/*
    * Themis: Java Project Framework
    * Copyright 2026. Tony Washer
    *
    * Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
   *
   * 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 io.github.tonywasher.joceanus.themis.parser.maven;
  
  import io.github.tonywasher.joceanus.oceanus.base.OceanusException;
  import io.github.tonywasher.joceanus.themis.exc.ThemisDataException;
  import io.github.tonywasher.joceanus.themis.exc.ThemisIOException;
  import io.github.tonywasher.joceanus.themis.parser.base.ThemisChar;
  import org.w3c.dom.Document;
  import org.w3c.dom.Element;
  import org.w3c.dom.Node;
  import org.xml.sax.SAXException;
  
  import javax.xml.XMLConstants;
  import javax.xml.parsers.DocumentBuilder;
  import javax.xml.parsers.DocumentBuilderFactory;
  import javax.xml.parsers.ParserConfigurationException;
  import javax.xml.xpath.XPath;
  import javax.xml.xpath.XPathConstants;
  import javax.xml.xpath.XPathExpressionException;
  import javax.xml.xpath.XPathFactory;
  import java.io.BufferedInputStream;
  import java.io.File;
  import java.io.FileInputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Objects;
  
  /**
   * Pom Parser.
   */
  public class ThemisMavenPomParser {
      /**
       * Document name.
       */
      private static final String DOC_NAME = "project";
  
      /**
       * Parent name.
       */
      private static final String PARENT_NAME = "parent";
  
      /**
       * GroupId name.
       */
      private static final String GROUP_NAME = "groupId";
  
      /**
       * Version name.
       */
      private static final String VERSION_NAME = "version";
  
      /**
       * Document path prefix.
       */
      private static final String DOC_PREFIX = "/" + DOC_NAME;
  
      /**
       * Properties XPath.
       */
      private static final String XPATH_PROPERTIES = DOC_PREFIX + "/properties";
  
      /**
       * Parent XPath.
       */
      private static final String XPATH_PARENT = DOC_PREFIX + ThemisChar.COMMENT + PARENT_NAME;
  
      /**
       * Modules XPath.
       */
      private static final String XPATH_MODULES = DOC_PREFIX + "/modules";
  
      /**
       * DependencyManagement XPath.
       */
      private static final String XPATH_DEPENDENCYMGMT = DOC_PREFIX + "/dependencyManagement/dependencies";
  
      /**
       * Dependencies XPath.
       */
      private static final String XPATH_DEPENDENCIES = DOC_PREFIX + "/dependencies";
  
     /**
      * Packaging XPath.
      */
     private static final String XPATH_PACKAGING = DOC_PREFIX + "/packaging";
 
     /**
      * XtraDirs XPath.
      */
     private static final String XPATH_XTRADIRS = DOC_PREFIX
             + "/build/plugins/plugin[artifactId='build-helper-maven-plugin']"
             + "/executions/execution/configuration/sources";
 
     /**
      * Module element.
      */
     private static final String EL_MODULE = "module";
 
     /**
      * Dependency element.
      */
     private static final String EL_DEPENDENCY = "dependency";
 
     /**
      * Source element.
      */
     private static final String EL_SOURCE = "source";
 
     /**
      * Parent groupId indication.
      */
     private static final String PARENT_GROUP = PARENT_NAME + ThemisChar.PERIOD + DOC_NAME + ThemisChar.PERIOD + GROUP_NAME;
 
     /**
      * Parent version indication.
      */
     private static final String PARENT_VERSION = PARENT_NAME + ThemisChar.PERIOD + DOC_NAME + ThemisChar.PERIOD + VERSION_NAME;
 
     /**
      * Project groupId indication.
      */
     private static final String PROJECT_GROUP = DOC_NAME + ThemisChar.PERIOD + GROUP_NAME;
 
     /**
      * Project version indication.
      */
     private static final String PROJECT_VERSION = DOC_NAME + ThemisChar.PERIOD + VERSION_NAME;
 
     /**
      * The parsed document.
      */
     private final Document theDoc;
 
     /**
      * The XPath.
      */
     private final XPath theXPath;
 
     /**
      * The PropertyCache.
      */
     private ThemisMavenPropertyCache theProperties;
 
