//
   //  ========================================================================
   //  Copyright (c) 1995-2013 Mort Bay Consulting Pty. Ltd.
   //  ------------------------------------------------------------------------
   //  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.opensource.org/licenses/apache2.0.php
  //
  //  You may elect to redistribute this code under either of these licenses.
  //  ========================================================================
  //
  
  package org.eclipse.jetty.security;
  
  import java.io.IOException;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.HashSet;
  import java.util.List;
  import java.util.Map;
  import java.util.Map.Entry;
  import java.util.Set;
  import java.util.concurrent.CopyOnWriteArrayList;
  import java.util.concurrent.CopyOnWriteArraySet;
  
  import javax.servlet.HttpConstraintElement;
  import javax.servlet.HttpMethodConstraintElement;
  import javax.servlet.ServletSecurityElement;
  import javax.servlet.annotation.ServletSecurity.EmptyRoleSemantic;
  import javax.servlet.annotation.ServletSecurity.TransportGuarantee;
  
  import org.eclipse.jetty.http.HttpStatus;
  import org.eclipse.jetty.http.PathMap;
  import org.eclipse.jetty.server.HttpChannel;
  import org.eclipse.jetty.server.HttpConfiguration;
  import org.eclipse.jetty.server.Request;
  import org.eclipse.jetty.server.Response;
  import org.eclipse.jetty.server.UserIdentity;
  import org.eclipse.jetty.util.security.Constraint;
  
  /* ------------------------------------------------------------ */
  /**
   * Handler to enforce SecurityConstraints. This implementation is servlet spec
   * 3.0 compliant and pre-computes the constraint combinations for runtime
   * efficiency.
   *
   */
  public class ConstraintSecurityHandler extends SecurityHandler implements ConstraintAware
  {
      private static final String OMISSION_SUFFIX = ".omission";
      private static final String ALL_METHODS = "*";
      private final List<ConstraintMapping> _constraintMappings= new CopyOnWriteArrayList<>();
      private final Set<String> _roles = new CopyOnWriteArraySet<>();
      private final PathMap<Map<String, RoleInfo>> _constraintMap = new PathMap<>();
      private boolean _strict = true;
  
      /* ------------------------------------------------------------ */
      /**
       * @return
       */
      public static Constraint createConstraint()
      {
          return new Constraint();
      }
      
      /* ------------------------------------------------------------ */
      /**
       * @param constraint
       * @return
       */
      public static Constraint createConstraint(Constraint constraint)
      {
          try
          {
              return (Constraint)constraint.clone();
          }
          catch (CloneNotSupportedException e)
          {
              throw new IllegalStateException (e);
          }
      }
      
      /* ------------------------------------------------------------ */
      /**
       * Create a security constraint
       * 
       * @param name
       * @param authenticate
       * @param roles
       * @param dataConstraint
      * @return
      */
     public static Constraint createConstraint (String name, boolean authenticate, String[] roles, int dataConstraint)
     {
         Constraint constraint = createConstraint();
         if (name != null)
             constraint.setName(name);
         constraint.setAuthenticate(authenticate);
         constraint.setRoles(roles);
         constraint.setDataConstraint(dataConstraint);
         return constraint;
     }
     
 
     /* ------------------------------------------------------------ */
     /**
      * @param name
      * @param element
      * @return
      */
     public static Constraint createConstraint (String name, HttpConstraintElement element)
     {
         return createConstraint(name, element.getRolesAllowed(), element.getEmptyRoleSemantic(), element.getTransportGuarantee());     
     }
 
 
     /* ------------------------------------------------------------ */
     /**
      * @param name
      * @param rolesAllowed
      * @param permitOrDeny
      * @param transport
      * @return
      */
     public static Constraint createConstraint (String name, String[] rolesAllowed, EmptyRoleSemantic permitOrDeny, TransportGuarantee transport)
     {
         Constraint constraint = createConstraint();
         
         if (rolesAllowed == null || rolesAllowed.length==0)
         {           
             if (permitOrDeny.equals(EmptyRoleSemantic.DENY))
             {
                 //Equivalent to <auth-constraint> with no roles
                 constraint.setName(name+"-Deny");
                 constraint.setAuthenticate(true);
             }
             else
             {
                 //Equivalent to no <auth-constraint>
                 constraint.setName(name+"-Permit");
                 constraint.setAuthenticate(false);
             }
         }
         else
         {
             //Equivalent to <auth-constraint> with list of <security-role-name>s
             constraint.setAuthenticate(true);
             constraint.setRoles(rolesAllowed);
             constraint.setName(name+"-RolesAllowed");           
         } 
 
