/*
 * Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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 */

package sun.security.jgss;

import org.ietf.jgss.*;
import sun.security.jgss.spi.*;
import java.util.*;
import com.sun.security.jgss.*;
import sun.security.jgss.spnego.SpNegoCredElement;

public class GSSCredentialImpl implements ExtendedGSSCredential {

    private GSSManagerImpl gssManager = null;
    private boolean destroyed = false;

    /*
     * We store all elements in a hashtable, using <oid, usage> as the
     * key. This makes it easy to locate the specific kind of credential we
     * need. The implementation needs to be optimized for the case where
     * there is just one element (tempCred).
     */
    private Hashtable<SearchKey, GSSCredentialSpi> hashtable = null;

    // XXX Optimization for single mech usage
    private GSSCredentialSpi tempCred = null;

    GSSCredentialImpl(GSSManagerImpl gssManager, int usage)
        throws GSSException {
        this(gssManager, null, GSSCredential.DEFAULT_LIFETIME,
             (Oid[]) null, usage);
    }

    GSSCredentialImpl(GSSManagerImpl gssManager, GSSName name,
                             int lifetime, Oid mech, int usage)
        throws GSSException {
        if (mech == null) mech = ProviderList.DEFAULT_MECH_OID;

        init(gssManager);
        add(name, lifetime, lifetime, mech, usage);
    }

    GSSCredentialImpl(GSSManagerImpl gssManager, GSSName name,
                      int lifetime, Oid mechs[], int usage)
        throws GSSException {
        init(gssManager);
        boolean defaultList = false;
        if (mechs == null) {
            mechs = gssManager.getMechs();
            defaultList = true;
        }

        for (int i = 0; i < mechs.length; i++) {
            try {
                add(name, lifetime, lifetime, mechs[i], usage);
            } catch (GSSException e) {
                if (defaultList) {
                    // Try the next mechanism
                    GSSUtil.debug("Ignore " + e + " while acquring cred for "
                        + mechs[i]);
                    //e.printStackTrace();
                } else throw e; // else try the next mechanism
            }
        }
        if ((hashtable.size() == 0) || (usage != getUsage()))
            throw new GSSException(GSSException.NO_CRED);
    }

    // Wrap a mech cred into a GSS cred
    public GSSCredentialImpl(GSSManagerImpl gssManager,
                      GSSCredentialSpi mechElement) throws GSSException {

        init(gssManager);
        int usage = GSSCredential.ACCEPT_ONLY;
        if (mechElement.isInitiatorCredential()) {
            if (mechElement.isAcceptorCredential()) {
                usage = GSSCredential.INITIATE_AND_ACCEPT;
            } else {
                usage = GSSCredential.INITIATE_ONLY;
            }
        }
        SearchKey key = new SearchKey(mechElement.getMechanism(),
                                        usage);
        tempCred = mechElement;
        hashtable.put(key, tempCred);
        // More mechs that can use this cred, say, SPNEGO
        if (!GSSUtil.isSpNegoMech(mechElement.getMechanism())) {
            key = new SearchKey(GSSUtil.GSS_SPNEGO_MECH_OID, usage);
            hashtable.put(key, new SpNegoCredElement(mechElement));
        }
    }

    void init(GSSManagerImpl gssManager) {
        this.gssManager = gssManager;
        hashtable = new Hashtable<SearchKey, GSSCredentialSpi>(
                                                gssManager.getMechs().length);
    }

    public void dispose() throws GSSException {
        if (!destroyed) {
            GSSCredentialSpi element;
            Enumeration<GSSCredentialSpi> values = hashtable.elements();
            while (values.hasMoreElements()) {
                element = values.nextElement();
                element.dispose();
            }
            destroyed = true;
        }
    }

    public GSSCredential impersonate(GSSName name) throws GSSException {
        if (destroyed) {
            throw new IllegalStateException("This credential is " +
                                        "no longer valid");
        }
        Oid mech = tempCred.getMechanism();
        GSSNameSpi nameElement = (name == null ? null :
                                  ((GSSNameImpl)name).getElement(mech));
        GSSCredentialSpi cred = tempCred.impersonate(nameElement);
        return (cred == null ?
            null : new GSSCredentialImpl(gssManager, cred));
    }

    public GSSName getName() throws GSSException {
        if (destroyed) {
            throw new IllegalStateException("This credential is " +
                                        "no longer valid");
        }
        return GSSNameImpl.wrapElement(gssManager, tempCred.getName());
    }

    public GSSName getName(Oid mech) throws GSSException {

        if (destroyed) {
            throw new IllegalStateException("This credential is " +
                                        "no longer valid");
        }

