package main

import (
	"fmt"
)

const (
	CAN_ID_100 = 256
	CAN_ID_101 = 257
	CAN_ID_102 = 258

	DISABLED VehicleChargingEnabled = iota
	ENABLED

	PARKING ShiftLeverPosition = iota
	OTHER

	NORMAL SystemFault = iota
	FAULT

	CONTACTOR_CLOSED ContactorVehicleStatus = iota
	CONTACTOR_OPEN

	NO_REQUEST StopRequest = iota
	STOP_REQUEST
)

type VehicleChargingEnabled uint8

type ShiftLeverPosition uint8

type SystemFault uint8

type ContactorVehicleStatus uint8

type StopRequest uint8

type ChademoEvent interface {
	// GetValue Return processed/calculated value and timestamp string
	GetValue() (interface{}, *string)
}

type frame struct {
	*CanFrame
}

// MaximumBatteryVoltage The maximum voltage value at the vehicle inlet terminals, at which the station stops charging to protect the vehicle battery
type MaximumBatteryVoltage frame

// ConstChargingRateInd Fixed value for charging rate indication, which is the maximum charging rate (100 %) 	of vehicle battery
type ConstChargingRateInd frame

// BatteryCapacity Rated capacity of battery
type BatteryCapacity frame

// MaxChargingTimeS Maximum charging time permitted by EV, set by 10 s
type MaxChargingTimeS frame

// MaxChargingTimeM Maximum charging time permitted by EV, set by minute
type MaxChargingTimeM frame

// EstChargingTimeM Estimated remaining time before the end of charging calculated by EV
type EstChargingTimeM frame

// ControlProtocolNumber Software version of control protocol to which EV corresponds
type ControlProtocolNumber frame

// TargetBatteryVoltage Target battery voltage ed charging voltage at the vehicle inlet terminals
type TargetBatteryVoltage frame

// ChargingCurrentReq Current value requested by EV during charging
type ChargingCurrentReq frame

// ChargingRate Charging rate of vehicle battery
type ChargingRate frame

// VehicleCharging Status flag indicating charge permission status of EV
type VehicleCharging frame

// ShiftLever Status flag indicating the shift lever position
type ShiftLever frame

// ChargingSystemFault Status flag indicating Charging system fault a malfunction caused by EV or the station, and detected by EV
type ChargingSystemFault frame

// VehicleStatus Status flag indicating the EV contactor status
type VehicleStatus frame

// NormalStopReq Status flag indicating the request of EV to stop charging control
type NormalStopReq frame

// BattOvervoltage Status flag indicating whether or not the vehicle battery voltage exceeds the maximum limit specified by EV
type BattOvervoltage frame

// BattUndervoltage Status flag indicating whether or not the vehicle battery voltage is less than the lower limit specified by EV
type BattUndervoltage frame

// BattCurrentDeviationErr Status flag indicating whether or not the output current deviates from EV requested current
type BattCurrentDeviationErr frame

// HighBattTemperature Status flag indicating whether or not the temperature of vehicle battery exceeds the maximum limit
type HighBattTemperature frame

// BattVoltageDeviationErr Status flag indicating whether or not the vehicle battery voltage deviates from the output voltage measured by the station
type BattVoltageDeviationErr frame

func FromCanFrames(frames <-chan *CanFrame) <-chan ChademoEvent {
	events := make(chan ChademoEvent)

	go func() {
		defer close(events)

		for frame := range frames {
			switch frame.canid {
			case CAN_ID_100:
				events <- &MaximumBatteryVoltage{frame}
				events <- &ConstChargingRateInd{frame}
			case CAN_ID_101:
				events <- &BatteryCapacity{frame}
				events <- &MaxChargingTimeS{frame}
				events <- &MaxChargingTimeM{frame}
				events <- &EstChargingTimeM{frame}
			case CAN_ID_102:
				events <- &ControlProtocolNumber{frame}
				events <- &TargetBatteryVoltage{frame}
				events <- &ChargingCurrentReq{frame}
				events <- &ChargingRate{frame}
				events <- &VehicleCharging{frame}
				events <- &ShiftLever{frame}
				events <- &ChargingSystemFault{frame}
				events <- &VehicleStatus{frame}
				events <- &NormalStopReq{frame}
				events <- &BattOvervoltage{frame}
				events <- &BattUndervoltage{frame}
				events <- &BattCurrentDeviationErr{frame}
				events <- &HighBattTemperature{frame}
				events <- &BattVoltageDeviationErr{frame}
			}
		}
	}()

	return events
}

func getVehicleShiftLever(bytes *[]byte) ShiftLeverPosition {
	if isBitSet((*bytes)[5], 1) {
		return OTHER
	}
	return PARKING
}

func getVehicleStatus(bytes *[]byte) ContactorVehicleStatus {
	if isBitSet((*bytes)[5], 3) {
		return CONTACTOR_OPEN
	}
	return CONTACTOR_CLOSED
}

