package at.procon.ted.service;

import at.procon.ted.model.entity.*;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Service;
import org.w3c.dom.*;
import org.xml.sax.InputSource;

import javax.xml.namespace.NamespaceContext;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.xpath.*;
import java.io.StringReader;
import java.time.LocalDate;
import java.time.LocalTime;
import java.time.OffsetDateTime;
import java.time.ZoneOffset;
import java.time.format.DateTimeParseException;
import java.util.*;

/**
 * Service for parsing EU eForms XML documents.
 * Extracts structured data from TED procurement notices.
 * 
 * Uses XPath for navigation through the UBL 2.3 document structure with eForms extensions.
 * 
 * @author Martin.Schweitzer@procon.co.at and claude.ai
 */
@Service
@RequiredArgsConstructor
@Slf4j
public class XmlParserService {

    // Namespace URIs for eForms/UBL documents
    private static final String NS_CN = "urn:oasis:names:specification:ubl:schema:xsd:ContractNotice-2";
    private static final String NS_CAC = "urn:oasis:names:specification:ubl:schema:xsd:CommonAggregateComponents-2";
    private static final String NS_CBC = "urn:oasis:names:specification:ubl:schema:xsd:CommonBasicComponents-2";
    private static final String NS_EFAC = "http://data.europa.eu/p27/eforms-ubl-extension-aggregate-components/1";
    private static final String NS_EFBC = "http://data.europa.eu/p27/eforms-ubl-extension-basic-components/1";
    private static final String NS_EFEXT = "http://data.europa.eu/p27/eforms-ubl-extensions/1";
    private static final String NS_EXT = "urn:oasis:names:specification:ubl:schema:xsd:CommonExtensionComponents-2";

    private final DocumentBuilderFactory documentBuilderFactory;
    private final XPathFactory xPathFactory;

    public XmlParserService() {
        this.documentBuilderFactory = DocumentBuilderFactory.newInstance();
        this.documentBuilderFactory.setNamespaceAware(true);
        this.xPathFactory = XPathFactory.newInstance();
    }

    /**
     * Parse an eForms XML document and extract structured data.
     * 
     * @param xmlContent The XML content as string
     * @return Populated ProcurementDocument entity (without ID or hash)
     */
    public ProcurementDocument parseDocument(String xmlContent) {
        try {
            DocumentBuilder builder = newDocumentBuilder();
            Document doc = builder.parse(new InputSource(new StringReader(xmlContent)));

            XPath xpath = newXPath();

            ProcurementDocument document = ProcurementDocument.builder()
                    .xmlDocument(xmlContent)
                    .build();

            // Parse basic notice information
            parseNoticeMetadata(doc, xpath, document);
            
            // Parse contracting party (buyer) information
            parseContractingParty(doc, xpath, document);
            
            // Parse procurement project information
            parseProcurementProject(doc, xpath, document);
            
            // Parse tendering process
            parseTenderingProcess(doc, xpath, document);
            
            // Parse organizations from extensions
            parseOrganizations(doc, xpath, document);
            
            // Parse lots
            parseLots(doc, xpath, document);
            
            // Parse publication information
            parsePublication(doc, xpath, document);
            
            // Generate text content for vectorization
            document.setTextContent(generateTextContent(document));

            return document;
            
        } catch (Exception e) {
            log.error("Error parsing XML document: {}", e.getMessage(), e);
            throw new XmlParsingException("Failed to parse XML document", e);
        }
    }

    private void parseNoticeMetadata(Document doc, XPath xpath, ProcurementDocument document) throws XPathExpressionException {
        // UBL Version
        document.setUblVersion(getTextContent(xpath, doc, "/*[local-name()='ContractNotice']/cbc:UBLVersionID"));
        
        // SDK Version (customization ID)
        document.setSdkVersion(getTextContent(xpath, doc, "/*[local-name()='ContractNotice']/cbc:CustomizationID"));
        
        // Notice ID
        document.setNoticeId(getTextContent(xpath, doc, "/*[local-name()='ContractNotice']/cbc:ID"));
        
        // Contract Folder ID
        document.setContractFolderId(getTextContent(xpath, doc, "/*[local-name()='ContractNotice']/cbc:ContractFolderID"));
        
        // Issue Date and Time - combined into single OffsetDateTime
        String issueDateStr = getTextContent(xpath, doc, "/*[local-name()='ContractNotice']/cbc:IssueDate");
        String issueTimeStr = getTextContent(xpath, doc, "/*[local-name()='ContractNotice']/cbc:IssueTime");
        if (issueDateStr != null) {
            document.setIssueDateTime(parseDateTime(issueDateStr, issueTimeStr));
        }

        // Notice Language
        document.setLanguageCode(getTextContent(xpath, doc, "/*[local-name()='ContractNotice']/cbc:NoticeLanguageCode"));
        
        // Notice Type Code
        String noticeTypeCode = getTextContent(xpath, doc, "/*[local-name()='ContractNotice']/cbc:NoticeTypeCode");
        document.setNoticeType(mapNoticeType(noticeTypeCode));
        
