package mujmail.protocols;

/*
MujMail - Simple mail client for J2ME
Copyright (C) 2006 Nguyen Son Tung <n.sontung@gmail.com>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program 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 for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

import java.util.Timer;
import java.util.TimerTask;
import java.util.Vector;

import mujmail.Lang;
import mujmail.MessageHeader;
import mujmail.MujMail;
import mujmail.MyException;
import mujmail.Settings;
import mujmail.account.MailAccount;
import mujmail.connections.ConnectionCompressed;
import mujmail.tasks.BackgroundTask;
import mujmail.tasks.StoppableBackgroundTask;
import mujmail.threading.Algorithm;
import mujmail.ui.AudioAlert;
import mujmail.util.Functions;

/**
 * Implements InProtocol using IMAP4.
 * 
 * The advantages of implementation using IMAP4 compared to POP3:
 * - it can use the command UID_SEARCH_UNSEEN for access to identifiers of 
 * unread mails
 * - easier deleting of mails (without disconnecting from the server)
 * - getting of required bodypart
 * 
 * IMAP supports more parallel connections to one account so identification of
 * the connection must be added before each command
 * 
 */
public class IMAP4 extends InProtocol {
    
    /** The name of this source file */
    private static final String SOURCE_FILE = "IMAP4";

    /** Flag signals if we want to print debug prints */
    private static final boolean DEBUG = false;

    int commandCounter = 0;
    //name of a selected IMAP4 folder followed with it's UIDVALIDITY encapsulated within two slashes //	
    String sld_mailBox_uidval; //so looks like: INBOX/12313/
    String flags;
    int indexOfFlags = -1;
    Vector deleted;
    Timer connectionKeeper;
    boolean pushing = false;

    protected boolean isMujMailServer = false; /// Flag signaling that you are connected to mujMail server
    static final byte GET_URL         = 5;     //re-retrieving mail bodies - redownload uncompleted mails

    /**
     * Resolves myException while running some task.
     * @param ex
     */
    private void resolveMyExceptionRun(MyException ex) {
        ex.printStackTrace();
        if (ex.getErrorCode() == MyException.COM_HALTED) {
            connection.unQuit();
        }
        resolveExceptions(ex.getDetails() + "/ " + account.getEmail(), SOURCE_FILE);
    }
    private class Keeper extends TimerTask {

        public void run() { //sends a command to check and keeps the connection alive to avoid long reconnecting
              if (DEBUG) System.out.println(account.getEmail() + ": keeping connection alive...");
            if (isBusy()) {
                return;
            }
            lock();
            if (!isConnected()) {
                _close(null);
            }
            unlock();
        }
    }

    public IMAP4(MailAccount account) {
        super(account);
        END_OF_MAIL = ")\r\n";
        deleted = new Vector();
    }

    public void addDeleted(MessageHeader header) {
        deleted.addElement(header);
    }

    /**
     * Sends a command to the server.
     * If resultOnly is <code>true</code> it flushes all response lines
     * to the last response line, that begins with the tag and returns the rest
     * of the line (without the tag).
     * 
     * @return tag, when resultOnly is <code>true</code>, rest of the last
     *         response line otherwise
     */ 
    protected String execute(String command, boolean resultOnly) throws MyException {
          if (DEBUG) System.out.println("DEBUG IMAP4.execute(command='" + command + "', resultOnly=" + resultOnly + ")");
        String tag = "A" + commandCounter++ + " ";
          if (DEBUG) System.out.println("DEBUG IMAP4.execute() tag: " + tag);
          if (DEBUG) System.out.println("DEBUG IMAP4.execute() sending CRLF");
        connection.sendCRLF(tag + command);
          if (DEBUG) System.out.println("DEBUG IMAP4.execute() CRLF sent");
        if (resultOnly) {
              if (DEBUG) System.out.println("DEBUG IMAP4.execute() result only, getting line");
            String reply = connection.getLine();
              if (DEBUG) System.out.println("DEBUG IMAP4.execute() line getted");
            while ( !reply.startsWith(tag) ) {
                  if (DEBUG) System.out.println("DEBUG IMAP4.execute() reply: " + reply);
                reply = connection.getLine();
            }

            if (DEBUG) System.out.println("DEBUG IMAP4.execute() reply: " + reply.substring(tag.length()));

            return reply.substring(tag.length());
        }
        return tag;
    }

    /**
     * Sends the command to server and returns the result that is 
     * mostly closed in brackets.
     */ 	
    protected String execute(String command, String arguments) throws MyException {
        String tag = "A" + commandCounter++ + " ";
        connection.sendCRLF(tag + command + (arguments == null ? "" : " " + arguments));       
        String result = "";

