/*
    * Apache License
    * Version 2.0, January 2004
    * http://www.apache.org/licenses/
    *
    * Copyright 2008 by chenillekit.org
    *
    * 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
   */
  package org.chenillekit.access.services.impl;
  
  import org.apache.tapestry5.runtime.Component;
  import org.apache.tapestry5.services.ApplicationStateManager;
  import org.apache.tapestry5.services.ComponentSource;
  import org.apache.tapestry5.services.MetaDataLocator;
  import org.chenillekit.access.ChenilleKitAccessConstants;
  import org.chenillekit.access.WebSessionUser;
  import org.chenillekit.access.internal.ChenillekitAccessInternalUtils;
  import org.chenillekit.access.services.AccessValidator;
  import org.slf4j.Logger;
  
  /**
   *
   * @version $Id: AccessValidatorImpl.java 380 2008-12-30 10:21:52Z mlusetti $
   */
  public class AccessValidatorImpl implements AccessValidator
  {
  	private final ComponentSource componentSource;
  	private final MetaDataLocator locator;
  	private final Logger logger;
  	private final ApplicationStateManager manager;
  	private final Class<? extends WebSessionUser> sessionUser;
  
  
  	public AccessValidatorImpl(ComponentSource componentSource, MetaDataLocator locator,
  							Logger logger, ApplicationStateManager manager, Class<? extends WebSessionUser> sessionUser)
  	{
  		this.componentSource = componentSource;
  		this.locator = locator;
  		this.logger = logger;
  		this.manager = manager;
  		this.sessionUser = sessionUser;
  	}
  
  
  	/**
  	 * We check for page/component and event type access rights.
  	 * <p/>
  	 * first we check the access rights for the requested page,
  	 * if access granted, we step down to the next level, the components.
  	 *
  	 * @see org.chenillekit.access.services.AccessValidator#hasAccess(java.lang.String, java.lang.String, java.lang.String)
  	 */
  	public boolean hasAccess(String pageName, String componentId, String eventType)
  	{
  		boolean hasAccess = true;
  
  		if (logger.isDebugEnabled())
  			logger.debug(ChenilleKitAccessConstants.CHENILLEKIT_ACCESS, "check access for pageName/componentId/eventType: {}/{}/{}",
  						new Object[]{pageName, componentId, eventType});
  
  		Component page = getPage(pageName);
  
  		if (page != null)
  		{
  			hasAccess = checkForPageAccess(page);
  			if (hasAccess)
  			{
  				hasAccess = checkForComponentEventHandlerAccess(page, componentId, eventType);
  
  //				if (hasAccess)
  //				{
  //					Field[] fields = page.getClass().getDeclaredFields();
  //					for (Field field : fields)
  //					{
  //						if (field.isAnnotationPresent(Restricted.class) &&
  //								field.isAnnotationPresent(org.apache.tapestry5.annotations.Component.class))
  //						{
  //							if (logger.isDebugEnabled())
  //								logger.debug("found restricted component '{}' in page '{}'", field.getName(), pageName);
  //
  //							Component pageComponent = page.getComponentResources().getEmbeddedComponent(field.getName());
  //						}
  //					}
  //				}
  			}
  		}
  
  		return hasAccess;
  	}
  
  	private boolean checkForComponentEventHandlerAccess(Component page,
  							String componentId,String eventType)
  	{
  		boolean hasAccess = true;
 		if (componentId != null && eventType != null)
 		{
 			try {
 				String groupMeta = ChenillekitAccessInternalUtils.buildMetaForHandlerMethod(componentId,
 						eventType,
 						ChenilleKitAccessConstants.RESTRICTED_EVENT_HANDLER_GROUPS_SUFFIX);
 
 				String roleMeta = ChenillekitAccessInternalUtils.buildMetaForHandlerMethod(componentId,
 						eventType,
 						ChenilleKitAccessConstants.RESTRICTED_EVENT_HANDLER_ROLE_SUFFIX);
 
