const calculateFactor = (min, max, size) => {
  const range = Math.abs(min) + max
  return range / (size == 1 ? 0xFF : 0xFFFF)
}

const scale = (min, max, size, value) => {
  const factor = calculateFactor(min, max, size)
  return (value * factor) + min
}

const scaleSigned = (min, max, size, value) => {
  const factor = calculateFactor(min, max, size)
  if (size === 1) {
    const positive = (value & (1 << 7)) === 0
    if (positive) {
      return value * factor
    }
    return (value - 0xFF) * factor
  } else {
    const positive = (value & (1 << 15)) === 0
    if (positive) {
      return value * factor
    }
    return (value - 0xFFFF) * factor
  }
}

const formatGear = (value) => {
  return value
}

const formatRpm = (value) => {
  const min = 0
  const max = 16383.75
  const size = 2
  const unit = 'rpm'
  return scale(min, max, size, value)
}

const formatSpeed = (value) => {
  const min = 0
  const max = 4096
  const size = 2
  const unit = 'km/h'
  return scale(min, max, size, value)
}

const formatLoad = (value) => {
  const min = 0
  const max = 1536.00933
  const size = 2
  const unit = '%'
  return scale(min, max, size, value)
}

const formatTorque = (value) => {
  const min = -2048
  const max = 2047.9375
  const size = 2
  const unit = 'Nm'
  return scaleSigned(min, max, size, value)
}

const formatThrottlePedalPosition = (value) => {
  const min = 0
  const max = 100.006410
  const size = 2
  const unit = '%'
  return scale(min, max, size, value)
}

const formatThrottleValvePosition = (value) => {
  const min = 0
  const max = 6553.5
  const size = 2
  const unit = '%'
  //return scale(min, max, size, value) TODO: debugging
  return value
}

const formatAmbientPressure = (value) => {
  const min = 0
  const max = 2559.993705
  const size = 2
  const unit = 'psi'
  const scaledValue = scale(min, max, size, value)
  return scaledValue * 0.0145038 // hPa -> psi
}

const formatBoost = (value) => {
  const min = 0
  const max = 5119.921875
  const size = 2
  const unit = 'psi'
  const scaledValue = scale(min, max, size, value)
  return scaledValue * 0.0145038 // hPa -> psi
}

const formatWastegate = (value) => {
  const min = 0
  const max = 99.998474
  const size = 2
  const unit = '%'
  return scale(min, max, size, value)
}

const formatShortTermFuelTrim = (value) => {
  const min = -1536
  const max = 1535.953125
  const size = 2
  const unit = '%'
  return scaleSigned(min, max, size, value)
}

const formatFuelPressureHigh = (value) => {
  const min = 0
  const max = 32.7675
  const size = 2
  const unit = 'psi'
  const scaledValue = scale(min, max, size, value)
  return scaledValue * 145 // MPa -> psi
}

const formatFuelPressureLow = (value) => {
  const min = 0
  const max = 6553.5
  const size = 2
  const unit = 'psi'
  const scaledValue = scale(min, max, size, value)
  return scaledValue / 6.895 // kPa -> psi
}

const formatIgnitionTiming = (value) => {
  const unit = 'degrees'
  const min = -96
  const max = 95.25
  const size = 1
  return scaleSigned(min, max, size, value)
}

const formatTemperature = (value) => {
  const unit = 'C'
  const min = -48
  const max = 143.25
  const size = 1
  return scale(min, max, size, value)
}

const formatLambda = (value) => {
  const min = 0
  const max = 15.99054
  const unit = 'ratio'
  const size = 2
  return scale(min, max, size, value)
}

const formatIntakeManifoldPressure = (value) => {
  const min = 0
  const max = 5119.921875
  const unit = 'psi'
  const size = 2
  const scaledValue = scale(min, max, size, value)
  return scaledValue * 0.0145038 // hPa -> psi
}

const formatMassAirFlow = (value) => {
  const min = 0
  const max = 6553.5
  const size = 2
  const unit = 'g/s'
  const scaledValue = scale(min, max, size, value)
  return scaledValue / 3.6 // kg/h -> g/s
}

const formatKnock = (value) => {
  const min = 0
  const max = 1
  const unit = 'flag'
  return value
}