        // Regulatory Domain
        document.setRegulatoryDomain(getTextContent(xpath, doc, "/*[local-name()='ContractNotice']/cbc:RegulatoryDomain"));
        
        // Notice Subtype from extensions
        String subtypeCode = getTextContent(xpath, doc, 
            "//efext:EformsExtension/efac:NoticeSubType/cbc:SubTypeCode");
        document.setNoticeSubtypeCode(subtypeCode);
    }

    private void parseContractingParty(Document doc, XPath xpath, ProcurementDocument document) throws XPathExpressionException {
        // Activity type
        document.setBuyerActivityType(getTextContent(xpath, doc,
            "//cac:ContractingParty/cac:ContractingActivity/cbc:ActivityTypeCode"));
        
        // Legal type
        document.setBuyerLegalType(getTextContent(xpath, doc,
            "//cac:ContractingParty/cac:ContractingPartyType/cbc:PartyTypeCode"));
        
        // Organization reference to link with organizations
        String orgRef = getTextContent(xpath, doc,
            "//cac:ContractingParty/cac:Party/cac:PartyIdentification/cbc:ID");
        
        // Buyer details will be populated from organizations
    }

    private void parseProcurementProject(Document doc, XPath xpath, ProcurementDocument document) throws XPathExpressionException {
        // Project title
        document.setProjectTitle(getTextContent(xpath, doc,
            "/*[local-name()='ContractNotice']/cac:ProcurementProject/cbc:Name"));
        
        // Project description
        document.setProjectDescription(getTextContent(xpath, doc,
            "/*[local-name()='ContractNotice']/cac:ProcurementProject/cbc:Description"));
        
        // Internal reference
        document.setInternalReference(getTextContent(xpath, doc,
            "/*[local-name()='ContractNotice']/cac:ProcurementProject/cbc:ID"));
        
        // Contract nature
        String contractNature = getTextContent(xpath, doc,
            "/*[local-name()='ContractNotice']/cac:ProcurementProject/cbc:ProcurementTypeCode");
        document.setContractNature(mapContractNature(contractNature));
        
        // CPV codes
        List<String> cpvCodes = getTextContents(xpath, doc,
            "/*[local-name()='ContractNotice']/cac:ProcurementProject/cac:MainCommodityClassification/cbc:ItemClassificationCode");
        cpvCodes.addAll(getTextContents(xpath, doc,
            "/*[local-name()='ContractNotice']/cac:ProcurementProject/cac:AdditionalCommodityClassification/cbc:ItemClassificationCode"));
        document.setCpvCodes(cpvCodes.toArray(new String[0]));
        
        // Location - country and NUTS codes
        document.setBuyerCountryCode(getTextContent(xpath, doc,
            "/*[local-name()='ContractNotice']/cac:ProcurementProject/cac:RealizedLocation/cac:Address/cac:Country/cbc:IdentificationCode"));
        document.setBuyerNutsCode(getTextContent(xpath, doc,
            "/*[local-name()='ContractNotice']/cac:ProcurementProject/cac:RealizedLocation/cac:Address/cbc:CountrySubentityCode"));
        document.setBuyerCity(getTextContent(xpath, doc,
            "/*[local-name()='ContractNotice']/cac:ProcurementProject/cac:RealizedLocation/cac:Address/cbc:CityName"));
        
        // All NUTS codes from project and lots
        List<String> nutsCodes = getTextContents(xpath, doc,
            "//cac:RealizedLocation/cac:Address/cbc:CountrySubentityCode");
        document.setNutsCodes(nutsCodes.stream().distinct().toArray(String[]::new));
    }

    private void parseTenderingProcess(Document doc, XPath xpath, ProcurementDocument document) throws XPathExpressionException {
        // Procedure type
        String procedureCode = getTextContent(xpath, doc,
            "/*[local-name()='ContractNotice']/cac:TenderingProcess/cbc:ProcedureCode");
        document.setProcedureType(mapProcedureType(procedureCode));
        
        // Lot distribution
        String maxLotsAwarded = getTextContent(xpath, doc,
            "/*[local-name()='ContractNotice']/cac:TenderingTerms/cac:LotDistribution/cbc:MaximumLotsAwardedNumeric");
        if (maxLotsAwarded != null) {
            document.setMaxLotsAwarded(Integer.parseInt(maxLotsAwarded));
        }
        
        String maxLotsSubmitted = getTextContent(xpath, doc,
            "/*[local-name()='ContractNotice']/cac:TenderingTerms/cac:LotDistribution/cbc:MaximumLotsSubmittedNumeric");
        if (maxLotsSubmitted != null) {
            document.setMaxLotsSubmitted(Integer.parseInt(maxLotsSubmitted));
        }
    }

    private void parseOrganizations(Document doc, XPath xpath, ProcurementDocument document) throws XPathExpressionException {
        NodeList orgNodes = (NodeList) xpath.evaluate(
            "//efac:Organizations/efac:Organization", doc, XPathConstants.NODESET);
        
        boolean buyerInfoSet = false;
        
        for (int i = 0; i < orgNodes.getLength(); i++) {
            Node orgNode = orgNodes.item(i);
            
