/*
 *
 * Conky, a system monitor, based on torsmo
 *
 * Any original torsmo code is licensed under the BSD license
 *
 * All code written since the fork of torsmo is licensed under the GPL
 *
 * Please see COPYING for details
 *
 * Copyright (c) 2004, Hannu Saransaari and Lauri Hakkarainen
 * Copyright (c) 2005-2021 Brenden Matthews, Philip Kovacs, et. al.
 *	(see AUTHORS)
 * All rights reserved.
 *
 * 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 3 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, see <http://www.gnu.org/licenses/>.
 *
 */

#include "config.h"

#include "mail.h"

#include "common.h"
#include "conky.h"
#include "logging.h"
#include "text_object.h"

#include <netdb.h>
#include <netinet/in.h>
#include <sys/param.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <unistd.h>
#include <cerrno>
#include <cinttypes>
#include <climits>
#include <cstdio>
#include <cstring>

#include <dirent.h>
#include <termios.h>

#include <cmath>
#include <memory>
#include <mutex>
#include <sstream>

#include "update-cb.hh"

struct local_mail_s {
  char *mbox;
  int mail_count;
  int new_mail_count;
  int seen_mail_count;
  int unseen_mail_count;
  int flagged_mail_count;
  int unflagged_mail_count;
  int forwarded_mail_count;
  int unforwarded_mail_count;
  int replied_mail_count;
  int unreplied_mail_count;
  int draft_mail_count;
  int trashed_mail_count;
  float interval;
  time_t last_mtime;
  time_t last_ctime; /* needed for mutt at least */
  double last_update;
};

class mail_fail : public std::runtime_error {
 public:
  explicit mail_fail(const std::string &what_arg) : runtime_error(what_arg) {}
};

std::pair<std::string, bool> priv::current_mail_spool_setting::do_convert(
    lua::state &l, int index) {
  auto ret = Base::do_convert(l, index);
  if (ret.second) { ret.first = variable_substitute(ret.first); }
  return ret;
}

priv::current_mail_spool_setting current_mail_spool;

namespace {
enum { DEFAULT_MAIL_INTERVAL = 300 /*seconds*/ };

enum { MP_USER, MP_PASS, MP_FOLDER, MP_COMMAND, MP_HOST, MP_PORT };

struct mail_result {
  unsigned long unseen{0};
  unsigned long used{0};
  unsigned long messages{0};

  mail_result() = default;
};

class mail_cb
    : public conky::callback<mail_result, std::string, std::string, std::string,
                             std::string, std::string, in_port_t> {
  typedef conky::callback<mail_result, std::string, std::string, std::string,
                          std::string, std::string, in_port_t>
      Base;

 protected:
  addrinfo *ai;

  uint16_t fail;
  uint16_t retries;

  void resolve_host() {
    struct addrinfo hints {};
    char portbuf[8];

    memset(&hints, 0, sizeof(struct addrinfo));
    hints.ai_family = AF_UNSPEC;
    hints.ai_socktype = SOCK_STREAM;
    hints.ai_protocol = IPPROTO_TCP;
    snprintf(portbuf, 8, "%" SCNu16, get<MP_PORT>());

    if (int res = getaddrinfo(get<MP_HOST>().c_str(), portbuf, &hints, &ai)) {
      throw mail_fail(std::string("IMAP getaddrinfo: ") + gai_strerror(res));
    }
  }

  int connect() {
    for (struct addrinfo *rp = ai; rp != nullptr; rp = rp->ai_next) {
      int sockfd = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
      if (sockfd == -1) { continue; }
      if (::connect(sockfd, rp->ai_addr, rp->ai_addrlen) != -1) {
        return sockfd;
      }
      close(sockfd);
    }
    throw mail_fail("Unable to connect to mail server");
  }

  void merge(callback_base &&other) override {
    auto &&o = dynamic_cast<mail_cb &&>(other);
    if (retries < o.retries) {
      retries = o.retries;
      fail = 0;
    }