         //Equivalent to //<user-data-constraint><transport-guarantee>CONFIDENTIAL</transport-guarantee></user-data-constraint>
         constraint.setDataConstraint((transport.equals(TransportGuarantee.CONFIDENTIAL)?Constraint.DC_CONFIDENTIAL:Constraint.DC_NONE));
         return constraint; 
     }
     
     
 
     /* ------------------------------------------------------------ */
     /**
      * @param pathSpec
      * @param constraintMappings
      * @return
      */
     public static List<ConstraintMapping> getConstraintMappingsForPath(String pathSpec, List<ConstraintMapping> constraintMappings)
     {
         if (pathSpec == null || "".equals(pathSpec.trim()) || constraintMappings == null || constraintMappings.size() == 0)
             return Collections.emptyList();
         
         List<ConstraintMapping> mappings = new ArrayList<ConstraintMapping>();
         for (ConstraintMapping mapping:constraintMappings)
         {
             if (pathSpec.equals(mapping.getPathSpec()))
             {
                mappings.add(mapping);
             }
         }
         return mappings;
     }
     
     
     /* ------------------------------------------------------------ */
     /** Take out of the constraint mappings those that match the 
      * given path.
      * 
      * @param pathSpec
      * @param constraintMappings a new list minus the matching constraints
      * @return
      */
     public static List<ConstraintMapping> removeConstraintMappingsForPath(String pathSpec, List<ConstraintMapping> constraintMappings)
     {
         if (pathSpec == null || "".equals(pathSpec.trim()) || constraintMappings == null || constraintMappings.size() == 0)
             return Collections.emptyList();
         
         List<ConstraintMapping> mappings = new ArrayList<ConstraintMapping>();
         for (ConstraintMapping mapping:constraintMappings)
         {
             //Remove the matching mappings by only copying in non-matching mappings
             if (!pathSpec.equals(mapping.getPathSpec()))
             {
                mappings.add(mapping);
             }
         }
         return mappings;
     }
     
     
     
     /* ------------------------------------------------------------ */
     /** Generate Constraints and ContraintMappings for the given url pattern and ServletSecurityElement
      * 
      * @param name
      * @param pathSpec
      * @param securityElement
      * @return
      */
     public static List<ConstraintMapping> createConstraintsWithMappingsForPath (String name, String pathSpec, ServletSecurityElement securityElement)
     {
         List<ConstraintMapping> mappings = new ArrayList<ConstraintMapping>();
 
         //Create a constraint that will describe the default case (ie if not overridden by specific HttpMethodConstraints)
         Constraint constraint = ConstraintSecurityHandler.createConstraint(name, securityElement);
 
         //Create a mapping for the pathSpec for the default case
         ConstraintMapping defaultMapping = new ConstraintMapping();
         defaultMapping.setPathSpec(pathSpec);
         defaultMapping.setConstraint(constraint);  
         mappings.add(defaultMapping);
 
 
         //See Spec 13.4.1.2 p127
         List<String> methodOmissions = new ArrayList<String>();
         
