-- scriptname nissan-xterra-tcu.txt

-- sometimes we want to cut a CAN bus and install rusEFI into that cut
-- https://en.wikipedia.org/wiki/Man-in-the-middle_attack

-- this controls onCanRx rate as well!
setTickRate(300)

ECU_BUS = 1
-- really 'not ECU'
TCU_BUS = 2


TCU_251_593 = 593
TCU_253_595 = 595

hexstr = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, "A", "B", "C", "D", "E", "F" }

function toHexString(num)
	if num == 0 then
		return '0'
	end

	local result = ""
	while num > 0 do
		local n = num % 16
		result = hexstr[n + 1] ..result
		num = math.floor(num / 16)
	end
	return result
end

function arrayToString(arr)
	local str = ""
	local index = 1
	while arr[index] ~= nil do
		str = str.." "..toHexString(arr[index])
		index = index + 1
	end
	return str
end

totalEcuMessages = 0
totalTcuMessages = 0
totalDropped = 0
totalReplaced = 0

ENGINE_1_1F9_505 = 505
ENGINE_2_561 = 561
ENGINE_7_233_563 = 563
ENGINE_3_23D_573 = 573
ENGINE_4_23E_574 = 574
ENGINE_5_551_1361 = 1361
ENGINE_6_580_1408 = 1408

function onAnythingFromECU(bus, id, dlc, data)
--	totalEcuMessages = totalEcuMessages + 1
	if id ~= 721
	and id ~= 734
	then
  	print('from ECU ' ..id .." " ..arrayToString(data) .." dropped=" ..totalDropped .." replaced " ..totalReplaced)
	end
	if id < 2048 then
  	txCan(TCU_BUS, id, 0, data) -- relay non-TCU message to TCU
  else
    print ("Not relaying EXT" .. id)
  end
end

function relayFromECU(bus, id, dlc, data)
	totalEcuMessages = totalEcuMessages + 1


	txCan(TCU_BUS, id, 0, data) -- relay non-TCU message to TCU
end

function onAnythingFromTCU(bus, id, dlc, data)
	totalTcuMessages = totalTcuMessages + 1
	if id ~= TCU_251_593 and id ~= TCU_253_595 then
	  print('from TCU ' ..id .." " ..arrayToString(data) .." dropped=" ..totalDropped .." replaced " ..totalReplaced)
	end
	txCan(ECU_BUS, id, 0, data) -- relay non-ECU message to ECU
end

--function getTwoBytesLSB(data, offset, factor)
--	return (data[offset + 2] * 256 + data[offset + 1]) * factor
--end

function getTwoBytesMSB(data, offset, factor)
	return (data[offset + 1] * 256 + data[offset + 2]) * factor
end

function setTwoBytesMsb(data, offset, value)
	value = math.floor(value)
	data[offset + 1] = value >> 8
	data[offset + 2] = value & 0xff
end

local rpm = 0

payloadENGINE_1_505 = {0x20, 0x00, 0x1a, 0x5e, 0x00, 0x00, 0x00, 0x00}
function onENGINE_1_505(bus, id, dlc, data)
  rpm = getTwoBytesMSB(data, 2, 0.125)
end

function sendENGINE_1_505()
-- wow it's happy without RPM?!  setTwoBytesMsb(payloadENGINE_1_505, 2, 8 * rpm)
	txCan(TCU_BUS, ENGINE_1_1F9_505, 0, payloadENGINE_1_505)
end

pps = 0
payloadENGINE_2_561 = {0xe0, 0x80, 0x09, 0xe0, 0xd4, 0xc3, 0x4c, 0x9e}
function sendENGINE_2_231_561()
	payloadENGINE_2_561[3] = pps / 0.5 -- tps or pps
	txCan(TCU_BUS, ENGINE_2_561, 0, payloadENGINE_2_561)
end

payloadENGINE_7_563 = {0x79, 0xa2, 0x00, 0x18, 0x0e, 0x00, 0x00, 0x01}
-- 233
function sendENGINE_7_233_563()
--	payloadENGINE_7_563[4] = data[4] -- RPMlow
--	payloadENGINE_7_563[7] = data[7] -- RPMhi
	txCan(TCU_BUS, ENGINE_7_233_563, 0, payloadENGINE_7_563)
end

