package org.webslinger.modules;

 import java.io.File;

 import java.io.IOException;

 import java.net.URL;

 import java.util.HashMap;

 import java.util.Iterator;

 import java.util.logging.Logger;

 import javax.xml.parsers.ParserConfigurationException;

 import org.w3c.dom.Document;

 import org.w3c.dom.Element;

 import org.w3c.dom.Node;

 import org.xml.sax.SAXException;

 import org.apache.commons.vfs.FileObject;

 import org.webslinger.xml.XmlUtil;

 public final class ModuleStateXML implements ModuleStorage {

     private static final Logger logger = Logger.getLogger(ModuleStateXML.class.getName());

     protected final FileObject file;

     protected Document moduleStateXml;

     public ModuleStateXML(FileObject file) throws IOException {

         this.file = file;

     }

     public void init(ModuleState moduleState) throws IOException {

         try {

             if (file.exists()) {

                 boolean needsSave = false;

                 moduleStateXml = XmlUtil.read(file.getContent().getInputStream());

                 Element element = moduleStateXml.getDocumentElement();

                 Iterator<Element> it = XmlUtil.getElementsNamed(element, "module").iterator();

                 while (it.hasNext()) {

                     Element moduleElement = it.next();

                     String moduleName = moduleElement.getAttribute("name");

                     moduleState.addModule(moduleName, moduleElement.getAttribute("url"));

                     Iterator<Element> it2 = XmlUtil.getElementsNamed(moduleElement, "alias").iterator();

                     while (it2.hasNext()) {

                         Element aliasElement = it2.next();

                         moduleElement.removeChild(aliasElement);

                         needsSave = true;

                     }

                     it2 = XmlUtil.getElementsNamed(moduleElement, "mount").iterator();

                     if (it2.hasNext()) {

                         while (it2.hasNext()) {

                             Element mountElement = it2.next();

                             moduleState.addModuleMount(moduleName, mountElement.getAttribute("src"), mountElement.getAttribute("dest"));

                         }

                     } else {

                         moduleState.addModuleMount(moduleName, "", "");

                     }

                 }

                 it = XmlUtil.getElementsNamed(element, "library").iterator();

                 while (it.hasNext()) {

                     Element libraryElement = it.next();

                     String libraryName = libraryElement.getAttribute("name");

                     moduleState.addLibrary(libraryName, libraryElement.getAttribute("url"));

                 }

                 it = XmlUtil.getElementsNamed(element, "module").iterator();

                 while (it.hasNext()) {

                     Element moduleElement = it.next();

                     if ("true".equals(moduleElement.getAttribute("enabled"))) moduleState.enableModule(moduleElement.getAttribute("name"));

                 }

                 if (needsSave) saveModuleState();

             } else {

                 moduleStateXml = XmlUtil.newDocument();

             }

         } catch (ParserConfigurationException e) {

             throw (IOException) new IOException(e.getMessage()).initCause(e);

         } catch (SAXException e) {

             throw (IOException) new IOException(e.getMessage()).initCause(e);

         }

     }

     protected Element findElement(String elementName, String moduleName) throws IOException {

         Node ptr = moduleStateXml.getDocumentElement().getFirstChild();

         while (ptr != null) {

             if (ptr instanceof Element && ptr.getNodeName().equals(elementName)) {

                 if (moduleName.equals(((Element) ptr).getAttribute("name"))) return (Element) ptr;

             }

             ptr = ptr.getNextSibling();

         }

         return null;

     }

     protected Element findLibraryElement(String moduleName) throws IOException {

         return findElement("module", moduleName);

     }

     protected Element findModuleElement(String moduleName) throws IOException {

         return findElement("module", moduleName);

     }

     protected Element findElementWithAttribute(String elementName, String attrName, String value) throws IOException {

         Node modulePtr = moduleStateXml.getDocumentElement().getFirstChild();

         while (modulePtr != null) {

             if (modulePtr instanceof Element && modulePtr.getNodeName().equals(elementName)) {

                 if (value.equals(((Element) modulePtr).getAttribute(attrName))) return (Element) modulePtr;

             }

             modulePtr = modulePtr.getNextSibling();

         }

         return null;

     }

     protected Element findLibraryElementWithAttribute(String attrName, String value) throws IOException {

         return findElementWithAttribute("library", attrName, value);

     }

     protected Element findModuleElementWithAttribute(String attrName, String value) throws IOException {

         return findElementWithAttribute("module", attrName, value);

     }

     protected void saveModuleState() throws IOException {

         try {

             XmlUtil.write(moduleStateXml, file.getContent().getOutputStream());

         } catch (RuntimeException e) {

             throw e;

         } catch (Exception e) {

             throw (IOException) new IOException(e.getMessage()).initCause(e);

         }

     }

     public boolean addLibrary(String name, File library) throws IOException {

         return addLibrary(name, file.getFileSystem().getFileSystemManager().toFileObject(library));

     }

     public boolean addLibrary(String name, String path) throws IOException {

         return addLibrary(name, file.getFileSystem().getFileSystemManager().resolveFile(path));