         //make constraint mappings for this url for each of the HttpMethodConstraintElements
         Collection<HttpMethodConstraintElement> methodConstraints = securityElement.getHttpMethodConstraints();
         if (methodConstraints != null)
         {
             for (HttpMethodConstraintElement methodConstraint:methodConstraints)
             {
                 //Make a Constraint that captures the <auth-constraint> and <user-data-constraint> elements supplied for the HttpMethodConstraintElement
                 Constraint mconstraint = ConstraintSecurityHandler.createConstraint(name, methodConstraint);
                 ConstraintMapping mapping = new ConstraintMapping();
                 mapping.setConstraint(mconstraint);
                 mapping.setPathSpec(pathSpec);
                 if (methodConstraint.getMethodName() != null)
                 {
                     mapping.setMethod(methodConstraint.getMethodName());
                     //See spec 13.4.1.2 p127 - add an omission for every method name to the default constraint
                     methodOmissions.add(methodConstraint.getMethodName());
                 }
                 mappings.add(mapping);
             }
         }
         //See spec 13.4.1.2 p127 - add an omission for every method name to the default constraint
         if (methodOmissions.size() > 0)
             defaultMapping.setMethodOmissions(methodOmissions.toArray(new String[methodOmissions.size()]));
      
         return mappings;
     }
     
     
     
     /* ------------------------------------------------------------ */
     /** Get the strict mode.
      * @return true if the security handler is running in strict mode.
      */
     public boolean isStrict()
     {
         return _strict;
     }
 
     /* ------------------------------------------------------------ */
     /** Set the strict mode of the security handler.
      * <p>
      * When in strict mode (the default), the full servlet specification
      * will be implemented.
      * If not in strict mode, some additional flexibility in configuration
      * is allowed:<ul>
      * <li>All users do not need to have a role defined in the deployment descriptor
      * <li>The * role in a constraint applies to ANY role rather than all roles defined in
      * the deployment descriptor.
      * </ul>
      *
      * @param strict the strict to set
      * @see #setRoles(Set)
      * @see #setConstraintMappings(List, Set)
      */
     public void setStrict(boolean strict)
     {
         _strict = strict;
     }
 
     /* ------------------------------------------------------------ */
     /**
      * @return Returns the constraintMappings.
      */
     @Override
     public List<ConstraintMapping> getConstraintMappings()
     {
         return _constraintMappings;
     }
 
     /* ------------------------------------------------------------ */
     @Override
     public Set<String> getRoles()
     {
         return _roles;
     }
 
     /* ------------------------------------------------------------ */
     /**
      * Process the constraints following the combining rules in Servlet 3.0 EA
      * spec section 13.7.1 Note that much of the logic is in the RoleInfo class.
      *
      * @param constraintMappings
      *            The constraintMappings to set, from which the set of known roles
      *            is determined.
      */
     public void setConstraintMappings(List<ConstraintMapping> constraintMappings)
     {
         setConstraintMappings(constraintMappings,null);
     }
 
     /**
      * Process the constraints following the combining rules in Servlet 3.0 EA
      * spec section 13.7.1 Note that much of the logic is in the RoleInfo class.
      *
      * @param constraintMappings
      *            The constraintMappings to set as array, from which the set of known roles
      *            is determined.  Needed to retain API compatibility for 7.x
      */
     public void setConstraintMappings( ConstraintMapping[] constraintMappings )
     {
         setConstraintMappings( Arrays.asList(constraintMappings), null);
     }
 
     /* ------------------------------------------------------------ */
     /**
      * Process the constraints following the combining rules in Servlet 3.0 EA
      * spec section 13.7.1 Note that much of the logic is in the RoleInfo class.
      *
      * @param constraintMappings
      *            The constraintMappings to set.
      * @param roles The known roles (or null to determine them from the mappings)
      */
     @Override
     public void setConstraintMappings(List<ConstraintMapping> constraintMappings, Set<String> roles)
     {
         _constraintMappings.clear();
         _constraintMappings.addAll(constraintMappings);
 
         if (roles==null)
         {
             roles = new HashSet<>();
             for (ConstraintMapping cm : constraintMappings)
             {
                 String[] cmr = cm.getConstraint().getRoles();
                 if (cmr!=null)
                 {
                     for (String r : cmr)
                         if (!ALL_METHODS.equals(r))
                             roles.add(r);
                 }
             }
         }
         setRoles(roles);
         
         if (isStarted())
         {
             for (ConstraintMapping mapping : _constraintMappings)
             {
                 processConstraintMapping(mapping);
             }
         }
     }
 