            Organization org = Organization.builder().build();
            
            // Organization reference
            org.setOrgReference(getTextContent(xpath, orgNode, ".//cac:PartyIdentification/cbc:ID"));
            
            // Name
            org.setName(getTextContent(xpath, orgNode, ".//cac:PartyName/cbc:Name"));
            if(org.getName() == null) org.setName("");

            // Company ID
            org.setCompanyId(getTextContent(xpath, orgNode, ".//cac:PartyLegalEntity/cbc:CompanyID"));
            
            // Address
            org.setStreetName(getTextContent(xpath, orgNode, ".//cac:PostalAddress/cbc:StreetName"));
            org.setCity(getTextContent(xpath, orgNode, ".//cac:PostalAddress/cbc:CityName"));
            org.setPostalCode(getTextContent(xpath, orgNode, ".//cac:PostalAddress/cbc:PostalZone"));
            org.setNutsCode(getTextContent(xpath, orgNode, ".//cac:PostalAddress/cbc:CountrySubentityCode"));
            org.setCountryCode(getTextContent(xpath, orgNode, ".//cac:PostalAddress/cac:Country/cbc:IdentificationCode"));
            
            // Contact
            org.setWebsiteUri(getTextContent(xpath, orgNode, ".//cbc:WebsiteURI"));
            org.setEmail(getTextContent(xpath, orgNode, ".//cac:Contact/cbc:ElectronicMail"));
            org.setPhone(getTextContent(xpath, orgNode, ".//cac:Contact/cbc:Telephone"));
            
            document.addOrganization(org);
            
            // Set buyer info from first organization (typically ORG-0001)
            if (!buyerInfoSet && "ORG-0001".equals(org.getOrgReference())) {
                document.setBuyerName(org.getName());
                if (document.getBuyerCountryCode() == null) {
                    document.setBuyerCountryCode(org.getCountryCode());
                }
                if (document.getBuyerCity() == null) {
                    document.setBuyerCity(org.getCity());
                }
                document.setBuyerPostalCode(org.getPostalCode());
                if (document.getBuyerNutsCode() == null) {
                    document.setBuyerNutsCode(org.getNutsCode());
                }
                buyerInfoSet = true;
            }
        }
    }

    private DocumentBuilder newDocumentBuilder() throws Exception {
        synchronized (documentBuilderFactory) {
            documentBuilderFactory.setNamespaceAware(true);
            return documentBuilderFactory.newDocumentBuilder();
        }
    }

    private XPath newXPath() {
        synchronized (xPathFactory) {
            XPath xpath = xPathFactory.newXPath();
            xpath.setNamespaceContext(createNamespaceContext());
            return xpath;
        }
    }

    private String getTextContent(XPath xpath, Object item, String expression) throws XPathExpressionException {
        Node node = (Node) xpath.evaluate(expression, item, XPathConstants.NODE);
        return node != null ? node.getTextContent().trim() : null;
    }

    private Node getNode(XPath xpath, Object item, String expression) throws XPathExpressionException {
        return (Node) xpath.evaluate(expression, item, XPathConstants.NODE);
    }

    private NodeList getNodes(XPath xpath, Object item, String expression) throws XPathExpressionException {
        return (NodeList) xpath.evaluate(expression, item, XPathConstants.NODESET);
    }

    private Element getDirectChild(Element parent, String namespaceUri, String localName) {
        Node child = parent.getFirstChild();
        while (child != null) {
            if (child.getNodeType() == Node.ELEMENT_NODE) {
                Element el = (Element) child;
                if (localName.equals(el.getLocalName()) && namespaceUri.equals(el.getNamespaceURI())) {
                    return el;
                }
            }
            child = child.getNextSibling();
        }
        return null;
    }

    private List<Element> getDirectChildren(Element parent, String namespaceUri, String localName) {
        List<Element> result = new ArrayList<>();
        Node child = parent.getFirstChild();
        while (child != null) {
            if (child.getNodeType() == Node.ELEMENT_NODE) {
                Element el = (Element) child;
                if (localName.equals(el.getLocalName()) && namespaceUri.equals(el.getNamespaceURI())) {
                    result.add(el);
                }
            }
            child = child.getNextSibling();
        }
        return result;
    }

    private String getDirectChildText(Element parent, String namespaceUri, String localName) {
        Element child = getDirectChild(parent, namespaceUri, localName);
        if (child == null) {
            return null;
        }
        return trimToNull(child.getTextContent());
    }

    private String trimToNull(String value) {
        if (value == null) {
            return null;
        }
        String trimmed = value.trim();
        return trimmed.isEmpty() ? null : trimmed;
    }

    private void parseLotsDOM(Document doc, XPath xpath, ProcurementDocument document) throws XPathExpressionException {
        NodeList lotNodes = getNodes(xpath, doc, "//cac:ProcurementProjectLot");
        document.setTotalLots(lotNodes.getLength());

        for (int i = 0; i < lotNodes.getLength(); i++) {
            Node lotNode = lotNodes.item(i);
            if (lotNode.getNodeType() != Node.ELEMENT_NODE) {
                continue;
            }

