# -*- ruby -*-
# nntp-lib.rb --
#   NNTP Client Library
#
# Modified at: <1999/4/15 01:56:16 by ttate>
#
# Norio Suzuki <nosuzuki@e-mail.ne.jp>
# 1999-02-18

##    QUIT
##    LIST
##    HELP
##    GROUP
##    ARTICLE
##    STAT
##    HEAD
##    BODY
##    NEXT
##    LAST
##    POST
##    NEWNEWS
##    NEWGROUPS
##    XOVER
# message-id: add or del

# From INN
# AUTHINFO USER name|PASS password
# Orig(same as APOP)
# server greeting
# 200 ... <charange>
# AUTHINFO MD5 name respons
# respons <- MD5.digest("<charange>" + secret)
# resond within 30 sec.

require "socket"
require "kconv"

class NNTPError < Exception ; end

class NNTP
  PORT = 119
  HOST = "localhost"

  def initialize(host="", port=PORT)
    port = port.to_i if port.type == String
    raise NNTPError, "port must be String or Fixnum class" unless port.type == Fixnum
    raise NNTPError, "port must be > 0" unless port > 0
    raise NNTPError, "host must be String class" unless host.type == String

    @del_msg_id = TRUE
    @data = []
    @stat = "new"

    open(host, port) if host != ""
  end

  def open(host=HOST, port=PORT)
    port = port.to_i if port.type == String
    raise NNTPError, "port must be String or Fixnum class" unless port.type == Fixnum
    raise NNTPError, "port must be > 0" unless port > 0
    raise NNTPError, "host must be String class" unless host.type == String

    @socket = TCPsocket.open(host, port)
    check_reply
  end

  def close
    command("QUIT")
    @socket.close
  end

  alias quit close

  def auth(pass)
    raise NNTPError, "pass must be String class" unless auth.type == String

    challenge = $1 if @reply =~ /(<.+>)/
    response = md5_digest(challenge + pass)
    command("AUTHINFO MD5 #{response}")
  end

  def reply?
    return @reply.gsub(/[\r\n]/,"")
  end

  def help
    @socket.write("HELP\r\n")
    reply = @socket.readline
    if reply[0] == ?1
      read_to_end
    else
      return FALSE
    end    
  end

  def list
    # newsgroup をキーとした連想配列を返す。
    # 内容は、[first, last, "mode"]
    list = {}
    if command("LIST")
      reply = read_to_end
      reply.each{|line|
	if line =~ /(\S+)\s+(\d+)\s+(\d+)\s+(\S+)/
	  list[$1] = [$3.to_i, $4.to_i, $4]
	end
      }
      return list
    else
      return FALSE
    end
  end

  def group(str)
    # [first, last]
    raise NNTPError, "group must be String class" unless str.type == String

    if command("GROUP #{str}")
      @reply =~ /\d+\s+\d+\s+(\d+)\s+(\d+)/
      return [$1.to_i, $2.to_i]
    else
      return FALSE
    end
  end

  def stat(nnn = "")
    nnn = nnn.to_s if nnn.type == Fixnum
    raise NNTPError, "article number must be String or Fixnum class" unless nnn.type == String
    nnn = "" if nnn == "0"

    if command("STAT #{nnn}")
      return $1 if @reply =~ /(<.+>)/
      return FALSE
    else
      return FALSE
    end
  end

  def article(nnn = "")
    nnn = nnn.to_s if nnn.type == Fixnum
    raise NNTPError, "article number must be String or Fixnum class" unless nnn.type == String
    nnn = "" if nnn == "0"

    if command("ARTICLE #{nnn}")
      read_to_end
    else
      return FALSE
    end
  end

  def head(nnn = "")
    nnn = nnn.to_s if nnn.type == Fixnum
    raise NNTPError, "article number must be String or Fixnum class" unless nnn.type == String
    nnn = "" if nnn == "0"

    if command("HEAD #{nnn}")
      read_to_end
    else
      return FALSE
    end
  end

  def body(nnn = "")
    nnn = nnn.to_s if nnn.type == Fixnum
    raise NNTPError, "article number must be String or Fixnum class" unless nnn.type == String
    nnn = "" if nnn == "0"

    if command("BODY #{nnn}")
      read_to_end
    else
      return FALSE
    end
  end

  def last
    # [pointer, msg-id]
    if command("LAST")
      return [$1.to_i, $2] if @reply =~ /\d+\s+(\d+)\s+(<.+>)/
      return FALSE
    else
      return FALSE
    end
  end

  def next
    # [pointer, msg-id]
    if command("NEXT")
      return [$1.to_i, $2] if @reply =~ /\d+\s+(\d+)\s+(<.+>)/
      return FALSE
    else
      return FALSE
    end
  end

