package ssob

import (
	"fmt"
	"io"
	"reflect"

	"gitea.olznet.de/OlzNet/slog"
)

type allocatorFunc func(vals ...interface{}) interface{}
type marshallerFunc func(interface{}, io.Writer) error
type unmarshallerFunc func(io.Reader) (interface{}, error)

type marshalFunc func(interface{}) ([]byte, error)
type nallocFunc func() interface{}

type RegisteredTypes struct {
	NextId uint32
	ntypes map[uint32]*NType
	nnames map[string]*NType
}

const (
	ST_COMMON = 0
	ST_SLICE  = 1
	ST_ARRAY  = 2
	ST_STRUCT = 3
	ST_MAP    = 4
	//ST_MINTERFACE = 5
)

type StructField struct {
	Id   uint32
	Name string
	Tag  string
	SId  int
}

type NType struct {
	Name         string
	Id           uint32
	Indirection  int
	MainTypeId   uint32
	ValType      uint32
	structFields []*StructField
	arrayLen     int
	alloc        nallocFunc
}

type Type struct {
	Name      string
	Id        uint32
	alloc     allocatorFunc
	marshal   marshallerFunc
	unmarshal unmarshallerFunc
}

type baseType struct {
}

var cacheTypes RegisteredTypes

const (
	ST_ID_SIZE = 4
)

const (
	ST_INVALID   = 0
	ST_BOOL      = 1
	ST_UINT8     = 2
	ST_UINT16    = 3
	ST_UINT32    = 4
	ST_UINT64    = 5
	ST_INT8      = 6
	ST_INT16     = 7
	ST_INT32     = 8
	ST_INT64     = 9
	ST_FLOAT32   = 10
	ST_FLOAT64   = 11
	ST_STRING    = 12
	ST_ERROR     = 13
	ST_NIL       = 14
	ST_INTERFACE = 15
)

func init() {
	cacheTypes.NextId = 128
	cacheTypes.ntypes = make(map[uint32]*NType)
	cacheTypes.nnames = make(map[string]*NType)

	boolType := &NType{
		"bool", ST_BOOL, 0, ST_COMMON, ST_BOOL, nil,
		0, func() interface{} { return new(bool) },
	}
	cacheTypes.ntypes[ST_BOOL] = boolType
	cacheTypes.nnames["bool"] = boolType

	uint8Type := &NType{
		"uint8", ST_UINT8, 0, ST_COMMON, ST_UINT8, nil,
		0, func() interface{} { return new(uint8) },
	}
	cacheTypes.ntypes[ST_UINT8] = uint8Type
	cacheTypes.nnames["uint8"] = uint8Type

	uint16Type := &NType{
		"uint16", ST_UINT16, 0, ST_COMMON, ST_UINT16, nil,
		0, func() interface{} { return new(uint16) },
	}
	cacheTypes.ntypes[ST_UINT16] = uint16Type
	cacheTypes.nnames["uint16"] = uint16Type

	uint32Type := &NType{
		"uint32", ST_UINT32, 0, ST_COMMON, ST_UINT32, nil,
		0, func() interface{} { return new(uint32) },
	}
	cacheTypes.ntypes[ST_UINT32] = uint32Type
	cacheTypes.nnames["uint32"] = uint32Type

	uint64Type := &NType{
		"uint64", ST_UINT64, 0, ST_COMMON, ST_UINT64, nil,
		0, func() interface{} { return new(uint64) },
	}
	cacheTypes.ntypes[ST_UINT64] = uint64Type
	cacheTypes.nnames["uint64"] = uint64Type

	int8Type := &NType{
		"int8", ST_INT8, 0, ST_COMMON, ST_INT8, nil,
		0, func() interface{} { return new(int8) },
	}
	cacheTypes.ntypes[ST_INT8] = int8Type
	cacheTypes.nnames["int8"] = int8Type

	int16Type := &NType{
		"int16", ST_INT16, 0, ST_COMMON, ST_INT16, nil,
		0, func() interface{} { return new(int16) },
	}
	cacheTypes.ntypes[ST_INT16] = int16Type
	cacheTypes.nnames["int16"] = int16Type

	int32Type := &NType{
		"int32", ST_INT32, 0, ST_COMMON, ST_INT32, nil,
		0, func() interface{} { return new(int32) },
	}
	cacheTypes.ntypes[ST_INT32] = int32Type
	cacheTypes.nnames["int32"] = int32Type

	int64Type := &NType{
		"int64", ST_INT64, 0, ST_COMMON, ST_INT64, nil,
		0, func() interface{} { return new(int64) },
	}
	cacheTypes.ntypes[ST_INT64] = int64Type
	cacheTypes.nnames["int64"] = int64Type

	float32Type := &NType{
		"float32", ST_FLOAT32, 0, ST_COMMON, ST_FLOAT32, nil,
		0, func() interface{} { return new(float32) },
	}
	cacheTypes.ntypes[ST_FLOAT32] = float32Type
	cacheTypes.nnames["float32"] = float32Type

	float64Type := &NType{
		"float64", ST_FLOAT64, 0, ST_COMMON, ST_FLOAT64, nil,
		0, func() interface{} { return new(float64) },
	}
	cacheTypes.ntypes[ST_FLOAT64] = float64Type
	cacheTypes.nnames["float64"] = float64Type

