#!/bin/sh

exec ruby -x -S $0 "$@"

#!/usr/bin/ruby

require "ftools"
require "net/smtp"
require "net/pop"

module MailClient
  Version = "0.3"

  POP = []

  BIND = binding

  def module_load file
    open(File.expand_path file) do |rc|
      eval rc.read, BIND
      raise $! if $!
    end
  end
  module_function :module_load

  module_load "~/.mailclient.rb"
  if defined? SPOOL_DIR
    SPOOL = File.expand_path(SPOOL_DIR)
  else
    SPOOL = File.expand_path("~/spool/mqueue")
  end

  File.makedirs SPOOL

  if defined? DONT_DELETE and DONT_DELETE
    DELETE = false
  elsif defined? DONT_DELETE_IMMEDIATELY and DONT_DELETE_IMMEDIATELY
    DELETE = :delete
  else
    DELETE = :delete!
  end

  class MailRead
    attr_reader :header, :body

    def initialize f
      #Fix me
      @header = f.gets("\n\n")
      @body = f.read || ''
    end

    def remove_bcc
      @header.gsub!(/^bcc:.*\n/i, '')
    end

    def field x
#    /^#{x}:[ \t]*(.*?)\n/i === @header
      /^#{x}:(.*?\n(?:[ \t]+.*?\n)*)/i === @header
      $1
    end

    def method_missing x
      field x.id2name
    end

    #Fix me
    def MailRead.extract addresses
      addresses.gsub(/\(.*?\)/, '').gsub(/"(.*),(.*)"/, "\"\\1\1\\2\"").
	split(/,\s*/).collect do |address|
	address.gsub!(/\1/, ',')
	address = $1 if /<(.+?)>/ === address
	address.strip
      end
    end
  end

  class Sendmail
    MDA_FORMAT = "|" + MDA
    
    attr_reader :contents, :sender, :recipients
    
    def initialize contents, sender, recipients
      @contents = contents
      @sender = sender
      @recipients = recipients
    end
    
    def save file
      file.chmod 0600
      file.print "<", @sender, "\n"
      for recipient in @recipients
	file.print ">", recipient, "\n"
      end
      file.print "\n", @contents
    end
    
    def send smtp
      unless @recipients.empty?
	smtp.sendmail @contents, @sender, @recipients
      end
    end
    
    def deliver user
      Sendmail.deliver @contents, user
    end
    
    def Sendmail.load file
      sender = file.gets[1..-2]
      recipients = []
      while /^$/ !~ line = file.gets
	recipients.push line[1..-2]
      end
      contents = file.read
      return new contents, sender, recipients
    end
    
    def Sendmail.parse stream, recipients = nil
      mail = MailRead.new(stream)
      if mail.From
	sender = MailRead.extract(mail.From)[0]
      elsif POP[0]
	sender = POP[0][:USER] + "@" + POP[0][:SERVER]
      else
	raise "can't get sender address"
      end
      if recipients.nil?
	recipients = []
	for addr in [mail.To, mail.Cc, mail.Bcc]
	  recipients += MailRead.extract(addr) if addr
	end
	mail.remove_bcc
      end

      contents = ''
      time = Time.now
      if not mail.field("Date")
	contents.concat time.strftime("Date: %a, %d %h %Y %X +0900\n")
      end
      if not mail.field("Message-Id")
	contents.concat time.strftime("Message-Id: <%Y%m%d%H%M%s.QAA") +
	  format("%05d", Process.pid) + "@" + LOCAL_DOMAIN_FQDN + ">\n"
      end
      contents.concat mail.header.sub(/(\r\n|\r|\n){2}\z/) {
	$1 + format("X-Dispatcher: mailclient-%s + maillib-%s (ruby %s [%s])",
	    MailClient::Version,
	    Net::Session::Version,
	    RUBY_VERSION, RUBY_PLATFORM) +
	    $1 + $1
      }
      contents.concat mail.body
      return Sendmail.new contents, sender, recipients
    end
    
    def Sendmail.deliver mail, user
      open(format(MDA_FORMAT, user), "w") do |dma|
	dma.write mail
      end
    end
  end

  def parseopts
    extract = false
    recipients = []
    if File.basename($0) =~ /^imput/
      extract = true
    else
      while arg = ARGV.shift
	if /^-/ =~ arg
	  case arg[1..-1]
	  when "t"
	    extract = true
	  when /^(?:C|oC|F|f|h|oA|oD|oE|oG|oL|oQ|oR|oT|oX|oM?)$/
	    # ignore option
	    ARGV.shift
	  else
	    # ignore option
	  end
	else
	  recipients.push arg
	end
      end
    end
    return extract, recipients
  end

  def smtpsend mail
    smtp = Net::SMTPSession.new(SMTP_SERVER)
    smtp.start LOCAL_DOMAIN_FQDN
    begin
      mail.send smtp
    ensure
      smtp.finish
    end
  end

  def generate_filename
    filename = File.expand_path Time.new.strftime("%Y%m%d%H%M-000"), SPOOL
    while File.exist? filename
      filename.succ!
    end
    return filename
  end

  def savemail mail
    filename = generate_filename
    file = open(filename, "w")
    begin
      begin
	mail.save file
      ensure
	file.close
      end
    rescue Exception
      File.delete filename if File.exist? filename
      raise
    end
  end

  def sendmail stream = STDIN
    extract, recipients = parseopts
    
    if extract
      mail = Sendmail.parse(stream)
    else
      mail = Sendmail.parse(stream, recipients)
    end
    
    mail.recipients.delete_if do |recipient|
      if /@/ !~ recipient
	mail.deliver recipient
	true
      else
	false
      end
    end
    return if mail.recipients.empty?
    
    begin
      smtpsend mail
    rescue
      savemail mail
    end
  end

  def sendqueue
    files = Dir[File.expand_path("*", SPOOL)].find_all { |i|
      /\/\d{12}-\d{3,}$/ =~ i
    }
    unless files.empty?
      puts "sending mails to #{SMTP_SERVER}..."
      smtp = Net::SMTPSession.new(SMTP_SERVER)
      smtp.start LOCAL_DOMAIN_FQDN
      begin
	for file in files
	  if File.file? file
	    open(file) do |f|
	      mail = Sendmail.load(f)
	      mail.send smtp
	    end
	    File.delete file
	  end
	end
      ensure
	smtp.finish
      end
    end
  end

  def fetchmail
    for popconf in POP
      if popconf[:TYPE] == :APOP
	client_class = Net::APOPSession
      else
	client_class = Net::POP3Session
      end
      pop = client_class.new(popconf[:SERVER])
      pop.start(popconf[:USER], popconf[:PASSWORD])
      begin
	count = pop.mails.size
	puts "#{count} message for #{popconf[:USER]} at #{popconf[:SERVER]}."
	i = 1
	for mail in pop.mails
	  print "reading message #{i} of #{count} (#{mail.size} bytes): "
	  Sendmail.deliver(mail.all.gsub!(/\r\n/, "\n"), ENV["USER"])
	  mail.send(DELETE) if DELETE
	  puts "flushed"
	  i += 1
	end
      ensure
	pop.finish
      end
    end
  end
end

if __FILE__ == $0
  include MailClient
  module_load MailClient::HOOK if defined? MailClient::HOOK

  STDOUT.sync = true

  if ARGV.include? "--pop"
    fetchmail
  elsif /^(sendmail|imput)/ =~ File.basename($0) or ARGV.include? "--sendmail"
    sendmail
  elsif ARGV.include? "-q"
    sendqueue
  else
    job = Thread.start { sendqueue }
    fetchmail
    job.join
  end
end