package org.webslinger;

 import java.io.IOException;

 import java.util.ArrayList;

 import java.util.Arrays;

 import java.util.HashMap;

 import java.util.Iterator;

 import java.util.Map;

 import java.util.Set;

 import java.util.concurrent.Callable;

 import java.util.concurrent.ExecutionException;

 import java.util.concurrent.Future;

 import javax.servlet.ServletConfig;

 import javax.servlet.ServletContext;

 import javax.servlet.ServletException;

 import javax.servlet.http.HttpServletRequest;

 import javax.servlet.http.HttpServletResponse;

 import org.apache.commons.vfs.FileObject;

 import org.apache.commons.vfs.FileSystemManager;

 import org.webslinger.lang.ConcurrentFreezableCache;

 import org.webslinger.lang.ExecutionPool;

 import org.webslinger.lang.Freezable;

 import org.webslinger.util.TTLObject;

 public abstract class AbstractMappingWebslingerServletContextFactory extends AbstractWebslingerServletContextFactory {

     static {

         TTLObject.setDefaultTTLForClass(ContextTTLObject.class, 60000);

     }

     protected final ConcurrentFreezableCache<String, ContextTTLObject> contextMapping = new ConcurrentFreezableCache<String, ContextTTLObject>(AbstractMappingWebslingerServletContextFactory.class, "contextMapping", null, ConcurrentFreezableCache.SOFT) {

         protected ContextTTLObject createValue(Object key, String hostName) {

             return new ContextTTLObject(hostName, ((MappingKey) key).contextPath);

         }

     };

     protected final ConcurrentFreezableCache<ContextKey, WebslingerServletContext> contexts = new ConcurrentFreezableCache<ContextKey, WebslingerServletContext>(AbstractMappingWebslingerServletContextFactory.class, "contexts", null, ConcurrentFreezableCache.SOFT) {

         protected WebslingerServletContext createValue(Object key, ContextKey frozen) throws Exception {

             return newWebslingerServletContext(((LayoutKey) key).layout);

         }

     };

     protected String moduleBase;

     public void init(ServletConfig config, String moduleBase) throws ServletException, IOException {

         this.moduleBase = moduleBase;

         ArrayList<Future> futures = new ArrayList<Future>();

         try {

             for (final Layout layout: getStartLayouts()) {

                 futures.add(ExecutionPool.submit(new Callable<Void>() {

                     public Void call() throws Exception {

                         WebslingerServletContext context = contexts.get(new LayoutKey(layout));

                         initializeContext(context, layout);

                         return null;

                     }

                 }));

             }

             try {

                 for (Future future: futures) {

                     future.get();

                 }

             } catch (ExecutionException e) {

                 throw e.getCause();

             }

         } catch (RuntimeException e) {

             throw e;

         } catch (IOException e) {

             throw e;

         } catch (ServletException e) {

             throw e;

         } catch (Error e) {

             throw e;

         } catch (Throwable e) {

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

         }

     }

     protected abstract Layout[] getStartLayouts() throws Exception;

     public void destroy() {

     }

     protected static final class MappingKey implements Freezable<String> {

         protected final String hostName;

         protected final String contextPath;

         protected MappingKey(String hostName, String contextPath) {

             this.hostName = hostName;

             this.contextPath = contextPath;

         }

         public String freeze() {

             return hostName;

         }

     }

     public WebslingerServletContext getWebslingerServletContext(HttpServletRequest request, HttpServletResponse response) throws ServletException {

         String hostName = request.getServerName();

         String contextPath = request.getContextPath();

         if (contextPath == null || contextPath.length() == 0) contextPath = "/";

         try {

             ContextTTLObject holder = contextMapping.get(new MappingKey(hostName, contextPath));

             WebslingerServletContext context = holder.getObject();

             initializeRequest(context, request);

             return context;

         } catch (RuntimeException e) {

             throw e;

         } catch (Exception e) {

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

         }

     }

     protected interface Layout {

         String getId();

         String getTarget();

         String[] getBases();

     }

     // Note: contextPath never changes, we just have to fetch it from a request.

