# pop3-lib.rb               -*- ruby -*-
# 
# Copyright (C) 1998 by Takaaki Tateishi
# License: GNU General Public License version 2 (GPL2)
# Require: ruby-1.3
# Modified at: <1999/4/23 23:26:45 by ttate>
# Changes:
#   1999/3/27 last_get,last_put was added
#
# Note:
# This library don't use the timeout. If you need, do "require 'timeout'".
# (example)
# require 'timeout'
# begin
#   timeout(5){
#     pop = POP3.open("yourhost")
#   }
# rescue TimeoutError
#   ....
# end

require "socket"

class POP3Error < StandardError; end

class POP3
  PORT = 110
  CRLF = "\r\n"
  EOL = "\n"

  attr_reader :last_get, :last_put

  # initialize
  # host: POP3 Host Name
  # port: POP3 Port Number
  def initialize(host,port=PORT)
    @last_get = ''
    @last_put = ''
    @socket = TCPsocket.open(host,port)
    ans = gets
    if( ! ok?(ans) )
      raise(POP3Error,"can't initialize")
    end
  end

  # open(=new)
  def POP3.open(host,port=PORT)
    new(host,port)
  end


  def puts(message)
    @socket.write(message+CRLF)
    @socket.flush
    @last_put = message
    if( $DEBUG )
      STDERR.print("puts:"+message.to_s+EOL)
    end
  end
  private :puts
  
  def gets
    message = @socket.gets
    if( $DEBUG )
      STDERR.print("gets:"+message.to_s)
    end
    if( message[0,1] == "." )
      if( message[1,2] != CRLF )
	message = message[1,message.length-1]
      else
	message = nil
      end
    end

    if( message )
      if( message[-1,1] == "\n" )
	message.chop!
      end
      if( message[-1,1] == "\r" )
	message.chop!
      end
    end

    @last_get = message
    message
  end
  private :gets
  
  def gets2
    loop = true

    messages = []
    while( line = gets )
      messages.push(line)
    end

    return messages
  end
  private :gets2
  
  def ok?(answer)
    result = false
    if( answer[0,3] == "+OK" )
      result = true
    else
      result = false
    end
    return result
  end
  private :ok?


  def login(user, passwd)
    result = false

    puts("USER "+user)
    ans = gets
    if( ok?(ans) )
      puts("PASS "+passwd)
      ans = gets
      if( ok?(ans) )
	result = true
      end
    end
    return result
  end

  
  def close
    result = false

    puts("QUIT")
    ans = gets
    if( ok?(ans) )
      result = true
    end
    @socket.close
     return result
  end

  # get_count: get the count of mails
  def get_count
    count = nil
    puts("STAT")
    ans = gets
    if( ok?(ans) )
      anslist = ans.split(/ +/)
      count = anslist[1].to_i
    end
    return count
  end

  # get_list: Get the mail number which is not marked for deleting
  def get_list
    maillist = []
    
    puts("LIST")
    ans = gets
    if( ok?(ans) )
      if ( msg = gets2 )
	msg.each{|line|
	  linelist = line.split(/ +/)
	  if( linelist[0] != nil )
	    maillist.push(linelist[0])
	  end
	}
      end
    else
      maillist = nil
    end

    return maillist
  end

  def get_mail_as_list(num)
    contents = nil

    puts("RETR "+num.to_s)
    ans = gets
    if( ok?(ans) )
      contents = gets2
    else
      contents = nil
    end
    
    return contents
  end

  # get_mail: Get the mail body(if fault,return nil)
  # num: mail number
  def get_mail(num, eol=EOL)
    contents = nil
    if( contents = get_mail_as_list(num) )
      contents = contents.join(eol)
    end
    
    return contents
  end


  # delete: Mark the mail for deleting
  # num: mail number
  def delete(num)
    result = false

    puts("DELE "+num.to_s)
    ans = gets
    if( ok?(ans) )
      result = true
    end

    return result
  end


  # reset: reset the mark
  def reset
    result = false

    puts("RSET")
    ans = gets
    if( ok?(ans) )
      result = true
    end

    return result
  end

end