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)
	local o = {
		type = type,
		direction = direction,
		position = position,
		causeupdate = causeupdate,
		state = false,
		gate = nil,
		group = nil,
	}
	return o
end

function Port.setstate(port, state) -- output state
	if state ~= port.state then
		local group = port.group
		group.state_num = group.state_num - (port.state and 1 or 0) + (state and 1 or 0)
		port.state = state
		
		if (group.state_num>0) ~= group.state then
			Simulation.queuegroup(GSim, group)
		end
	end
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)
	if port.group == nil then
		return false
	end
	return port.group.state and (port.group.updatetick == GSim.currenttick)
end

function Port.isfalling(port)
	if port.group == nil then
		return false
	end
	return port.group.state == false and (port.updatetick == GSim.currenttick)
end

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

function Port.setgate(port, gate)
	port.gate = gate
end

function Port.setgroup(port, group)
	port.group = group
end

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

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

function Port.getstate(port)
	return port.state
end