            Element lotEl = (Element) lotNode;
            ProcurementLot lot = ProcurementLot.builder().build();

            // Direct child values on the lot
            lot.setLotId(getDirectChildText(lotEl, NS_CBC, "ID"));

            Element procurementProjectEl = getDirectChild(lotEl, NS_CAC, "ProcurementProject");
            if (procurementProjectEl != null) {
                lot.setInternalId(getDirectChildText(procurementProjectEl, NS_CBC, "ID"));
                lot.setTitle(getDirectChildText(procurementProjectEl, NS_CBC, "Name"));
                lot.setDescription(getDirectChildText(procurementProjectEl, NS_CBC, "Description"));

                // CPV codes
                List<String> lotCpvCodes = new ArrayList<>();
                for (Element mainCommodityEl : getDirectChildren(procurementProjectEl, NS_CAC, "MainCommodityClassification")) {
                    String cpv = getDirectChildText(mainCommodityEl, NS_CBC, "ItemClassificationCode");
                    if (cpv != null && !cpv.isEmpty()) {
                        lotCpvCodes.add(cpv);
                    }
                }
                lot.setCpvCodes(lotCpvCodes.toArray(new String[0]));

                // NUTS codes
                List<String> lotNutsCodes = new ArrayList<>();
                for (Element realizedLocationEl : getDirectChildren(procurementProjectEl, NS_CAC, "RealizedLocation")) {
                    Element addressEl = getDirectChild(realizedLocationEl, NS_CAC, "Address");
                    if (addressEl != null) {
                        String nuts = getDirectChildText(addressEl, NS_CBC, "CountrySubentityCode");
                        if (nuts != null && !nuts.isEmpty()) {
                            lotNutsCodes.add(nuts);
                        }
                    }
                }
                lot.setNutsCodes(lotNutsCodes.toArray(new String[0]));

                // Duration
                Element plannedPeriodEl = getDirectChild(procurementProjectEl, NS_CAC, "PlannedPeriod");
                if (plannedPeriodEl != null) {
                    Element durationEl = getDirectChild(plannedPeriodEl, NS_CBC, "DurationMeasure");
                    if (durationEl != null) {
                        String durationValue = trimToNull(durationEl.getTextContent());
                        if (durationValue != null) {
                            try {
                                lot.setDurationValue(Double.parseDouble(durationValue));
                            } catch (NumberFormatException e) {
                                log.warn("Invalid duration value '{}' in lot {}, skipping", durationValue, lot.getLotId());
                            }
                        }

                        String unitCode = trimToNull(durationEl.getAttribute("unitCode"));
                        if (unitCode != null) {
                            lot.setDurationUnit(unitCode);
                        }
                    }
                }
            }

            // Submission deadline
            Element tenderingProcessEl = getDirectChild(lotEl, NS_CAC, "TenderingProcess");
            if (tenderingProcessEl != null) {
                Element deadlinePeriodEl = getDirectChild(tenderingProcessEl, NS_CAC, "TenderSubmissionDeadlinePeriod");
                if (deadlinePeriodEl != null) {
                    String endDate = getDirectChildText(deadlinePeriodEl, NS_CBC, "EndDate");
                    if (endDate != null) {
                        String endTime = getDirectChildText(deadlinePeriodEl, NS_CBC, "EndTime");
                        lot.setSubmissionDeadline(parseDateTime(endDate, endTime));

                        if (document.getSubmissionDeadline() == null) {
                            document.setSubmissionDeadline(lot.getSubmissionDeadline());
                        }
                    }
                }
            }

            // EU funded
            Element tenderingTermsEl = getDirectChild(lotEl, NS_CAC, "TenderingTerms");
            if (tenderingTermsEl != null) {
                String fundingProgramCode = getDirectChildText(tenderingTermsEl, NS_CBC, "FundingProgramCode");
                lot.setEuFunded(fundingProgramCode != null && !fundingProgramCode.contains("no-eu-funds"));
            }

            document.addLot(lot);
        }

        document.setEuFunded(document.getLots().stream().anyMatch(l -> Boolean.TRUE.equals(l.getEuFunded())));
    }

    private void parseLots(Document doc, XPath xpath, ProcurementDocument document) throws XPathExpressionException {
        NodeList lotNodes = getNodes(xpath, doc, "//cac:ProcurementProjectLot");
        document.setTotalLots(lotNodes.getLength());

        for (int i = 0; i < lotNodes.getLength(); i++) {
            Node lotNode = lotNodes.item(i);
            if (lotNode.getNodeType() != Node.ELEMENT_NODE) {
                continue;
            }

            Element lotEl = (Element) lotNode;
            ProcurementLot lot = ProcurementLot.builder().build();