     protected WebslingerServletContext getContext(String hostName, String contextPath) throws Exception {

         Layout layout = findLayout(hostName, contextPath);

         WebslingerServletContext context = contexts.get(new LayoutKey(layout));

         initializeContext(context, layout);

         return context;

     }

     protected void initializeContext(WebslingerServletContext context, Layout layout) throws Exception {

     }

     protected WebslingerServletContext newWebslingerServletContext(Layout layout) throws Exception {

         FileObject root = getRoot(layout.getTarget(), moduleBase);

         return newWebslingerServletContext(layout.getId(), root, resolveBases(root.getFileSystem().getFileSystemManager(), layout.getBases()));

     }

     protected FileObject[] resolveBases(FileSystemManager fsm, String[] bases) throws IOException {

         FileObject[] fileBases = new FileObject[bases.length];

         for (int i = 0; i < fileBases.length; i++) {

             fileBases[i] = fsm.resolveFile(bases[i]);

         }

         return fileBases;

     }

     protected abstract Set<String> getSuffixes() throws Exception;

     protected Layout findLayout(String hostName, String contextPath) throws Exception {

         System.err.println("findLayout(" + hostName + ", " + contextPath + ")");

         Layout layout = searchLayout(hostName, contextPath);

         if (layout != null) return layout;

 OUTER:

         while (true) {

             for (String suffix: getSuffixes()) {

                 if (hostName.endsWith(suffix)) {

                     hostName = hostName.substring(0, hostName.length() - suffix.length());

                     continue OUTER;

                 }

             }

             break;

         }

         layout = searchLayout(hostName, contextPath);

         if (layout != null) return layout;

         System.err.println("returning default");

         return searchLayout("*", contextPath);

     }

     protected Layout searchLayout(String hostName, String contextPath) throws Exception {

         System.err.println("searchLayout(" + hostName + ", " + contextPath + ")");

         StringBuilder pattern = new StringBuilder(hostName.length() + 1);

         pattern.append('.').append(hostName);

         do {

             System.err.println("1 checking(" + pattern + ")");

             Layout layout = lookupLayout(pattern.toString(), contextPath);

             if (layout != null) return layout;

             pattern.deleteCharAt(0);

             System.err.println("2 checking(" + pattern + ")");

             layout = lookupLayout(pattern.toString(), contextPath);

             if (layout != null) return layout;

             int period = pattern.indexOf(".");

             if (period == -1) break; // FIXME?

             pattern.delete(0, period);

         } while (true);

         return null;

     }

     protected abstract Layout lookupLayout(String hostName, String contextPath) throws Exception;

     private final class ContextTTLObject extends TTLObject<WebslingerServletContext> {

         protected final String hostName;

         protected final String contextPath;

         protected ContextTTLObject(String hostName, String contextPath) {

             this.hostName = hostName;

             this.contextPath = contextPath;

         }

         protected WebslingerServletContext load(WebslingerServletContext old) throws IOException {

             try {

                 return getContext(hostName, contextPath);

             } catch (IOException e) {

                 throw e;

             } catch (RuntimeException e) {

                 throw e;

             } catch (Exception e) {

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

             }

         }

     }

     private final class LayoutKey implements Freezable<ContextKey> {

         protected final Layout layout;

         protected LayoutKey(Layout layout) {

             this.layout = layout;

         }

         public ContextKey freeze() {

             return new ContextKey(layout);

         }

     }

     private final class ContextKey {

         private final String target;

         private final String[] bases;

         private final int hashCode;

         protected ContextKey(Layout layout) {

             target = layout.getTarget();

             bases = layout.getBases();

             int hashCode = target.hashCode();

             for (String base: bases) {

                 hashCode ^= base.hashCode();

             }

             this.hashCode = hashCode;

         }

         public int hashCode() {

             return hashCode;

         }

         public boolean equals(Object o) {

             if (!(o instanceof ContextKey)) return false;

             ContextKey other = (ContextKey) o;

             if (!target.equals(other.target)) return false;

             return Arrays.equals(bases, other.bases);

         }

     }

 }