require 'net/imap'

class Message
	
	attr_reader :message_id, :subject, :sender_name, :sender_email, :date, :text

	def initialize( imap, message_id )
		@imap, @message_id = imap, message_id
		envelope = @imap.fetch( @message_id, 'ENVELOPE' ).first.attr['ENVELOPE']
		@subject = envelope['subject']
		@sender_name = envelope['from'].first['name']
		@sender_email = envelope['from'].first['mailbox'] + '@' + envelope['from'].first['host']
		@text = plain_text_content_from_message( message_id )
	end
	
	def plain_text_content_from_message( id )
		text = @imap.fetch( id, 'BODY[1]' ).first.attr['BODY[1]']
		text.gsub!(/\r\n/,"\n")
		text.gsub!(/\r/,"\n")
		text.gsub!(/=\n/,'')
		text.gsub!(/((?:=[0-9a-fA-F]{2})+)/n) { [$1.delete('=')].pack('H*') }
		text
	end

end

class Mail2WikiHelper

	DEFAULT_SETTINGS = {
		:server => 'imap.hermes.cam.ac.uk',
		:username => 'tamc2',
		:password => '',
		:mailbox => 'mcr notices',
		:check_frequency => 600, # Seconds
		:subject_regexp => /.*/,
	}
	
	def initialize( wiki, settings = {} )
		@settings = DEFAULT_SETTINGS.merge( settings )
		@wiki = wiki
		check_mailbox
		Thread.new do 
			loop do
				sleep @settings[:check_frequency ]
				check_mailbox
			end
		end
	end
	
	private
	
	def check_mailbox
		login
		select_mailbox
		p "Checking for emails in #{@settings[:server]}"
		new_messages_for_wiki do |message_id|
			this_message = Message.new( @imap, message_id )
			if this_message.subject =~ @settings[:subject_regexp]
				add_message_to_wiki( this_message ) 
				mark_as_added( message_id )
			end
		end
		logout
	end
	
	def add_message_to_wiki( message )
		current_page = @wiki.page( message.subject )
		if current_page.empty?
			text = "h1. #{message.subject}"
		else
			text = current_page.textile
		end
		text << "\n\n----\n\n"
		text << "#{message.date} from #{message.sender_name} #{message.sender_email}\n"
		text << message.text.gsub(/[\*-]{2,}/,'').gsub(/\n\s+/,"\n").gsub(/\n/,"\n\n") 		
		@wiki.revise(message.subject, text, message.sender_name )
	end
	
	def login
		@imap = Net::IMAP.new(@settings[:server])
		@imap.login( @settings[:username], @settings[:password] )
	end
	
	def logout
		@imap.logout
		@imap.disconnect
	end
	
	def select_mailbox
		@imap.select @settings[:mailbox]
	end
	
	def new_messages_for_wiki 
		@imap.search('UNKEYWORD PutInWiki').each { |id| yield id } 		
	end
	
	def mark_as_added( id )
		# @imap.store( id, '+FLAGS', ['PutInWiki'] )
	end
	
end