            // Fast direct children
            Element procurementProjectEl = getDirectChild(lotEl, NS_CAC, "ProcurementProject");
            Element tenderingProcessEl = getDirectChild(lotEl, NS_CAC, "TenderingProcess");
            Element tenderingTermsEl = getDirectChild(lotEl, NS_CAC, "TenderingTerms");

            // --- Lot ID ---
            String lotId = getDirectChildText(lotEl, NS_CBC, "ID");
            if (lotId == null) {
                lotId = getTextContent(xpath, lotNode, "cbc:ID");
            }
            lot.setLotId(lotId);

            // --- Internal ID ---
            String internalId = null;
            if (procurementProjectEl != null) {
                internalId = getDirectChildText(procurementProjectEl, NS_CBC, "ID");
            }
            if (internalId == null) {
                internalId = getTextContent(xpath, lotNode, "cac:ProcurementProject/cbc:ID");
            }
            lot.setInternalId(internalId);

            // --- Title ---
            String title = null;
            if (procurementProjectEl != null) {
                title = getDirectChildText(procurementProjectEl, NS_CBC, "Name");
            }
            if (title == null) {
                title = getTextContent(xpath, lotNode, "cac:ProcurementProject/cbc:Name");
            }
            lot.setTitle(title);

            // --- Description ---
            String description = null;
            if (procurementProjectEl != null) {
                description = getDirectChildText(procurementProjectEl, NS_CBC, "Description");
            }
            if (description == null) {
                description = getTextContent(xpath, lotNode, "cac:ProcurementProject/cbc:Description");
            }
            lot.setDescription(description);

            // --- CPV codes ---
            List<String> lotCpvCodes = new ArrayList<>();
            if (procurementProjectEl != null) {
                for (Element mainCommodityEl : getDirectChildren(procurementProjectEl, NS_CAC, "MainCommodityClassification")) {
                    String cpv = getDirectChildText(mainCommodityEl, NS_CBC, "ItemClassificationCode");
                    if (cpv != null && !cpv.isEmpty()) {
                        lotCpvCodes.add(cpv);
                    }
                }
            }
            if (lotCpvCodes.isEmpty()) {
                NodeList cpvNodes = getNodes(xpath, lotNode,
                        ".//cac:MainCommodityClassification/cbc:ItemClassificationCode");
                for (int j = 0; j < cpvNodes.getLength(); j++) {
                    String cpv = trimToNull(cpvNodes.item(j).getTextContent());
                    if (cpv != null) {
                        lotCpvCodes.add(cpv);
                    }
                }
            }
            lot.setCpvCodes(lotCpvCodes.toArray(new String[0]));

            // --- NUTS codes ---
            List<String> lotNutsCodes = new ArrayList<>();
            if (procurementProjectEl != null) {
                for (Element realizedLocationEl : getDirectChildren(procurementProjectEl, NS_CAC, "RealizedLocation")) {
                    Element addressEl = getDirectChild(realizedLocationEl, NS_CAC, "Address");
                    if (addressEl != null) {
                        String nuts = getDirectChildText(addressEl, NS_CBC, "CountrySubentityCode");
                        if (nuts != null && !nuts.isEmpty()) {
                            lotNutsCodes.add(nuts);
                        }
                    }
                }
            }
            if (lotNutsCodes.isEmpty()) {
                NodeList nutsNodes = getNodes(xpath, lotNode,
                        ".//cac:RealizedLocation/cac:Address/cbc:CountrySubentityCode");
                for (int j = 0; j < nutsNodes.getLength(); j++) {
                    String nuts = trimToNull(nutsNodes.item(j).getTextContent());
                    if (nuts != null) {
                        lotNutsCodes.add(nuts);
                    }
                }
            }
            lot.setNutsCodes(lotNutsCodes.toArray(new String[0]));

            // --- Duration ---
            boolean durationSet = false;
            if (procurementProjectEl != null) {
                Element plannedPeriodEl = getDirectChild(procurementProjectEl, NS_CAC, "PlannedPeriod");
                if (plannedPeriodEl != null) {
                    Element durationEl = getDirectChild(plannedPeriodEl, NS_CBC, "DurationMeasure");
                    if (durationEl != null) {
                        String durationValue = trimToNull(durationEl.getTextContent());
                        if (durationValue != null) {
                            try {
                                lot.setDurationValue(Double.parseDouble(durationValue));
                            } catch (NumberFormatException e) {
                                log.warn("Invalid duration value '{}' in lot {}, skipping", durationValue, lot.getLotId());
                            }
                        }

                        String unitCode = trimToNull(durationEl.getAttribute("unitCode"));
                        if (unitCode != null) {
                            lot.setDurationUnit(unitCode);
                        }
                        durationSet = true;
                    }
                }
            }
            if (!durationSet) {
                Node durationNode = getNode(xpath, lotNode,
                        "cac:ProcurementProject/cac:PlannedPeriod/cbc:DurationMeasure");
                if (durationNode != null) {
                    String durationValue = trimToNull(durationNode.getTextContent());
                    if (durationValue != null) {
                        try {
                            lot.setDurationValue(Double.parseDouble(durationValue));
                        } catch (NumberFormatException e) {
                            log.warn("Invalid duration value '{}' in lot {}, skipping", durationValue, lot.getLotId());
                        }
                    }
                    if (durationNode instanceof Element durationEl) {
                        String unitCode = trimToNull(durationEl.getAttribute("unitCode"));
                        if (unitCode != null) {
                            lot.setDurationUnit(unitCode);
                        }
                    }
                }
            }

