/*
 *  Licensed to the Apache Software Foundation (ASF) under one
 *  or more contributor license agreements.  See the NOTICE file
 *  distributed with this work for additional information
 *  regarding copyright ownership.  The ASF licenses this file
 *  to you 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.
 *
 */

/*
 *                        AT&T - PROPRIETARY
 *          THIS FILE CONTAINS PROPRIETARY INFORMATION OF
 *        AT&T AND IS NOT TO BE DISCLOSED OR USED EXCEPT IN
 *             ACCORDANCE WITH APPLICABLE AGREEMENTS.
 *
 *          Copyright (c) 2013 AT&T Knowledge Ventures
 *              Unpublished and Not for Publication
 *                     All Rights Reserved
 */
package org.apache.openaz.xacml.pdp.policy;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;

import org.apache.openaz.xacml.api.Decision;
import org.apache.openaz.xacml.api.Identifier;
import org.apache.openaz.xacml.api.Result;
import org.apache.openaz.xacml.api.StatusCode;
import org.apache.openaz.xacml.api.trace.Traceable;
import org.apache.openaz.xacml.pdp.eval.EvaluationContext;
import org.apache.openaz.xacml.pdp.eval.EvaluationException;
import org.apache.openaz.xacml.pdp.eval.EvaluationResult;
import org.apache.openaz.xacml.pdp.eval.MatchResult;
import org.apache.openaz.xacml.std.StdStatus;
import org.apache.openaz.xacml.std.StdStatusCode;
import org.apache.openaz.xacml.std.trace.StdTraceEvent;
import org.apache.openaz.xacml.util.StringUtils;

/**
 * PolicySet extends {@link PolicyDef} to represent a XACML PolicySet element.
 */
public class PolicySet extends PolicyDef {
    private TargetedCombinerParameterMap<Identifier, PolicySetChild> policyCombinerParameters = new TargetedCombinerParameterMap<Identifier, PolicySetChild>();
    private List<PolicySetChild> children;
    private List<CombiningElement<PolicySetChild>> combiningPolicies;
    private CombiningAlgorithm<PolicySetChild> combiningAlgorithm;

    private void ensureChildren() {
        if (this.children == null) {
            this.children = new ArrayList<PolicySetChild>();
        }
    }

    /**
     * Performs lazy evaluation of the combining parameters from this <code>Policy</code>.
     *
     * @return the <code>List</code> of <code>CombiningElement</code>s for all of the <code>Rule</code>s
     */
    protected List<CombiningElement<PolicySetChild>> getCombiningPolicies() {
        if (this.combiningPolicies == null) {
            this.combiningPolicies = new ArrayList<CombiningElement<PolicySetChild>>();
            Iterator<PolicySetChild> iterPolicies = this.getChildren();
            if (iterPolicies != null) {
                while (iterPolicies.hasNext()) {
                    PolicySetChild policySetChild = iterPolicies.next();
                    this.combiningPolicies
                        .add(new CombiningElement<PolicySetChild>(policySetChild,
                                                                  this.policyCombinerParameters
                                                                      .getCombinerParameters(policySetChild)));
                }
            }
        }
        return this.combiningPolicies;
    }

    @Override
    protected boolean validateComponent() {
        if (super.validateComponent()) {
            if (this.getPolicyCombiningAlgorithm() == null) {
                this.setStatus(StdStatusCode.STATUS_CODE_SYNTAX_ERROR, "Missing policy combining algorithm");
                return false;
            } else {
                return true;
            }
        } else {
            return false;
        }
    }

    public PolicySet(StatusCode statusCodeIn, String statusMessageIn) {
        super(statusCodeIn, statusMessageIn);
    }

    public PolicySet(StatusCode statusCodeIn) {
        super(statusCodeIn);
    }

    public PolicySet(PolicySet policySetParent) {
        super(policySetParent);
    }

    public PolicySet() {
    }

    /**
     * Gets an <code>Iterator</code> over the
     * {@link org.apache.openaz.xacml.pdp.policy.TargetedCombinerParameter}s for {@link Policy} elements in
     * this <code>PolicySet</code>.
     *
     * @return an <code>Iterator</code> over the <code>TargetedCombinerParameter</code>s for
     *         <code>Policy</code> elements in this <code>PolicySet</code>.
     */
    public Iterator<TargetedCombinerParameter<Identifier, PolicySetChild>> getPolicyCombinerParameters() {
        return this.policyCombinerParameters.getTargetedCombinerParameters();
    }

    /**
     * Sets the Policy combiner parameters for this <code>PolicySet</code> from the contents of the given
     * <code>Collection</code> of <code>TargetedCombinerParameter</code>s.
     *
     * @param policyCombinerParametersIn the <code>Collection</code> of <code>TargetedCombinerParameter</code>
     *            s.
     */
    public void setPolicyCombinerParameters(Collection<TargetedCombinerParameter<Identifier, PolicySetChild>> policyCombinerParametersIn) {
        this.policyCombinerParameters.setCombinerParameters(policyCombinerParametersIn);
    }

    public void addPolicyCombinerParameter(TargetedCombinerParameter<Identifier, PolicySetChild> policyCombinerParameter) {
        this.policyCombinerParameters.addCombinerParameter(policyCombinerParameter);
    }

    public void addPolicyCombinerParameters(Collection<TargetedCombinerParameter<Identifier, PolicySetChild>> policyCombinerParametersIn) {
        this.policyCombinerParameters.addCombinerParameters(policyCombinerParametersIn);
    }