     /* ------------------------------------------------------------ */
     /**
      * Set the known roles.
      * This may be overridden by a subsequent call to {@link #setConstraintMappings(ConstraintMapping[])} or
      * {@link #setConstraintMappings(List, Set)}.
      * @see #setStrict(boolean)
      * @param roles The known roles (or null to determine them from the mappings)
      */
     public void setRoles(Set<String> roles)
     {
         _roles.clear();
         _roles.addAll(roles);
     }
 
 
 
     /* ------------------------------------------------------------ */
     /**
      * @see org.eclipse.jetty.security.ConstraintAware#addConstraintMapping(org.eclipse.jetty.security.ConstraintMapping)
      */
     @Override
     public void addConstraintMapping(ConstraintMapping mapping)
     {
         _constraintMappings.add(mapping);
         if (mapping.getConstraint()!=null && mapping.getConstraint().getRoles()!=null)
             for (String role :  mapping.getConstraint().getRoles())
                 addRole(role);
 
         if (isStarted())
         {
             processConstraintMapping(mapping);
         }
     }
 
     /* ------------------------------------------------------------ */
     /**
      * @see org.eclipse.jetty.security.ConstraintAware#addRole(java.lang.String)
      */
     @Override
     public void addRole(String role)
     {
         boolean modified = _roles.add(role);
         if (isStarted() && modified && isStrict())
         {
             // Add the new role to currently defined any role role infos
             for (Map<String,RoleInfo> map : _constraintMap.values())
             {
                 for (RoleInfo info : map.values())
                 {
                     if (info.isAnyRole())
                         info.addRole(role);
                 }
             }
         }
     }
 
     /* ------------------------------------------------------------ */
     /**
      * @see org.eclipse.jetty.security.SecurityHandler#doStart()
      */
     @Override
     protected void doStart() throws Exception
     {
         _constraintMap.clear();
         if (_constraintMappings!=null)
         {
             for (ConstraintMapping mapping : _constraintMappings)
             {
                 processConstraintMapping(mapping);
             }
         }
         super.doStart();
     }
     
     
     /* ------------------------------------------------------------ */
     @Override
     protected void doStop() throws Exception
     {
         super.doStop();
         _constraintMap.clear();
     }
     
     
     /* ------------------------------------------------------------ */
     /**
      * Create and combine the constraint with the existing processed
      * constraints.
      * 
      * @param mapping
      */
     protected void processConstraintMapping(ConstraintMapping mapping)
     {
         Map<String, RoleInfo> mappings = _constraintMap.get(mapping.getPathSpec());
         if (mappings == null)
         {
             mappings = new HashMap<String,RoleInfo>();
             _constraintMap.put(mapping.getPathSpec(),mappings);
         }
         RoleInfo allMethodsRoleInfo = mappings.get(ALL_METHODS);
         if (allMethodsRoleInfo != null && allMethodsRoleInfo.isForbidden())
             return;
 
         if (mapping.getMethodOmissions() != null && mapping.getMethodOmissions().length > 0)
         {
             processConstraintMappingWithMethodOmissions(mapping, mappings);
             return;
         }
 
         String httpMethod = mapping.getMethod();
         if (httpMethod==null)
             httpMethod=ALL_METHODS;
         RoleInfo roleInfo = mappings.get(httpMethod);
         if (roleInfo == null)
         {
             roleInfo = new RoleInfo();
             mappings.put(httpMethod,roleInfo);
             if (allMethodsRoleInfo != null)
             {
                 roleInfo.combine(allMethodsRoleInfo);
             }
         }
         if (roleInfo.isForbidden())
             return;
 
         //add in info from the constraint
         configureRoleInfo(roleInfo, mapping);
         
         if (roleInfo.isForbidden())
         {
             if (httpMethod.equals(ALL_METHODS))
             {
                 mappings.clear();
                 mappings.put(ALL_METHODS,roleInfo);
             }
         }
         else
         {
             //combine with any entry that covers all methods
             if (httpMethod == null)
             {
                 for (Map.Entry<String, RoleInfo> entry : mappings.entrySet())
                 {
                     if (entry.getKey() != null)
                     {
                         RoleInfo specific = entry.getValue();
                         specific.combine(roleInfo);
                     }
                 }
             }
         }
     }
 
