

	/**
	 * @see org.json.simple.parser.Yytoken
	 * 
	 * @return One of the following base on the value of errorType:
	 *         ERROR_UNEXPECTED_CHAR java.lang.Character ERROR_UNEXPECTED_TOKEN
	 *         org.json.simple.parser.Yytoken ERROR_UNEXPECTED_EXCEPTION
	 *         java.lang.Exception
	 */
	public Object getUnexpectedObject() {
		return this.unexpectedObject;
	}

	public void setUnexpectedObject(final Object unexpectedObject) {
		this.unexpectedObject = unexpectedObject;
	}

	@Override
	public String getMessage() {
		final StringBuffer sb = new StringBuffer();

		switch (this.errorType) {
		case ERROR_UNEXPECTED_CHAR:
			sb.append("Unexpected character (").append(this.unexpectedObject).append(") at position ").append(this.position).append(".");
			break;
		case ERROR_UNEXPECTED_TOKEN:
			sb.append("Unexpected token ").append(this.unexpectedObject).append(" at position ").append(this.position).append(".");
			break;
		case ERROR_UNEXPECTED_EXCEPTION:
			sb.append("Unexpected exception at position ").append(this.position).append(": ").append(this.unexpectedObject);
			break;
		default:
			sb.append("Unkown error at position ").append(this.position).append(".");
			break;
		}
		return sb.toString();
	}
}