/*

 * 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

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

/*

 * @(#)InternetHeaders.java   1.16 02/08/08

 */

package com.sun.xml.internal.messaging.saaj.packaging.mime.internet;

import com.sun.xml.internal.messaging.saaj.packaging.mime.Header;

import com.sun.xml.internal.messaging.saaj.packaging.mime.MessagingException;

import com.sun.xml.internal.messaging.saaj.packaging.mime.util.LineInputStream;

import com.sun.xml.internal.messaging.saaj.util.FinalArrayList;

import java.io.IOException;

import java.io.InputStream;

import java.util.AbstractList;

import java.util.List;

import java.util.NoSuchElementException;

/**

 * InternetHeaders is a utility class that manages RFC822 style

 * headers. Given an RFC822 format message stream, it reads lines

 * until the blank line that indicates end of header. The input stream

 * is positioned at the start of the body. The lines are stored

 * within the object and can be extracted as either Strings or

 * {@link Header} objects. <p>

 * <p/>

 * This class is mostly intended for service providers. MimeMessage

 * and MimeBody use this class for holding their headers. <p>

 * <p/>

 * <hr> <strong>A note on RFC822 and MIME headers</strong><p>

 * <p/>

 * RFC822 and MIME header fields <strong>must</strong> contain only

 * US-ASCII characters. If a header contains non US-ASCII characters,

 * it must be encoded as per the rules in RFC 2047. The MimeUtility

 * class provided in this package can be used to to achieve this.

 * Callers of the <code>setHeader</code>, <code>addHeader</code>, and

 * <code>addHeaderLine</code> methods are responsible for enforcing

 * the MIME requirements for the specified headers.  In addition, these

 * header fields must be folded (wrapped) before being sent if they

 * exceed the line length limitation for the transport (1000 bytes for

 * SMTP).  Received headers may have been folded.  The application is

 * responsible for folding and unfolding headers as appropriate. <p>

 *

 * @author John Mani

 * @author Bill Shannon

 * @see MimeUtility

 */

public final class InternetHeaders {

    private final FinalArrayList<hdr> headers = new FinalArrayList<hdr>();

    /**

     * Lazily cerated view of header lines (Strings).

     */

    private List<String> headerValueView;

    /**

     * Create an empty InternetHeaders object.

     */

    public InternetHeaders() {

    }

    /**

     * Read and parse the given RFC822 message stream till the

     * blank line separating the header from the body. The input

     * stream is left positioned at the start of the body. The

     * header lines are stored internally. <p>

     * <p/>

     * For efficiency, wrap a BufferedInputStream around the actual

     * input stream and pass it as the parameter.

     *

     * @param   is RFC822 input stream

     */

    public InternetHeaders(InputStream is) throws MessagingException {

        load(is);

    }

    /**

     * Read and parse the given RFC822 message stream till the

     * blank line separating the header from the body. Store the

     * header lines inside this InternetHeaders object. <p>

     * <p/>

     * Note that the header lines are added into this InternetHeaders

     * object, so any existing headers in this object will not be

     * affected.

     *

     * @param   is RFC822 input stream

     */

    public void load(InputStream is) throws MessagingException {

        // Read header lines until a blank line. It is valid

        // to have BodyParts with no header lines.

        String line;

        LineInputStream lis = new LineInputStream(is);

        String prevline = null; // the previous header line, as a string

        // a buffer to accumulate the header in, when we know it's needed

        StringBuilder lineBuffer = new StringBuilder();

        try {

            //while ((line = lis.readLine()) != null) {

            do {

                line = lis.readLine();

                if (line != null &&

                        (line.startsWith(" ") || line.startsWith("\t"))) {

                    // continuation of header

                    if (prevline != null) {

                        lineBuffer.append(prevline);

                        prevline = null;

                    }

                    lineBuffer.append("\r\n");

                    lineBuffer.append(line);

                } else {

                    // new header

                    if (prevline != null)

                        addHeaderLine(prevline);

                    else if (lineBuffer.length() > 0) {

                        // store previous header first

                        addHeaderLine(lineBuffer.toString());

                        lineBuffer.setLength(0);

                    }

                    prevline = line;

                }

            } while (line != null && line.length() > 0);

        } catch (IOException ioex) {

            throw new MessagingException("Error in input stream", ioex);

        }

    }

    /**

     * Return all the values for the specified header. The

     * values are String objects.  Returns <code>null</code>

     * if no headers with the specified name exist.

     *

     * @param   name header name

     * @return          array of header values, or null if none

     */

    public String[] getHeader(String name) {

        // XXX - should we just step through in index order?

        FinalArrayList<String> v = new FinalArrayList<String>(); // accumulate return values

        int len = headers.size();

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

            hdr h = headers.get(i);

            if (name.equalsIgnoreCase(h.name)) {

                v.add(h.getValue());

            }

        }

        if (v.size() == 0)

            return (null);

        // convert Vector to an array for return

        return v.toArray(new String[v.size()]);

    }

    /**

     * Get all the headers for this header name, returned as a single

     * String, with headers separated by the delimiter. If the

     * delimiter is <code>null</code>, only the first header is

     * returned.  Returns <code>null</code>

     * if no headers with the specified name exist.

