// ========================================================================
   // Copyright (c) Webtide LLC
   // ------------------------------------------------------------------------
   // All rights reserved. This program and the accompanying materials
   // are made available under the terms of the Eclipse Public License v1.0
   // and Apache License v2.0 which accompanies this distribution.
   //
   // The Eclipse Public License is available at 
   // http://www.eclipse.org/legal/epl-v10.html
  //
  // The Apache License v2.0 is available at
  // http://www.apache.org/licenses/LICENSE-2.0.txt
  //
  // You may elect to redistribute this code under either of these licenses. 
  // ========================================================================
  package org.eclipse.jetty.deploy;
  
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.Iterator;
  import java.util.LinkedList;
  import java.util.List;
  import java.util.ListIterator;
  import java.util.Map;
  
  import org.eclipse.jetty.deploy.bindings.StandardDeployer;
  import org.eclipse.jetty.deploy.bindings.StandardStarter;
  import org.eclipse.jetty.deploy.bindings.StandardStopper;
  import org.eclipse.jetty.deploy.bindings.StandardUndeployer;
  import org.eclipse.jetty.deploy.graph.Edge;
  import org.eclipse.jetty.deploy.graph.Node;
  import org.eclipse.jetty.deploy.graph.Path;
  import org.eclipse.jetty.server.Server;
  import org.eclipse.jetty.server.handler.ContextHandlerCollection;
  import org.eclipse.jetty.util.AttributesMap;
  import org.eclipse.jetty.util.component.AbstractLifeCycle;
  import org.eclipse.jetty.util.log.Log;
  
  /**
   * The Deployment Manager.
   * <p>
   * Responsibilities:
   * <p>
   * <img src="doc-files/DeploymentManager_Roles.png">
   * <ol>
   * <li>Tracking Apps and their LifeCycle Location</li>
   * <li>Managing AppProviders and the Apps that they provide.</li>
   * <li>Executing AppLifeCycle on App based on current and desired LifeCycle Location.</li>
   * </ol>
   * <p>
   * <img src="doc-files/DeploymentManager.png">
   */
  public class DeploymentManager extends AbstractLifeCycle
  {
      /**
       * Represents a single tracked app within the deployment manager.
       */
      public class AppEntry
      {
          /**
           * Version of the app.
           * 
           * Note: Auto-increments on each {@link DeploymentManager#addApp(App)}
           */
          private int version;
  
          /**
           * The app being tracked.
           */
          private App app;
  
          /**
           * The lifecycle node location of this App
           */
          private Node lifecyleNode;
  
          /**
           * Tracking the various AppState timestamps (in system milliseconds)
           */
          private Map<Node, Long> stateTimestamps = new HashMap<Node, Long>();
  
          public App getApp()
          {
              return app;
          }
  
          public Node getLifecyleNode()
          {
              return lifecyleNode;
          }
  
          public Map<Node, Long> getStateTimestamps()
          {
              return stateTimestamps;
          }
  
          public int getVersion()
         {
             return version;
         }
 
         void setLifeCycleNode(Node node)
         {
             this.lifecyleNode = node;
             this.stateTimestamps.put(node,Long.valueOf(System.currentTimeMillis()));
         }
     }
 
     private final List<AppProvider> _providers = new ArrayList<AppProvider>();
     private final AppLifeCycle _lifecycle = new AppLifeCycle();
     private final LinkedList<AppEntry> _apps = new LinkedList<AppEntry>();
     private AttributesMap _contextAttributes = new AttributesMap();
     private ContextHandlerCollection _contexts;
     private boolean _useStandardBindings = true;
     private String _defaultLifeCycleGoal = AppLifeCycle.STARTED;
 
     /**
      * Receive an app for processing.
      * 
      * Most commonly used by the various {@link AppProvider} implementations.
      */
     public void addApp(App app)
     {
         Log.info("Deployable added: " + app.getOriginId());
         AppEntry entry = new AppEntry();
         entry.app = app;
         entry.setLifeCycleNode(_lifecycle.getNodeByName("undeployed"));
         _apps.add(entry);
 
         if (isRunning() && _defaultLifeCycleGoal != null)
         {
             // Immediately attempt to go to default lifecycle state
             this.requestAppGoal(entry,_defaultLifeCycleGoal);
         }
     }
 
     public void setAppProviders(Collection<AppProvider> providers)
     {
         if (isRunning())
             throw new IllegalStateException();
         
         _providers.clear();
         for (AppProvider provider:providers)
             _providers.add(provider);
     }
 
     public Collection<AppProvider> getAppProviders()
     {
         return Collections.unmodifiableList(_providers);
     }
     
     public void addAppProvider(AppProvider provider)
     {
         if (isRunning())
             throw new IllegalStateException();
         
