/**
 *  @file imapserver.cc
 *  @brief Implementation of the IMAPServer class.
 *  @author Andreas Aardal Hanssen
 *  @date 2005
 */

#include "imapserver.h"

#include "broker.h"
#include "globals.h"
#include "imapparser.h"
#include "iodevice.h"
#include "iofactory.h"
#include "operators.h"
#include "session.h"

#include <cstdint>

using namespace Binc;
using std::endl;

namespace Binc {
  void showGreeting();
};

IMAPServer::IMAPServer(int argc, char **argv)
{
  this->argc = argc;
  this->argv = argv;
  this->stubMode = false;
  Session::getInstance().setState(Session::AUTHENTICATED);
}

IMAPServer::~IMAPServer() {}

int IMAPServer::initialize()
{
  Session &session = Session::getInstance();
  if (!session.initialize(argc, argv)) return 111;
  return 0;
}

void IMAPServer::prepareForNextRequest()
{
  serverStatus = ServerStatus::OK;

  bincClient.setFlags(IODevice::HasInputLimit);
  bincClient.flush();
  bincClient.setMaxInputBufferSize(INPUT_BUFFER_LIMIT);

  Session::getInstance().setLastError("");
  Session::getInstance().clearResponseCode();
}

int IMAPServer::runStub()
{
  bincDebug << "IMAPServer::runStub(), running stub" << endl;
  this->stubMode = true;
  Session::getInstance().setState(Session::NONAUTHENTICATED);
  return run();
}

int IMAPServer::run()
{
  Session &session = Session::getInstance();
  bincLog.setOutputLevelLimit(IODevice::LogLevel::InfoLevel);
  std::string pid = std::to_string(session.getPid());

  bincDebug << "IMAPServer::run(), started server" << endl;

  if (this->stubMode) {
    if (session.hasEnv("PROTOCOLDUMP")) bincClient.enableProtocolDumping();
    bincLog << "bincimap-up: pid " << pid << " Connected: <" << session.getIP() << ">\n";
    showGreeting();
  } else {
    bincLog << "bincimapd: pid " << pid << " Logged in: <" << session.getEnv("USER") << "@"
            << session.getEnv("TCPREMOTEIP") << ">\n";
  }
  bincLog.flush();

  do {
    bincDebug << "IMAPServer::run(), preparing for next request" << endl;

    prepareForNextRequest();

    // Find the current state's broker.
    BrokerFactory &brokerFactory = BrokerFactory::getInstance();
    Broker *broker = brokerFactory.getBroker(session.getState());

    bincDebug << "IMAPServer::run(), found broker " << (uintptr_t)broker << " for state "
              << session.getState() << endl;

    bool skipToNextRequest = false;

    // Parse the stub of the IMAP request.
    Request clientRequest;
    Parser::ParseResult stubParseResult = broker->parseStub(clientRequest);
    if (stubParseResult == Parser::ParseResult::TIMEOUT) {
      serverStatus = ServerStatus::Timeout;
      break;
    } else if (stubParseResult == Parser::ParseResult::REJECT) {
      serverStatus = ServerStatus::RequestRejected;
    } else if (stubParseResult == Parser::ParseResult::ERROR) {
      serverStatus = ServerStatus::RequestError;
    } else {
      // Find an operator that recognizes the name of the request, and
      // have it continue the parsing.
      Operator *o = broker->get(clientRequest.getName());
      if (!o) {
        serverStatus = ServerStatus::RequestRejected;
        std::string err = "The command \"";
        if (clientRequest.getUidMode()) err += "UID ";
        err += clientRequest.getName();
        err += "\" is unsupported in this state. ";
        session.setLastError(err);
        skipToNextRequest = true;
      } else {
        Parser::ParseResult parseResult = o->parse(clientRequest);
        if (parseResult == Parser::ParseResult::TIMEOUT) {
          serverStatus = ServerStatus::Timeout;
        } else if (parseResult == Parser::ParseResult::REJECT) {
          serverStatus = ServerStatus::RequestRejected;
        } else if (parseResult == Parser::ParseResult::ERROR) {
          serverStatus = ServerStatus::RequestError;
        } else {
          session.addStatement();
          Depot *dep = session.getDepot();

          switch (o->process(*dep, clientRequest)) {
          case Operator::ProcessResult::OK:
            break;
          case Operator::ProcessResult::NO:
            serverStatus = ServerStatus::RequestRejected;
            break;
          case Operator::ProcessResult::BAD:
            serverStatus = ServerStatus::RequestError;
            break;
          case Operator::ProcessResult::NOTHING:
            serverStatus = ServerStatus::RequestIgnore;  // answer given already
            break;
          case Operator::ProcessResult::ABORT:
            session.setState(Session::LOGOUT);
          }
        }
      }
    }

    // If a syntax error was detected, we skip all characters in the
    // input stream up to and including '\n'.
    if (serverStatus == ServerStatus::RequestRejected) {
      bincClient << clientRequest.getTag() << " NO " << session.getResponseCode()
                 << clientRequest.getName() << " failed: " << session.getLastError() << endl;
    } else if (serverStatus == ServerStatus::RequestError) {
      bincClient << "* BAD " << session.getLastError() << endl;
      skipToNextRequest = true;
    } else if (serverStatus == ServerStatus::RequestIgnore) {
      ;
    } else if (serverStatus == ServerStatus::OK && session.getState() != Session::LOGOUT) {
      bincClient << clientRequest.getTag() << " OK";
      if (clientRequest.getUidMode()) bincClient << " UID";
      bincClient << " " << session.getResponseCode() << clientRequest.getName()
                 << " completed";
      if (clientRequest.getContextInfo() != "")
        bincClient << " (" << clientRequest.getContextInfo() << ")";

      bincClient << endl;
    } else {
      // Timeout, ClientDisconnected
      session.setState(Session::LOGOUT);
    }

    bincClient.flush();

    if (skipToNextRequest) {
      if (!bincClient.skipTo('\n')) {
        if (bincClient.getLastError() == IODevice::Error::Timeout)
          serverStatus = ServerStatus::Timeout;
        else
          serverStatus = ServerStatus::ClientDisconnected;
        break;
      }
    }
  } while (session.getState() != Session::LOGOUT);  // do line 81

  // Session finished - write some log information

  std::string userID = this->stubMode ? session.getIP() : session.getEnv("USER");

  if (this->stubMode) {
    bincLog << "bincimap-up: pid " << pid << " (Read: " << session.getReadBytes()
            << " Written: " << session.getWriteBytes() << ")\n";
  } else {
    bincLog << "bincimapd: pid " << pid << " (Bodies: " << session.getBodies()
            << " Statements: " << session.getStatements() << ")\n";
  }

  if (serverStatus == ServerStatus::Timeout) {
    bincClient << "* BYE Timeout after " << session.timeout() << " seconds of inactivity\n";
    bincClient.flush();
    bincLog << "bincimapd: pid " << pid << " Timed out: <" << userID << "> after "
            << IDLE_TIMEOUT << "s";
  } else if (serverStatus == ServerStatus::ClientDisconnected) {
    bincLog << "bincimapd: pid " << pid << "Disconnected: <" << userID << ">\n";
  } else {
    if (this->stubMode) {
      bincLog << "bincimap-up: pid " << pid << " Logged out: <" << userID << ">\n";
    } else {
      bincLog << "bincimapd: pid " << pid << " Disconnected: <" << userID << ">\n";
    }
  }
  bincLog.flush();

  return 0;
}