     *

     * @param delimiter delimiter

     * @return the value fields for all headers with

     *         this name, or null if none

     * @param   name header name

     */

    public String getHeader(String name, String delimiter) {

        String[] s = getHeader(name);

        if (s == null)

            return null;

        if ((s.length == 1) || delimiter == null)

            return s[0];

        StringBuilder r = new StringBuilder(s[0]);

        for (int i = 1; i < s.length; i++) {

            r.append(delimiter);

            r.append(s[i]);

        }

        return r.toString();

    }

    /**

     * Change the first header line that matches name

     * to have value, adding a new header if no existing header

     * matches. Remove all matching headers but the first. <p>

     * <p/>

     * Note that RFC822 headers can only contain US-ASCII characters

     *

     * @param   name    header name

     * @param   value   header value

     */

    public void setHeader(String name, String value) {

        boolean found = false;

        for (int i = 0; i < headers.size(); i++) {

            hdr h = headers.get(i);

            if (name.equalsIgnoreCase(h.name)) {

                if (!found) {

                    int j;

                    if (h.line != null && (j = h.line.indexOf(':')) >= 0) {

                        h.line = h.line.substring(0, j + 1) + " " + value;

                    } else {

                        h.line = name + ": " + value;

                    }

                    found = true;

                } else {

                    headers.remove(i);

                    i--;    // have to look at i again

                }

            }

        }

        if (!found) {

            addHeader(name, value);

        }

    }

    /**

     * Add a header with the specified name and value to the header list. <p>

     * <p/>

     * Note that RFC822 headers can only contain US-ASCII characters.

     *

     * @param   name    header name

     * @param   value   header value

     */

    public void addHeader(String name, String value) {

        int pos = headers.size();

        for (int i = headers.size() - 1; i >= 0; i--) {

            hdr h = headers.get(i);

            if (name.equalsIgnoreCase(h.name)) {

                headers.add(i + 1, new hdr(name, value));

                return;

            }

            // marker for default place to add new headers

            if (h.name.equals(":"))

                pos = i;

        }

        headers.add(pos, new hdr(name, value));

    }

    /**

     * Remove all header entries that match the given name

     *

     * @param   name header name

     */

    public void removeHeader(String name) {

        for (int i = 0; i < headers.size(); i++) {

            hdr h = headers.get(i);

            if (name.equalsIgnoreCase(h.name)) {

                headers.remove(i);

                i--;    // have to look at i again

            }

        }

    }

    /**

     * Return all the headers as an Enumeration of

     * {@link Header} objects.

     *

     * @return  Header objects

     */

        return headers; // conceptually it should be read-only, but for performance reason I'm not wrapping it here

    }

    /**

     * Add an RFC822 header line to the header store.

     * If the line starts with a space or tab (a continuation line),

     * add it to the last header line in the list. <p>

     * <p/>

     * Note that RFC822 headers can only contain US-ASCII characters

     *

     * @param   line    raw RFC822 header line

     */

    public void addHeaderLine(String line) {

        try {

            char c = line.charAt(0);

            if (c == ' ' || c == '\t') {

                hdr h = headers.get(headers.size() - 1);

                h.line += "\r\n" + line;

            } else

                headers.add(new hdr(line));

        } catch (StringIndexOutOfBoundsException e) {

            // line is empty, ignore it

            return;

        } catch (NoSuchElementException e) {

            // XXX - vector is empty?

        }

    }

    /**

     * Return all the header lines as a collection

     */

    public List<String> getAllHeaderLines() {

        if(headerValueView==null)

            headerValueView = new AbstractList<String>() {

                public String get(int index) {

                    return headers.get(index).line;

                }

                public int size() {

                    return headers.size();

                }

            };

        return headerValueView;

    }

}

/*

 * A private utility class to represent an individual header.

 */

class hdr implements Header {

    // XXX - should these be private?

    String name;    // the canonicalized (trimmed) name of this header

    // XXX - should name be stored in lower case?

    String line;    // the entire RFC822 header "line"

    /*

     * Constructor that takes a line and splits out

     * the header name.

     */

    hdr(String l) {

        int i = l.indexOf(':');

        if (i < 0) {

            // should never happen

            name = l.trim();

        } else {

            name = l.substring(0, i).trim();

        }

        line = l;

    }

    /*

     * Constructor that takes a header name and value.

     */

    hdr(String n, String v) {

        name = n;

        line = n + ": " + v;

    }

    /*

     * Return the "name" part of the header line.

     */

    public String getName() {

        return name;

    }

    /*

     * Return the "value" part of the header line.

     */

    public String getValue() {

        int i = line.indexOf(':');

        if (i < 0)

            return line;

        int j;

        if (name.equalsIgnoreCase("Content-Description")) {

            // Content-Description should retain the folded whitespace after header unfolding -

            // rf. RFC2822 section 2.2.3, rf. RFC2822 section 3.2.3

            for (j = i + 1; j < line.length(); j++) {

                char c = line.charAt(j);

                if (!(/*c == ' ' ||*/c == '\t' || c == '\r' || c == '\n'))

                    break;

            }

        } else {

            // skip whitespace after ':'

            for (j = i + 1; j < line.length(); j++) {

                char c = line.charAt(j);

                if (!(c == ' ' || c == '\t' || c == '\r' || c == '\n'))

                    break;

            }

        }

        return line.substring(j);

    }

}