package org.webslinger.types;

 import java.io.InputStream;

 import java.io.IOException;

 import java.io.StringReader;

 import java.net.URL;

 import java.util.Enumeration;

 import java.util.HashMap;

 import javax.servlet.RequestDispatcher;

 import javax.servlet.ServletConfig;

 import javax.servlet.ServletContext;

 import javax.servlet.ServletException;

 import javax.servlet.ServletRequestWrapper;

 import javax.servlet.http.HttpServlet;

 import javax.servlet.http.HttpServletRequest;

 import javax.servlet.http.HttpServletResponse;

 import org.apache.commons.vfs.FileObject;

 import org.codehaus.janino.ClassBodyEvaluator;

 import org.webslinger.PathContext;

 import org.webslinger.TypeHandler;

 import org.webslinger.Webslinger;

 import org.webslinger.bsf.Compiler;

 import org.webslinger.io.Charsets;

 import org.webslinger.io.IOUtil;

 import org.webslinger.lang.ConcurrentFreezingCache;

 import org.webslinger.lang.Freezer;

 import org.webslinger.util.GeneratedResult;

 import org.webslinger.util.TTLCachedObject;

 import org.webslinger.util.TTLObject;

 public class servlet extends TypeHandler {

     protected static Object setAndGet(HttpServletRequest request, String name, Object newValue) {

         Object oldValue = request.getAttribute(name);

         request.setAttribute(name, newValue);

         return oldValue;

     }

     protected final ConcurrentFreezingCache<PathContext, String, TTLCachedObject<HttpServlet>> servlets = new ConcurrentFreezingCache<PathContext, String, TTLCachedObject<HttpServlet>>(servlet.class, "servlets", null, ConcurrentFreezingCache.SOFT, new Freezer<PathContext, String>() {

         public String freeze(PathContext pc) {

             return pc.getServletPath();

         }

     }) {

         protected TTLCachedObject<HttpServlet> createValue(Object id, String path) {

             return new CompiledServlet((PathContext) id);

         }

     };

     private final class CompiledServlet extends TTLCachedObject<HttpServlet> implements ServletConfig {

         private final PathContext pc;

         protected CompiledServlet(PathContext pc) {

             this.pc = pc;

         }

         protected long getTimestamp(HttpServlet old) throws IOException {

             FileObject file = pc.getFile();

             return file.exists() ? file.getContent().getLastModifiedTime() : NOT_EXISTANT_TIMESTAMP;

         }

         protected GeneratedResult<HttpServlet> generate(HttpServlet old) throws IOException {

             try {

                 GeneratedResult<HttpServlet> result = compile(pc);

                 result.object.init(this);

                 return result;

             } catch (IOException e) {

                 throw e;

             } catch (ServletException e) {

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

             }

         }

         public String getServletName() {

             return pc.getServletPath();

         }

         public String getInitParameter(String name) {

             try {

                 return (String) pc.getAttribute("servlet-init-" + name);

             } catch (IOException e) {

                 return null;

             }

         }

         public Enumeration getInitParameterNames() {

             throw new UnsupportedOperationException();

         }

         public ServletContext getServletContext() {

             return getContext();

         }

     }

     protected HttpServlet getServlet(Webslinger webslinger) throws IOException, ServletException {

         try {

             return servlets.get(webslinger.getPathContext()).getObject();

         } catch (RuntimeException e) {

             throw e;

         } catch (IOException e) {

             throw e;

         } catch (ServletException e) {

             throw e;

         } catch (Exception e) {

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

         }

     }

     protected GeneratedResult<HttpServlet> compile(PathContext pc) throws IOException, ServletException {

         FileObject file = pc.getFile();

         String servletName = pc.getServletPath();

         long lastModifiedTime = file.getContent().getLastModifiedTime();

         String content = IOUtil.readString(file.getContent().getInputStream(), Charsets.UTF8);

         ClassBodyEvaluator cbe = new ClassBodyEvaluator();

         cbe.setExtendedType(HttpServlet.class);

         cbe.setParentClassLoader(getContext().getClassLoader());

         StringBuilder packageName = new StringBuilder();

         StringBuilder className = new StringBuilder();

         Compiler.STANDARD_NAME_ENCODER.makePackageClassName(packageName, className, servletName);

         if (packageName.length() > 0) packageName.append('.');

         packageName.append(className);

         cbe.setClassName(packageName.toString());

         try {

             cbe.cook(servletName, new StringReader(content));

             Class clz = cbe.getClazz();

             return new GeneratedResult<HttpServlet>(lastModifiedTime, (HttpServlet) clz.newInstance());

         } catch (IOException e) {

             throw e;

         } catch (RuntimeException e) {

             throw e;

         } catch (Exception e) {

             throw new ServletException(e.getMessage(), e);

         }

     }

     public Object run(Webslinger webslinger) throws IOException, ServletException {

         HttpServlet servlet = getServlet(webslinger);

         HttpServletRequest request = webslinger.getRequest();

         HttpServletResponse response = webslinger.getResponse();

         Object servletPath = setAndGet(request, "javax.servlet.include.servlet_path", webslinger.getCurrentFile().getName().getPath());

         Object queryString = setAndGet(request, "javax.servlet.include.query_string", null);

         Object pathInfo = setAndGet(request, "javax.servlet.include.path_info", webslinger.getPathInfo());

         Object oldWebslinger = setAndGet(request, "org.webslinger.Webslinger", webslinger);

         try {

             servlet.service(request, response);

         } finally {

             request.setAttribute("javax.servlet.include.servlet_path", servletPath);

             request.setAttribute("javax.servlet.include.query_string", queryString);

             request.setAttribute("javax.servlet.include.path_info", pathInfo);

             request.setAttribute("org.webslinger.Webslinger", oldWebslinger);

         }

         return null;

     }

 }