     /**
      * Constructor.
      *
      * @param pLocation   the pomFile location      the parent pom
      * @param pProperties the properties cache
      * @throws OceanusException on error
      */
     public ThemisMavenPomParser(final File pLocation,
                                 final ThemisMavenPropertyCache pProperties) throws OceanusException {
         /* Record the cache */
         theProperties = pProperties;
 
         /* Protect against exceptions */
         try (InputStream myInputStream = new FileInputStream(pLocation);
              BufferedInputStream myInBuffer = new BufferedInputStream(myInputStream)) {
             final DocumentBuilderFactory myFactory = DocumentBuilderFactory.newInstance();
             myFactory.setFeature(XMLConstants.FEATURE_SECURE_PROCESSING, true);
             myFactory.setAttribute(XMLConstants.ACCESS_EXTERNAL_DTD, "");
             myFactory.setAttribute(XMLConstants.ACCESS_EXTERNAL_SCHEMA, "");
             final DocumentBuilder myBuilder = myFactory.newDocumentBuilder();
 
             /* Create the XPath */
             theXPath = XPathFactory.newInstance().newXPath();
 
             /* Build the document from the input stream */
             theDoc = myBuilder.parse(myInBuffer);
 
             /* Access the document element */
             final Element myDoc = theDoc.getDocumentElement();
 
             /* Check that the document name is correct */
             if (!Objects.equals(myDoc.getNodeName(), DOC_NAME)) {
                 throw new ThemisDataException("Invalid document type");
             }
 
             /* Handle exceptions */
         } catch (IOException
                  | ParserConfigurationException
                  | SAXException e) {
             throw new ThemisIOException("Exception accessing Pom file", e);
         }
     }
 
     /**
      * Read the properties into the cache.
      *
      * @throws OceanusException on error
      */
     void readProperties() throws OceanusException {
         /* Store any properties */
         final Node myProps = findNode(XPATH_PROPERTIES);
         if (myProps != null) {
             for (Node myNode = myProps.getFirstChild(); myNode != null; myNode = myNode.getNextSibling()) {
                 if (myNode instanceof Element myElement) {
                     theProperties.setProperty(myElement.getNodeName(),
                             myElement.getTextContent());
                 }
             }
         }
     }
 
     /**
      * Is this jar packaging?
      *
      * @return true/false
      * @throws OceanusException on error
      */
     boolean isJarPackaging() throws OceanusException {
         /* Obtain packaging definition if any */
         final Element myPackageEl = (Element) findNode(XPATH_PACKAGING);
         return myPackageEl == null
                 || "jar".equals(myPackageEl.getTextContent())
                 || "bundle".equals(myPackageEl.getTextContent());
     }
 
     /**
      * Obtain the parentId.
      *
      * @return the parentId (or null)
      * @throws OceanusException on error
      */
     ThemisMavenId getParent() throws OceanusException {
         /* Obtain parent definition if any */
         final Element myParentEl = (Element) findNode(XPATH_PARENT);
         final ThemisMavenId myParent = myParentEl == null
                 ? null
                 : new ThemisMavenId(theProperties, myParentEl);
 
         /* Store parent properties if we have a parent */
         if (myParent != null) {
             storeParentProperties(myParent);
         }
 
         /* Return the parent */
         return myParent;
     }
 
     /**
      * Store parent properties.
      *
      * @param pParent the parent
      */
     private void storeParentProperties(final ThemisMavenId pParent) {
         /* Store parent groupId and version */
         theProperties.setProperty(PARENT_GROUP, pParent.getGroupId());
         theProperties.setProperty(PARENT_VERSION, pParent.getVersion());
     }
 
     /**
      * Obtain the Id.
      *
      * @param pParent the parent id
      * @return the Id (or null)
      * @throws OceanusException on error
      */
     ThemisMavenId getId(final ThemisMavenId pParent) throws OceanusException {
         /* Obtain definition */
         final ThemisMavenId myProject = new ThemisMavenId(theProperties, theDoc.getDocumentElement(), pParent);
 
         /* Store self properties */
         storeSelfProperties(myProject);
 
