=begin
Feed2Imap - RSS/Atom Aggregator uploading to an IMAP Server
Copyright (c) 2005 Lucas Nussbaum <lucas@lucas-nussbaum.net>

This file contains classes to parse a feed and store it as a Channel object.

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 2 of the License, 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, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
=end

require 'rexml/document'
require 'time'
require 'rmail'
require 'feedparser'
require 'feedparser/text-output'
require 'feedparser/html-output'
require 'base64'
require 'rmail'
require 'digest/md5'

class String
  def needMIME
    utf8 = false
    begin
      self.unpack('U*').each do |c|
        if c > 127
          utf8 = true
          break
        end
      end
    rescue
      # safe fallback in case of problems
      utf8 = true
    end
    utf8
  end
end

def item_to_mail(config, item, id, updated, from = 'Feed2Imap', inline_images = false, wrapto = false)
  message = RMail::Message::new
  if item.creator and item.creator != ''
    if item.creator.include?('@')
      message.header['From'] = item.creator.chomp
    else
      message.header['From'] = "=?utf-8?b?#{Base64::encode64(item.creator.chomp).gsub("\n",'')}?= <#{config.default_email}>"
    end
  else
    message.header['From'] = "=?utf-8?b?#{Base64::encode64(from).gsub("\n",'')}?= <#{config.default_email}>"
  end
  message.header['To'] = "=?utf-8?b?#{Base64::encode64(from).gsub("\n",'')}?= <#{config.default_email}>"

  if item.date.nil?
    message.header['Date'] = Time::new.rfc2822
  else
    message.header['Date'] = item.date.rfc2822
  end
  message.header['X-Feed2Imap-Version'] = F2I_VERSION if defined?(F2I_VERSION)
  message.header['Message-Id'] = id
  message.header['X-F2IStatus'] = "Updated" if updated
  # treat subject. Might need MIME encoding.
  subj = item.title or (item.date and item.date.to_s) or item.link
  if subj
    if subj.needMIME
      message.header['Subject'] = "=?utf-8?b?#{Base64::encode64(subj).gsub("\n",'')}?="
    else
      message.header['Subject'] = subj
    end
  end
  textpart = htmlpart = nil
  parts = config.parts
  if parts.include?('text')
    textpart = parts.size == 1 ? message : RMail::Message::new
    textpart.header['Content-Type'] = 'text/plain; charset=utf-8; format=flowed'
    textpart.header['Content-Transfer-Encoding'] = '8bit'
    textpart.body = item.to_text(true, wrapto, false)
  end
  if parts.include?('html')
    htmlpart = parts.size == 1 ? message : RMail::Message::new
    htmlpart.header['Content-Type'] = 'text/html; charset=utf-8'
    htmlpart.header['Content-Transfer-Encoding'] = '8bit'
    htmlpart.body = item.to_html
  end

  # inline images as attachments
  imgs = []
  if inline_images
    cids = []
    htmlpart.body.gsub!(/(<img[^>]+)src="(\S+?\/([^\/]+?\.(png|gif|jpe?g)))"([^>]*>)/i) do |match|
      # $2 contains url, $3 the image name, $4 the image extension
      begin
        image = Base64.encode64(HTTPFetcher::fetch($2, Time.at(0)).chomp) + "\n"
        cid = "#{Digest::MD5.hexdigest($2)}@#{config.hostname}"
        if not cids.include?(cid)
          cids << cid
          imgpart = RMail::Message.new
          imgpart.header.set('Content-ID', "<#{cid}>")
          type = $4
          type = 'jpeg' if type.downcase == 'jpg' # hack hack hack
          imgpart.header.set('Content-Type', "image/#{type}", 'name' => $3)
          imgpart.header.set('Content-Disposition', 'attachment', 'filename' => $3)
          imgpart.header.set('Content-Transfer-Encoding', 'base64')
          imgpart.body = image
          imgs << imgpart
        end
        # now to specify what to replace with
        newtag = "#{$1}src=\"cid:#{cid}\"#{$5}"
        #print "#{cid}: Replacing '#{$&}' with '#{newtag}'...\n"
        newtag
      rescue
        #print "Error while fetching image #{$2}: #{$!}...\n"
        $& # don't modify on exception
      end
    end
  end
  if imgs.length > 0
    message.header.set('Content-Type', 'multipart/related', 'type'=> 'multipart/alternative')
    texthtml = RMail::Message::new
    texthtml.header.set('Content-Type', 'multipart/alternative')
    texthtml.add_part(textpart)
    texthtml.add_part(htmlpart)
    message.add_part(texthtml)
    imgs.each do |i|
      message.add_part(i)
    end
  elsif parts.size != 1
    message.header['Content-Type'] = 'multipart/alternative'
    message.add_part(textpart)
    message.add_part(htmlpart)
  end
  return message.to_s
end