 				String groups = locator.findMeta(groupMeta, page.getComponentResources(), String.class);
 				Integer role = locator.findMeta(roleMeta, page.getComponentResources(), Integer.class);
 
 				hasAccess = hasAccess(groups, role, page);
 
 			} catch (RuntimeException re)
 			{
 				// FIXME Swallow?
 			}
 		}
 
 		return hasAccess;
 
 	}
 
 	/**
 	 * check for page restriction, and if page restricted we check for users access rights.
 	 *
 	 * @param page the page(component) object
 	 *
 	 * @return true if user has access or the page is not restricted
 	 */
 	private boolean checkForPageAccess(Component page)
 	{
 		String groups = locator.findMeta(ChenilleKitAccessConstants.RESTRICTED_PAGE_GROUP, page.getComponentResources(), String.class);
 		Integer role = locator.findMeta(ChenilleKitAccessConstants.RESTRICTED_PAGE_ROLE, page.getComponentResources(), Integer.class);
 
 		if (logger.isDebugEnabled())
 		{
 			logger.debug("Page  : " + page.getComponentResources().getPageName());
 			logger.debug("Groups: " + groups);
 			logger.debug("Role  : " + role);
 		}
 
 		return hasAccess(groups, role, page);
 	}
 
 	private boolean hasAccess(String groups, Integer role, Component page)
 	{
 		if (groups.equals(ChenilleKitAccessConstants.NO_RESTRICTION) && role.equals(Integer.valueOf(0)))
 		{
 			return true;
 		}
 
 		boolean hasAccess = true;
 
 		if (groups != null || role != null)
 		{
 			WebSessionUser webSessionUser = manager.getIfExists(sessionUser);
 
 			if (webSessionUser == null)
 			{
 				if (logger.isDebugEnabled())
 					logger.debug( "No user defined just yet" );
 				return false;
 			}
 
 			boolean hasGroup = true;
 			if (groups != null)
 			{
 				if (logger.isDebugEnabled())
 					logger.debug("groups "+webSessionUser.getGroups()+" section "+groups);
 				hasGroup = ChenillekitAccessInternalUtils.hasUserRequiredGroup(webSessionUser.getGroups(),
 								ChenillekitAccessInternalUtils.getStringAsStringArray(groups));
 			}
 
 			boolean hasRole = true;
 			if (role != null)
 			{
 				if (logger.isDebugEnabled())
 					logger.debug("role "+webSessionUser.getRoleWeight()+">="+role);
 				hasRole = ChenillekitAccessInternalUtils.hasUserRequiredRole(webSessionUser.getRoleWeight(),
 								role);
 			}
 
 			hasAccess = hasGroup && hasRole;
 
 			if (logger.isDebugEnabled())
 			{
 				logger.debug("Page '{}' - hasRole = {} / hasGroup = {}",
 						new Object[]{page.getComponentResources().getPageName(), hasRole, hasGroup});
 			}
 		}
 		else
 		{
 			// XXX Notify?
 		}
 
 		return hasAccess;
 
 	}
 
 	/**
 	 * get the page component.
 	 *
 	 * @param pageName the name of page
 	 *
 	 * @return may be null if not found
 	 */
 	private Component getPage(String pageName)
 	{
 		Component component = null;
 
 		// This should be unnecessary...
 		boolean found = false;
 		while (!found)
 		{
 			try
 			{
 				component = componentSource.getPage(pageName);
 				found = true;
 			}
 			catch (IllegalArgumentException iae)
 			{
 				if (pageName.lastIndexOf('/') != -1)
 				{
 					pageName = pageName.substring(0, pageName.lastIndexOf('/'));
 					if (logger.isTraceEnabled())
 						logger.trace(ChenilleKitAccessConstants.CHENILLEKIT_ACCESS, "New pagename: {}", pageName);
 				}
 				else
 				{
 					throw iae;
 				}
 			}
 		}
 
 		return component;
 	}
 
 }