            // --- Submission deadline ---
            String endDate = null;
            String endTime = null;
            if (tenderingProcessEl != null) {
                Element deadlinePeriodEl = getDirectChild(tenderingProcessEl, NS_CAC, "TenderSubmissionDeadlinePeriod");
                if (deadlinePeriodEl != null) {
                    endDate = getDirectChildText(deadlinePeriodEl, NS_CBC, "EndDate");
                    endTime = getDirectChildText(deadlinePeriodEl, NS_CBC, "EndTime");
                }
            }
            if (endDate == null) {
                endDate = getTextContent(xpath, lotNode,
                        "cac:TenderingProcess/cac:TenderSubmissionDeadlinePeriod/cbc:EndDate");
                endTime = getTextContent(xpath, lotNode,
                        "cac:TenderingProcess/cac:TenderSubmissionDeadlinePeriod/cbc:EndTime");
            }
            if (endDate != null) {
                lot.setSubmissionDeadline(parseDateTime(endDate, endTime));
                if (document.getSubmissionDeadline() == null) {
                    document.setSubmissionDeadline(lot.getSubmissionDeadline());
                }
            }

            // --- EU funded ---
            String fundingProgramCode = null;
            if (tenderingTermsEl != null) {
                fundingProgramCode = getDirectChildText(tenderingTermsEl, NS_CBC, "FundingProgramCode");
            }
            if (fundingProgramCode == null) {
                fundingProgramCode = getTextContent(xpath, lotNode,
                        "cac:TenderingTerms/cbc:FundingProgramCode");
            }
            lot.setEuFunded(fundingProgramCode != null && !fundingProgramCode.contains("no-eu-funds"));

            document.addLot(lot);
        }

        document.setEuFunded(document.getLots().stream().anyMatch(l -> Boolean.TRUE.equals(l.getEuFunded())));
    }

    private void parseLotsOld(Document doc, XPath xpath, ProcurementDocument document) throws XPathExpressionException {
        NodeList lotNodes = (NodeList) xpath.evaluate(
            "//cac:ProcurementProjectLot", doc, XPathConstants.NODESET);
        
        document.setTotalLots(lotNodes.getLength());
        
        for (int i = 0; i < lotNodes.getLength(); i++) {
            Node lotNode = lotNodes.item(i);
            
            ProcurementLot lot = ProcurementLot.builder().build();
            
            // Lot ID
            lot.setLotId(getTextContent(xpath, lotNode, "cbc:ID"));
            
            // Internal ID
            lot.setInternalId(getTextContent(xpath, lotNode, "cac:ProcurementProject/cbc:ID"));
            
            // Title and description
            lot.setTitle(getTextContent(xpath, lotNode, "cac:ProcurementProject/cbc:Name"));
            lot.setDescription(getTextContent(xpath, lotNode, "cac:ProcurementProject/cbc:Description"));
            
            // CPV codes for this lot
            List<String> lotCpvCodes = new ArrayList<>();
            NodeList cpvNodes = (NodeList) xpath.evaluate(
                ".//cac:MainCommodityClassification/cbc:ItemClassificationCode",
                lotNode, XPathConstants.NODESET);
            for (int j = 0; j < cpvNodes.getLength(); j++) {
                lotCpvCodes.add(cpvNodes.item(j).getTextContent());
            }
            lot.setCpvCodes(lotCpvCodes.toArray(new String[0]));
            
            // NUTS codes for this lot
            List<String> lotNutsCodes = new ArrayList<>();
            NodeList nutsNodes = (NodeList) xpath.evaluate(
                ".//cac:RealizedLocation/cac:Address/cbc:CountrySubentityCode",
                lotNode, XPathConstants.NODESET);
            for (int j = 0; j < nutsNodes.getLength(); j++) {
                lotNutsCodes.add(nutsNodes.item(j).getTextContent());
            }
            lot.setNutsCodes(lotNutsCodes.toArray(new String[0]));

            // Duration
            String durationValue = getTextContent(xpath, lotNode,
                "cac:ProcurementProject/cac:PlannedPeriod/cbc:DurationMeasure");
            if (durationValue != null) {
                try {
                    lot.setDurationValue(Double.parseDouble(durationValue));
                } catch (NumberFormatException e) {
                    log.warn("Invalid duration value '{}' in lot {}, skipping", durationValue, lot.getLotId());
                }
            }
            lot.setDurationUnit(getAttributeValue(xpath, lotNode,
                "cac:ProcurementProject/cac:PlannedPeriod/cbc:DurationMeasure", "unitCode"));
            