    Base::merge(std::move(other));
  }

  mail_cb(uint32_t period, const Tuple &tuple, uint16_t retries_)
      : Base(period, false, tuple, true),
        ai(nullptr),
        fail(0),
        retries(retries_) {}

  ~mail_cb() override {
    if (ai != nullptr) { freeaddrinfo(ai); }
  }
};

struct mail_param_ex : public mail_cb::Tuple {
  uint16_t retries{0};
  uint32_t period{1};

  mail_param_ex() = default;
};

class imap_cb : public mail_cb {
  using Base = mail_cb;

  void check_status(char *recvbuf);
  void unseen_command(unsigned long old_unseen, unsigned long old_messages);

 protected:
  void work() override;

 public:
  imap_cb(uint32_t period, const Tuple &tuple, uint16_t retries_)
      : Base(period, tuple, retries_) {}
};

class pop3_cb : public mail_cb {
  using Base = mail_cb;

 protected:
  void work() override;

 public:
  pop3_cb(uint32_t period, const Tuple &tuple, uint16_t retries_)
      : Base(period, tuple, retries_) {}
};

struct mail_param_ex *global_mail;
}  // namespace

static void update_mail_count(struct local_mail_s *mail) {
  struct stat st {};

  if (mail == nullptr) { return; }

  /* TODO: use that fine file modification notify on Linux 2.4 */

  /* don't check mail so often (9.5s is minimum interval) */
  if (current_update_time - mail->last_update < 9.5) { return; }
  mail->last_update = current_update_time;

  if (stat(mail->mbox, &st) != 0) {
    static int rep = 0;

    if (rep == 0) {
      NORM_ERR("can't stat %s: %s", mail->mbox, strerror(errno));
      rep = 1;
    }
    return;
  }
#if HAVE_DIRENT_H
  /* maildir format */
  if (S_ISDIR(st.st_mode)) {
    DIR *dir;
    std::string dirname(mail->mbox);
    struct dirent *dirent;
    char *mailflags;

    mail->mail_count = mail->new_mail_count = 0;
    mail->seen_mail_count = mail->unseen_mail_count = 0;
    mail->flagged_mail_count = mail->unflagged_mail_count = 0;
    mail->forwarded_mail_count = mail->unforwarded_mail_count = 0;
    mail->replied_mail_count = mail->unreplied_mail_count = 0;
    mail->draft_mail_count = mail->trashed_mail_count = 0;
    /* checking the cur subdirectory */
    dirname = dirname + "/cur";

    dir = opendir(dirname.c_str());
    if (dir == nullptr) {
      NORM_ERR("cannot open directory");
      return;
    }
    dirent = readdir(dir);
    while (dirent != nullptr) {
      /* . and .. are skipped */
      if (dirent->d_name[0] != '.') {
        mail->mail_count++;
        mailflags = strdup(dirent->d_name);
        if (mailflags == nullptr) {
          NORM_ERR("malloc");
          return;
        }
        strncpy(mailflags, strrchr(dirent->d_name, ','),
                strlen(strrchr(dirent->d_name, ',')));
        if (strchr(mailflags, 'T') ==
            nullptr) { /* The message is not in the trash */
          if (strchr(mailflags, 'S') !=
              nullptr) { /*The message has been seen */
            mail->seen_mail_count++;
          } else {
            mail->unseen_mail_count++;
          }
          if (strchr(mailflags, 'F') != nullptr) { /*The message was flagged */
            mail->flagged_mail_count++;
          } else {
            mail->unflagged_mail_count++;
          }
          if (strchr(mailflags, 'P') !=
              nullptr) { /*The message was forwarded */
            mail->forwarded_mail_count++;
          } else {
            mail->unforwarded_mail_count++;
          }
          if (strchr(mailflags, 'R') != nullptr) { /*The message was replied */
            mail->replied_mail_count++;
          } else {
            mail->unreplied_mail_count++;
          }
          if (strchr(mailflags, 'D') != nullptr) { /*The message is a draft */
            mail->draft_mail_count++;
          }
        } else {
          mail->trashed_mail_count++;
        }
        free(mailflags);
      }
      dirent = readdir(dir);
    }
    closedir(dir);

