package at.gv.egovernment.moa.spss.server.xmlbind;

import java.io.IOException;
import java.util.Date;

import org.w3c.dom.Element;

import at.gv.egovernment.moa.spss.MOAApplicationException;
import at.gv.egovernment.moa.spss.api.xmlbind.RequestParserUtils;
import at.gv.egovernment.moaspss.util.Base64Utils;
import at.gv.egovernment.moaspss.util.Constants;
import at.gv.egovernment.moaspss.util.DOMUtils;
import at.gv.egovernment.moaspss.util.XPathUtils;

public class VerifyPDFRequestParser {

	//
	// XPath expressions for selecting parts of the DOM message
	//
	private static final String MOA = Constants.MOA_PREFIX + ":";
	private static final String DATE_TIME_XPATH = MOA + "DateTime";
	private static final String PDF_SIGNATURE_XPATH = MOA + "PDFSignature";
	private static final String TRUST_PROFILE_ID_XPATH = MOA + "TrustProfileID";

	public VerifyPDFRequest parse(Element requestElem) throws MOAApplicationException {

		VerifyPDFRequest verifyPDFRequest = new VerifyPDFRequest();
		
		Date dateTime = RequestParserUtils.parseDateTime(requestElem, DATE_TIME_XPATH);
		byte[] signedPDF = null;
		try {
			signedPDF = parsePDF(requestElem);
		} catch (IOException e) {
			throw new MOAApplicationException("Failed to extract signed pdf data", null, e);
		}
		String trustProfileID = XPathUtils.getElementValue(requestElem, TRUST_PROFILE_ID_XPATH, null);
		verifyPDFRequest.setDateTime(dateTime);
		verifyPDFRequest.setSignedPDF(signedPDF);
		verifyPDFRequest.setTrustProfileID(trustProfileID);

		return verifyPDFRequest;
	}

	/**
	 * Parse the content contained in a <code>CMSContentBaseType</code> kind of
	 * DOM element.
	 * 
	 * @param contentElem
	 *            The <code>CMSContentBaseType</code> kind of element to parse.
	 * @return A <code>CMSDataObject</code> API object containing the data from
	 *         the given DOM element.
	 * @throws IOException 
	 */
	private byte[] parsePDF(Element contentElem) throws IOException {
		Element base64ContentElem = (Element) XPathUtils.selectSingleNode(contentElem, PDF_SIGNATURE_XPATH);

		String base64Str = DOMUtils.getText(base64ContentElem);
		return Base64Utils.decode(base64Str, true);
	}
}