require 'rex/proto/iax2/constants'
require 'rex/proto/iax2/codecs'
require 'rex/proto/iax2/call'

require 'rex/socket'
require 'thread'
require 'digest/md5'
require 'timeout'

module Rex
module Proto
module IAX2
class Client

	attr_accessor :caller_number, :caller_name, :server_host, :server_port
	attr_accessor :username, :password
	attr_accessor :sock, :monitor
	attr_accessor :src_call_idx
	attr_accessor :debugging
	attr_accessor :calls	

	def initialize(uopts={})
		opts = {
			:caller_number => '15555555555',
			:caller_name   => '',
			:server_port   => IAX2_DEFAULT_PORT,
			:context       => { }
		}.merge(uopts)
		
		self.caller_name   = opts[:caller_name]
		self.caller_number = opts[:caller_number]
		self.server_host   = opts[:server_host]
		self.server_port   = opts[:server_port]
		self.username      = opts[:username]
		self.password      = opts[:password]
		
		self.sock = Rex::Socket::Udp.create(
			'PeerHost' => self.server_host,
			'PeerPort' => self.server_port,
			'Context'  => opts[:context]
		)
		
		self.monitor   = ::Thread.new { monitor_socket }

		self.src_call_idx = 0
		self.calls = {}
		
	end
	
	def shutdown
		self.monitor.kill rescue nil
	end
	
	def create_call
		cid  = allocate_call_id()
		self.calls[ cid ] = IAX2::Call.new(self, cid)
	end

	#
	# Transport
	#

	def monitor_socket
		while true
			begin
				pkt, src = self.sock.recvfrom(65535)
				next if not pkt
				
				# Find the matching call object 
				mcall = matching_call(pkt)				
				next if not mcall
	
				if (pkt[0,1].unpack("C")[0] & 0x80) != 0
					mcall.handle_control(pkt)
				else
					# Dispatch the buffer via the call handler
					mcall.handle_audio(pkt)
				end
			rescue ::Exception => e
				dprint("monitor_socket: #{e.class} #{e} #{e.backtrace}")
				break
			end
		end
		self.sock.close rescue nil
	end
	
	def matching_call(pkt)
		src_call = pkt[0,2].unpack('n')[0]
		dst_call = nil
		
		if (src_call & 0x8000 != 0)
			dst_call = pkt[2,2].unpack('n')[0]
			dst_call ^= 0x8000 if (dst_call & 0x8000 != 0)
		end
		
		src_call ^= 0x8000 if (src_call & 0x8000 != 0)
		
		# Find a matching call in our list
		mcall = self.calls.values.select {|x| x.dcall == src_call or (dst_call and x.scall == dst_call) }.first
		if not mcall
			dprint("Packet received for non-existent call #{[src_call, dst_call].inspect}  vs #{self.calls.values.map{|x| [x.dcall, x.scall]}.inspect}")
			return
		end
		mcall	
	end
	
	def allocate_call_id
		res = ( self.src_call_idx += 1 )
		if ( res > 0x8000 )
			self.src_call_idx = 1
			res = 1
		end
		res
	end

	def dprint(msg)
		return if not self.debugging
		$stderr.puts "[#{Time.now.to_s}] #{msg}"
	end

	def send_data(call, data, inc_seq = true )
		r = self.sock.sendto(data, self.server_host, self.server_port, 0)
		if inc_seq
			call.oseq = (call.oseq + 1) & 0xff
		end
		r
	end

	def send_ack(call)
		data =	[ IAX_SUBTYPE_ACK ].pack('C')
		send_data( call, create_pkt( call.scall, call.dcall, call.timestamp, call.oseq, call.iseq, IAX_TYPE_IAX, data ), false )
	end
	
	def send_pong(call, stamp)
		data =	[ IAX_SUBTYPE_PONG ].pack('C')
		send_data( call, create_pkt( call.scall, call.dcall, stamp, call.oseq, call.iseq, IAX_TYPE_IAX, data ) )
	end

