/*
 * Copyright 2015 Red Hat, Inc. and/or its affiliates.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * 
 *      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.eclipse.webdav.internal.authentication;

import java.util.Hashtable;
import org.eclipse.webdav.client.Policy;

/**
 * Parses the HTTP "Authentication-Info" header field. The header field
 * has the following form:
 *
 * <code>
 * auth-info        = 1#(nextnonce | [ message-qop ]
 *                         | [ response-auth ] | [ cnonce ]
 *                         | [ nonce-count ] )
 * nextnonce        = "nextnonce" "=" nonce-value
 * nonce-value        = quoted-string
 * message-qop        = "qop" "=" qop-value
 * qop-value        = "auth" | "auth-int" | token
 * response-auth    = "rspauth" "=" response-digest
 * response-digest    = <"> *LHEX <">
 * cnonce            = "cnonce" "=" cnonce-value
 * cnonce-value        = nonce-value
 * nonce-count        = "nc" "=" nc-value
 * nc-value            = 8LHEX
 * </code>
 *
 * An auth-info may look like this:
 *
 * <code>
 * Authentication-Info:
 * nextnonce="dcd98b7102dd2f0e8b11d0f600bfb0c093",
 * qop="auth",
 * rspauth="5ccc069c403ebaf9f0171e9517f40e41",
 * cnonce="0a4f113b",
 * nc=00000001
 * </code>
 */
public class AuthenticationInfo {
    private String authInfo;
    private Parser parser;
    private Hashtable info;

    /**
     * Parses the given authentication info.
     *
     * @param authInfo
     * @throws ParserException if the info is malformed
     */
    public AuthenticationInfo(String authInfo) throws ParserException {
        this.authInfo = authInfo;
        this.parser = new Parser(authInfo);
        parse();
    }

    /**
     * Returns the value of the cnonce parameter, or <code>null</code> if
     * the parameter does not exist.
     */
    public String getCNonce() {
        return (String) info.get("cnonce"); //$NON-NLS-1$
    }

    /**
     * Returns the value of the qop parameter, or <code>null</code> if
     * the parameter does not exist.
     */
    public String getMessageQop() {
        return (String) info.get("qop"); //$NON-NLS-1$
    }

    /**
     * Returns the value of the nextnonce parameter, which must exist.
     */
    public String getNextNonce() {
        return (String) info.get("nextnonce"); //$NON-NLS-1$
    }

    /**
     * Returns the value of the nc parameter, or <code>null</code> if
     * the parameter does not exist.
     */
    public String getNonceCount() {
        return (String) info.get("nc"); //$NON-NLS-1$
    }

    /**
     * Returns the value of the rspauth parameter, or <code>null</code> if
     * the parameter does not exist.
     */
    public String getResponseAuth() {
        return (String) info.get("rspauth"); //$NON-NLS-1$
    }

    private void parse() throws ParserException {
        info = new Hashtable(5);

        boolean done = false;
        while (!done) {
            String param = parser.nextToken();
            parser.match('=');
            String value = null;
            parser.checkPosition();
            if (authInfo.charAt(parser.pos) == '"') { //$NON-NLS-1$
                value = parser.nextQuotedString();
            } else {
                value = parser.nextToken();
            }
            info.put(param, value);
            parser.skipWhiteSpace();
            done = parser.pos == authInfo.length();
            if (!done) {
                parser.match(',');
                parser.skipWhiteSpace();
            }
        }

        if (getNextNonce() == null) {
            throw new ParserException(Policy.bind("exception.missingNextnonce")); //$NON-NLS-1$
        }
    }
}