         /* Return the id */
         return myProject;
     }
 
     /**
      * Store self properties.
      *
      * @param pProject the project
      */
     private void storeSelfProperties(final ThemisMavenId pProject) {
         /* Determine project groupId */
         String myGroupId = pProject.getGroupId();
         myGroupId = myGroupId != null ? myGroupId : theProperties.getProperty(PARENT_GROUP);
 
         /* Determine project version */
         String myVersion = pProject.getVersion();
         myVersion = myVersion != null ? myVersion : theProperties.getProperty(PARENT_VERSION);
 
         /* Store project details */
         theProperties.setProperty(PROJECT_GROUP, myGroupId);
         theProperties.setProperty(PROJECT_VERSION, myVersion);
     }
 
     /**
      * Obtain modules.
      *
      * @return the list of modules
      * @throws OceanusException on error
      */
     List<String> getModules() throws OceanusException {
         /* Process any modules */
         final List<String> myList = new ArrayList<>();
         final Node myModules = findNode(XPATH_MODULES);
         if (myModules != null) {
             /* Loop through the children */
             for (Node myChild = myModules.getFirstChild();
                  myChild != null;
                  myChild = myChild.getNextSibling()) {
                 /* Return result if we have a match */
                 if (myChild instanceof Element
                         && EL_MODULE.equals(myChild.getNodeName())) {
                     myList.add(myChild.getTextContent());
                 }
             }
         }
 
         /* Return the list */
         return myList;
     }
 
     /**
      * Get dependencyManagement.
      *
      * @return the list
      * @throws OceanusException on error
      */
     List<ThemisMavenId> getDependencyManagement() throws OceanusException {
         return getDependencies(XPATH_DEPENDENCYMGMT);
     }
 
     /**
      * Get dependencies.
      *
      * @return the list
      * @throws OceanusException on error
      */
     List<ThemisMavenId> getDependencies() throws OceanusException {
         return getDependencies(XPATH_DEPENDENCIES);
     }
 
     /**
      * Get dependencies.
      *
      * @param pPath XPath to dependencies
      * @return the list
      * @throws OceanusException on error
      */
     private List<ThemisMavenId> getDependencies(final String pPath) throws OceanusException {
         /* Process any dependencies */
         final List<ThemisMavenId> myList = new ArrayList<>();
         final Node myDependencies = findNode(pPath);
         if (myDependencies != null) {
             /* Loop through the children */
             for (Node myChild = myDependencies.getFirstChild();
                  myChild != null;
                  myChild = myChild.getNextSibling()) {
                 /* Return result if we have a match */
                 if (myChild instanceof Element myElement
                         && EL_DEPENDENCY.equals(myChild.getNodeName())) {
                     final ThemisMavenId myId = new ThemisMavenId(theProperties, myElement);
                     if (!myId.isSkippable()) {
                         myList.add(myId);
                     }
                 }
             }
         }
 
         /* Return the list */
         return myList;
     }
 
     /**
      * Get extra directories.
      *
      * @return the list
      * @throws OceanusException on error
      */
     List<String> getXtraDirs() throws OceanusException {
         /* Process any modules */
         final List<String> myList = new ArrayList<>();
         final Node myXtraDirs = findNode(XPATH_XTRADIRS);
         if (myXtraDirs != null) {
             /* Loop through the children */
             for (Node myChild = myXtraDirs.getFirstChild();
                  myChild != null;
                  myChild = myChild.getNextSibling()) {
                 /* Return result if we have a match */
                 if (myChild instanceof Element
                         && EL_SOURCE.equals(myChild.getNodeName())) {
                     myList.add(myChild.getTextContent());
                 }
             }
         }
 
         /* Return the list */
         return myList;
     }
 
     /**
      * Obtain the XPath node.
      *
      * @param pPath the Path
      * @return the Node (or null if not found)
      * @throws OceanusException on error
      */
     private Node findNode(final String pPath) throws OceanusException {
         /* Protect against exceptions */
         try {
             return (Node) theXPath.compile(pPath).evaluate(theDoc, XPathConstants.NODE);
         } catch (XPathExpressionException e) {
             throw new ThemisDataException("Exception locating XPath: " + pPath, e);
         }
     }
 }