	def send_lagrp(call, stamp)
		data =	[ IAX_SUBTYPE_LAGRP ].pack('C')
		send_data( call, create_pkt( call.scall, call.dcall, stamp, call.oseq, call.iseq, IAX_TYPE_IAX, data ) )
	end


	def send_invalid(call)
		data =	[ IAX_SUBTYPE_INVAL ].pack('C')
		send_data( call, create_pkt( call.scall, call.dcall, call.timestamp, call.oseq, call.iseq, IAX_TYPE_IAX, data ) )
	end
	
	def send_hangup(call)
		data =	[ IAX_SUBTYPE_HANGUP ].pack('C')
		send_data( call, create_pkt( call.scall, call.dcall, call.timestamp, call.oseq, call.iseq, IAX_TYPE_IAX, data ) )
	end
	
	def send_new(call, number)
		data = [ IAX_SUBTYPE_NEW ].pack('C')
		
		cid = call.caller_number || self.caller_number
		cid = number if cid == 'SELF'
		
		data << create_ie(IAX_IE_CALLING_NUMBER, cid )
		data << create_ie(IAX_IE_CALLING_NAME, call.caller_name || self.caller_name)
		data << create_ie(IAX_IE_DESIRED_CODEC, [IAX_SUPPORTED_CODECS].pack("N") )
		data << create_ie(IAX_IE_ACTUAL_CODECS, [IAX_SUPPORTED_CODECS].pack("N") )
		data << create_ie(IAX_IE_USERNAME, self.username) if self.username
		data << create_ie(IAX_IE_CALLED_NUMBER, number)
		data << create_ie(IAX_IE_ORIGINAL_DID, number)

		send_data( call, create_pkt( call.scall, call.dcall, call.timestamp, call.oseq, call.iseq, IAX_TYPE_IAX, data ) )
	end

	def send_authrep_chall_response(call, chall)
		data =
			[ IAX_SUBTYPE_AUTHREP ].pack('C') +
			create_ie(IAX_IE_CHALLENGE_RESP, ::Digest::MD5.hexdigest( chall + self.password ))

		send_data( call, create_pkt( call.scall, call.dcall, call.timestamp, call.oseq, call.iseq, IAX_TYPE_IAX, data ) )
	end

	def send_regreq(call)
		data = [ IAX_SUBTYPE_REGREQ ].pack('C')
		data << create_ie(IAX_IE_USERNAME, self.username) if self.username
		data << create_ie(IAX_IE_REG_REFRESH, [IAX_DEFAULT_REG_REFRESH].pack('n'))

		send_data( call, create_pkt( call.scall, call.dcall, call.timestamp, call.oseq, call.iseq, IAX_TYPE_IAX, data ) )
	end

	def send_regreq_chall_response(call, chall)
		data =
			[ IAX_SUBTYPE_REGREQ ].pack('C') +
			create_ie(IAX_IE_USERNAME, self.username) +
			create_ie(IAX_IE_CHALLENGE_RESP, ::Digest::MD5.hexdigest( chall + self.password )) +
			create_ie(IAX_IE_REG_REFRESH, [IAX_DEFAULT_REG_REFRESH].pack('n'))

		send_data( call, create_pkt( call.scall, call.dcall, call.timestamp, call.oseq, call.iseq, IAX_TYPE_IAX, data ) )
	end

	def create_ie(ie_type, ie_data)
		[ie_type, ie_data.length].pack('CC') + ie_data
	end

	def create_pkt(src_call, dst_call, tstamp, out_seq, inp_seq, itype, data)
		[
			src_call | 0x8000,  # High bit indicates a full packet
			dst_call,
			tstamp,
			out_seq & 0xff,     # Sequence numbers wrap at 8-bits
			inp_seq & 0xff,     # Sequence numbers wrap at 8-bits
			itype
		].pack('nnNCCC') + data
	end

end
end
end
end