  def post(msg)
    id = ""
    data = []
    if msg.type == File
      # File の時
      begin
	msg.pos =0
	msg.readlines.each{|line|
	  line.gsub!(/[\r\n]/,"")
	  line.sub!(/^\./,"..")
	  data << line
	}
      rescue
	raise NNTPError, "File Read Error"
      end
    elsif msg.type == String
      if msg == ""
	data << ""
      else
	msg.split(/\n/).each {|line|
	  line.gsub!(/\r/,"")
	  line.sub!(/^\./,"..")
	  data << line
	}
      end
    elsif msg.type == Array
      msg.each {|line|
	line.gsub!(/[\r\n]/,"")
	line.sub!(/^\./,"..")
	data << line
      }
    else
      raise NNTPError, "post message must be Array, String, or File class"
    end
    @socket.write("POST\r\n")
    reply = @socket.readline
    if reply[0] == ?3
      data.each {|line|
	if line =~ /^Message-Id:\s*(<.*>)/i
	  next if @del_msg_id
	end
	line_jis = Kconv::tojis(line)
	@socket.write("#{line_jis}\r\n")
      }
      @socket.write(".\r\n")
      check_reply
    else  
      return FALSE
    end
  end

  def newgroups(date, time = "000000")
    raise NNTPError, "time must be String class" unless time.type == String
    if date.type == Time
      tmp = date
      date = tmp.strftime("%y%m%d")
      time = tmp.strftime("%H%M%S")
    end
    raise NNTPError, "date must String or Time class" unless date.type == String
    raise NNTPError, "date must be 6 digit" unless date =~ /\d{6,6}/
    raise NNTPError, "time must be 6 digit" unless time =~ /\d{6,6}/

    if command("NEWGROUPS #{date} #{time}")
      array = read_to_end
      new_groups = []
      array.each{|group|
	new_groups << $1 if group =~ /^(\S+)/
      }
      return new_groups
    end
  end

  def newnews(group, date, time = "000000")
    raise NNTPError, "group must be String class" unless group.type == String
    raise NNTPError, "time must be String class" unless time.type == String
    if date.type == Time
      tmp = date
      date = tmp.strftime("%y%m%d")
      time = tmp.strftime("%H%M%S")
    end
    raise NNTPError, "date must String or Time class" unless date.type == String
    raise NNTPError, "date must be 6 digit" unless date =~ /\d{6,6}/
    raise NNTPError, "time must be 6 digit" unless time =~ /\d{6,6}/

    if command("NEWNEWS #{group} #{date} #{time}")
      array = read_to_end
      new_news = []
      array.each{|group|
	new_news << $1 if group =~ /^(<.+>)/
      }
      return new_news
    end
  end

  def del_msg_id
    @del_msg_id = TRUE
  end

  def no_check_msg_id
    @del_msg_id = FALSE
  end

  def del_msg_id?
    return @del_msg_id
  end

  # XOVER does NOT described in RFC977
  def xover(min = 0, max = 0)
    min = min.to_i if min.type == String
    max = min.to_i if max.type == String
    raise NNTPError, "min must be String or Fixnum class" unless min.type == Fixnum
    raise NNTPError, "max must be String or Fixnum class" unless max.type == Fixnum

    if min <= 0
      range = ""
    elsif max <= 0
      range = min.to_s + "-"
    else
      range = min.to_s + "-" + max.to_s
    end
    return FALSE unless command("XOVER #{range}")
    reply = read_to_end
    list = {}
    reply.each{|line|
      tmp = {}
      line =~ /(\d+)\s+(.*)/
      article = $1
      fields = $2
      tag = fields.split(/\t/)
      tmp["subject"] = tag[0]
      tmp["from"] = tag[1]
      tmp["date"] = tag[2]
      tmp["id"] = tag[3]
      tmp["ref"] = tag[4]
      tmp["bytes"] = tag[5]
      tmp["lines"] = tag[6]
      tmp["opt"] = ""
      if tag.size > 7
	tmp["opt"] = tag[7]
	counter = 8
	while counter < tag.size
	  tmp["opt"] = tmp["opt"] + "\t" + tag[counter]
	  counter = counter +1
	end
      end
      list[article] = tmp
    }
    return list
  end

  def xover?
    return FALSE unless command("LIST OVERVIEW.FMT")
    return read_to_end
  end

  # ここから下は、private です。
  private

  def check_reply
    @reply = @socket.readline
    #p @reply
    if @reply[0] == ?2
      return TRUE
    else
      return FALSE
    end
  end

  def read_to_end
    reply = []
    while true
      line = @socket.readline
      line.sub!(/\r/, "")
      return reply if line =~ /^\.$/
      line.sub!(/^\.\./, ".")
      reply = reply << line
    end
  end

  def command(str)
    @socket.write(str + "\r\n")
    check_reply
  end

  def md5_digest(str)
    if str.type == String
      md5 = MD5.new(str)
      digest = md5.digest.unpack("H*")[0]
      return digest
    else
      return ""
    end
  end
end