/**
 * Copyright (c) Istituto Nazionale di Fisica Nucleare (INFN). 2006-2016
 *
 * 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
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.glite.security.voms.admin.taglib;

import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;

import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspTagException;
import javax.servlet.jsp.PageContext;

import org.glite.security.voms.admin.error.VOMSSyntaxException;
import org.glite.security.voms.admin.operations.CurrentAdmin;
import org.glite.security.voms.admin.operations.VOMSContext;
import org.glite.security.voms.admin.operations.VOMSPermission;

public class TagUtils {

  // CONSTANTS
  public static final String CONTAINER_RW_PERMISSIONS = "rw";

  public static final String CONTAINER_R_PERMISSIONS = "r";

  public static final String CONTAINER_W_PERMISSIONS = "w";

  public static boolean hasPermissions(PageContext pageContext,
    Map permissionMap) throws JspException {

    if (permissionMap.isEmpty())
      return false;

    Iterator i = permissionMap.entrySet().iterator();

    while (i.hasNext()) {

      Map.Entry entry = (Entry) i.next();
      if (!isAuthorized(pageContext, (String) entry.getKey(),
        (String) entry.getValue()))
        return false;
    }

    return true;

  }

  public static boolean isAuthorized(PageContext pageContext,
    String vomsContext, String permissions) throws JspException {

    CurrentAdmin admin = (CurrentAdmin) CurrentAdmin.instance();

    if (admin == null)
      throw new JspTagException(
        "No admin defined in the org.glite.security.voms.admin.request context!");

    return admin.hasPermissions(buildContext(vomsContext),
      buildPermissions(permissions));

  }


  public static VOMSContext buildContext(String context) throws JspException {

    if (context.equals("vo"))
      return VOMSContext.getVoContext();

    else {

      if (context.matches("^vo/.*$"))
        context = context.replace("vo", VOMSContext.getVoContext().getGroup()
          .getName());
      try {

        return VOMSContext.instance(context);

      } catch (VOMSSyntaxException e) {

        throw new JspTagException(
          "VOMS security context creation error (context: " + context + "): "
            + e.getMessage());

      } catch (IllegalArgumentException e) {

        throw new JspTagException(
          "VOMS security context creation error (context: " + context + "): "
            + e.getMessage());

      }
    }
  }

  public static VOMSPermission buildPermissions(String permission)
    throws JspException {

    try {

      if (permission.equals(CONTAINER_R_PERMISSIONS))
        return VOMSPermission.fromString("CONTAINER_READ|MEMBERSHIP_READ");

      if (permission.equals(CONTAINER_W_PERMISSIONS))
        return VOMSPermission.fromString("CONTAINER_WRITE|MEMBERSHIP_WRITE");

      if (permission.equals(CONTAINER_RW_PERMISSIONS))
        return VOMSPermission
          .fromString("CONTAINER_READ|CONTAINER_WRITE|MEMBERSHIP_READ|MEMBERSHIP_WRITE");

      return VOMSPermission.fromString(permission);

    } catch (IllegalArgumentException e) {

      throw new JspTagException("VOMS permission parse error (permission: "
        + permission + "): " + e.getMessage());

    }
  }

}