/*

 * 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.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

/*-

 *      news stream opener

 */

package sun.net.www;

import java.io.*;

import java.util.Collections;

import java.util.Map;

import java.util.HashMap;

import java.util.List;

import java.util.ArrayList;

import java.util.Set;

import java.util.Iterator;

import java.util.NoSuchElementException;

/** An RFC 844 or MIME message header.  Includes methods

    for parsing headers from incoming streams, fetching

    values, setting values, and printing headers.

    Key values of null are legal: they indicate lines in

    the header that don't have a valid key, but do have

    a value (this isn't legal according to the standard,

    but lines like this are everywhere). */

public

class MessageHeader {

    private String keys[];

    private String values[];

    private int nkeys;

    public MessageHeader () {

        grow();

    }

    public MessageHeader (InputStream is) throws java.io.IOException {

        parseHeader(is);

    }

    /**

     * Reset a message header (all key/values removed)

     */

    public synchronized void reset() {

        keys = null;

        values = null;

        nkeys = 0;

        grow();

    }

    /**

     * Find the value that corresponds to this key.

     * It finds only the first occurrence of the key.

     * @param k the key to find.

     * @return null if not found.

     */

    public synchronized String findValue(String k) {

        if (k == null) {

            for (int i = nkeys; --i >= 0;)

                if (keys[i] == null)

                    return values[i];

        } else

            for (int i = nkeys; --i >= 0;) {

                if (k.equalsIgnoreCase(keys[i]))

                    return values[i];

            }

        return null;

    }

    // return the location of the key

    public synchronized int getKey(String k) {

        for (int i = nkeys; --i >= 0;)

            if ((keys[i] == k) ||

                (k != null && k.equalsIgnoreCase(keys[i])))

                return i;

        return -1;

    }

    public synchronized String getKey(int n) {

        if (n < 0 || n >= nkeys) return null;

        return keys[n];

    }

    public synchronized String getValue(int n) {

        if (n < 0 || n >= nkeys) return null;

        return values[n];

    }

    /** Deprecated: Use multiValueIterator() instead.

     *

     *  Find the next value that corresponds to this key.

     *  It finds the first value that follows v. To iterate

     *  over all the values of a key use:

     *  <pre>

     *          for(String v=h.findValue(k); v!=null; v=h.findNextValue(k, v)) {

     *              ...

     *          }

     *  </pre>

     */

    public synchronized String findNextValue(String k, String v) {

        boolean foundV = false;

        if (k == null) {

            for (int i = nkeys; --i >= 0;)

                if (keys[i] == null)

                    if (foundV)

                        return values[i];

                    else if (values[i] == v)

                        foundV = true;

        } else

            for (int i = nkeys; --i >= 0;)

                if (k.equalsIgnoreCase(keys[i]))

                    if (foundV)

                        return values[i];

                    else if (values[i] == v)

                        foundV = true;

        return null;

    }

    class HeaderIterator implements Iterator<String> {

        int index = 0;

        int next = -1;

        String key;

        boolean haveNext = false;

        Object lock;

        public HeaderIterator (String k, Object lock) {

            key = k;

            this.lock = lock;

        }

        public boolean hasNext () {

            synchronized (lock) {

                if (haveNext) {

                    return true;

                }

                while (index < nkeys) {

                    if (key.equalsIgnoreCase (keys[index])) {

                        haveNext = true;

                        next = index++;

                        return true;

                    }

                    index ++;

                }

                return false;

            }

        }

        public String next() {

            synchronized (lock) {

                if (haveNext) {

                    haveNext = false;

                    return values [next];

                }

                if (hasNext()) {

                    return next();

                } else {

                    throw new NoSuchElementException ("No more elements");

                }

            }

        }

        public void remove () {

            throw new UnsupportedOperationException ("remove not allowed");

        }

    }

    /**

     * return an Iterator that returns all values of a particular

     * key in sequence

     */

    public Iterator<String> multiValueIterator (String k) {

        return new HeaderIterator (k, this);

    }

    public synchronized Map<String, List<String>> getHeaders() {

        return getHeaders(null);

    }

    public synchronized Map<String, List<String>> getHeaders(String[] excludeList) {

        boolean skipIt = false;

        Map<String, List<String>> m = new HashMap<String, List<String>>();

        for (int i = nkeys; --i >= 0;) {

            if (excludeList != null) {

                // check if the key is in the excludeList.

                // if so, don't include it in the Map.

                for (int j = 0; j < excludeList.length; j++) {

                    if ((excludeList[j] != null) &&

                        (excludeList[j].equalsIgnoreCase(keys[i]))) {

                        skipIt = true;

                        break;

                    }

                }

            }

            if (!skipIt) {

                List<String> l = m.get(keys[i]);

                if (l == null) {

                    l = new ArrayList<String>();

                    m.put(keys[i], l);

                }

                l.add(values[i]);

            } else {

                // reset the flag

                skipIt = false;

            }

        }

        for (String key : m.keySet()) {

            m.put(key, Collections.unmodifiableList(m.get(key)));

        }

        return Collections.unmodifiableMap(m);

    }

    /** Prints the key-value pairs represented by this

        header.  Also prints the RFC required blank line

        at the end. Omits pairs with a null key. */

    public synchronized void print(PrintStream p) {

        for (int i = 0; i < nkeys; i++)

            if (keys[i] != null) {

                p.print(keys[i] +

                    (values[i] != null ? ": "+values[i]: "") + "\r\n");

            }

        p.print("\r\n");

        p.flush();

    }

    /** Adds a key value pair to the end of the

        header.  Duplicates are allowed */

    public synchronized void add(String k, String v) {

        grow();

        keys[nkeys] = k;

        values[nkeys] = v;

        nkeys++;

    }

    /** Prepends a key value pair to the beginning of the

        header.  Duplicates are allowed */

    public synchronized void prepend(String k, String v) {

        grow();

        for (int i = nkeys; i > 0; i--) {

            keys[i] = keys[i-1];

            values[i] = values[i-1];

        }

        keys[0] = k;

        values[0] = v;

        nkeys++;

    }

    /** Overwrite the previous key/val pair at location 'i'

     * with the new k/v.  If the index didn't exist before

     * the key/val is simply tacked onto the end.

