/*
 *  Baltisot
 *  Copyright (C) 1999-2008 Nicolas "Pixel" Noble
 *
 *  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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include <vector>
#include <TaskMan.h>
#include <MailServer.h>
#include <BRegex.h>
#include <CopyJob.h>
#include <ReadJob.h>
#include <Variables.h>

const timeval timeout = { 8, 0 };

const timeval timeout_sending = { 80, 0 };

class ProcessSMTPRequest : public Task {
  public:
      ProcessSMTPRequest(const Socket & out) : s(out) {
          SetBurst();
      }
      virtual ~ProcessSMTPRequest() {
      }
    virtual String GetName() {
        return "Processing SMTP request";
    }
  protected:
    virtual int Do() throw (GeneralException);
  private:
    Socket s;
    Buffer b;
    Task * c;
    String from;
    std::vector<String> tos;
};

static Regex single_dot("^\\.$"), dotted_line("^\\..+$");

int ProcessSMTPRequest::Do() throw (GeneralException) {
    String l, cmd;
    Buffer * out;

    if (TaskMan::Event() == Task::EVT_TIMEOUT) {
        Suspend(TASK_DONE);
    }
    RemoveTimeout();
        
    switch (current) {
    case 0:
        if (!s.IsConnected()) return TASK_DONE;

        b << "220 foo.bar Service Ready\r\n";
        c = new CopyJob(&b, &s);
        WaitFor(c);
        current = 1;
        WaitFor(timeout);
        Suspend(TASK_ON_HOLD);

    case 1:
        delete c;

        b.reset();
        c = new ReadJob(&s, &b, any);
        WaitFor(c);
	current = 2;
        WaitFor(timeout);
        Suspend(TASK_ON_HOLD);

    case 2:
        delete c;

        current = 1;

        b >> l;
        l.toupper();
        cmd = l.extract(0, 3);

        if (cmd == "HELO") {
            b << "250 World.\r\n";
        } else if (cmd == "MAIL") {
            if (l.extract(0, 9) != "MAIL FROM:") {
                b << "501 Syntax error.\r\n";
            } else {
                b << "250 Ok.\r\n";
                from = l.extract(10).trim();
            }
        } else if (cmd == "RCPT") {
            if (l.extract(0, 7) != "RCPT TO:") {
                b << "501 Syntax error.\r\n";
            } else {
                b << "250 Ok.\r\n";
                tos.push_back(l.extract(8).trim());
            }
        } else if (cmd == "DATA") {
            current = 4;
            b << "354 Ok, go ahead.\r\n";
        } else if (cmd == "RSET") {
            from = "";
            while (!tos.empty())
                tos.pop_back();
            b << "250 Ok.\r\n";
        } else if (cmd == "NOOP") {
            b << "250 Zzz.\r\n";
        } else if (cmd == "QUIT") {
            b << "221 Bye.\r\n";
            current = 3;
        } else {
            b << "502 Unknow command.\r\n";
        }

        c = new CopyJob(&b, &s);
        WaitFor(c);
        WaitFor(timeout);
        Suspend(TASK_ON_HOLD);
    
    case 3:
        delete c;
        Suspend(TASK_DONE);

    case 4:
        delete c;

        b.reset();
        c = new ReadJob(&s, &b, single_dot);
        WaitFor(c);
	current = 5;
        WaitFor(timeout_sending);
        Suspend(TASK_ON_HOLD);

    case 5:
        delete c;

        out = new Buffer();

        for (;;) {
            b >> l;
            if (single_dot.Match(l))
                break;
            if (dotted_line.Match(l)) {
                (*out) << l.extract(1);
            } else {
                (*out) << l;
            }
        }

        c = MailHandler::ProcessMail(out, from, tos);

        if (c) {
            current = 6;
            WaitFor(c);
            Suspend(TASK_ON_HOLD);
        }
    case 6:

        if (c)
            delete c;

        delete out;

        from = "";
        while (!tos.empty())
            tos.pop_back();
        b << "250 Ok.\r\n";
        c = new CopyJob(&b, &s);
        WaitFor(c);
        current = 1;
        WaitFor(timeout);
        Suspend(TASK_ON_HOLD);
    }
}

MailHandler * MailHandler::head = 0;

MailHandler::MailHandler() {
    prev = 0;
    next = head;
    head = this;
    if (next)
        next->prev = this;
}

MailHandler::~MailHandler() {
    if (prev)
        prev->next = next;
    if (next)
        next->prev = prev;
    if (head == this)
        head = next;
}

Task * MailHandler::ProcessMail(Handle * in, const String & from, std::vector<String> tos) {
    MailHandler * cur;
    Task * r;

    for (cur = head; cur; cur = cur->next) {
        if (( r = cur->ProcessMail(in, from, tos)))
            return r;
    }
    return 0;
}

void MailHandler::OnTop() {
    if (head == this)
        return;
    if (prev)
        prev->next = next;
    if (next)
        next->prev = prev;
    prev = 0;
    next = head;
    head = this;
    if (next)
        next->prev = this;
}

MailServer::MailServer(int _port, const String & _name) throw (GeneralException) : name(_name), localport(_port) {
    bool r;
    
    r = Listener.SetLocal("", localport);
    if (!r) {
	throw GeneralException("Initialisation of the Mini SMTP-Server failed: can't bind");
    }
    
    r = Listener.Listen();
    
    if (!r) {
	throw GeneralException("Initialisation of the Mini SMTP-Server failed: can't listen");
    }
    
    Listener.SetNonBlock();
    WaitFor(&Listener, W4_STICKY | W4_READING);
}

MailServer::~MailServer(void) {
    Listener.close();
}

int MailServer::Do() throw (GeneralException) {
    try {
	Socket s = Listener.Accept();
	s.SetNonBlock();
	new ProcessSMTPRequest(s);
    }
    catch (GeneralException) {
    }
    return TASK_ON_HOLD;
}

String MailServer::GetName() {
    return String("Mini SMTP-Server '") + name + "'";
}