payloadENGINE_3_573 = {0x00, 0x0e, 0x0b, 0x0e, 0x01, 0x38, 0x00, 0x79}
-- 23D
function onENGINE_3_573(bus, id, dlc, data)
	pps = data[2] * 0.392
end

function sendENGINE_3_573()
	payloadENGINE_3_573[2] = pps / 0.392
	payloadENGINE_3_573[3] = pps / 0.392 -- Throttle_position_capped
	txCan(TCU_BUS, ENGINE_3_23D_573, 0, payloadENGINE_3_573)
--	txCan(TCU_BUS, ENGINE_3_23D_573, 0, data)
end

payloadENGINE_4_574 = {0x00, 0x40, 0xff, 0x45, 0x00, 0xd6, 0x00, 0xa2}
function sendENGINE_4_23E_574()
	payloadENGINE_4_574[3] = (100 - pps) / 0.392 -- data[3] -- affects desired torque converter pressure Throttle_position_inverted
	payloadENGINE_4_574[7] = pps / 0.392 -- data[7] -- TPS
	txCan(TCU_BUS, ENGINE_4_23E_574, 0, payloadENGINE_4_574)
end

payloadENGINE_5 = {0x7d, 0xdb, 0x00, 0xa0, 0x00, 0x02, 0x80, 0xff}
function sendENGINE_5_551_1361()
	txCan(TCU_BUS, ENGINE_5_551_1361, 0, payloadENGINE_5)
end

payloadENGINE_6 = {0x00, 0x82, 0x40, 0x00, 0x00, 0x00, 0x00, 0x00}
function sendEngine6_580_1408()
	txCan(TCU_BUS, ENGINE_6_580_1408, 0, payloadENGINE_6)
end

canRxAdd(ECU_BUS, ENGINE_1_1F9_505, onENGINE_1_505)

canRxAdd(ECU_BUS, ENGINE_3_23D_573, onENGINE_3_573)

CAN_721_2d1 = 721
payload721_2d1 = {0x00, 0x84, 0x00, 0x00, 0x31, 0xf8, 0x01}
function sendCan721_2d1()
	txCan(TCU_BUS, CAN_721_2d1, 0, payload721_2d1)
end


CAN_734_2de = 734
payload734_2de = {0x0f, 0x08, 0x02, 0x00, 0x19, 0x65, 0x07, 0xa8}
function sendCan734_2de()
	txCan(TCU_BUS, CAN_734_2de, 0, payload734_2de)
end

--function onCan734_2de(bus, id, dlc, data)
--end
--function onCan721_2d1(bus, id, dlc, data)
--end
--canRxAdd(ECU_BUS, CAN_721_2d1, onCan721_2d1)
--canRxAdd(ECU_BUS, CAN_734_2de, onCan734_2de)

--canRxAdd(ECU_BUS, 721, onAnythingFromECU) -- required for TCU not to throw code
--canRxAdd(ECU_BUS, 734, onAnythingFromECU) -- required for TCU not to throw code


-- last option: unconditional forward of all remaining messages
--canRxAddMask(ECU_BUS, 0, 0, onAnythingFromECU)
canRxAddMask(TCU_BUS, 0, 0, onAnythingFromTCU)

everySecondTimer = Timer.new()

_10msPeriodTimer = Timer.new()
_15msPeriodTimer = Timer.new()

function onTick()
	if everySecondTimer : getElapsedSeconds() > 1 then
	  print("rpm " .. rpm .. " pps " .. pps)
		everySecondTimer : reset()
		print("Total from ECU " ..totalEcuMessages .." from TCU " ..totalTcuMessages .." dropped=" ..totalDropped .." replaced " ..totalReplaced)
	end

  rpm = getSensor("RPM") or 0
  pps = getSensor("AcceleratorPedal") or 0

	if _10msPeriodTimer : getElapsedSeconds() > 0.01 then
    _10msPeriodTimer : reset()
    sendENGINE_1_505()
    sendENGINE_2_231_561()
    sendENGINE_7_233_563()
    sendENGINE_3_573()
    sendENGINE_4_23E_574()
    sendCan721_2d1()
    sendCan734_2de()
	end

	if _15msPeriodTimer : getElapsedSeconds() > 0.015 then
    _15msPeriodTimer : reset()
    sendENGINE_5_551_1361()
    sendEngine6_580_1408()
	end


end