receiving_files = {}

ibb_block_size  = 4096

current_sid_number = 0

-- FIXME: read from /dev/urandom?

function gen_unique_sid ()

	current_sid_number = current_sid_number + 1

	return 'mc-' .. tostring ( current_sid_number )

end

ibb_incoming_iq_handler = lm.message_handler.new ( 

	function ( conn, mess )

		local id   = mess:attribute ( 'id' )

		local from = mess:attribute ( 'from' )

		if mess:child ( 'open' ) and mess:child( 'open' ):attribute ( 'xmlns' ) == 'http://jabber.org/protocol/ibb' then

			local sid  = mess:child( 'open' ):attribute ( 'sid' )

			if not receiving_files[sid] then

				local buffer = ''

				receiving_files[sid] = { from = from, status = 'pending' }

				receiving_files[sid].accept =

					function ( name )

						main.print_info ( from, string.format ( "Receiving stream from %s, id %s", from, sid ) )

						conn:send ( lm.message.create { to = from, mtype = 'iq-result', id = id } )

						receiving_files[sid].name = name

						receiving_files[sid].status = 'accepted'

					end

				receiving_files[sid].reject =

					function ()

						conn:send (

							lm.message.create { to = from, mtype = 'iq-error', id = id,

								error = { code = '405', type = 'cancel',

									['not-allowed'] = { xmlns = 'urn:ietf:params:xml:ns:xmpp-stanzas' }

								}

							} )

						receiving_files[sid].status = 'rejected'

					end

				print ( 'You have a new bytestream to receive. To save it use /ibb accept ' .. sid .. ' filename' )

			else

				conn:send (

					lm.message.create { to = from, mtype = 'iq-error', id = id,

						error = { code = '409', type = 'cancel',

							conflict = { xmlns = 'urn:ietf:params:xml:ns:xmpp-stanzas' }

						}

					} )

			end

		elseif mess:child ( 'data' ) and mess:child( 'data' ):attribute ( 'xmlns' ) == 'http://jabber.org/protocol/ibb' then

			local sid  = mess:child( 'data' ):attribute ( 'sid' )

			local seq  = mess:child( 'data' ):attribute ( 'seq' )

			if receiving_files[sid] and from == receiving_files[sid].from and not receiving_files[sid][tonumber(seq)+1] then

				local data = mess:child( 'data' ):value ()

				main.print_info ( from, string.format ( " - stream part %s, id %s, %d bytes", seq, sid, data:len() ) )

				conn:send ( lm.message.create { to = from, mtype = 'iq-result', id = id } )

				receiving_files[sid][tonumber(seq)+1] = data

			else

				receiving_files[sid] = nil -- invalidate session

				conn:send (

					lm.message.create { to = from, mtype = 'iq-error', id = id,

						error = { code = '409', type = 'cancel',

							conflict = { xmlns = 'urn:ietf:params:xml:ns:xmpp-stanzas' }

						}

					} )

			end

		elseif mess:child ( 'close' ) and mess:child( 'close' ):attribute ( 'xmlns' ) == 'http://jabber.org/protocol/ibb' then

			local sid  = mess:child( 'close' ):attribute ( 'sid' )

			if receiving_files[sid] and from == receiving_files[sid].from then

				main.print_info ( from, "Done with stream id " .. sid )

				conn:send ( lm.message.create { to = from, mtype = 'iq-result', id = id } )

				local decoder = io.popen ( string.format ( "base64 -d -i >%q", receiving_files[sid].name ), "w" )

				if not decoder then

					main.print_info ( from, "Error opening decoder" )

				else

					for i, v in ipairs ( receiving_files[sid] ) do

						decoder:write ( v )

					end

					decoder:close ()

				end

			else

				receiving_files[sid] = nil -- invalidate session

				conn:send (

					lm.message.create { to = from, mtype = 'iq-error', id = id,

						error = { code = '409', type = 'cancel',

							conflict = { xmlns = 'urn:ietf:params:xml:ns:xmpp-stanzas' }

						}

					} )

			end

		else

			return false

		end

		return true

	end )

-- You must specify a full jid with resource!

function send_file ( to, name )

	local sid = gen_unique_sid ()

	local conn = lm.connection.bless ( main.connection () )

	conn:send (

		lm.message.create { to = to, mtype = 'iq-set',

			open = { sid = sid, ['block-size'] = ibb_block_size, xmlns = 'http://jabber.org/protocol/ibb' }

		},

		function ( conn, message )

			if message:child ( 'error' ) then

				main.print_info ( to, "Stream request refused: " .. message:child( 'error' ):children():name () )

			else

				main.print_info ( to, "Stream accepted, starting sequence" )

				local buffer = ''

				main.bgread ( string.format ( 'base64 -w 0 %q', name ),

					function ( data )

						if data then

							buffer = buffer .. data

							return true

						else

							local seq = 0

							local msgbuf = buffer:sub ( 1, ibb_block_size )

							buffer = buffer:sub ( ibb_block_size + 1 )

							local function handler ( conn, message )

								if message:child ( 'error' ) then

									main.print_info ( to, "Stream error, transfer ceased at seq = " .. seq .. ": " .. message:child( 'error' ):children():name () )

								else

									main.print_info ( to, " - acquired seq = " .. seq )

									seq = seq + 1

									if buffer:len () == 0 then

										conn:send (

											lm.message.create { to = to, mtype = 'iq-set',

												close = { sid = sid, xmlns = 'http://jabber.org/protocol/ibb' }

											},

											function ( conn, message )

												if message:child ( 'error' ) then

													main.print_info ( to, "Error at closing stream: " .. message:child( 'error' ):children():name () )

												else

													main.print_info ( to, "File successfully transferred" )

												end

												return true

											end )

									else

										local msgbuf = buffer:sub ( 1, ibb_block_size )

										buffer = buffer:sub ( ibb_block_size )

										conn:send (

											lm.message.create { to = to, mtype = 'iq-set',

												data = { sid = sid, xmlns = 'http://jabber.org/protocol/ibb', seq = seq,

													msgbuf

												}

											},

											handler )

									end

								end

								return true

							end

							conn:send (

								lm.message.create { to = to, mtype = 'iq-set',

									data = { sid = sid, xmlns = 'http://jabber.org/protocol/ibb', seq = seq,

										msgbuf

									}

								},

								handler )

							return false

						end

					end )

			end

			return true

		end )

end

main.add_command ( 'ibb',

	function ( args )

		args = parse_args ( args )

		if args[1] == 'send' then

			local who

			if args.t then

				who = args.t

				args.t = nil

			else

				who = full_current_jid ()

			end

			args[1] = nil

			send_file ( who, rebuild_args_string ( args ) )

		elseif args[1] == 'accept' then

			local id = args[2]

			args[1] = nil

			args[2] = nil

			if receiving_files[id] then

				receiving_files[id].accept ( rebuild_args_string ( args ) )

			end

		elseif args[1] == 'reject' then

			local id = args[2]

			if receiving_files[id] then

				receiving_files[id].reject ()

			end

		elseif args[1] == 'del' then

			local id = args[2]

			receiving_files[id] = nil

		else

			print ( 'List of incoming streams:' )

			for sid, data in pairs ( receiving_files ) do

				print ( sid .. ': ' .. ( data.name or '(not set)' ) .. ' [' .. data.status .. ']' )

			end

		end

	end )

commands_help['ibb'] = "[[-t target_jid] send filename | accept sid filename | reject sid filename | del sid]\n\nRequests, accepts or rejects sending file via in-band bytestream."

-- vim: se ts=4: --