# smtp-lib.rb             -*- ruby -*-
#
# Copyright (C) 1998 by Takaaki Tateishi
# License: GNU General Public License (GPL2)
# Modified at: <1999/4/23 23:27:47 by ttate>
# Require: ruby-1.3
# Changes:
#   1999/03/27 last_get,last_put was added.
#
# Note:
# This library don't use the timeout. If you need, do "require 'timeout'".
# (e.g)
# require 'timeout'
# begin
#   timeout(5){
#     smtp = SMTP.open("yourhost")
#   }
# rescue TimeoutError
#   ...
# end

require "socket"

class SMTPError < StandardError; end

class SMTP
  PORT = 25
  CRLF = "\r\n"
  EOL = "\n"

  attr_reader :last_get, :last_put
  
  # initialize: but not login
  # host: SMTP Server Host Name
  # port: SMTP Port Number
  def initialize(host,port=PORT)
    @last_get = ""
    @last_put = ""
    @socket = TCPsocket.open(host,port)
    ans = gets2
    if( ! ok?(ans) )
      @socket.close
      raise(SMTPError,"can't initialize.")
    end
    super
  end

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

  def puts(message)
    if( ! message )
      @socket.write("."+CRLF)
      @socket.flush
      @last_put = "."
    else
      if( message[0,1] == "." )
	message = "." + message
      end
      @socket.write(message+CRLF)
      @socket.flush
      @last_put = message
    end
    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+EOL)
    end
    message.chop!
    
    @last_get = message
    message
  end
  private :gets

  def gets2
    message = ""

    line = gets
    message = line
    if( line[3,1] == '-' )
      loop = true
      while( loop )
	line = gets
	message = message + EOL + line
	if( line[3,1] != '-' )
	  loop = false
	end
      end
    end

    @last_get = message
    return message
  end
  private :gets2
  
  def ok?(answer)
    result = true
    
    answer.each_line(EOL){|line|
      if( (line[0,1] != '2')&&(line[0,1] != '3') )
	if( result == true )
	  result = false
	end
      end
    }
    
    return result
  end
  private :ok?

  # hello: =login
  def hello(host,address=nil)
    result = false
    puts("HELO "+host)
    ans = gets2
    if( ok?(ans) )
      if( address != nil )
	puts("MAIL FROM:<"+address+">")
	ans = gets2
	if( ok?(ans) )
	  result = true
	end
      else
	result = true
      end
    end
    return result
  end

  # login: login to the SMTP Server
  def login(host,address=nil)
    hello(host,address)
  end

  def from(address)
    result = false
    puts("MAIL FROM:<"+address+">")
    ans = gets2
    if( ok?(ans) )
      result = true
    end
    return result
  end

  def close
    result = false
    puts("QUIT")
    ans = gets2
    if( ok?(ans) )
      result = true
    end
    @socket.close
    return result
  end

  # rcpt: set the addresses to send
  # addresses: address list
  def rcpt(*addresses)
    result = true
    addresses.each{|address|
      puts("RCPT TO:<"+address+">")
      ans = gets2
      if( ! ok?(ans) )
	result = false
      end
    }
    return result
  end

  # mail: send a mail
  # header: mail header
  # body: mail body
  def mail(header,body)
    result = false
    if( (! header.is_a?(String)) or (! body.is_a?(String)) )
      raise(SMTPError,"mail body must be a kind of String.")
    end
    puts("DATA")
    ans = gets2
    if( ok?(ans) )
      header.each_line{|line|
	if( line[-1,1] == "\n" )
	  line.chop!
	end
	if( line[-1,1] == "\r" )
	  line.chop!
	end
	puts(line)
      }
      puts("")
      body.each_line{|line|
	if( line[-1,1] == "\n" )
	  line.chop!
	end
	if( line[-1,1] == "\r" )
	  line.chop!
	end
	puts(line)
      }
      puts(nil)
      ans = gets2
      if( ok?(ans) )
	result = true
      end
    end
    return result
  end       

  # data: =mail
  def data(header,body)
    mail(header,body)
  end
end