     }

     public boolean addModule(String name, File module) throws IOException {

         return addModule(name, file.getFileSystem().getFileSystemManager().toFileObject(module));

     }

     public boolean addModule(String name, String path) throws IOException {

         return addModule(name, file.getFileSystem().getFileSystemManager().resolveFile(path));

     }

     protected FileObject makeLocalFile(FileObject file) throws IOException {

         return file;

     }

     protected void deleteLocalFile(String url) throws IOException {

     }

     public boolean addLibrary(String name, FileObject file) throws IOException {

         logger.info("addLibrary(" + name + ", " + file + ")");

         Element libraryElement = findLibraryElement(name);

         String url = file.getURL().toExternalForm();

         if (libraryElement != null) {

             if (url.equals(libraryElement.getAttribute("url"))) return false;

             throw new IOException("library already exists");

         }

         libraryElement = moduleStateXml.createElement("library");

         libraryElement.setAttribute("name", name);

         libraryElement.setAttribute("url", url);

         moduleStateXml.getDocumentElement().appendChild(libraryElement);

         saveModuleState();

         return true;

     }

     public boolean addModule(String name, FileObject file) throws IOException {

         logger.info("addModule(" + name + ", " + file + ")");

         Element moduleElement = findModuleElement(name);

         String url = file.getURL().toExternalForm();

         if (moduleElement != null) {

             if (url.equals(moduleElement.getAttribute("url"))) return false;

             throw new IOException("module already exists");

         }

         moduleElement = moduleStateXml.createElement("module");

         moduleElement.setAttribute("name", name);

         moduleElement.setAttribute("url", url);

         moduleStateXml.getDocumentElement().appendChild(moduleElement);

         saveModuleState();

         return true;

     }

     public boolean removeLibrary(String name) throws IOException {

         Element libraryElement = findLibraryElement(name);

         if (libraryElement == null) return false;

         moduleStateXml.removeChild(libraryElement);

         String url = libraryElement.getAttribute("url");

         if (findLibraryElementWithAttribute("url", url) == null) {

             // no other modules reference this url, remove it from the cache

             deleteLocalFile(url);

         }

         saveModuleState();

         return true;

     }

     public boolean removeModule(String name) throws IOException {

         if (!disableModule(name)) return false;

         Element moduleElement = findModuleElement(name);

         if (moduleElement == null) return false;

         moduleStateXml.removeChild(moduleElement);

         String url = moduleElement.getAttribute("url");

         if (findModuleElementWithAttribute("url", url) == null) {

             // no other modules reference this url, remove it from the cache

             deleteLocalFile(url);

         }

         saveModuleState();

         return true;

     }

     public boolean enableModule(String name) throws IOException {

         Element moduleElement = findModuleElement(name);

         if (moduleElement == null) throw new IOException("no module found with name(" + name + ")");

         if ("true".equals(moduleElement.getAttribute("enabled"))) return false;

         moduleElement.setAttribute("enabled", "true");

         saveModuleState();

         return true;

     }

     public boolean disableModule(String name) throws IOException {

         Element moduleElement = findModuleElement(name);

         if (moduleElement == null) throw new IOException("no module found with name(" + name + ")");

         if ("false".equals(moduleElement.getAttribute("enabled"))) return false;

         moduleElement.removeAttribute("enabled");

         saveModuleState();

         return true;

     }

     public boolean addModuleMount(String name, String src, String dest) throws IOException {

         Element moduleElement = findModuleElement(name);

         if (moduleElement == null) throw new IOException("no module found with name(" + name + ")");

         Node modulePtr = moduleElement.getFirstChild();

         while (modulePtr != null) {

             if (modulePtr instanceof Element && modulePtr.getNodeName().equals("mount")) {

                 Element mountElement = (Element) modulePtr;

                 if (dest.equals(mountElement.getAttribute("dest"))) {

                     if (src.equals(mountElement.getAttribute("src"))) throw new IOException("Something already mounted on (" + dest + ") for module (" + name + ")");

                     return false;

                 }

             }

             modulePtr = modulePtr.getNextSibling();

         }

         Element mountElement = moduleStateXml.createElement("mount");

         mountElement.setAttribute("src", src);

         mountElement.setAttribute("dest", dest);

         moduleElement.appendChild(mountElement);

         saveModuleState();

         return true;

     }

     public boolean removeModuleMount(String name, String dest) throws IOException {

         Element moduleElement = findModuleElement(name);

         if (moduleElement == null) throw new IOException("no module found with name(" + name + ")");

         Node modulePtr = moduleElement.getFirstChild();

         while (modulePtr != null) {

             if (modulePtr instanceof Element && modulePtr.getNodeName().equals("mount")) {

                 Element mountElement = (Element) modulePtr;

                 if (dest.equals(mountElement.getAttribute("dest"))) {

                     moduleElement.removeChild(mountElement);

                     saveModuleState();

                     return true;

                 }

             }

             modulePtr = modulePtr.getNextSibling();

         }

         return false;

     }

 }