            // Submission deadline
            String endDate = getTextContent(xpath, lotNode,
                "cac:TenderingProcess/cac:TenderSubmissionDeadlinePeriod/cbc:EndDate");
            String endTime = getTextContent(xpath, lotNode,
                "cac:TenderingProcess/cac:TenderSubmissionDeadlinePeriod/cbc:EndTime");
            if (endDate != null) {
                lot.setSubmissionDeadline(parseDateTime(endDate, endTime));
                // Set document-level deadline from first lot if not set
                if (document.getSubmissionDeadline() == null) {
                    document.setSubmissionDeadline(lot.getSubmissionDeadline());
                }
            }
            
            // EU funded
            String euFunded = getTextContent(xpath, lotNode,
                "cac:TenderingTerms/cbc:FundingProgramCode");
            lot.setEuFunded(euFunded != null && !euFunded.contains("no-eu-funds"));
            
            document.addLot(lot);
        }
        
        // Check if any lot is EU funded
        document.setEuFunded(document.getLots().stream().anyMatch(l -> Boolean.TRUE.equals(l.getEuFunded())));
    }

    private void parsePublication(Document doc, XPath xpath, ProcurementDocument document) throws XPathExpressionException {
        // Publication ID (OJS notice ID)
        document.setPublicationId(getTextContent(xpath, doc,
            "//efac:Publication/efbc:NoticePublicationID"));
        
        // OJS ID (gazette ID)
        document.setOjsId(getTextContent(xpath, doc,
            "//efac:Publication/efbc:GazetteID"));
        
        // Publication date
        String pubDate = getTextContent(xpath, doc,
            "//efac:Publication/efbc:PublicationDate");
        if (pubDate != null) {
            document.setPublicationDate(parseDate(pubDate));
        }
        
        // Fallback to requested publication date
        if (document.getPublicationDate() == null) {
            String requestedPubDate = getTextContent(xpath, doc,
                "/*[local-name()='ContractNotice']/cbc:RequestedPublicationDate");
            if (requestedPubDate != null) {
                document.setPublicationDate(parseDate(requestedPubDate));
            }
        }
    }

    /**
     * Generate a textual representation for vectorization.
     */
    private String generateTextContent(ProcurementDocument document) {
        StringBuilder sb = new StringBuilder();
        
        // Title (most important)
        if (document.getProjectTitle() != null) {
            sb.append("Title: ").append(document.getProjectTitle()).append("\n\n");
        }
        
        // Description
        if (document.getProjectDescription() != null) {
            sb.append("Description: ").append(document.getProjectDescription()).append("\n\n");
        }
        
        // Buyer information
        if (document.getBuyerName() != null) {
            sb.append("Contracting Authority: ").append(document.getBuyerName());
            if (document.getBuyerCity() != null) {
                sb.append(", ").append(document.getBuyerCity());
            }
            if (document.getBuyerCountryCode() != null) {
                sb.append(" (").append(document.getBuyerCountryCode()).append(")");
            }
            sb.append("\n\n");
        }
        
        // Contract type and procedure
        if (document.getContractNature() != null) {
            sb.append("Contract Type: ").append(document.getContractNature()).append("\n");
        }
        if (document.getProcedureType() != null) {
            sb.append("Procedure: ").append(document.getProcedureType()).append("\n");
        }
        
        // CPV classification
        if (document.getCpvCodes() != null && document.getCpvCodes().length > 0) {
            sb.append("CPV Codes: ").append(String.join(", ", document.getCpvCodes())).append("\n");
        }
        
        // Lot information
        if (document.getLots() != null && !document.getLots().isEmpty()) {
            sb.append("\nLots (").append(document.getLots().size()).append("):\n");
            for (ProcurementLot lot : document.getLots()) {
                if (lot.getTitle() != null) {
                    sb.append("- ").append(lot.getLotId()).append(": ").append(lot.getTitle());
                    if (lot.getDescription() != null && !lot.getDescription().equals(lot.getTitle())) {
                        sb.append(" - ").append(lot.getDescription());
                    }
                    sb.append("\n");
                }
            }
        }
        
        return sb.toString().trim();
    }

    // Helper methods

    private List<String> getTextContents(XPath xpath, Object item, String expression) throws XPathExpressionException {
        List<String> results = new ArrayList<>();
        NodeList nodes = getNodes(xpath, item, expression);
        for (int i = 0; i < nodes.getLength(); i++) {
            String text = nodes.item(i).getTextContent().trim();
            if (!text.isEmpty()) {
                results.add(text);
            }
        }
        return results;
    }

    private String getAttributeValue(XPath xpath, Object item, String expression, String attrName) throws XPathExpressionException {
        Node node = getNode(xpath, item, expression);
        if (node instanceof Element element) {
            String value = element.getAttribute(attrName);
            return trimToNull(value);
        }
        return null;
    }

    private LocalDate parseDate(String dateStr) {
        if (dateStr == null || dateStr.isEmpty()) return null;
        try {
            // Handle various date formats
            dateStr = dateStr.trim();

