package at.gv.egiz.moazs.scheme;

import at.gv.egiz.eaaf.core.impl.utils.DOMUtils;
import at.gv.egiz.moazs.MoaZSException;
import org.apache.cxf.binding.soap.Soap11;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;

import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.TransformerException;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.util.LinkedList;
import java.util.List;

import static at.gv.egiz.moazs.MoaZSException.moaZSException;


@Component
public class SOAPUtils {

    private static final Logger log = LoggerFactory.getLogger(SOAPUtils.class);
    private static final String SOAP_BODY_MISSING_ERROR_MSG = "<soap11:Body> is missing.";
    private static final String SOAP_BODY_CHILDREN_MISSING_ERROR_MSG = "<soap11:Body> has no child elements.";
    private static final String APP_DELIVERY_ID_MISSING_ERROR_MSG = "<msg:AppDeliveryID> is missing.";
    private static final String APP_DELIVERY_ID_EMPTY_ERROR_MSG = "<msg:AppDeliveryID> is empty.";
    private static final String MULTIPLE_MSG = "Found multiple {} elements. Will choose first element.";
    private static final String APP_DELIVERY_ID_FULL_TAG_NAME = "<msg:" + NameSpace.MSG_APP_DELIVERY_ID + ">";

    public Element toDOM(byte[] bytes) throws IOException, SAXException, ParserConfigurationException {
        var stream = new ByteArrayInputStream(bytes);
        return DOMUtils.parseXmlNonValidating(stream);
    }

    public Node getChildElementOfSoapBody(Element document) throws MoaZSException {

        var bodyList = document.getElementsByTagNameNS(Soap11.SOAP_NAMESPACE, "Body");
        if (bodyList.getLength() == 0) throw moaZSException(SOAP_BODY_MISSING_ERROR_MSG);
        if (bodyList.getLength() > 1)  log.warn(MULTIPLE_MSG, "<soap11:Body>");

        var body = bodyList.item(0);
        var children = body.getChildNodes();
        var candidates = filterNodeByType(children, Node.ELEMENT_NODE);

        if (candidates.isEmpty())  throw moaZSException(SOAP_BODY_CHILDREN_MISSING_ERROR_MSG);
        if (candidates.size() > 1) log.warn(MULTIPLE_MSG, "<soap11:Body> child");

        return candidates.get(0);
    }

    private List<Node> filterNodeByType(NodeList children, short nodeType) {
        var candidates = new LinkedList<Node>();
        for (int i = 0; i < children.getLength(); i++) {
            var child = children.item(i);
            if (child.getNodeType() == nodeType) {
                candidates.add(child);
            }
        }

        return candidates;
    }

    public byte[] toBytes(Node node) throws TransformerException, IOException {
        return DOMUtils.serializeNode(node, true).getBytes(StandardCharsets.UTF_8);
    }

    public String getAppDeliveryIDFrom(Element document) {
        var elementList = document.getElementsByTagNameNS(NameSpace.MSG, NameSpace.MSG_APP_DELIVERY_ID);

        if (elementList.getLength() == 0) throw moaZSException(APP_DELIVERY_ID_MISSING_ERROR_MSG);
        if (elementList.getLength() > 1)  log.warn(MULTIPLE_MSG, APP_DELIVERY_ID_FULL_TAG_NAME);

        var children = elementList.item(0).getChildNodes();
        var candidates = filterNodeByType(children, Node.TEXT_NODE);
        if (candidates.isEmpty() || candidates.get(0).getNodeValue().isBlank())
            throw moaZSException(APP_DELIVERY_ID_EMPTY_ERROR_MSG);
        if (candidates.size() > 1) log.warn(MULTIPLE_MSG, APP_DELIVERY_ID_FULL_TAG_NAME);

        return candidates.get(0).getNodeValue();
    }
}