package fields

// VerticalDataAvailableSourceIndicator is the Vertical Data Available / Source Indicator definition
//
// Specified in Doc 9871 / B.2.3.9.3
type VerticalDataAvailableSourceIndicator byte

const (
	VDANoValidDataAvailable VerticalDataAvailableSourceIndicator = iota // No data available
	VDAAutopilot                                                        // Autopilot control panel selected value, such as Mode Control Panel (MCP) or Flight Control Unit (FCU)
	VDAHoldingAltitude                                                  // Holding altitude
	VDAFMS                                                              // FMS/RNAV system
)

func ParseVerticalDataAvailableSourceIndicator(data []byte) VerticalDataAvailableSourceIndicator {
	return VerticalDataAvailableSourceIndicator((data[0]&0x01)<<1 + (data[1]&0x80)>>7)
}

// TargetAltitudeType is the Target Altitude Type definition
//
// Specified in Doc 9871 / B.2.3.9.4
type TargetAltitudeType byte

const (
	TATReferencedToPressureAltitude   TargetAltitudeType = iota // Referenced to pressure-altitude (flight level)
	TATReferencedToBarometricAltitude                           // Referenced to barometric corrected altitude (mean sea level)
)

// ReadTargetAltitudeType reads the TargetAltitudeType from a 56 bits data field
func ParseTargetAltitudeType(data []byte) TargetAltitudeType {
	return TargetAltitudeType((data[1] & 0x40) >> 6)
}

// TargetAltitudeCapability is the Target Altitude Capability definition
//
// Specified in Doc 9871 / B.2.3.9.5
type TargetAltitudeCapability byte

const (
	TACAltitudeOnly             TargetAltitudeCapability = iota // Holding altitude only
	TACAltitudeOrAutopilot                                      // Either holding altitude or autopilot control panel selected altitude
	TACAltitudeOrAutopilotOrFMS                                 // Either holding altitude, autopilot control panel selected altitude, or any FMS/RNAV level-off altitude
	TACReserved3                                                // Reserved
)

// ParseTargetAltitudeCapability reads the TargetAltitudeCapability from a 56 bits data field
func ParseTargetAltitudeCapability(data []byte) TargetAltitudeCapability {
	return TargetAltitudeCapability((data[1] & 0x18) >> 3)
}

// VerticalModeIndicator is the Vertical Mode Indicator definition
//
// Specified in Doc 9871 / B.2.3.9.6
type VerticalModeIndicator byte

const (
	VMIUnknown       VerticalModeIndicator = iota // Unknown mode or information unavailable
	VMIAcquiringMode                              //  Acquiring Mode
	VMICapturingMode                              // Capturing or Maintaining Mode
	VMIReserved3                                  // Reserved
)

// ParseVerticalModeIndicator reads the VerticalModeIndicator from a 56 bits data field
func ParseVerticalModeIndicator(data []byte) VerticalModeIndicator {
	return VerticalModeIndicator((data[1] & 0x06) >> 1)
}

// HorizontalDataAvailableSourceIndicator is the Horizontal Data Available / Source Indicator definition
//
// Specified in Doc 9871 / B.2.3.9.8
type HorizontalDataAvailableSourceIndicator byte

const (
	HDANoValidDataAvailable HorizontalDataAvailableSourceIndicator = iota // No data available
	HDAAutopilot                                                          // Autopilot control panel selected value, such as Mode Control Panel (MCP) or Flight Control Unit (FCU)
	HDAHoldingAltitude                                                    // Maintaining current heading or track angle (e.g. autopilot mode select)
	HDAFMS                                                                // FMS/RNAV system (indicates track angle specified by leg type)
)

// ParseHorizontalDataAvailableSourceIndicator reads the HorizontalDataAvailableSourceIndicator from a 56 bits data field
func ParseHorizontalDataAvailableSourceIndicator(data []byte) HorizontalDataAvailableSourceIndicator {
	return HorizontalDataAvailableSourceIndicator((data[3] & 0x60) >> 5)
}

// TargetHeadingTrackIndicator is the Target Heading / Track Angle Indicator definition
//
// Specified in Doc 9871 / B.2.3.9.10
type TargetHeadingTrackIndicator byte

const (
	TargetTrackHeadingAngle TargetHeadingTrackIndicator = iota // Target heading angle is being reported
	TargetTrackAngle                                           // Track angle is being reported

)

// ParseTargetHeadingTrackIndicator reads the TargetHeadingTrackIndicator from a 56 bits data field
func ParseTargetHeadingTrackIndicator(data []byte) TargetHeadingTrackIndicator {
	return TargetHeadingTrackIndicator((data[4] & 0x08) >> 3)
}