    dirname.resize(dirname.size() - 3);
    dirname = dirname + "new";

    dir = opendir(dirname.c_str());
    if (dir == nullptr) {
      NORM_ERR("cannot open directory");
      return;
    }
    dirent = readdir(dir);
    while (dirent != nullptr) {
      /* . and .. are skipped */
      if (dirent->d_name[0] != '.') {
        mail->new_mail_count++;
        mail->mail_count++;
        mail->unseen_mail_count++; /* new messages cannot have been seen */
      }
      dirent = readdir(dir);
    }
    closedir(dir);

    return;
  }
#endif
  /* mbox format */
  if (st.st_mtime != mail->last_mtime || st.st_ctime != mail->last_ctime) {
    /* yippee, modification time has changed, let's read mail count! */
    static int rep;
    FILE *fp;
    int reading_status = 0;

    /* could lock here but I don't think it's really worth it because
     * this isn't going to write mail spool */

    mail->new_mail_count = mail->mail_count = 0;

    /* these flags are not supported for mbox */
    mail->seen_mail_count = mail->unseen_mail_count = -1;
    mail->flagged_mail_count = mail->unflagged_mail_count = -1;
    mail->forwarded_mail_count = mail->unforwarded_mail_count = -1;
    mail->replied_mail_count = mail->unreplied_mail_count = -1;
    mail->draft_mail_count = mail->trashed_mail_count = -1;

    fp = open_file(mail->mbox, &rep);
    if (fp == nullptr) { return; }

    /* NOTE: adds mail as new if there isn't Status-field at all */

    while (feof(fp) == 0) {
      char buf[128];

      if (fgets(buf, 128, fp) == nullptr) { break; }

      if (strncmp(buf, "From ", 5) == 0) {
        /* ignore MAILER-DAEMON */
        if (strncmp(buf + 5, "MAILER-DAEMON ", 14) != 0) {
          mail->mail_count++;

          if (reading_status == 1) {
            mail->new_mail_count++;
          } else {
            reading_status = 1;
          }
        }
      } else {
        if (reading_status == 1 && strncmp(buf, "X-Mozilla-Status:", 17) == 0) {
          int xms = strtol(buf + 17, nullptr, 16);
          /* check that mail isn't marked for deletion */
          if ((xms & 0x0008) != 0) {
            mail->trashed_mail_count++;
            reading_status = 0;
            /* Don't check whether the trashed email is unread */
            continue;
          }
          /* check that mail isn't already read */
          if ((xms & 0x0001) == 0) { mail->new_mail_count++; }

          /* check for an additional X-Status header */
          reading_status = 2;
          continue;
        }
        if (reading_status == 1 && strncmp(buf, "Status:", 7) == 0) {
          /* check that mail isn't already read */
          if (strchr(buf + 7, 'R') == nullptr) { mail->new_mail_count++; }

          reading_status = 2;
          continue;
        }
        if (reading_status >= 1 && strncmp(buf, "X-Status:", 9) == 0) {
          /* check that mail isn't marked for deletion */
          if (strchr(buf + 9, 'D') != nullptr) { mail->trashed_mail_count++; }

          reading_status = 0;
          continue;
        }
      }

      /* skip until \n */
      while (strchr(buf, '\n') == nullptr && (feof(fp) == 0)) {
        if (fgets(buf, 128, fp) == nullptr) { break; }
      }
    }

    fclose(fp);

    if (reading_status != 0) { mail->new_mail_count++; }

    mail->last_mtime = st.st_mtime;
    mail->last_ctime = st.st_ctime;
  }
}

void parse_local_mail_args(struct text_object *obj, const char *arg) {
  float n1;
  char mbox[256];
  struct local_mail_s *locmail;