     */

    public synchronized void set(int i, String k, String v) {

        grow();

        if (i < 0) {

            return;

        } else if (i >= nkeys) {

            add(k, v);

        } else {

            keys[i] = k;

            values[i] = v;

        }

    }

    /** grow the key/value arrays as needed */

    private void grow() {

        if (keys == null || nkeys >= keys.length) {

            String[] nk = new String[nkeys + 4];

            String[] nv = new String[nkeys + 4];

            if (keys != null)

                System.arraycopy(keys, 0, nk, 0, nkeys);

            if (values != null)

                System.arraycopy(values, 0, nv, 0, nkeys);

            keys = nk;

            values = nv;

        }

    }

    /**

     * Remove the key from the header. If there are multiple values under

     * the same key, they are all removed.

     * Nothing is done if the key doesn't exist.

     * After a remove, the other pairs' order are not changed.

     * @param k the key to remove

     */

    public synchronized void remove(String k) {

        if(k == null) {

            for (int i = 0; i < nkeys; i++) {

                while (keys[i] == null && i < nkeys) {

                    for(int j=i; j<nkeys-1; j++) {

                        keys[j] = keys[j+1];

                        values[j] = values[j+1];

                    }

                    nkeys--;

                }

            }

        } else {

            for (int i = 0; i < nkeys; i++) {

                while (k.equalsIgnoreCase(keys[i]) && i < nkeys) {

                    for(int j=i; j<nkeys-1; j++) {

                        keys[j] = keys[j+1];

                        values[j] = values[j+1];

                    }

                    nkeys--;

                }

            }

        }

    }

    /** Sets the value of a key.  If the key already

        exists in the header, it's value will be

        changed.  Otherwise a new key/value pair will

        be added to the end of the header. */

    public synchronized void set(String k, String v) {

        for (int i = nkeys; --i >= 0;)

            if (k.equalsIgnoreCase(keys[i])) {

                values[i] = v;

                return;

            }

        add(k, v);

    }

    /** Set's the value of a key only if there is no

     *  key with that value already.

     */

    public synchronized void setIfNotSet(String k, String v) {

        if (findValue(k) == null) {

            add(k, v);

        }

    }

    /** Convert a message-id string to canonical form (strips off

        leading and trailing <>s) */

    public static String canonicalID(String id) {

        if (id == null)

            return "";

        int st = 0;

        int len = id.length();

        boolean substr = false;

        int c;

        while (st < len && ((c = id.charAt(st)) == '<' ||

                            c <= ' ')) {

            st++;

            substr = true;

        }

        while (st < len && ((c = id.charAt(len - 1)) == '>' ||

                            c <= ' ')) {

            len--;

            substr = true;

        }

        return substr ? id.substring(st, len) : id;

    }

    /** Parse a MIME header from an input stream. */

    public void parseHeader(InputStream is) throws java.io.IOException {

        synchronized (this) {

            nkeys = 0;

        }

        mergeHeader(is);

    }

    /** Parse and merge a MIME header from an input stream. */

    public void mergeHeader(InputStream is) throws java.io.IOException {

        if (is == null)

            return;

        char s[] = new char[10];

        int firstc = is.read();

        while (firstc != '\n' && firstc != '\r' && firstc >= 0) {

            int len = 0;

            int keyend = -1;

            int c;

            boolean inKey = firstc > ' ';

            s[len++] = (char) firstc;

    parseloop:{

                while ((c = is.read()) >= 0) {

                    switch (c) {

                      case ':':

                        if (inKey && len > 0)

                            keyend = len;

                        inKey = false;

                        break;

                      case '\t':

                        c = ' ';

                      case ' ':

                        inKey = false;

                        break;

                      case '\r':

                      case '\n':

                        firstc = is.read();

                        if (c == '\r' && firstc == '\n') {

                            firstc = is.read();

                            if (firstc == '\r')

                                firstc = is.read();

                        }

                        if (firstc == '\n' || firstc == '\r' || firstc > ' ')

                            break parseloop;

                        /* continuation */

                        c = ' ';

                        break;

                    }

                    if (len >= s.length) {

                        char ns[] = new char[s.length * 2];

                        System.arraycopy(s, 0, ns, 0, len);

                        s = ns;

                    }

                    s[len++] = (char) c;

                }

                firstc = -1;

            }

            while (len > 0 && s[len - 1] <= ' ')

                len--;

            String k;

            if (keyend <= 0) {

                k = null;

                keyend = 0;

            } else {

                k = String.copyValueOf(s, 0, keyend);

                if (keyend < len && s[keyend] == ':')

                    keyend++;

                while (keyend < len && s[keyend] <= ' ')

                    keyend++;

            }

            String v;

            if (keyend >= len)

                v = new String();

            else

                v = String.copyValueOf(s, keyend, len - keyend);

            add(k, v);

        }

    }

    public synchronized String toString() {

        String result = super.toString() + nkeys + " pairs: ";

        for (int i = 0; i < keys.length && i < nkeys; i++) {

            result += "{"+keys[i]+": "+values[i]+"}";

        }

        return result;

    }

}