     /* ------------------------------------------------------------ */
     /** Constraints that name method omissions are dealt with differently.
      * We create an entry in the mappings with key "method.omission". This entry
      * is only ever combined with other omissions for the same method to produce a
      * consolidated RoleInfo. Then, when we wish to find the relevant constraints for
      *  a given Request (in prepareConstraintInfo()), we consult 3 types of entries in 
      * the mappings: an entry that names the method of the Request specifically, an
      * entry that names constraints that apply to all methods, entries of the form
      * method.omission, where the method of the Request is not named in the omission.
      * @param mapping
      * @param mappings
      */
     protected void processConstraintMappingWithMethodOmissions (ConstraintMapping mapping, Map<String, RoleInfo> mappings)
     {
         String[] omissions = mapping.getMethodOmissions();
         StringBuilder sb = new StringBuilder();
         for (int i=0; i<omissions.length; i++)
         {
             if (i > 0)
                 sb.append(".");
             sb.append(omissions[i]);
         }
         sb.append(OMISSION_SUFFIX);
 
         RoleInfo ri = new RoleInfo();
         mappings.put(sb.toString(), ri);
         configureRoleInfo(ri, mapping);
     }
 
     
     /* ------------------------------------------------------------ */
     /**
      * Initialize or update the RoleInfo from the constraint
      * @param ri
      * @param mapping
      */
     protected void configureRoleInfo (RoleInfo ri, ConstraintMapping mapping)
     {
         Constraint constraint = mapping.getConstraint();
         boolean forbidden = constraint.isForbidden();
         ri.setForbidden(forbidden);
         
         //set up the data constraint (NOTE: must be done after setForbidden, as it nulls out the data constraint
         //which we need in order to do combining of omissions in prepareConstraintInfo
         UserDataConstraint userDataConstraint = UserDataConstraint.get(mapping.getConstraint().getDataConstraint());
         ri.setUserDataConstraint(userDataConstraint);
         
 
         //if forbidden, no point setting up roles
         if (!ri.isForbidden())
         {
             //add in the roles
             boolean checked = mapping.getConstraint().getAuthenticate();
             ri.setChecked(checked);
             if (ri.isChecked())
             {
                 if (mapping.getConstraint().isAnyRole())
                  {
                      if (_strict)
                      {
                          // * means "all defined roles"
                          for (String role : _roles)
                             ri.addRole(role);
                      }
                      else
                          // * means any role
                         ri.setAnyRole(true);
                  }
                  else
                  {
                     String[] newRoles = mapping.getConstraint().getRoles();
                      for (String role : newRoles)
                      {
                          if (_strict &&!_roles.contains(role))
                              throw new IllegalArgumentException("Attempt to use undeclared role: " + role + ", known roles: " + _roles);
                         ri.addRole(role);
                      }
                  }
              }
          }
      }
 
    
     /* ------------------------------------------------------------ */
     /** 
      * Find constraints that apply to the given path.
      * In order to do this, we consult 3 different types of information stored in the mappings for each path - each mapping
      * represents a merged set of user data constraints, roles etc -:
      * <ol>
      * <li>A mapping of an exact method name </li>
      * <li>A mapping will null key that matches every method name</li>
      * <li>Mappings with keys of the form "&lt;method&gt;.&lt;method&gt;.&lt;method&gt;.omission" that indicates it will match every method name EXCEPT those given</li>
      * </ol>
      * 
      * @see org.eclipse.jetty.security.SecurityHandler#prepareConstraintInfo(java.lang.String, org.eclipse.jetty.server.Request)
      */
     @Override
     protected RoleInfo prepareConstraintInfo(String pathInContext, Request request)
     {
         Map<String, RoleInfo> mappings = (Map<String, RoleInfo>)_constraintMap.match(pathInContext);
 
         if (mappings != null)
         {
             String httpMethod = request.getMethod();
             RoleInfo roleInfo = mappings.get(httpMethod);
             if (roleInfo == null)
             {
                 //No specific http-method names matched
                 List<RoleInfo> applicableConstraints = new ArrayList<RoleInfo>();
 
