local ffi = FFI

PortTypes = {
	output = 0,
	input = 1,
}

PortDirections = {
	[0] = {-1, 0, 0},
	[1] = {0, 1, 0},
	[2] = {1, 0, 0},
	[3] = {0, -1, 0},
	[4] = {0, 0, 1},
	[5] = {0, 0, -1}
}

Port = {}

function Port.new(type, direction, position, causeupdate, idx, gate)
	local o = {
		group = nil,
		type = type,
		direction = direction,
		position = position,
		causeupdate = causeupdate,
		gate = gate,
		idx = idx,
	}
	return o
end

function Port.getconnectionposition(port)
	local offset = PortDirections[port.direction]
	return {port.position[1]+offset[1], port.position[2]+offset[2], port.position[3]+offset[3]}
end

function Port.isrising(port)
	return port.group.state[0]==1 and (port.group.update_tick[0] == GSim.current_tick)
end

function Port.isfalling(port)
	return port.group.state[0]==0 and (port.group.update_tick[0] == GSim.current_tick)
end

function Port.getgate(port)
	return port.gate
end

function Port.setgroup(port, group)
	port.group = group
	Port.getgate(port).port_nets[port.idx] = group
	if group then
		Port.getgate(port).port_net_state    [port.idx] = group.state
		Port.getgate(port).port_net_state_num[port.idx] = group.state_num
		Port.getgate(port).port_net_in_queue [port.idx] = group.in_queue
	else
		Port.getgate(port).port_net_state    [port.idx] = ffi.cast("int*", 0)
		Port.getgate(port).port_net_state_num[port.idx] = ffi.cast("int*", 0)
		Port.getgate(port).port_net_in_queue [port.idx] = ffi.cast("int*", 0)
	end
end

function Port.getgroup(port)
	return port.group
end

function Port.gettype(port)
	return port.type
end

function Port.getstate(port)
	return Port.getgate(port).port_states[port.idx]
end