// format is [requestArbitrationId, dataIdentifier, name, formatter, size]
module.exports = [
  // 1. general (gear + rpm + speed)
  [0x7E5, 0x6340, 'Gear', formatGear, 1], // Ganganzeige_aktuell_eingelegter_Gang
  [0x7E0, 0x2000, 'RPM', formatRpm, 2], // Motordrehzahl
  [0x7E5, 0x6346, 'Speed', formatSpeed, 2], // Fahrzeuggeschwindigkeit
  // 2. load
  // LoadAdapted Momentenadaption_Teillast
  [0x7E0, 0x2001, 'CalculatedLoad', formatLoad, 2], // Motorlast
  // 3. torque (target + actual)
  // TorqueReducedActual Momentenanforderung Durch Reduzierstufe Ist
  // TorqueReducedTarget Momentenanforderung Durch Reduzierstufe Soll
//  [0x7E0, 0x6000, 'EngineTorque', formatTorque], // Motordrehmoment
  [0x7E5, 0x6256, 'TorqueActual', formatTorque, 2], // Istmoment_Verbrennungsmotor
  [0x7E5, 0x6257, 'TorqueTarget', formatTorque, 2], // Sollmoment_Verbrennungsmotor
  //[0x7E5, 0x625A, 'CoordinatedTorqueTarget', formatTorque], // Sollmoment_aus_der_Momentenkoordination
  // 4. accelerator pedal
  [0x7E0, 0x2029, 'ThrottlePedalPosition', formatThrottlePedalPosition, 2], // Pedalwertgeber
  // 5. throttle valve
  // [0x7E0, 0xD023, 'ThrottleValvePosition', formatThrottleValvePosition, 2], // Drosselklappenwinkel
  // 6. boost (target + actual)
  [0x7E0, 0x2040, 'AmbientPressure', formatAmbientPressure, 2], // Umgebungsdruck
  [0x7E0, 0x2018, 'IntakeManifoldPressure', formatIntakeManifoldPressure, 2], // Saugrohrdruck
  [0x7E0, 0x207A, 'BoostActual', formatBoost, 2], // Ladedruck_korrigiert
  [0x7E0, 0x2077, 'BoostTarget', formatBoost, 2], // Ladedruck
  // 7. wastegate duty cycle
  [0x7E0, 0xD062, 'WastegateDutyCycle', formatWastegate, 2], // Wastegate
  // 8. fuel trims (short term)
  [0x7E0, 0x6088, 'ShortTermFuelTrim1', formatShortTermFuelTrim, 2], // Gemischadaption_Additiv_Lernwert_Links
  [0x7E0, 0x6087, 'ShortTermFuelTrim2', formatShortTermFuelTrim, 2], // Gemischadaption_Additiv_Lernwert_Recht
  // 9. fuel pressure (high + low)
  [0x7E0, 0x2071, 'FuelPressureHigh', formatFuelPressureHigh, 2], // Kraftstoffdruck_Hochdruck
  [0x7E0, 0x2098, 'FuelPressureLow', formatFuelPressureLow, 2], // Kraftstoffdruck_Niederdruck
  // 10. ignition timing
  [0x7E0, 0xD010, 'IgnitionTiming', formatIgnitionTiming, 1], // ROZ_Korrektur_Zundwinkelausgabe
  // 11. temperatures (ambient + coolant + intake + oil)
  [0x7E0, 0x5030, 'AmbientTemp', formatTemperature, 1], // Aussenlufttemperatur
  //[0x7E0, 0x2013, 'CoolantTemp', formatTemperature, 1], // Kuehlmitteltemperatur
  [0x7E0, 0x2014, 'IntakeAirTemp', formatTemperature, 1], // Ansauglufttemperatur_im_Saugrohr_Bank1
  //[0x7E0, 0x2095, 'OilTemp', formatTemperature, 1], // Oeltemperatur
  // 12. afr / lambda (before kat = wideband; after kat = narrowband)
  [0x7E0, 0x6252, 'MassAirFlow', formatMassAirFlow, 2], // Luftmasse_Vorgabe
  [0x7E0, 0x2046, 'LambdaAcutal1', formatLambda, 2], // O2_Sonde_Vor_Kat_Lambda_Recht
  //[0x7E0, 0x2047, 'LambdaAcutal2', formatLambda, 2], // O2_Sonde_Vor_Kat_Lambda_Links
  [0x7E0, 0x6144, 'LambdaTarget1', formatLambda, 2], // Lambda_Sollwert_Links
  //[0x7E0, 0x6143, 'LambdaTarget2', formatLambda, 2], // Lambda_Sollwert_Recht
  // 13. knock
  [0x7E0, 0x2006, 'KnockSensor', formatKnock, 1], // Klopfsensor
]

const { isoTpSend } = require('./iso-tp')

const startDiagnosticSession = async (device, arbitrationId, mode) => {
  return isoTpSend(device, arbitrationId, 0x10, [mode])
}

