package descriptor

import (
	"bytes"
	"encoding/binary"
	"errors"
)

var configurationCDCHID = [configurationTypeLen]byte{
	configurationTypeLen,
	TypeConfiguration,
	0x64, 0x00, // adjust length as needed
	0x03, // number of interfaces
	0x01, // configuration value
	0x00, // index to string description
	0xa0, // attributes
	0x32, // maxpower
}

var ConfigurationCDCHID = ConfigurationType{
	data: configurationCDCHID[:],
}

var interfaceHID = [interfaceTypeLen]byte{
	interfaceTypeLen,
	TypeInterface,
	0x02, // InterfaceNumber
	0x00, // AlternateSetting
	0x02, // NumEndpoints
	0x03, // InterfaceClass
	0x00, // InterfaceSubClass
	0x00, // InterfaceProtocol
	0x00, // Interface
}

var InterfaceHID = InterfaceType{
	data: interfaceHID[:],
}

const (
	ClassHIDTypeLen = 9
)

type ClassHIDType struct {
	data []byte
}

func (d ClassHIDType) Bytes() []byte {
	return d.data[:]
}

func (d ClassHIDType) Length(v uint8) {
	d.data[0] = byte(v)
}

func (d ClassHIDType) Type(v uint8) {
	d.data[1] = byte(v)
}

func (d ClassHIDType) HID(v uint16) {
	binary.LittleEndian.PutUint16(d.data[2:4], v)
}

func (d ClassHIDType) CountryCode(v uint8) {
	d.data[4] = byte(v)
}

func (d ClassHIDType) NumDescriptors(v uint8) {
	d.data[5] = byte(v)
}

func (d ClassHIDType) ClassType(v uint8) {
	d.data[6] = byte(v)
}

func (d ClassHIDType) ClassLength(v uint16) {
	binary.LittleEndian.PutUint16(d.data[7:9], v)
}

var errNoClassHIDFound = errors.New("no classHID found")

// FindClassHIDType tries to find the ClassHID class in the descriptor.
func FindClassHIDType(des, class []byte) (ClassHIDType, error) {
	if len(des) < ClassHIDTypeLen || len(class) == 0 {
		return ClassHIDType{}, errNoClassHIDFound
	}

	// search only for ClassHIDType without the ClassLength,
	// in case it has already been set.
	idx := bytes.Index(des, class[:ClassHIDTypeLen-2])
	if idx == -1 {
		return ClassHIDType{}, errNoClassHIDFound
	}

	return ClassHIDType{data: des[idx : idx+ClassHIDTypeLen]}, nil
}

var classHID = [ClassHIDTypeLen]byte{
	ClassHIDTypeLen,
	TypeClassHID,
	0x11, // HID version L
	0x01, // HID version H
	0x00, // CountryCode
	0x01, // NumDescriptors
	0x22, // ClassType
	0x90, // ClassLength L
	0x00, // ClassLength H
}

var ClassHID = ClassHIDType{
	data: classHID[:],
}

var CDCHID = Descriptor{
	Device: DeviceCDC.Bytes(),
	Configuration: Append([][]byte{
		ConfigurationCDCHID.Bytes(),
		InterfaceAssociationCDC.Bytes(),
		InterfaceCDCControl.Bytes(),
		ClassSpecificCDCHeader.Bytes(),
		ClassSpecificCDCACM.Bytes(),
		ClassSpecificCDCUnion.Bytes(),
		ClassSpecificCDCCallManagement.Bytes(),
		EndpointEP1IN.Bytes(),
		InterfaceCDCData.Bytes(),
		EndpointEP2OUT.Bytes(),
		EndpointEP3IN.Bytes(),
		InterfaceHID.Bytes(),
		ClassHID.Bytes(),
		EndpointEP4IN.Bytes(),
		EndpointEP5OUT.Bytes(),
	}),
	HID: map[uint16][]byte{
		2: Append([][]byte{
			HIDUsagePageGenericDesktop,
			HIDUsageDesktopKeyboard,
			HIDCollectionApplication,
			HIDReportID(2),

			HIDUsagePageKeyboard,
			HIDUsageMinimum(224),
			HIDUsageMaximum(231),
			HIDLogicalMinimum(0),
			HIDLogicalMaximum(1),
			HIDReportSize(1),
			HIDReportCount(8),
			HIDInputDataVarAbs,
			HIDReportCount(1),
			HIDReportSize(8),
			HIDInputConstVarAbs,
			HIDReportCount(3),
			HIDReportSize(1),
			HIDUsagePageLED,
			HIDUsageMinimum(1),
			HIDUsageMaximum(3),
			HIDOutputDataVarAbs,
			HIDReportCount(5),
			HIDReportSize(1),
			HIDOutputConstVarAbs,
			HIDReportCount(6),
			HIDReportSize(8),
			HIDLogicalMinimum(0),
			HIDLogicalMaximum(255),

			HIDUsagePageKeyboard,
			HIDUsageMinimum(0),
			HIDUsageMaximum(255),
			HIDInputDataAryAbs,
			HIDCollectionEnd,

			HIDUsagePageGenericDesktop,
			HIDUsageDesktopMouse,
			HIDCollectionApplication,
			HIDUsageDesktopPointer,
			HIDCollectionPhysical,
			HIDReportID(1),

			HIDUsagePageButton,
			HIDUsageMinimum(1),
			HIDUsageMaximum(5),
			HIDLogicalMinimum(0),
			HIDLogicalMaximum(1),
			HIDReportCount(5),
			HIDReportSize(1),
			HIDInputDataVarAbs,
			HIDReportCount(1),
			HIDReportSize(3),
			HIDInputConstVarAbs,

			HIDUsagePageGenericDesktop,
			HIDUsageDesktopX,
			HIDUsageDesktopY,
			HIDUsageDesktopWheel,
			HIDLogicalMinimum(-127),
			HIDLogicalMaximum(127),
			HIDReportSize(8),
			HIDReportCount(3),
			HIDInputDataVarRel,
			HIDCollectionEnd,
			HIDCollectionEnd,

			HIDUsagePageConsumer,
			HIDUsageConsumerControl,
			HIDCollectionApplication,
			HIDReportID(3),
			HIDLogicalMinimum(0),
			HIDLogicalMaximum(8191),
			HIDUsageMinimum(0),
			HIDUsageMaximum(0x1FFF),
			HIDReportSize(16),
			HIDReportCount(1),
			HIDInputDataAryAbs,
			HIDCollectionEnd}),
	},
}