        SearchKey key = null;
        GSSCredentialSpi element = null;

        if (mech == null) mech = ProviderList.DEFAULT_MECH_OID;

        key = new SearchKey(mech, GSSCredential.INITIATE_ONLY);
        element = hashtable.get(key);

        if (element == null) {
            key = new SearchKey(mech, GSSCredential.ACCEPT_ONLY);
            element = hashtable.get(key);
        }

        if (element == null) {
            key = new SearchKey(mech, GSSCredential.INITIATE_AND_ACCEPT);
            element = hashtable.get(key);
        }

        if (element == null) {
            throw new GSSExceptionImpl(GSSException.BAD_MECH, mech);
        }

        return GSSNameImpl.wrapElement(gssManager, element.getName());

    }

    
Returns the remaining lifetime of this credential. The remaining
lifetime is defined as the minimum lifetime, either for initiate or
for accept, across all elements contained in it. Not terribly
useful, but required by GSS-API.
/**
     * Returns the remaining lifetime of this credential. The remaining
     * lifetime is defined as the minimum lifetime, either for initiate or
     * for accept, across all elements contained in it. Not terribly
     * useful, but required by GSS-API.
     */
    public int getRemainingLifetime() throws GSSException {

        if (destroyed) {
            throw new IllegalStateException("This credential is " +
                                        "no longer valid");
        }

        SearchKey tempKey;
        GSSCredentialSpi tempCred;
        int tempLife = 0, tempInitLife = 0, tempAcceptLife = 0;
        int min = INDEFINITE_LIFETIME;

        for (Enumeration<SearchKey> e = hashtable.keys();
                                        e.hasMoreElements(); ) {
            tempKey = e.nextElement();
            tempCred = hashtable.get(tempKey);
            if (tempKey.getUsage() == INITIATE_ONLY)
                tempLife = tempCred.getInitLifetime();
            else if (tempKey.getUsage() == ACCEPT_ONLY)
                tempLife = tempCred.getAcceptLifetime();
            else {
                tempInitLife = tempCred.getInitLifetime();
                tempAcceptLife = tempCred.getAcceptLifetime();
                tempLife = (tempInitLife < tempAcceptLife ?
                            tempInitLife:
                            tempAcceptLife);
            }
            if (min > tempLife)
                min = tempLife;
        }

        return min;
    }

    public int getRemainingInitLifetime(Oid mech) throws GSSException {

        if (destroyed) {
            throw new IllegalStateException("This credential is " +
                                        "no longer valid");
        }

        GSSCredentialSpi element = null;
        SearchKey key = null;
        boolean found = false;
        int max = 0;

        if (mech == null) mech = ProviderList.DEFAULT_MECH_OID;

        key = new SearchKey(mech, GSSCredential.INITIATE_ONLY);
        element = hashtable.get(key);

        if (element != null) {
            found = true;
            if (max < element.getInitLifetime())
                max = element.getInitLifetime();
        }

        key = new SearchKey(mech, GSSCredential.INITIATE_AND_ACCEPT);
        element = hashtable.get(key);

        if (element != null) {
            found = true;
            if (max < element.getInitLifetime())
                max = element.getInitLifetime();
        }

        if (!found) {
            throw new GSSExceptionImpl(GSSException.BAD_MECH, mech);
        }

        return max;

    }

    public int getRemainingAcceptLifetime(Oid mech) throws GSSException {

        if (destroyed) {
            throw new IllegalStateException("This credential is " +
                                        "no longer valid");
        }