  if (arg == nullptr) {
    n1 = 9.5;
    strncpy(mbox, current_mail_spool.get(*state).c_str(), sizeof(mbox));
  } else {
    if (sscanf(arg, "%s %f", mbox, &n1) != 2) {
      n1 = 9.5;
      strncpy(mbox, arg, sizeof(mbox));
    }
  }

  std::string dst = variable_substitute(mbox);

  locmail =
      static_cast<struct local_mail_s *>(malloc(sizeof(struct local_mail_s)));
  memset(locmail, 0, sizeof(struct local_mail_s));
  locmail->mbox = strndup(dst.c_str(), text_buffer_size.get(*state));
  locmail->interval = n1;
  obj->data.opaque = locmail;
}

#define PRINT_MAILS_GENERATOR(x)                                            \
  void print_##x##mails(struct text_object *obj, char *p,                   \
                        unsigned int p_max_size) {                          \
    struct local_mail_s *locmail = (struct local_mail_s *)obj->data.opaque; \
    if (!locmail) return;                                                   \
    update_mail_count(locmail);                                             \
    snprintf(p, p_max_size, "%d", locmail->x##mail_count);                  \
  }

PRINT_MAILS_GENERATOR()
PRINT_MAILS_GENERATOR(new_)
PRINT_MAILS_GENERATOR(seen_)
PRINT_MAILS_GENERATOR(unseen_)
PRINT_MAILS_GENERATOR(flagged_)
PRINT_MAILS_GENERATOR(unflagged_)
PRINT_MAILS_GENERATOR(forwarded_)
PRINT_MAILS_GENERATOR(unforwarded_)
PRINT_MAILS_GENERATOR(replied_)
PRINT_MAILS_GENERATOR(unreplied_)
PRINT_MAILS_GENERATOR(draft_)
PRINT_MAILS_GENERATOR(trashed_)

void free_local_mails(struct text_object *obj) {
  auto *locmail = static_cast<struct local_mail_s *>(obj->data.opaque);

  if (locmail == nullptr) { return; }

  free_and_zero(locmail->mbox);
  free_and_zero(obj->data.opaque);
}

#define MAXDATASIZE 1000

namespace {
enum mail_type { POP3_TYPE, IMAP_TYPE };
}  // namespace

std::unique_ptr<mail_param_ex> parse_mail_args(mail_type type,
                                               const char *arg) {
  using std::get;

  std::unique_ptr<mail_param_ex> mail;
  char *tmp;
  char host[129];
  char user[129];
  char pass[129];

  if (sscanf(arg, "%128s %128s %128s", host, user, pass) != 3) {
    if (type == POP3_TYPE) {
      NORM_ERR("Scanning POP3 args failed");
    } else if (type == IMAP_TYPE) {
      NORM_ERR("Scanning IMAP args failed");
    }
    return mail;
  }

  // see if password needs prompting
  if (pass[0] == '*' && pass[1] == '\0') {
    int fp = fileno(stdin);
    struct termios term {};

    tcgetattr(fp, &term);
    term.c_lflag &= ~ECHO;
    tcsetattr(fp, TCSANOW, &term);
    printf("Enter mailbox password (%s@%s): ", user, host);
    if (scanf("%128s", pass) != 1) { pass[0] = 0; }
    printf("\n");
    term.c_lflag |= ECHO;
    tcsetattr(fp, TCSANOW, &term);
  }

  mail = std::make_unique<mail_param_ex>();
  get<MP_HOST>(*mail) = host;
  get<MP_USER>(*mail) = user;
  get<MP_PASS>(*mail) = pass;

