// Copyright 2000-2006 the Contributors, as shown in the revision logs.
// Licensed under the Apache Public Source License 2.0 ("the License").
// You may not use this file except in compliance with the License.

package org.ibex.mail;
import java.io.*;
import java.util.*;
import org.ibex.js.*;
import org.ibex.io.*;
import org.ibex.io.Fountain;

// FIXME FIXME: rate limiting

// FIXME: DSN's: RFC 3464 ==> NOTIFY=NEVER
// FIXME: MDN's: RFC 3798

// FIXME
// SHOULD NOT issue the same response to the same sender more
// than once within a period of several days, even though that
// sender may have sent multiple messages.  A 7-day period is
// RECOMMENDED as a default.

// Personal and Group responses whose purpose is to notify the
// sender of a message of a temporary absence of the recipient
// (e.g., "vacation" and "out of the office" notices) SHOULD
// NOT be issued unless a valid address for the recipient is
// explicitly included in a recipient (e.g., To, Cc, Bcc,
// Resent-To, Resent-Cc, or Resent- Bcc) field of the subject
// message.

// FIXME: be sure to never, ever return large responses (> a few kb)

/** Implements RFC3834-safe/compliant auto-generated messages+replies */
public class Auto {

    /**
     *  Compose an auto-generated message (not a reply) compliant with RFC3834.
     *
     *  @param from
     *    <b>personal</b>: should be the recipient of the message, might guess from message, MUST be customizable<br>
     *    <b>service</b>:  should be a human, and description should describe the service
     *  @param includeAutoInSubject if true; the string "Auto: " is prepended to the subject
     */
    public Message autoGenerate(Headers headers, Fountain body, Address autoFrom, Address autoTo, boolean includeAutoInSubject) {
	return Message.newMessageFromHeadersAndBody(new Headers(headers, new String[] {
            "Auto-Submitted", "auto-generated",
            "Precedence",     "bulk",
            "Subject",        (includeAutoInSubject ? "Auto: " : "")+headers.get("subject"),
            "From",           autoFrom.toString(true),
            "Reply-To",       autoFrom.toString(false)
        }),
                                                    body, null, autoTo);
    }

    /**
     *  Compose an auto-generated reply compliant with RFC3834.
     *
     *  @param from
     *    <b>personal</b>: should be the recipient of the message, might guess from message, MUST be customizable<br>
     *    <b>service</b>:  should be a human, and description should describe the service
     *  @param includeAutoInSubject if true; the string "Auto: " is prepended to the subject
     */
    public Message autoReply(Fountain fountain, Message m, Address autoFrom, boolean includeAutoInSubject) {

	if (m.envelopeFrom==null) return null;

	String auto = m.headers.get("auto-submittted");
	if (auto!=null && !auto.equals("no"))                             return null;

	String precedence = m.headers.get("precedence");
        if (precedence != null) precedence = precedence.trim().toLowerCase();
	if ("bulk".equals(precedence)) return null;
	if ("list".equals(precedence)) return null;
	if ("junk".equals(precedence)) return null;

	// recommended, not required.
	if (m.envelopeFrom.user.endsWith("-request"))                     return null;
	if (m.envelopeFrom.user.startsWith("owner-"))                     return null;
	if (m.envelopeFrom.description.equalsIgnoreCase("mailer-daemon")) return null;
	for(String key : m.headers.getHeaderNames())
	    if (key.toLowerCase().startsWith("list-")) return null;

	return m.reply(new String[] {
            "Auto-Submitted", "auto-replied",
            "Precedence",     "bulk",
            "Subject",        (includeAutoInSubject ? "Auto: " : "")+m.subject,
            "From",           autoFrom.toString(true),
            "Reply-To",       autoFrom.toString(false)
        },
                       fountain, null, false);
    }

}