        GSSCredentialSpi element = null;
        SearchKey key = null;
        boolean found = false;
        int max = 0;

        if (mech == null) mech = ProviderList.DEFAULT_MECH_OID;

        key = new SearchKey(mech, GSSCredential.ACCEPT_ONLY);
        element = hashtable.get(key);

        if (element != null) {
            found = true;
            if (max < element.getAcceptLifetime())
                max = element.getAcceptLifetime();
        }

        key = new SearchKey(mech, GSSCredential.INITIATE_AND_ACCEPT);
        element = hashtable.get(key);

        if (element != null) {
            found = true;
            if (max < element.getAcceptLifetime())
                max = element.getAcceptLifetime();
        }

        if (!found) {
            throw new GSSExceptionImpl(GSSException.BAD_MECH, mech);
        }

        return max;

    }

    
Returns the usage mode for this credential. Returns
INITIATE_AND_ACCEPT if any one element contained in it supports
INITIATE_AND_ACCEPT or if two different elements exist where one
support INITIATE_ONLY and the other supports ACCEPT_ONLY.
/**
     * Returns the usage mode for this credential. Returns
     * INITIATE_AND_ACCEPT if any one element contained in it supports
     * INITIATE_AND_ACCEPT or if two different elements exist where one
     * support INITIATE_ONLY and the other supports ACCEPT_ONLY.
     */
    public int getUsage() throws GSSException {

        if (destroyed) {
            throw new IllegalStateException("This credential is " +
                                        "no longer valid");
        }

        SearchKey tempKey;
        boolean initiate = false;
        boolean accept = false;

        for (Enumeration<SearchKey> e = hashtable.keys();
                                        e.hasMoreElements(); ) {
            tempKey = e.nextElement();
            if (tempKey.getUsage() == INITIATE_ONLY)
                initiate = true;
            else if (tempKey.getUsage() == ACCEPT_ONLY)
                accept = true;
            else
                return INITIATE_AND_ACCEPT;
        }
        if (initiate) {
            if (accept)
                return INITIATE_AND_ACCEPT;
            else
                return INITIATE_ONLY;
        } else
            return ACCEPT_ONLY;
    }

    public int getUsage(Oid mech) throws GSSException {

        if (destroyed) {
            throw new IllegalStateException("This credential is " +
                                        "no longer valid");
        }

        GSSCredentialSpi element = null;
        SearchKey key = null;
        boolean initiate = false;
        boolean accept = false;

        if (mech == null) mech = ProviderList.DEFAULT_MECH_OID;

        key = new SearchKey(mech, GSSCredential.INITIATE_ONLY);
        element = hashtable.get(key);

        if (element != null) {
            initiate = true;
        }

        key = new SearchKey(mech, GSSCredential.ACCEPT_ONLY);
        element = hashtable.get(key);

        if (element != null) {
            accept = true;
        }

        key = new SearchKey(mech, GSSCredential.INITIATE_AND_ACCEPT);
        element = hashtable.get(key);

        if (element != null) {
            initiate = true;
            accept = true;
        }

        if (initiate && accept)
            return GSSCredential.INITIATE_AND_ACCEPT;
        else if (initiate)
            return GSSCredential.INITIATE_ONLY;
        else if (accept)
            return GSSCredential.ACCEPT_ONLY;
        else {
            throw new GSSExceptionImpl(GSSException.BAD_MECH, mech);
        }
    }

    public Oid[] getMechs() throws GSSException {

        if (destroyed) {
            throw new IllegalStateException("This credential is " +
                                        "no longer valid");
        }
        Vector<Oid> result = new Vector<Oid>(hashtable.size());

        for (Enumeration<SearchKey> e = hashtable.keys();
                                                e.hasMoreElements(); ) {
            SearchKey tempKey = e.nextElement();
            result.addElement(tempKey.getMech());
        }
        return result.toArray(new Oid[0]);
    }

    public void add(GSSName name, int initLifetime, int acceptLifetime,
                    Oid mech, int usage) throws GSSException {

        if (destroyed) {
            throw new IllegalStateException("This credential is " +
                                        "no longer valid");
        }
        if (mech == null) mech = ProviderList.DEFAULT_MECH_OID;

        SearchKey key = new SearchKey(mech, usage);
        if (hashtable.containsKey(key)) {
            throw new GSSExceptionImpl(GSSException.DUPLICATE_ELEMENT,
                                       "Duplicate element found: " +
                                       getElementStr(mech, usage));
        }