    /**
     * Gets an <code>Iterator</code> over the <code>PolicySetChild</code> children of this
     * <code>PolicySet</code>.
     *
     * @return an <code>Iterator</code> over the <code>PolicySetChild</code> children of this
     *         <code>PolicySet</code> or null if there are none.
     */
    public Iterator<PolicySetChild> getChildren() {
        return (this.children == null ? null : this.children.iterator());
    }

    public void setChildren(Collection<PolicySetChild> policySetChildren) {
        this.children = null;
        if (policySetChildren != null) {
            this.addChildren(policySetChildren);
        }
    }

    public void addChild(PolicySetChild policySetChild) {
        this.ensureChildren();
        this.children.add(policySetChild);
    }

    public void addChildren(Collection<PolicySetChild> policySetChildren) {
        this.ensureChildren();
        this.children.addAll(policySetChildren);
    }

    /**
     * Gets the {@link org.apache.openaz.xacml.pdp.policy.CombiningAlgorithm} for
     * <code>PolicySetChild</code> children for this <code>PolicySet</code>.
     *
     * @return the <code>CombiningAlgorithm</code> for <code>PolicySetChild</code> children for this
     *         <code>PolicySet</code>.
     */
    public CombiningAlgorithm<PolicySetChild> getPolicyCombiningAlgorithm() {
        return this.combiningAlgorithm;
    }

    public void setPolicyCombiningAlgorithm(CombiningAlgorithm<PolicySetChild> combiningAlgorithmIn) {
        this.combiningAlgorithm = combiningAlgorithmIn;
    }

    @Override
    public EvaluationResult evaluate(EvaluationContext evaluationContext) throws EvaluationException {
        /*
         * First check to see if we are valid. If not, return an error status immediately
         */
        if (evaluationContext.isTracing()) {
            evaluationContext.trace(new StdTraceEvent<Object>("PolicySet", this, null));
        }
        if (!this.validate()) {
            return new EvaluationResult(new StdStatus(this.getStatusCode(), this.getStatusMessage()));
        }

        /*
         * See if we match
         */
        MatchResult thisMatchResult = this.match(evaluationContext);
        assert thisMatchResult != null;
        if (evaluationContext.isTracing()) {
            evaluationContext.trace(new StdTraceEvent<MatchResult>("Match", this, thisMatchResult));
        }
        switch (thisMatchResult.getMatchCode()) {
        case INDETERMINATE:
            return new EvaluationResult(Decision.INDETERMINATE, thisMatchResult.getStatus());
        case MATCH:
            break;
        case NOMATCH:
            return new EvaluationResult(Decision.NOTAPPLICABLE);
        }

        /*
         * Get the combining elements
         */
        List<CombiningElement<PolicySetChild>> listCombiningElements = this.getCombiningPolicies();
        assert listCombiningElements != null;

        /*
         * Run the PolicyCombiningAlgorithm
         */
        assert this.getPolicyCombiningAlgorithm() != null;
        EvaluationResult evaluationResultCombined = this.getPolicyCombiningAlgorithm()
            .combine(evaluationContext, listCombiningElements, getCombinerParameterList());
        assert evaluationResultCombined != null;

        /*
         * Add my id to the policy set identifiers
         */
        if (evaluationContext.getRequest().getReturnPolicyIdList()) {
            evaluationResultCombined.addPolicySetIdentifier(this.getIdReference());
        }

        if (evaluationResultCombined.getDecision() == Decision.DENY
            || evaluationResultCombined.getDecision() == Decision.PERMIT) {
            this.updateResult(evaluationResultCombined, evaluationContext);

        }
        if (evaluationContext.isTracing()) {
            evaluationContext.trace(new StdTraceEvent<Result>("Result", this, evaluationResultCombined));
        }
        return evaluationResultCombined;
    }

    @Override
    public String toString() {
        StringBuilder stringBuilder = new StringBuilder("{");
        stringBuilder.append("super=");
        stringBuilder.append(super.toString());

        String iteratorToDump;
        if ((iteratorToDump = StringUtils.toString(this.getPolicyCombinerParameters())) != null) {
            stringBuilder.append(",policyCombinerParameters=");
            stringBuilder.append(iteratorToDump);
        }
        if ((iteratorToDump = StringUtils.toString(this.getChildren())) != null) {
            stringBuilder.append(",children=");
            stringBuilder.append(iteratorToDump);
        }
        Object objectToDump;
        if ((objectToDump = this.getPolicyCombiningAlgorithm()) != null) {
            stringBuilder.append(",policyCombiningAlgorithm=");
            stringBuilder.append(objectToDump.toString());
        }

        stringBuilder.append('}');
        return stringBuilder.toString();
    }

    @Override
    public String getTraceId() {
        return this.getIdentifier().stringValue();
    }

    @Override
    public Traceable getCause() {
        return null;
    }
}