  // now we check for optional args
  tmp = const_cast<char *>(strstr(arg, "-r "));
  if (tmp != nullptr) {
    tmp += 3;
    sscanf(tmp, "%" SCNu16, &mail->retries);
  } else {
    mail->retries = 5;  // 5 retries after failure
  }

  float interval = DEFAULT_MAIL_INTERVAL;
  tmp = const_cast<char *>(strstr(arg, "-i "));
  if (tmp != nullptr) {
    tmp += 3;
    sscanf(tmp, "%f", &interval);
  }
  mail->period = std::max(lround(interval / active_update_interval()), 1l);

  tmp = const_cast<char *>(strstr(arg, "-p "));
  if (tmp != nullptr) {
    tmp += 3;
    sscanf(tmp, "%" SCNu16, &get<MP_PORT>(*mail));
  } else {
    if (type == POP3_TYPE) {
      get<MP_PORT>(*mail) = 110;  // default pop3 port
    } else if (type == IMAP_TYPE) {
      get<MP_PORT>(*mail) = 143;  // default imap port
    }
  }
  if (type == IMAP_TYPE) {
    tmp = const_cast<char *>(strstr(arg, "-f "));
    if (tmp != nullptr) {
      int len = 0;
      tmp += 3;
      if (tmp[0] == '\'') {
        len = strstr(tmp + 1, "'") - tmp - 1;
        tmp++;
      }
      get<MP_FOLDER>(*mail).assign(tmp, len);
    } else {
      get<MP_FOLDER>(*mail) = "INBOX";  // default imap inbox
    }
  }
  tmp = const_cast<char *>(strstr(arg, "-e "));
  if (tmp != nullptr) {
    int len = 0;
    tmp += 3;

    if (tmp[0] == '\'') { len = strstr(tmp + 1, "'") - tmp - 1; }
    get<MP_COMMAND>(*mail).assign(tmp + 1, len);
  }

  return mail;
}

void parse_imap_mail_args(struct text_object *obj, const char *arg) {
  static int rep = 0;

  if (arg == nullptr) {
    if ((global_mail == nullptr) && (rep == 0)) {
      // something is wrong, warn once then stop
      NORM_ERR(
          "There's a problem with your mail settings.  "
          "Check that the global mail settings are properly defined"
          " (line %li).",
          obj->line);
      rep = 1;
      return;
    }
    obj->data.opaque = global_mail;
    return;
  }
  // process
  obj->data.opaque = parse_mail_args(IMAP_TYPE, arg).release();
}

void parse_pop3_mail_args(struct text_object *obj, const char *arg) {
  static int rep = 0;

  if (arg == nullptr) {
    if ((global_mail == nullptr) && (rep == 0)) {
      // something is wrong, warn once then stop
      NORM_ERR(
          "There's a problem with your mail settings.  "
          "Check that the global mail settings are properly defined"
          " (line %li).",
          obj->line);
      rep = 1;
      return;
    }
    obj->data.opaque = global_mail;
    return;
  }
  // process
  obj->data.opaque = parse_mail_args(POP3_TYPE, arg).release();
}

namespace {
class mail_setting : public conky::simple_config_setting<std::string> {
  using Base = conky::simple_config_setting<std::string>;

  mail_type type;

 protected:
  void lua_setter(lua::state &l, bool init) override {
    lua::stack_sentry s(l, -2);

    Base::lua_setter(l, init);

    if (init && (global_mail == nullptr)) {
      const std::string &t = do_convert(l, -1).first;
      if (static_cast<unsigned int>(!t.empty()) != 0u) {
        global_mail = parse_mail_args(type, t.c_str()).release();
      }
    }

    ++s;
  }

  void cleanup(lua::state &l) override {
    lua::stack_sentry s(l, -1);

    delete global_mail;
    global_mail = nullptr;

    l.pop();
  }

 public:
  mail_setting(const std::string &name, mail_type type_)
      : Base(name), type(type_) {}
};

mail_setting imap("imap", IMAP_TYPE);
mail_setting pop3("pop3", POP3_TYPE);
}  // namespace

void free_mail_obj(struct text_object *obj) {
  if (obj->data.opaque == nullptr) { return; }

  if (obj->data.opaque != global_mail) {
    auto *mail = static_cast<mail_param_ex *>(obj->data.opaque);
    delete mail;
    obj->data.opaque = nullptr;
  }
}