        String temp = connection.getLine();
        while (!temp.startsWith(tag)) { //multiline response
            if (temp.indexOf(" " + command + " ") != -1) { //is it the response for the executed command?
                int p = temp.indexOf('(');
                int q = temp.indexOf(')', p + 1);

                if (p != -1 && q > p) {	//a response in the form of "* command (result)"			
                    result = temp.substring(p + 1, q);
                } else //a response in the form of "* command result"
                {
                    result += temp.substring(2 + command.length() + 1);
                } //2 - "* ", 1 - the space after the command
            }
            temp = connection.getLine();
        }

        temp = temp.substring(tag.length());
        if (temp.startsWith("BAD ") || temp.startsWith("NO ")) {
            throw new MyException(MyException.PROTOCOL_COMMAND_NOT_EXECUTED);
        }

        return result;
    }

    public boolean isConnected() {
        try {
              if (DEBUG) System.out.println("DEBUG IMAP4.isConnected() calling connection.isConnected");
            if (connection.isConnected()) {
                  if (DEBUG) System.out.println("DEBUG IMAP4.isConnected() is connected, clearing input");
                connection.clearInput();
                  if (DEBUG) System.out.println("DEBUG IMAP4.isConnected() executing noop");
                if (execute("NOOP", true).startsWith("OK")) {
                      if (DEBUG) System.out.println("DEBUG IMAP4.isConnected() OK");
                    return true;
                }
            }
        } catch (Exception ex) {
            connection.close();
            ex.printStackTrace();
        }
          if (DEBUG) System.out.println("DEBUG IMAP4.isConnected() is not");
        return false;
    }

    public int countNew() throws MyException {
        return searchMailsMatching("UNSEEN").size();
    }

    /**
     * Returns Vector having UID of mails matching the concrete criteria.
     */
    private Vector searchMailsMatching(String criteria) throws MyException {
        Vector mails = new Vector();
        String tag;
        execute("UID SEARCH " + criteria, false);
        String line = connection.getLine();
        line = line.substring(line.indexOf("SEARCH") + 7).trim() + " ";
        int i = 0, j = 0, mailsCount = 0;
        try {
            while (line.length() - 1 > i) {
            	// Break only in case Synchronization
            	// is not running
            	if (!targetBox.isSyncRunning() &&
            		Settings.maxMailsRetrieve > 0 && mailsCount >= Settings.maxMailsRetrieve) //limit exceeded
                {
                    break;
                }
                j = line.indexOf(" ", i);
                tag = line.substring(i, j);

                // In case of synchronization we 
                // want all mails 
                if (targetBox.isSyncRunning()) {
                	mails.addElement(tag);
            	}
                else if (!targetBox.wasOnceDownloaded(account.getEmail(), sld_mailBox_uidval + tag)) {
                    // If the mail with given message ID was 
                    // already downloaded, remove it from 
                    // the list of new mails
                	mails.addElement(tag);
                	mailsCount++;
                }
                i = j + 1;
            }
        } catch (Exception ex) {
              // process chybicky ... proc tu odchytavat
        	  // protoze line.substring() vyhodi Exception
        	  // na konci: tohle by asi melo byt silent
        	  // exception
        	  // TODO (Betlista): tohle je hodně debilní :-/
            ex.printStackTrace();
        }
        return mails;
    }

    private String parseUID(String s) {
        return s.substring(s.lastIndexOf(MessageHeader.MSG_ID_SEPARATOR) + 1);
    }

    // Note task can be null (polling)
    protected boolean open(BackgroundTask task) throws MyException {
        if (DEBUG) System.out.println("DEBUG IMAP4.open() calling isConnected");
        if (isConnected()) {
            if (DEBUG) System.out.println("DEBUG IMAP4.open() is connected");
            return true;
        }
        if (DEBUG) System.out.println("DEBUG IMAP4.open() is not connected");

        _close(task); //we'd better close inactive connections
        try {
            commandCounter = 0;//reset the counter for each connection			
            String reply;

            if (task != null) { task.setTitle(Lang.get(Lang.ALRT_PL_CONNECTING) + " " + account.getEmail()); }
            connection.open(account.getServer() + ":" + account.getPort(),account.isSSL(), account.getSSLType());
            reply = connection.getLine(); // Welcome message from server

            isMujMailServer = reply.indexOf("mujMail") > 0;
            if (reply.length() == 0) {
                if (task != null) { task.setTitle(Lang.get(Lang.ALRT_PL_CONNECTING) + account.getEmail() + Lang.get(Lang.FAILED)); }
                return false;