/* This file is part of Mailfromd.
   Copyright (C) 2008 Sergey Poznyakoff

   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, 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 "status.mfh"
#pragma regex push +extended +icase

string sav_database "%__statedir__/sav.db"
number sav_positive_ttl interval("1 day")
number sav_negative_ttl interval("1 day")

func sav_get_cache(string key) returns string
do
  catch *
  do
    echo "Exception $1 while reading from %sav_database: $2"
    return ""
  done
  string record dbget(%sav_database, %key, "", 0)
  if %record != ""
    if %record matches '([0-9]+) ([0-9]+)'
      number timediff time() - \1
      number result \2
      number ttl
      if %result = success
	set ttl %sav_positive_ttl
      else
	set ttl %sav_negative_ttl
      fi

      if %timediff > %ttl
	echo "$i: CLEARING record %record"
	set result ""
      fi
      return %result
    else
      echo "$i: ERROR: Malformed DB line: %record"
    fi
  fi
  return ""
done

func sav_put_cache(string key, number value)
do
  catch *
  do
    echo "Exception $1 while writing to %sav_database: $2"
    return
  done
  dbput(%sav_database, %key, time() " %value", 0)
done

func __safe_getmx(string domain) returns string
do
  catch e_failure
  do
    return ""
  done
  return getmx(%domain)
done

func __safe_pollhost(string ip, string email, string domain, string mailfrom)
  returns number
do
  catch *
  do
    return $1
  done
  return _pollhost(%ip, %email, %domain, %mailfrom)
done

func mf_resolved(number code) returns number
do
  return %code == success or %code == not_found
done

func sav(string email, string ehlo, string mailfrom)
  alias stdpoll
  returns number
do
  number rc sav_get_cache(%email)

  if mf_resolved(%rc)
    set last_poll_host ""
    set last_poll_send ""
    set last_poll_recv ""
    set cache_used 1
    return %rc
  fi

  set cache_used 0

  catch e_temp_failure
  do
    return $1
  done
  string mxlist __safe_getmx(domainpart(%email))

  if %mxlist == ""
    set rc __safe_pollhost(domainpart(%email), %email, %ehlo, %mailfrom)
  else
    loop for string mxs %mxlist " "
	     number i index(%mxs, " "),
         while %i != -1,
         set mxs substr(%mxs, %i + 1)
         set i index(%mxs, " ")
    do
      string host substr(%mxs, 0, %i)
      set rc __safe_pollhost(%host, %email, %ehlo, %mailfrom)
      if mf_resolved(%rc)
	sav_put_cache(%email, %rc)
	break
      fi
    done
  fi
  
  return %rc
done

func sav_strict(string email, string ehlo, string mailfrom)
  alias strictpoll
  returns number
do
  number rc sav_get_cache(%email)

  if mf_resolved(%rc)
    set last_poll_host ""
    set last_poll_send ""
    set last_poll_recv ""
    set cache_used 1
    return %rc
  fi

  set cache_used 0
  set rc __safe_pollhost(domainpart(%email), %email, %ehlo, %mailfrom)
  if mf_resolved(%rc)
    return %rc
  fi
  
  catch e_temp_failure
  do
    return $1
  done
  string mxlist __safe_getmx(domainpart(%email))

  if %mxlist == ""
    return %rc
  else
    # FIXME: The loop is same as in sav. Use macro.
    loop for string mxs %mxlist " "
	     number i index(%mxs, " "),
         while %i != -1,
         set mxs substr(%mxs, %i + 1)
         set i index(%mxs, " ")
    do
      string host substr(%mxs, 0, %i)
      set rc __safe_pollhost(%host, %email, %ehlo, %mailfrom)
      if mf_resolved(%rc)
	sav_put_cache(%email, %rc)
	break
      fi
    done
  fi
  
  return %rc
done
							     
#pragma regex pop