static void command(int sockfd, const std::string &cmd, char *response,
                    const char *verify) {
  struct timeval fetchtimeout {};
  fd_set fdset;
  ssize_t total = 0;
  int numbytes = 0;

  if (send(sockfd, cmd.c_str(), cmd.length(), 0) == -1) {
    throw mail_fail("send: " + strerror_r(errno));
  }
  DBGP2("command()  command: %s", cmd.c_str());

  while (1) {
    fetchtimeout.tv_sec = 60;  // 60 second timeout i guess
    fetchtimeout.tv_usec = 0;
    FD_ZERO(&fdset);
    FD_SET(sockfd, &fdset);

    if (select(sockfd + 1, &fdset, nullptr, nullptr, &fetchtimeout) == 0) {
      throw mail_fail("select: read timeout");
    }

    if ((numbytes = recv(sockfd, response + total, MAXDATASIZE - 1 - total,
                         0)) == -1) {
      throw mail_fail("recv: " + strerror_r(errno));
    }

    total += numbytes;
    response[total] = '\0';
    DBGP2("command() received: %s", response);

    if (strstr(response, verify) != nullptr) { return; }

    if (numbytes == 0) { throw mail_fail("Unexpected response from server"); }
  }
}

void imap_cb::check_status(char *recvbuf) {
  char *reply;
  reply = strstr(recvbuf, " (MESSAGES ");
  if ((reply == nullptr) || strlen(reply) < 2) {
    throw mail_fail("Unexpected response from server");
  }

  reply += 2;
  *strchr(reply, ')') = '\0';

  std::lock_guard<std::mutex> lock(result_mutex);
  if (sscanf(reply, "MESSAGES %lu UNSEEN %lu", &result.messages,
             &result.unseen) != 2) {
    throw mail_fail(std::string("Error parsing response: ") + recvbuf);
  }
}

void imap_cb::unseen_command(unsigned long old_unseen,
                             unsigned long old_messages) {
  if (!get<MP_COMMAND>().empty() &&
      (result.unseen > old_unseen ||
       (result.messages > old_messages && result.unseen > 0)) &&
      system(get<MP_COMMAND>().c_str()) == -1) {
    perror("system()");
  }
}

void imap_cb::work() {
  int sockfd, numbytes;
  char recvbuf[MAXDATASIZE];
  unsigned long old_unseen = ULONG_MAX;
  unsigned long old_messages = ULONG_MAX;
  bool has_idle = false;

  while (fail < retries) {
    struct timeval fetchtimeout {};
    int res;
    fd_set fdset;

    if (ai == nullptr) { resolve_host(); }

    try {
      sockfd = connect();

      command(sockfd, "", recvbuf, "* OK");

      command(sockfd, "abc CAPABILITY\r\n", recvbuf, "abc OK");
      if (strstr(recvbuf, " IDLE ") != nullptr) { has_idle = true; }

      std::ostringstream str;
      str << "a1 login " << get<MP_USER>() << " {" << get<MP_PASS>().length()
          << "}\r\n";
      command(sockfd, str.str(), recvbuf, "+");

      command(sockfd, get<MP_PASS>() + "\r\n", recvbuf, "a1 OK");

      command(sockfd,
              "a2 STATUS \"" + get<MP_FOLDER>() + "\" (MESSAGES UNSEEN)\r\n",
              recvbuf, "a2 OK");
      check_status(recvbuf);

      unseen_command(old_unseen, old_messages);
      fail = 0;
      old_unseen = result.unseen;
      old_messages = result.messages;

      if (!has_idle) {
        try {
          command(sockfd, "a3 LOGOUT\r\n", recvbuf, "a3 OK");
        } catch (mail_fail &e) {
          NORM_ERR("Error while communicating with IMAP server: %s", e.what());
        }
        close(sockfd);
        return;
      }

      command(sockfd, "a4 SELECT \"" + get<MP_FOLDER>() + "\"\r\n", recvbuf,
              "a4 OK");