            // Handle datetime with dash separator (e.g. "2025-04-23-03:00")
            // Extract only the date part (first 10 characters: YYYY-MM-DD)
            if (dateStr.matches("\\d{4}-\\d{2}-\\d{2}-\\d{2}:\\d{2}.*")) {
                dateStr = dateStr.substring(0, 10);
            }

            if (dateStr.contains("+")) {
                dateStr = dateStr.substring(0, dateStr.indexOf("+"));
            }
            if (dateStr.endsWith("Z")) {
                dateStr = dateStr.substring(0, dateStr.length() - 1);
            }
            return LocalDate.parse(dateStr);
        } catch (DateTimeParseException e) {
            log.warn("Failed to parse date: {} . Error: {}", dateStr, e.getMessage());
            return null;
        }
    }

    private LocalTime parseTime(String timeStr) {
        if (timeStr == null || timeStr.isEmpty()) return null;
        try {
            timeStr = timeStr.trim();

            // Handle time with offset (e.g. "12:00:00-03:00")
            // Extract only the time part (first 8 characters: HH:mm:ss)
            if (timeStr.matches("\\d{2}:\\d{2}:\\d{2}[+-]\\d{2}:\\d{2}")) {
                timeStr = timeStr.substring(0, 8);
            }

            if (timeStr.contains("+")) {
                timeStr = timeStr.substring(0, timeStr.indexOf("+"));
            }
            if (timeStr.endsWith("Z")) {
                timeStr = timeStr.substring(0, timeStr.length() - 1);
            }
            return LocalTime.parse(timeStr);
        } catch (DateTimeParseException e) {
            log.warn("Failed to parse time: {} . Error: {}", timeStr, e.getMessage());
            return null;
        }
    }

    private OffsetDateTime parseDateTime(String dateStr, String timeStr) {
        LocalDate date = parseDate(dateStr);
        if (date == null) return null;
        
        LocalTime time = timeStr != null ? parseTime(timeStr) : LocalTime.MIDNIGHT;
        if (time == null) time = LocalTime.MIDNIGHT;
        
        // Parse timezone offset if present in date string
        ZoneOffset offset = ZoneOffset.UTC;
        if (dateStr != null && dateStr.contains("+")) {
            try {
                String offsetStr = dateStr.substring(dateStr.indexOf("+"));
                offset = ZoneOffset.of(offsetStr);
            } catch (Exception e) {
                // Default to UTC
            }
        }
        
        return OffsetDateTime.of(date, time, offset);
    }

    private NoticeType mapNoticeType(String code) {
        if (code == null) return NoticeType.OTHER;
        return switch (code.toLowerCase()) {
            case "cn-standard", "cn-social", "cn-defence" -> NoticeType.CONTRACT_NOTICE;
            case "pin-only", "pin-rtl", "pin-cfc-standard" -> NoticeType.PRIOR_INFORMATION_NOTICE;
            case "can-standard", "can-social", "can-modif" -> NoticeType.CONTRACT_AWARD_NOTICE;
            default -> NoticeType.OTHER;
        };
    }

    private ContractNature mapContractNature(String code) {
        if (code == null) return ContractNature.UNKNOWN;
        return switch (code.toLowerCase()) {
            case "supplies" -> ContractNature.SUPPLIES;
            case "services" -> ContractNature.SERVICES;
            case "works" -> ContractNature.WORKS;
            case "mixed" -> ContractNature.MIXED;
            default -> ContractNature.UNKNOWN;
        };
    }

    private ProcedureType mapProcedureType(String code) {
        if (code == null) return ProcedureType.OTHER;
        return switch (code.toLowerCase()) {
            case "open" -> ProcedureType.OPEN;
            case "restricted" -> ProcedureType.RESTRICTED;
            case "comp-dial" -> ProcedureType.COMPETITIVE_DIALOGUE;
            case "innovation" -> ProcedureType.INNOVATION_PARTNERSHIP;
            case "neg-wo-pub" -> ProcedureType.NEGOTIATED_WITHOUT_PUBLICATION;
            case "neg-w-pub" -> ProcedureType.NEGOTIATED_WITH_PUBLICATION;
            default -> ProcedureType.OTHER;
        };
    }

    private NamespaceContext createNamespaceContext() {
        return new NamespaceContext() {
            @Override
            public String getNamespaceURI(String prefix) {
                return switch (prefix) {
                    case "cn" -> NS_CN;
                    case "cac" -> NS_CAC;
                    case "cbc" -> NS_CBC;
                    case "efac" -> NS_EFAC;
                    case "efbc" -> NS_EFBC;
                    case "efext" -> NS_EFEXT;
                    case "ext" -> NS_EXT;
                    default -> null;
                };
            }

            @Override
            public String getPrefix(String namespaceURI) {
                return null;
            }

            @Override
            public Iterator<String> getPrefixes(String namespaceURI) {
                return null;
            }
        };
    }

    /**
     * Exception thrown when XML parsing fails.
     */
    public static class XmlParsingException extends RuntimeException {
        public XmlParsingException(String message, Throwable cause) {
            super(message, cause);
        }
    }
}