// ReadTargetHeadingTrackAngle reads the TargetAltitude from a 56 bits data field
// Specified in Doc 9871 / B.2.3.9.9
func ReadTargetHeadingTrackAngle(data []byte) (uint16, NumericValueStatus) {
	heading := (uint16(data[3]&0x1F)<<8 | uint16(data[2]&0xF0)) >> 4
	if heading > 359 {
		return 0, NVSMaximum
	}
	return heading, NVSRegular
}

// HorizontalModeIndicator is the Horizontal Mode Indicator definition
//
// Specified in Doc 9871 / B.2.3.9.11
type HorizontalModeIndicator byte

const (
	HMIUnknown       HorizontalModeIndicator = iota // Unknown mode or information unavailable
	HMIAcquiringMode                                // Acquiring Mode
	HMICapturingMode                                // Capturing or Maintaining Mode
	HMIReserved3                                    // Reserved
)

// ParseHorizontalModeIndicator reads the HorizontalModeIndicator from a 56 bits data field
func ParseHorizontalModeIndicator(data []byte) HorizontalModeIndicator {
	return HorizontalModeIndicator((data[4] & 0x06) >> 1)
}

// NavigationalAccuracyCategoryPositionV1 is the Navigational Accuracy Category Position definition
//
// Specified in Doc 9871 / B.2.3.9.12
type NavigationalAccuracyCategoryPositionV1 byte

const (
	NACPV1EPUGreaterThan18Point52Km          NavigationalAccuracyCategoryPositionV1 = iota // EPU >= 18.52 km (10 NM) - Unknown accuracy
	NACPV1EPULowerThan18Point52Km                                                          // EPU < 18.52 km (10 NM) - RNP-10 accuracy
	NACPV1EPULowerThan7Point408Km                                                          // EPU < 7.408 km (4 NM) - RNP-4 accuracy
	NACPV1EPULowerThan3Point704Km                                                          // EPU < 3.704 km (2 NM) - RNP-2 accuracy
	NACPV1EPUGreaterThan1852M                                                              // EPU < 1 852 m (1 NM) - RNP-1 accuracy
	NACPV1EPULowerThan926M                                                                 // EPU < 926 m (0.5 NM) - RNP-0.5 accuracy
	NACPV1EPUGreaterThan555Point6M                                                         // EPU < 555.6 m ( 0.3 NM) - RNP-0.3 accuracy
	NACPV1EPULowerThan185Point2M                                                           // EPU < 185.2 m (0.1 NM) - RNP-0.1 accuracy
	NACPV1EPUGreaterThan92Point6M                                                          // EPU < 92.6 m (0.05 NM) - e.g. GPS (with SA)
	NACPV1EPULowerThan30MAndVEPULowerThan45M                                               // EPU < 30 m and VEPU < 45 m - e.g. GPS (SA off)
	NACPV1EPULowerThan10MAndVEPULowerThan15M                                               // EPU < 10 m and VEPU < 15 m - e.g. WAAS
	NACPV1EPULowerThan4MAndVEPULowerThan3M                                                 // EPU < 3 m and VEPU < 4 m - e.g. LAAS
	NACPV1Reserved12                                                                       // Reserved
	NACPV1Reserved13                                                                       // Reserved
	NACPV1Reserved14                                                                       // Reserved
	NACPV1Reserved15                                                                       // Reserved
)

// ParseNavigationalAccuracyCategoryPositionV1 reads the NavigationalAccuracyCategoryPositionV1 from a 56 bits data field
func ParseNavigationalAccuracyCategoryPositionV1(data []byte) NavigationalAccuracyCategoryPositionV1 {
	return NavigationalAccuracyCategoryPositionV1((data[4]&0x01)<<3 + (data[5]&0xE0)>>5)
}

// NICBaro is the NIC Baro definition
//
// Specified in Doc 9871 / B.2.3.9.13
type NICBaro byte

const (
	// NICBGilhamNotCrossChecked indicates that the barometric altitude that is being reported in the Airborne
	// Position Message is based on a Gilham coded input that has not been cross-checked against another source of
	// pressure-altitude
	NICBGilhamNotCrossChecked NICBaro = iota
	// NICBGilhamCrossCheckedOrNonGilham indicates that the barometric altitude that is being reported in the Airborne
	// Position Message is either based on a Gilham code input that has been cross-checked against another source of
	// pressure-altitude and verified as being consistent, or is based on a non-Gilham coded source
	NICBGilhamCrossCheckedOrNonGilham
)

// ParseNICBaro reads the NICBaro from a 56 bits data field
func ParseNICBaro(data []byte) NICBaro {
	return NICBaro((data[5] & 0x10) >> 4)
}