        // XXX If not instance of GSSNameImpl then throw exception
        // Application mixing GSS implementations
        GSSNameSpi nameElement = (name == null ? null :
                                  ((GSSNameImpl)name).getElement(mech));

        tempCred = gssManager.getCredentialElement(nameElement,
                                                   initLifetime,
                                                   acceptLifetime,
                                                   mech,
                                                   usage);
        /*
         * Not all mechanisms support the concept of one credential element
         * that can be used for both initiating and accepting a context. In
         * the event that an application requests usage INITIATE_AND_ACCEPT
         * for a credential from such a mechanism, the GSS framework will
         * need to obtain two different credential elements from the
         * mechanism, one that will have usage INITIATE_ONLY and another
         * that will have usage ACCEPT_ONLY. The mechanism will help the
         * GSS-API realize this by returning a credential element with
         * usage INITIATE_ONLY or ACCEPT_ONLY prompting it to make another
         * call to getCredentialElement, this time with the other usage
         * mode.
         */

        if (tempCred != null) {
            if (usage == GSSCredential.INITIATE_AND_ACCEPT &&
                (!tempCred.isAcceptorCredential() ||
                !tempCred.isInitiatorCredential())) {

                int currentUsage;
                int desiredUsage;

                if (!tempCred.isInitiatorCredential()) {
                    currentUsage = GSSCredential.ACCEPT_ONLY;
                    desiredUsage = GSSCredential.INITIATE_ONLY;
                } else {
                    currentUsage = GSSCredential.INITIATE_ONLY;
                    desiredUsage = GSSCredential.ACCEPT_ONLY;
                }

                key = new SearchKey(mech, currentUsage);
                hashtable.put(key, tempCred);

                tempCred = gssManager.getCredentialElement(nameElement,
                                                        initLifetime,
                                                        acceptLifetime,
                                                        mech,
                                                        desiredUsage);

                key = new SearchKey(mech, desiredUsage);
                hashtable.put(key, tempCred);
            } else {
                hashtable.put(key, tempCred);
            }
        }
    }

    public boolean equals(Object another) {

        if (destroyed) {
            throw new IllegalStateException("This credential is " +
                                        "no longer valid");
        }

        if (this == another) {
            return true;
        }

        if (!(another instanceof GSSCredentialImpl)) {
            return false;
        }

        // NOTE: The specification does not define the criteria to compare
        // credentials.
        /*
         * XXX
         * The RFC says: "Tests if this GSSCredential refers to the same
         * entity as the supplied object.  The two credentials must be
         * acquired over the same mechanisms and must refer to the same
         * principal.  Returns "true" if the two GSSCredentials refer to
         * the same entity; "false" otherwise."
         *
         * Well, when do two credentials refer to the same principal? Do
         * they need to have one GSSName in common for the different
         * GSSName's that the credential elements return? Or do all
         * GSSName's have to be in common when the names are exported with
         * their respective mechanisms for the credential elements?
         */
        return false;

    }

    
Returns a hashcode value for this GSSCredential.
Returns:
a hashCode value/**
     * Returns a hashcode value for this GSSCredential.
     *
     * @return a hashCode value
     */
    public int hashCode() {

        if (destroyed) {
            throw new IllegalStateException("This credential is " +
                                        "no longer valid");
        }

        // NOTE: The specification does not define the criteria to compare
        // credentials.
        /*
         * XXX
         * Decide on a criteria for equals first then do this.
         */
        return 1;
    }

    
Returns the specified mechanism's credential-element.
Params:
mechOid – the oid for mechanism to retrieve
initiate – boolean indicating if the function is
   to throw exception or return null when element is not
   found.
Throws:
GSSException – of invalid mechanism
Returns:
mechanism credential object/**
     * Returns the specified mechanism's credential-element.
     *
     * @param mechOid the oid for mechanism to retrieve
     * @param initiate boolean indicating if the function is
     *    to throw exception or return null when element is not
     *    found.
     * @return mechanism credential object
     * @exception GSSException of invalid mechanism
     */
    public GSSCredentialSpi getElement(Oid mechOid, boolean initiate)
        throws GSSException {

        if (destroyed) {
            throw new IllegalStateException("This credential is " +
                                        "no longer valid");
        }

