/**
 *  @file  operator-lsub.cc
 *  @brief Implementation of the LSUB command.
 *  @author Andreas Aardal Hanssen
 *  @date 2002-2005
 */

#include "convert.h"
#include "depot.h"
#include "iodevice.h"
#include "iofactory.h"
#include "mailbox.h"
#include "operators.h"
#include "recursivedescent.h"
#include "regmatch.h"
#include "session.h"

#include <algorithm>
#include <iostream>
#include <string>
#include <vector>

namespace {
  const int DIR_SELECT = 0x01;
  const int DIR_MARKED = 0x02;
  const int DIR_NOINFERIORS = 0x04;
  const int DIR_LEAF = 0x08;
}

using namespace Binc;
using std::multimap;
using std::string;

LsubOperator::LsubOperator() {}

LsubOperator::~LsubOperator() {}

const string LsubOperator::getName() const
{
  return "LSUB";
}

Session::State LsubOperator::getState() const
{
  return Session::State(Session::AUTHENTICATED | Session::SELECTED);
}

Operator::ProcessResult LsubOperator::process(Depot &depot, Request &command)
{
  const char delim = depot.getDelimiter();

  // remove leading or trailing delimiter in wildcard
  string wildcard = command.getListMailbox();
  trim(wildcard, string(&delim, 1));

  // convert wildcard to regular expression
  string regex = toRegex(wildcard, depot.getDelimiter());
  string wildcardLower = regex;
  lowercase(wildcardLower);
  if (wildcardLower.substr(0, 6) == "^inbox")
    regex = "^[iI][nN][bB][oO][xX]" + regex.substr(6);

  // remove leading or trailing delimiter in reference
  string ref = command.getMailbox();
  trim(ref, string(&delim, 1));
  wildcardLower = ref;
  lowercase(wildcardLower);
  if (wildcardLower.substr(0, 5) == "inbox"
      && (wildcardLower.length() == 5 || wildcardLower[5] == delim))
  {
    ref = "INBOX" + ref.substr(5);
  }

  // a multimap from mailbox name to flags
  multimap<string, int> mailboxes;

  // read through all entries in depository.
  for (auto i = depot.begin("."); i != depot.end(); ++i) {
    const string path = *i;
    const string mpath = depot.filenameToMailbox(path);
    Mailbox *m = nullptr;

    // skip entries that are not identified as mailboxes
    if ((m = depot.get(mpath)) == nullptr) continue;

    // convert file name to mailbox name. skip it if there is no
    // corresponding mailbox name.
    string tmp = toCanonMailbox(depot.filenameToMailbox(path));
    trim(tmp, string(&delim, 1));
    if (tmp == "") {
      continue;
    } else {
      int flags = DIR_SELECT;
      multimap<string, int>::iterator mi = mailboxes.find(tmp);
      if (mi != mailboxes.end()) {
        flags |= mi->second;
        mailboxes.erase(mi);
      }
      mailboxes.insert(make_pair(tmp, flags));
    }

    // now add all superior mailboxes with no flags set if not
    // added already.
    string::size_type pos = tmp.rfind(delim);
    while (pos != string::npos) {
      tmp = tmp.substr(0, pos);
      trim(tmp, string(&delim, 1));

      multimap<string, int>::iterator mi = mailboxes.find(tmp);
      if (mi == mailboxes.end()) mailboxes.insert(make_pair(tmp, 0));

      pos = tmp.rfind(delim);
    }
  }

  // find leaf nodes O(N^2)
  multimap<string, int>::iterator i;
  for (i = mailboxes.begin(); i != mailboxes.end(); ++i) {
    string mailbox = i->first;
    mailbox += delim;

    bool leaf = true;
    multimap<string, int>::const_iterator j;
    for (j = mailboxes.begin(); j != mailboxes.end(); ++j) {
      string::size_type pos = j->first.rfind(delim);
      if (pos == string::npos) continue;
      string base = j->first.substr(0, pos + 1);
      if (mailbox == base) {
        leaf = false;
        break;
      }
    }
    if (leaf) {
      unsigned int flags = i->second;
      flags |= DIR_LEAF;
      i->second = flags;
    }
  }

  depot.loadSubscribes();

  std::vector<string> subscribed = depot.getSubscriptions();
  sort(subscribed.begin(), subscribed.end());

  // finally, print all mailbox entries with flags.
  for (const auto &j : subscribed) {
    if (ref == "" || (ref.length() <= j.length() && ref == j.substr(0, ref.length()))) {
      if (regexMatch(j.substr(ref.length()), regex) == 0) {
        int flags = 0;
        for (i = mailboxes.begin(); i != mailboxes.end(); ++i) {
          if (i->first == j) {
            flags = i->second;
            break;
          }
        }
        bincClient << "* LSUB (";
        string sep = "";
        bool noselect = false;
        if (!(flags & DIR_SELECT)) {
          bincClient << sep << "\\Noselect";
          sep = " ";
          noselect = true;
        }
        if (!noselect) {
          if (flags & DIR_MARKED)
            bincClient << sep << "\\Marked";
          else
            bincClient << sep << "\\Unmarked";
          sep = " ";
        }
        if (flags & DIR_LEAF)
          bincClient << sep << "\\HasNoChildren";
        else
          bincClient << sep << "\\HasChildren";
        sep = " ";
        if (flags & DIR_NOINFERIORS) bincClient << sep << "\\Noinferiors";
        bincClient << ") \"" << depot.getDelimiter() << "\" " << toImapString(j) << std::endl;
      }
    }
  }

  return Operator::ProcessResult::OK;
}

Parser::ParseResult LsubOperator::parse(Request &c_in, Parser &p)
{
  constexpr auto ACCEPT = Parser::ParseResult::ACCEPT;
  constexpr auto ERROR = Parser::ParseResult::ERROR;
  constexpr auto REJECT = Parser::ParseResult::REJECT;

  Session &session = Session::getInstance();

  if (c_in.getUidMode()) return REJECT;

  Parser::ParseResult res;
  if ((res = p.expectSPACE()) != ACCEPT) {
    session.setLastError("Expected SPACE after LSUB");
    return ERROR;
  }

  string mailbox;
  if ((res = p.expectMailbox(mailbox)) != ACCEPT) {
    session.setLastError("Expected mailbox after LSUB SPACE");
    return ERROR;
  }

  c_in.setMailbox(mailbox);

  if ((res = p.expectSPACE()) != ACCEPT) {
    session.setLastError("Expected SPACE after LSUB SPACE mailbox");
    return ERROR;
  }

  string listmailbox;
  if ((res = p.expectListMailbox(listmailbox)) != ACCEPT) {
    session.setLastError("Expected list_mailbox after LSUB SPACE"
                         " mailbox SPACE");
    return ERROR;
  }

  if ((res = p.expectCRLF()) != ACCEPT) {
    session.setLastError("Expected CRLF after LSUB SPACE"
                         " mailbox SPACE list_mailbox");
    return ERROR;
  }

  c_in.setListMailbox(listmailbox);
  c_in.setName("LSUB");

  return ACCEPT;
}