// do not define more than 20 to one data identifier
const dynamicallyDefineIdentifier = async (device, requestArbitrationId, dataIdentifier, definitions) => {
  const output = []
  output.push(0x01) // defineByIdentifier subfunction
  output.push(dataIdentifier >> 8) // dynamicallyDefinedDataIdentifier
  output.push(dataIdentifier & 0xFF) // dynamicallyDefinedDataIdentifier
  for (let i = 0; i < definitions.length; ++i) {
    const definition = definitions[i]
    const definitionDataIdentifier = definition[1]
    const definitionSize = definition[4]
    output.push(definitionDataIdentifier >> 8) // sourceDataIdentifier
    output.push(definitionDataIdentifier & 0xFF) // sourceDataIdentifier
    output.push(0x01) // positionInSourceDataRecord
    output.push(definitionSize)
  }
  return isoTpSend(device, requestArbitrationId, 0x2C, output)
}

const clearDynamicallyDefinedIdentifier = async (device, requestArbitrationId, dataIdentifier) => {
  const output = []
  output.push(0x03) // clearDynamicallyDefinedDataIdentifier subfunction
  output.push(dataIdentifier >> 8) // dynamicallyDefinedDataIdentifier
  output.push(dataIdentifier & 0xFF) // dynamicallyDefinedDataIdentifier
  return isoTpSend(device, requestArbitrationId, 0x2C, output)
}

module.exports = {
  startDiagnosticSession,
  dynamicallyDefineIdentifier,
  clearDynamicallyDefinedIdentifier
}

// from https://atgtraining.com/atg-volumetric-efficiency-calculator/

const calculateVolumetricEfficiency = ({engineSize, cylinder, drivetrainLoss, rpm, maf, iat, pressure, mafSelection, iatSelection, pressureSelection}) => {
  let val = 0, cid = 0, lb = 0, degc = 0, degf = 0, tempK = 0, v = 0, molorMass = 0.28705, gb_air_vol = 0, gsec = 0
  let gb_theo_air_vol = 0, lMin = 0, estV = 0, load = 0, cylAir = 0, refCylAir = 0, estGross = 0, estRWHP = 0
  cid = engineSize / 0.0163871
  if (mafSelection == 'g/sec') { // g/sec
    lb = maf * 0.00220462 * 60
  } else { // lb/min
    gsec = maf / (0.00220462 * 60)
    maf = gsec
    lb = gsec * 0.00220462 * 60
  }
  if (iatSelection == 'F') { // fahrenheit
    degc = (iat - 32) * 5 / 9
  } else { // celsius
    degf = iat * 9 / 5 + 32
    degc = (degf - 32) * 5 / 9
  }
  tempK = degc + 273.15
  degc = (degc).toFixed(2)
  tempK = (tempK).toFixed(2)
  if (pressureSelection == 'kPa') { // kPa

  } else if (pressureSelection == 'in/hg') { // in/hg
    pressure = pressure / 0.2953
  } else { // psi
    pressure = pressure / 6.895
  }
  v = (maf * tempK * 0.28705) / pressure
  gb_air_vol = v * 60
  gb_theo_air_vol = engineSize * rpm / 2
  estV = (gb_air_vol / gb_theo_air_vol) * 100
  cylAir = maf * 120 / (rpm * cylinder)
  refCylAir = engineSize * 1.168 / cylinder
  estGross = lb * 10
  estRWHP = estGross * (1 - drivetrainLoss)
  load = (cylAir / refCylAir) * 100
  return {
    volumetricEfficiency: estV,
    theoreticalLoad: load,
    whp: estRWHP
  }
}

module.exports = {
  calculateVolumetricEfficiency
}