      command(sockfd, "a5 IDLE\r\n", recvbuf, "+ idling");
      recvbuf[0] = '\0';

      while (1) {
        /*
         * RFC 2177 says we have to re-idle every 29 minutes.
         * We'll do it every 20 minutes to be safe.
         */
        fetchtimeout.tv_sec = 1200;
        fetchtimeout.tv_usec = 0;
        DBGP2("idling...");
        FD_ZERO(&fdset);
        FD_SET(sockfd, &fdset);
        FD_SET(donefd(), &fdset);
        res = select(std::max(sockfd, donefd()) + 1, &fdset, nullptr, nullptr,
                     &fetchtimeout);
        if ((res == -1 && errno == EINTR) || FD_ISSET(donefd(), &fdset)) {
          try {
            command(sockfd, "DONE\r\n", recvbuf, "a5 OK");
            command(sockfd, "a3 LOGOUT\r\n", recvbuf, "a3 OK");
          } catch (mail_fail &e) {
            NORM_ERR("Error while communicating with IMAP server: %s",
                     e.what());
          }
          close(sockfd);
          return;
        }
        if (res > 0) {
          if ((numbytes = recv(sockfd, recvbuf, MAXDATASIZE - 1, 0)) == -1) {
            throw mail_fail("recv idling");
          }
        } else {
          throw mail_fail("");
        }

        recvbuf[numbytes] = '\0';
        DBGP2("imap_thread() received: %s", recvbuf);
        unsigned long messages, recent = 0;
        bool force_check = 0;
        if (strlen(recvbuf) > 2) {
          char *buf = recvbuf;
          buf = strstr(buf, "EXISTS");
          while ((buf != nullptr) && strlen(buf) > 1 &&
                 (strstr(buf + 1, "EXISTS") != nullptr)) {
            buf = strstr(buf + 1, "EXISTS");
          }
          if (buf != nullptr) {
            // back up until we reach '*'
            while (buf >= recvbuf && buf < (recvbuf + MAXDATASIZE) - 1 &&
                   buf[0] != '*') {
              buf--;
            }
            if (sscanf(buf, "* %lu EXISTS\r\n", &messages) == 1) {
              std::lock_guard<std::mutex> lock(result_mutex);
              if (result.messages != messages) {
                force_check = 1;
                result.messages = messages;
              }
            }
          }
          buf = recvbuf;
          buf = strstr(buf, "RECENT");
          while ((buf != nullptr) && strlen(buf) > 1 &&
                 (strstr(buf + 1, "RECENT") != nullptr)) {
            buf = strstr(buf + 1, "RECENT");
          }
          if (buf != nullptr) {
            // back up until we reach '*'
            while (buf >= recvbuf && buf < (recvbuf + MAXDATASIZE) - 1 &&
                   buf[0] != '*') {
              buf--;
            }
            if (sscanf(buf, "* %lu RECENT\r\n", &recent) != 1) { recent = 0; }
          }
        }
        /* check if we got a BYE from server */
        if (strstr(recvbuf, "* BYE") != nullptr) {
          // need to re-connect
          throw mail_fail("");
        }

        /*
         * check if we got a FETCH from server, recent was
         * something other than 0, or we had a timeout
         */
        if (recent > 0 || (strstr(recvbuf, " FETCH ") != nullptr) ||
            fetchtimeout.tv_sec == 0 || force_check) {
          // re-check messages and unseen
          command(sockfd, "DONE\r\n", recvbuf, "a5 OK");

          command(
              sockfd,
              "a2 STATUS \"" + get<MP_FOLDER>() + "\" (MESSAGES UNSEEN)\r\n",
              recvbuf, "a2 OK");

          check_status(recvbuf);

          command(sockfd, "a5 IDLE\r\n", recvbuf, "+ idling");
        }
        unseen_command(old_unseen, old_messages);
        fail = 0;
        old_unseen = result.unseen;
        old_messages = result.messages;
      }
    } catch (mail_fail &e) {
      if (sockfd != -1) { close(sockfd); }
      freeaddrinfo(ai);
      ai = nullptr;