         _providers.add(provider);
     }
 
     public void setLifeCycleBindings(Collection<AppLifeCycle.Binding> bindings)
     {
         if (isRunning())
             throw new IllegalStateException();
         for (AppLifeCycle.Binding b : _lifecycle.getBindings())
             _lifecycle.removeBinding(b);
         for (AppLifeCycle.Binding b : bindings)
             _lifecycle.addBinding(b);
     }
 
     public Collection<AppLifeCycle.Binding> getLifeCycleBindings()
     {
         return Collections.unmodifiableSet(_lifecycle.getBindings());
     }
     
     public void addLifeCycleBinding(AppLifeCycle.Binding binding)
     {
         _lifecycle.addBinding(binding);
     }
 
     /**
      * Convenience method to allow for insertion of nodes into the lifecycle.
      * 
      * @param existingFromNodeName
      * @param existingToNodeName
      * @param insertedNodeName
      */
     public void insertLifeCycleNode(String existingFromNodeName, String existingToNodeName, String insertedNodeName)
     {
         Node fromNode = _lifecycle.getNodeByName(existingFromNodeName);
         Node toNode = _lifecycle.getNodeByName(existingToNodeName);
         Edge edge = new Edge(fromNode,toNode);
         _lifecycle.insertNode(edge,insertedNodeName);
     }
 
     @Override
     protected void doStart() throws Exception
     {
         if (_useStandardBindings)
         {
             Log.debug("DeploymentManager using standard bindings");
             addLifeCycleBinding(new StandardDeployer());
             addLifeCycleBinding(new StandardStarter());
             addLifeCycleBinding(new StandardStopper());
             addLifeCycleBinding(new StandardUndeployer());
         }
 
         // Start all of the AppProviders
         for (AppProvider provider : _providers)
         {
             startAppProvider(provider);
         }
         super.doStart();
     }
 
     @Override
     protected void doStop() throws Exception
     {
         // Stop all of the AppProviders
         for (AppProvider provider : _providers)
         {
             try
             {
                 provider.stop();
             }
             catch (Exception e)
             {
                 Log.warn("Unable to start AppProvider",e);
             }
         }
         super.doStop();
     }
 
     private AppEntry findAppByContextId(String contextId)
     {
         if (contextId == null)
         {
             return null;
         }
 
         for (AppEntry entry : _apps)
         {
             if (contextId.equals(entry.app.getContextId()))
             {
                 return entry;
             }
         }
         return null;
     }
 
     private AppEntry findAppByOriginId(String originId)
     {
         if (originId == null)
         {
             return null;
         }
 
         for (AppEntry entry : _apps)
         {
             if (originId.equals(entry.app.getOriginId()))
             {
                 return entry;
             }
         }
         return null;
     }
 
     public App getAppByContextId(String contextId)
     {
         AppEntry entry = findAppByContextId(contextId);
         if (entry == null)
         {
             return null;
         }
         return entry.app;
     }
 
     public App getAppByOriginId(String originId)
     {
         AppEntry entry = findAppByOriginId(originId);
         if (entry == null)
         {
             return null;
         }
         return entry.app;
     }
 
     public Collection<AppEntry> getAppEntries()
     {
         return _apps;
     }
 
     public Collection<App> getApps()
     {
         List<App> ret = new ArrayList<App>();
         for (AppEntry entry : _apps)
         {
             ret.add(entry.app);
         }
         return ret;
     }
 
     /**
      * Get Set of {@link App}s by {@link Node}
      * 
      * @param node
      *            the node to look for.
      * @return the collection of apps for the node
      */
     public Collection<App> getApps(Node node)
     {
         List<App> ret = new ArrayList<App>();
         for (AppEntry entry : _apps)
         {
             if (entry.lifecyleNode == node)
             {
                 ret.add(entry.app);
             }
         }
         return ret;
     }
 
     public List<App> getAppsWithSameContext(App app)
     {
         List<App> ret = new ArrayList<App>();
         if (app == null)
         {
             return ret;
         }
 
         String contextId = app.getContextId();
         if (contextId == null)
         {
             // No context? Likely not deployed or started yet.
             return ret;
         }
 
         for (AppEntry entry : _apps)
         {
             if (entry.app.equals(app))
             {
                 // Its the input app. skip it.
                 // TODO: is this filter needed?
                 continue;
             }
 
             if (contextId.equals(entry.app.getContextId()))
             {
                 ret.add(entry.app);
             }
         }
         return ret;
     }
 
     /**
      * Get a contextAttribute that will be set for every Context deployed by this provider.
      * 
      * @param name
      * @return the context attribute value
      */
     public Object getContextAttribute(String name)
     {
         return _contextAttributes.getAttribute(name);
     }
 
     public AttributesMap getContextAttributes()
     {
         return _contextAttributes;
     }
 
     public ContextHandlerCollection getContexts()
     {
         return _contexts;
     }
 
     public String getDefaultLifeCycleGoal()
     {
         return _defaultLifeCycleGoal;
     }
 
     public AppLifeCycle getLifeCycle()
     {
         return _lifecycle;
     }
 
     public Server getServer()
     {
         if (_contexts == null)
         {
             return null;
         }
         return _contexts.getServer();
     }
 
