/*
 * ====================================================================
 * 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.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 */

package org.apache.http.impl.cookie;

import java.util.List;

import org.apache.http.FormattedHeader;
import org.apache.http.Header;
import org.apache.http.HeaderElement;
import org.apache.http.annotation.NotThreadSafe;
import org.apache.http.cookie.Cookie;
import org.apache.http.cookie.CookieOrigin;
import org.apache.http.cookie.CookieSpec;
import org.apache.http.cookie.MalformedCookieException;
import org.apache.http.cookie.SM;
import org.apache.http.cookie.SetCookie2;
import org.apache.http.message.ParserCursor;
import org.apache.http.util.Args;
import org.apache.http.util.CharArrayBuffer;

/**
 * 'Meta' cookie specification that picks up a cookie policy based on
 * the format of cookies sent with the HTTP response.
 *
 * @since 4.0
 */
@NotThreadSafe // CookieSpec fields are @NotThreadSafe
public class BestMatchSpec implements CookieSpec {

    private final String[] datepatterns;
    private final boolean oneHeader;

    // Cached values of CookieSpec instances
    private RFC2965Spec strict; // @NotThreadSafe
    private RFC2109Spec obsoleteStrict; // @NotThreadSafe
    private BrowserCompatSpec compat; // @NotThreadSafe

    public BestMatchSpec(final String[] datepatterns, final boolean oneHeader) {
        super();
        this.datepatterns = datepatterns == null ? null : datepatterns.clone();
        this.oneHeader = oneHeader;
    }

    public BestMatchSpec() {
        this(null, false);
    }

    private RFC2965Spec getStrict() {
        if (this.strict == null) {
             this.strict = new RFC2965Spec(this.datepatterns, this.oneHeader);
        }
        return strict;
    }

    private RFC2109Spec getObsoleteStrict() {
        if (this.obsoleteStrict == null) {
             this.obsoleteStrict = new RFC2109Spec(this.datepatterns, this.oneHeader);
        }
        return obsoleteStrict;
    }

    private BrowserCompatSpec getCompat() {
        if (this.compat == null) {
            this.compat = new BrowserCompatSpec(this.datepatterns);
        }
        return compat;
    }

    public List<Cookie> parse(
            final Header header,
            final CookieOrigin origin) throws MalformedCookieException {
        Args.notNull(header, "Header");
        Args.notNull(origin, "Cookie origin");
        HeaderElement[] helems = header.getElements();
        boolean versioned = false;
        boolean netscape = false;
        for (final HeaderElement helem: helems) {
            if (helem.getParameterByName("version") != null) {
                versioned = true;
            }
            if (helem.getParameterByName("expires") != null) {
               netscape = true;
            }
        }
        if (netscape || !versioned) {
            // Need to parse the header again, because Netscape style cookies do not correctly
            // support multiple header elements (comma cannot be treated as an element separator)
            final NetscapeDraftHeaderParser parser = NetscapeDraftHeaderParser.DEFAULT;
            final CharArrayBuffer buffer;
            final ParserCursor cursor;
            if (header instanceof FormattedHeader) {
                buffer = ((FormattedHeader) header).getBuffer();
                cursor = new ParserCursor(
                        ((FormattedHeader) header).getValuePos(),
                        buffer.length());
            } else {
                final String s = header.getValue();
                if (s == null) {
                    throw new MalformedCookieException("Header value is null");
                }
                buffer = new CharArrayBuffer(s.length());
                buffer.append(s);
                cursor = new ParserCursor(0, buffer.length());
            }
            helems = new HeaderElement[] { parser.parseHeader(buffer, cursor) };
            return getCompat().parse(helems, origin);
        } else {
            if (SM.SET_COOKIE2.equals(header.getName())) {
                return getStrict().parse(helems, origin);
            } else {
                return getObsoleteStrict().parse(helems, origin);
            }
        }
    }

    public void validate(
            final Cookie cookie,
            final CookieOrigin origin) throws MalformedCookieException {
        Args.notNull(cookie, "Cookie");
        Args.notNull(origin, "Cookie origin");
        if (cookie.getVersion() > 0) {
            if (cookie instanceof SetCookie2) {
                getStrict().validate(cookie, origin);
            } else {
                getObsoleteStrict().validate(cookie, origin);
            }
        } else {
            getCompat().validate(cookie, origin);
        }
    }

    public boolean match(final Cookie cookie, final CookieOrigin origin) {
        Args.notNull(cookie, "Cookie");
        Args.notNull(origin, "Cookie origin");
        if (cookie.getVersion() > 0) {
            if (cookie instanceof SetCookie2) {
                return getStrict().match(cookie, origin);
            } else {
                return getObsoleteStrict().match(cookie, origin);
            }
        } else {
            return getCompat().match(cookie, origin);
        }
    }

    public List<Header> formatCookies(final List<Cookie> cookies) {
        Args.notNull(cookies, "List of cookies");
        int version = Integer.MAX_VALUE;
        boolean isSetCookie2 = true;
        for (final Cookie cookie: cookies) {
            if (!(cookie instanceof SetCookie2)) {
                isSetCookie2 = false;
            }
            if (cookie.getVersion() < version) {
                version = cookie.getVersion();
            }
        }
        if (version > 0) {
            if (isSetCookie2) {
                return getStrict().formatCookies(cookies);
            } else {
                return getObsoleteStrict().formatCookies(cookies);
            }
        } else {
            return getCompat().formatCookies(cookies);
        }
    }

    public int getVersion() {
        return getStrict().getVersion();
    }

    public Header getVersionHeader() {
        return getStrict().getVersionHeader();
    }

    @Override
    public String toString() {
        return "best-match";
    }

}