                 //Get info for constraint that matches all methods if it exists
                 RoleInfo all = mappings.get(ALL_METHODS);
                 if (all != null)
                     applicableConstraints.add(all);
           
                 
                 //Get info for constraints that name method omissions where target method name is not omitted
                 //(ie matches because target method is not omitted, hence considered covered by the constraint)
                 for (Entry<String, RoleInfo> entry: mappings.entrySet())
                 {
                     if (entry.getKey() != null && entry.getKey().endsWith(OMISSION_SUFFIX) && ! entry.getKey().contains(httpMethod))
                         applicableConstraints.add(entry.getValue());
                 }
                 
                 if (applicableConstraints.size() == 1)
                     roleInfo = applicableConstraints.get(0);
                 else
                 {
                     roleInfo = new RoleInfo();
                     roleInfo.setUserDataConstraint(UserDataConstraint.None);
                     
                     for (RoleInfo r:applicableConstraints)
                         roleInfo.combine(r);
                 }
 
             }
             return roleInfo;
         }
 
         return null;
     }
 
     @Override
     protected boolean checkUserDataPermissions(String pathInContext, Request request, Response response, RoleInfo roleInfo) throws IOException
     {
         if (roleInfo == null)
             return true;
 
         if (roleInfo.isForbidden())
             return false;
 
         UserDataConstraint dataConstraint = roleInfo.getUserDataConstraint();
         if (dataConstraint == null || dataConstraint == UserDataConstraint.None)
             return true;
 
         HttpConfiguration httpConfig = HttpChannel.getCurrentHttpChannel().getHttpConfiguration();
 
 
         if (dataConstraint == UserDataConstraint.Confidential || dataConstraint == UserDataConstraint.Integral)
         {
             if (request.isSecure())
                 return true;
 
             if (httpConfig.getSecurePort() > 0)
             {
                 String scheme = httpConfig.getSecureScheme();
                 int port = httpConfig.getSecurePort();
                 String url = ("https".equalsIgnoreCase(scheme) && port==443)
                     ? "https://"+request.getServerName()+request.getRequestURI()
                     : scheme + "://" + request.getServerName() + ":" + port + request.getRequestURI();                    
                 if (request.getQueryString() != null)
                     url += "?" + request.getQueryString();
                 response.setContentLength(0);
                 response.sendRedirect(url);
             }
             else
                 response.sendError(HttpStatus.FORBIDDEN_403,"!Secure");
 
             request.setHandled(true);
             return false;
         }
         else
         {
             throw new IllegalArgumentException("Invalid dataConstraint value: " + dataConstraint);
         }
 
     }
 
     @Override
     protected boolean isAuthMandatory(Request baseRequest, Response base_response, Object constraintInfo)
     {
         return constraintInfo != null && ((RoleInfo)constraintInfo).isChecked();
     }
     
     
     /* ------------------------------------------------------------ */
     /** 
      * @see org.eclipse.jetty.security.SecurityHandler#checkWebResourcePermissions(java.lang.String, org.eclipse.jetty.server.Request, org.eclipse.jetty.server.Response, java.lang.Object, org.eclipse.jetty.server.UserIdentity)
      */
     @Override
     protected boolean checkWebResourcePermissions(String pathInContext, Request request, Response response, Object constraintInfo, UserIdentity userIdentity)
             throws IOException
     {
         if (constraintInfo == null)
         {
             return true;
         }
         RoleInfo roleInfo = (RoleInfo)constraintInfo;
 
         if (!roleInfo.isChecked())
         {
             return true;
         }
 
         if (roleInfo.isAnyRole() && request.getAuthType()!=null)
             return true;
 
         for (String role : roleInfo.getRoles())
         {
             if (userIdentity.isUserInRole(role, null))
                 return true;
         }
         return false;
     }
 
     /* ------------------------------------------------------------ */
     @Override
     public void dump(Appendable out,String indent) throws IOException
     {
         // TODO these should all be beans
         dumpBeans(out,indent,
                 Collections.singleton(getLoginService()),
                 Collections.singleton(getIdentityService()),
                 Collections.singleton(getAuthenticator()),
                 Collections.singleton(_roles),
                 _constraintMap.entrySet());
     }
 
 }