     /**
      * Remove the app from the tracking of the DeploymentManager
      * 
      * @param app
      *            if the app is Unavailable remove it from the deployment manager.
      */
     public void removeApp(App app)
     {
         ListIterator<AppEntry> it = _apps.listIterator();
         while (it.hasNext())
         {
             AppEntry entry = it.next();
             if (entry.app.equals(app))
             {
                 if (! AppLifeCycle.UNDEPLOYED.equals(entry.lifecyleNode.getName()))
                     requestAppGoal(entry.app,AppLifeCycle.UNDEPLOYED);
                 it.remove();
                 Log.info("Deployable removed: " + entry.app);
             }
         }
     }
 
     public void removeAppProvider(AppProvider provider)
     {
         _providers.remove(provider);
         try
         {
             provider.stop();
         }
         catch (Exception e)
         {
             Log.warn("Unable to stop Provider",e);
         }
     }
 
     /**
      * Remove a contextAttribute that will be set for every Context deployed by this provider.
      * 
      * @param name
      */
     public void removeContextAttribute(String name)
     {
         _contextAttributes.removeAttribute(name);
     }
 
     /**
      * Move an {@link App} through the {@link AppLifeCycle} to the desired {@link Node}, executing each lifecycle step
      * in the process to reach the desired state.
      * 
      * @param app
      *            the app to move through the process
      * @param nodeName
      *            the name of the node to attain
      */
     public void requestAppGoal(App app, String nodeName)
     {
         AppEntry appentry = findAppByContextId(app.getContextId());
         if (appentry == null)
         {
             appentry = findAppByOriginId(app.getOriginId());
             if (appentry == null)
             {
                 throw new IllegalStateException("App not being tracked by Deployment Manager: " + app);
             }
         }
         requestAppGoal(appentry,nodeName);
     }
 
     /**
      * Move an {@link App} through the {@link AppLifeCycle} to the desired {@link Node}, executing each lifecycle step
      * in the process to reach the desired state.
      * 
      * @param appentry
      *            the internal appentry to move through the process
      * @param nodeName
      *            the name of the node to attain
      */
     private void requestAppGoal(AppEntry appentry, String nodeName)
     {
         Node destinationNode = _lifecycle.getNodeByName(nodeName);
         // Compute lifecycle steps
         Path path = _lifecycle.getPath(appentry.lifecyleNode,destinationNode);
         if (path.isEmpty())
         {
             // nothing to do. already there.
             return;
         }
 
         // Execute each Node binding.  Stopping at any thrown exception.
         try
         {
             Iterator<Node> it = path.getNodes().iterator();
             if (it.hasNext()) // Any entries?
             {
                 // The first entry in the path is always the start node
                 // We don't want to run bindings on that entry (again)
                 it.next(); // skip first entry
                 while (it.hasNext())
                 {
                     Node node = it.next();
                     Log.debug("Executing Node: " + node);
                     _lifecycle.runBindings(node,appentry.app,this);
                     appentry.setLifeCycleNode(node);
                 }
             }
         }
         catch (Throwable t)
         {
             Log.warn("Unable to reach node goal: " + nodeName,t);
         }
     }
 
     /**
      * Move an {@link App} through the {@link AppLifeCycle} to the desired {@link Node}, executing each lifecycle step
      * in the process to reach the desired state.
      * 
      * @param appId
      *            the id of the app to move through the process
      * @param nodeName
      *            the name of the node to attain
      */
     public void requestAppGoal(String appId, String nodeName)
     {
         AppEntry appentry = findAppByContextId(appId);
         if (appentry == null)
         {
             appentry = findAppByOriginId(appId);
             if (appentry == null)
             {
                 throw new IllegalStateException("App not being tracked by Deployment Manager: " + appId);
             }
         }
         requestAppGoal(appentry,nodeName);
     }
 
     /**
      * Set a contextAttribute that will be set for every Context deployed by this provider.
      * 
      * @param name
      * @param value
      */
     public void setContextAttribute(String name, Object value)
     {
         _contextAttributes.setAttribute(name,value);
     }
 
     public void setContextAttributes(AttributesMap contextAttributes)
     {
         this._contextAttributes = contextAttributes;
     }
 
     public void setContexts(ContextHandlerCollection contexts)
     {
         this._contexts = contexts;
     }
 
     public void setDefaultLifeCycleGoal(String defaultLifeCycleState)
     {
         this._defaultLifeCycleGoal = defaultLifeCycleState;
     }
 
     private void startAppProvider(AppProvider provider)
     {
         try
         {
             provider.setDeploymentManager(this);
             provider.start();
         }
         catch (Exception e)
         {
             Log.warn("Unable to start AppProvider",e);
         }
     }
 
     public void undeployAll()
     {
         Log.info("Undeploy All");
         for (AppEntry appentry : _apps)
         {
             requestAppGoal(appentry,"undeployed");
         }
     }
 
     public boolean isUseStandardBindings()
     {
         return _useStandardBindings;
     }
 
     public void setUseStandardBindings(boolean useStandardBindings)
     {
         this._useStandardBindings = useStandardBindings;
     }
 }