func getNormalStopReq(bytes *[]byte) StopRequest {
	if isBitSet((*bytes)[5], 4) {
		return STOP_REQUEST
	}
	return NO_REQUEST
}

func getFault(bytes *[]byte, octet byte, bit byte) SystemFault {
	if isBitSet((*bytes)[octet], bit) {
		return FAULT
	}
	return NORMAL
}

func getVehicleCharging(bytes *[]uint8) VehicleChargingEnabled {
	if isBitSet((*bytes)[5], 0) {
		return ENABLED
	}
	return DISABLED
}

func isBitSet(buf uint8, num uint8) bool {
	mask := uint8(1) << num
	val := buf & mask
	if val == mask {
		return true
	}
	return false
}

func bytesToUint16(bytes []uint8) uint16 {
	if len(bytes) != 2 {
		fmt.Println("Wrong array size in bytesToUint16()")
		return 0
	}

	var result uint16
	result = uint16(bytes[1]) << 8
	result = result | uint16(bytes[0])
	return result
}

func (m MaximumBatteryVoltage) GetValue() (interface{}, *string) {
	return bytesToUint16(m.payload[4:6]), &m.date
}

func (c ConstChargingRateInd) GetValue() (interface{}, *string) {
	return c.payload[6], &c.date
}

func (b BatteryCapacity) GetValue() (interface{}, *string) {
	return 0.1 * float32(bytesToUint16(b.payload[5:7])), &b.date
}

func (m MaxChargingTimeS) GetValue() (interface{}, *string) {
	return 10 * uint16(m.payload[1]), &m.date
}

func (m MaxChargingTimeM) GetValue() (interface{}, *string) {
	return m.payload[2], &m.date
}

func (e EstChargingTimeM) GetValue() (interface{}, *string) {
	return e.payload[3], &e.date
}

func (c ControlProtocolNumber) GetValue() (interface{}, *string) {
	return c.payload[0], &c.date
}

func (t TargetBatteryVoltage) GetValue() (interface{}, *string) {
	return bytesToUint16(t.payload[1:3]), &t.date
}

func (c ChargingCurrentReq) GetValue() (interface{}, *string) {
	return c.payload[3], &c.date
}

func (c ChargingRate) GetValue() (interface{}, *string) {
	return c.payload[6], &c.date
}

func (s ShiftLever) GetValue() (interface{}, *string) {
	return getVehicleShiftLever(&s.payload), &s.date
}

func (v VehicleCharging) GetValue() (interface{}, *string) {
	return getVehicleCharging(&v.payload), &v.date
}

func (c ChargingSystemFault) GetValue() (interface{}, *string) {
	return getFault(&c.payload, 5, 2), &c.date
}

func (v VehicleStatus) GetValue() (interface{}, *string) {
	return getVehicleStatus(&v.payload), &v.date
}

func (n NormalStopReq) GetValue() (interface{}, *string) {
	return getNormalStopReq(&n.payload), &n.date
}

func (b BattOvervoltage) GetValue() (interface{}, *string) {
	return getFault(&b.payload, 4, 0), &b.date
}

func (b BattUndervoltage) GetValue() (interface{}, *string) {
	return getFault(&b.payload, 4, 1), &b.date
}

func (b BattCurrentDeviationErr) GetValue() (interface{}, *string) {
	return getFault(&b.payload, 4, 2), &b.date
}

func (h HighBattTemperature) GetValue() (interface{}, *string) {
	return getFault(&h.payload, 4, 3), &h.date
}

func (b BattVoltageDeviationErr) GetValue() (interface{}, *string) {
	return getFault(&b.payload, 4, 4), &b.date
}

func (v VehicleChargingEnabled) String() string {
	switch v {
	case DISABLED:
		return "disabled"
	case ENABLED:
		return "enabled"
	default:
		panic("VehicleChargingEnabled not implemented")
	}
}

func (s ShiftLeverPosition) String() string {
	switch s {
	case PARKING:
		return "parking"
	case OTHER:
		return "other"
	default:
		panic("ShiftLeverPosition not implemented")
	}
}

func (s SystemFault) String() string {
	switch s {
	case NORMAL:
		return "normal"
	case FAULT:
		return "fault"
	default:
		panic("SystemFault not implemented")
	}
}

func (c ContactorVehicleStatus) String() string {
	switch c {
	case CONTACTOR_CLOSED:
		return "contactor closed"
	case CONTACTOR_OPEN:
		return "contactor open"
	default:
		panic("ContactorVehicleStatus not implemented")
	}
}

func (s StopRequest) String() string {
	switch s {
	case NO_REQUEST:
		return "no request"
	case STOP_REQUEST:
		return "stop request"
	default:
		panic("StopRequest not implemented")
	}
}