        SearchKey key;
        GSSCredentialSpi element;

        if (mechOid == null) {
            /*
             * First see if the default mechanism satisfies the
             * desired usage.
             */
            mechOid = ProviderList.DEFAULT_MECH_OID;
            key = new SearchKey(mechOid,
                                 initiate? INITIATE_ONLY : ACCEPT_ONLY);
            element = hashtable.get(key);
            if (element == null) {
                key = new SearchKey(mechOid, INITIATE_AND_ACCEPT);
                element = hashtable.get(key);
                if (element == null) {
                    /*
                     * Now just return any element that satisfies the
                     * desired usage.
                     */
                    Object[] elements = hashtable.entrySet().toArray();
                    for (int i = 0; i < elements.length; i++) {
                        element = (GSSCredentialSpi)
                            ((Map.Entry)elements[i]).getValue();
                        if (element.isInitiatorCredential() == initiate)
                            break;
                    } // for loop
                }
            }
        } else {

            if (initiate)
                key = new SearchKey(mechOid, INITIATE_ONLY);
            else
                key = new SearchKey(mechOid, ACCEPT_ONLY);

            element = hashtable.get(key);

            if (element == null) {
                key = new SearchKey(mechOid, INITIATE_AND_ACCEPT);
                element = hashtable.get(key);
            }
        }

        if (element == null)
            throw new GSSExceptionImpl(GSSException.NO_CRED,
                                       "No credential found for: " +
                                       getElementStr(mechOid,
                                       initiate? INITIATE_ONLY : ACCEPT_ONLY));
        return element;
    }

    Set<GSSCredentialSpi> getElements() {
        HashSet<GSSCredentialSpi> retVal =
                        new HashSet<GSSCredentialSpi>(hashtable.size());
        Enumeration<GSSCredentialSpi> values = hashtable.elements();
        while (values.hasMoreElements()) {
            GSSCredentialSpi o = values.nextElement();
            retVal.add(o);
        }
        return retVal;
    }

    private static String getElementStr(Oid mechOid, int usage) {
        String displayString = mechOid.toString();
        if (usage == GSSCredential.INITIATE_ONLY) {
            displayString =
                displayString.concat(" usage: Initiate");
        } else if (usage == GSSCredential.ACCEPT_ONLY) {
            displayString =
                displayString.concat(" usage: Accept");
        } else {
            displayString =
                displayString.concat(" usage: Initiate and Accept");
        }
        return displayString;
    }

    public String toString() {

        if (destroyed) {
            throw new IllegalStateException("This credential is " +
                                        "no longer valid");
        }

        GSSCredentialSpi element = null;
        StringBuffer buffer = new StringBuffer("[GSSCredential: ");
        Object[] elements = hashtable.entrySet().toArray();
        for (int i = 0; i < elements.length; i++) {
            try {
                buffer.append('\n');
                element = (GSSCredentialSpi)
                    ((Map.Entry)elements[i]).getValue();
                buffer.append(element.getName());
                buffer.append(' ');
                buffer.append(element.getMechanism());
                buffer.append(element.isInitiatorCredential() ?
                              " Initiate" : "");
                buffer.append(element.isAcceptorCredential() ?
                              " Accept" : "");
                buffer.append(" [");
                buffer.append(element.getClass());
                buffer.append(']');
            } catch (GSSException e) {
                // skip to next element
            }
        }
        buffer.append(']');
        return buffer.toString();
    }

    static class SearchKey {
        private Oid mechOid = null;
        private int usage = GSSCredential.INITIATE_AND_ACCEPT;
        public SearchKey(Oid mechOid, int usage) {

            this.mechOid = mechOid;
            this.usage = usage;
        }
        public Oid getMech() {
            return mechOid;
        }
        public int getUsage() {
            return usage;
        }
        public boolean equals(Object other) {
            if (! (other instanceof SearchKey))
                return false;
            SearchKey that = (SearchKey) other;
            return ((this.mechOid.equals(that.mechOid)) &&
                    (this.usage == that.usage));
        }
        public int hashCode() {
            return mechOid.hashCode();
        }
    }

}