      ++fail;
      if (*e.what() != 0) {
        NORM_ERR("Error while communicating with IMAP server: %s", e.what());
      }
      NORM_ERR("Trying IMAP connection again for %s@%s (try %u/%u)",
               get<MP_USER>().c_str(), get<MP_HOST>().c_str(), fail + 1,
               retries);
      sleep(fail); /* sleep more for the more failures we have */
    }

    if (is_done()) { return; }
  }
}

void print_imap_unseen(struct text_object *obj, char *p,
                       unsigned int p_max_size) {
  auto *mail = static_cast<struct mail_param_ex *>(obj->data.opaque);

  if (mail == nullptr) { return; }

  auto cb = conky::register_cb<imap_cb>(mail->period, *mail, mail->retries);

  snprintf(p, p_max_size, "%lu", cb->get_result_copy().unseen);
}

void print_imap_messages(struct text_object *obj, char *p,
                         unsigned int p_max_size) {
  auto *mail = static_cast<struct mail_param_ex *>(obj->data.opaque);

  if (mail == nullptr) { return; }

  auto cb = conky::register_cb<imap_cb>(mail->period, *mail, mail->retries);

  snprintf(p, p_max_size, "%lu", cb->get_result_copy().messages);
}

void pop3_cb::work() {
  int sockfd;
  char recvbuf[MAXDATASIZE];
  char *reply;
  unsigned long old_unseen = ULONG_MAX;

  while (fail < retries) {
    if (ai == nullptr) { resolve_host(); }

    try {
      sockfd = connect();

      command(sockfd, "", recvbuf, "+OK ");
      command(sockfd, "USER " + get<MP_USER>() + "\r\n", recvbuf, "+OK ");
      command(sockfd, "PASS " + get<MP_PASS>() + "\r\n", recvbuf, "+OK ");
      command(sockfd, "STAT\r\n", recvbuf, "+OK ");

      // now we get the data
      reply = recvbuf + 4;
      {
        std::lock_guard<std::mutex> lock(result_mutex);
        sscanf(reply, "%lu %lu", &result.unseen, &result.used);
      }

      command(sockfd, "QUIT\r\n", recvbuf, "+OK");

      if (get<MP_COMMAND>().length() > 1 && result.unseen > old_unseen &&
          system(get<MP_COMMAND>().c_str()) == -1) {
        perror("system()");
      }
      fail = 0;
      return;
    } catch (mail_fail &e) {
      if (sockfd != -1) { close(sockfd); }
      freeaddrinfo(ai);
      ai = nullptr;

      ++fail;
      if (*e.what() != 0) {
        NORM_ERR("Error while communicating with POP3 server: %s", e.what());
      }
      NORM_ERR("Trying POP3 connection again for %s@%s (try %u/%u)",
               get<MP_USER>().c_str(), get<MP_HOST>().c_str(), fail + 1,
               retries);
      sleep(fail); /* sleep more for the more failures we have */
    }

    if (is_done()) { return; }
  }
}

void print_pop3_unseen(struct text_object *obj, char *p,
                       unsigned int p_max_size) {
  auto *mail = static_cast<struct mail_param_ex *>(obj->data.opaque);

  if (mail == nullptr) { return; }

  auto cb = conky::register_cb<pop3_cb>(mail->period, *mail, mail->retries);

  snprintf(p, p_max_size, "%lu", cb->get_result_copy().unseen);
}

void print_pop3_used(struct text_object *obj, char *p,
                     unsigned int p_max_size) {
  auto *mail = static_cast<struct mail_param_ex *>(obj->data.opaque);

  if (mail == nullptr) { return; }

  auto cb = conky::register_cb<pop3_cb>(mail->period, *mail, mail->retries);

  snprintf(p, p_max_size, "%.1f", cb->get_result_copy().used / 1024.0 / 1024.0);
}