	stringType := &NType{
		"string", ST_STRING, 0, ST_COMMON, ST_STRING, nil,
		0, func() interface{} { return new(string) },
	}
	cacheTypes.ntypes[ST_STRING] = stringType
	cacheTypes.nnames["string"] = stringType

	errorType := &NType{
		"error", ST_ERROR, 0, ST_COMMON, ST_ERROR, nil,
		0, func() interface{} { return new(error) },
	}
	cacheTypes.ntypes[ST_ERROR] = errorType
	cacheTypes.nnames["error"] = errorType

	nilType := &NType{
		"nil", ST_NIL, 0, ST_NIL, ST_NIL, nil,
		0, func() interface{} { return nil },
	}
	cacheTypes.ntypes[ST_NIL] = nilType
	cacheTypes.nnames["nil"] = nilType

	interfaceType := &NType{
		"interface {}", ST_INTERFACE, 0, ST_INTERFACE, ST_INTERFACE, nil,
		0, func() interface{} { return new(interface{}) },
	}
	cacheTypes.ntypes[ST_INTERFACE] = interfaceType
	cacheTypes.nnames["interface {}"] = interfaceType
}

func getTypeById(id uint32) (ret *NType) {
	if ret, ok := cacheTypes.ntypes[id]; !ok {
		return nil
	} else {
		return ret
	}
}

func getTypeByName(name string) (ret *NType) {
	if ret, ok := cacheTypes.nnames[name]; !ok {
		return nil
	} else {
		return ret
	}
}

func parseType(t reflect.Type) (ret nallocFunc, mainTypeId uint32, indirection int, valType uint32, base bool, sfields []*StructField, arrayLen int, err error) {
	indirection = 0
	ret = func() interface{} {
		vret := reflect.New(t)
		val := vret.Elem()

		for {
			if val.Kind() == reflect.Ptr {
				val.Set(reflect.New(val.Type().Elem()))
				val = val.Elem()
			} else {
				break
			}
		}
		//return vret
		return vret.Interface()
	}

	sfields = []*StructField{}
	arrayLen = 0
	vret := reflect.New(t)
	val := vret.Elem()
	nval := vret

	base = true

	for {
		if val.Kind() == reflect.Ptr {
			nval = nval.Elem()
			val.Set(reflect.New(val.Type().Elem()))
			val = val.Elem()
			indirection += 1
			base = false
		} else {
			switch val.Kind() {
			case reflect.Slice:
				typ := reflect.TypeOf(val.Interface())
				vt, err := getTypeByNameRegister(typ.Elem().String(), typ.Elem())
				if err != nil {
					return ret, mainTypeId, indirection, valType, base, sfields, arrayLen, err
				}
				valType = vt.Id
				base = false
				mainTypeId = ST_SLICE
			case reflect.Array:
				typ := reflect.TypeOf(val.Interface())
				arrayLen = val.Len()
				vt, err := getTypeByNameRegister(typ.Elem().String(), typ.Elem())
				if err != nil {
					return ret, mainTypeId, indirection, valType, base, sfields, arrayLen, err
				}
				valType = vt.Id
				base = false
				mainTypeId = ST_ARRAY
			case reflect.Struct:
				typ := reflect.TypeOf(val.Interface())
				if !base {
					vt, err := getTypeByNameRegister(typ.String(), typ)
					if err != nil {
						return ret, mainTypeId, indirection, valType, base, sfields, arrayLen, err
					}
					valType = vt.Id
				} else {
					sl := val.NumField()
					for i := 0; i < sl; i++ {
						if val.Field(i).CanSet() {
							sfield := new(StructField)
							sfield.Name = val.Type().Field(i).Name
							sfield.Tag = string(val.Type().Field(i).Tag)
							slog.LOG_DEBUGFLN("ts: %v", val.Field(i).Type().String())
							slog.LOG_DEBUGFLN("tt: %v", val.Field(i).Type())
							vt, err := getTypeByNameRegister(val.Field(i).Type().String(), val.Field(i).Type())
							if err != nil {
								return ret, mainTypeId, indirection, valType, base, sfields, arrayLen, err
							}
							sfield.Id = vt.Id
							sfield.SId = i
							sfields = append(sfields, sfield)
						}
					}
					base = true
				}
				mainTypeId = ST_STRUCT
			case reflect.Map:
				typ := reflect.TypeOf(val.Interface())
				if !base {
					vt, err := getTypeByNameRegister(typ.String(), typ)
					if err != nil {
						return ret, mainTypeId, indirection, valType, base, sfields, arrayLen, err
					}
					valType = vt.Id
				} else {
					// Key
					vt, err := getTypeByNameRegister(typ.Key().String(), typ.Key())
					if err != nil {
						return ret, mainTypeId, indirection, valType, base, sfields, arrayLen, err
					}
					valType = vt.Id

					// Val
					vt, err = getTypeByNameRegister(typ.Elem().String(), typ.Elem())
					if err != nil {
						return ret, mainTypeId, indirection, valType, base, sfields, arrayLen, err
					}
					valType = vt.Id
					base = false
				}
				mainTypeId = ST_MAP
			default:
				typ := reflect.TypeOf(val.Interface())
				if !base {
					vt, err := getTypeByNameRegister(typ.Kind().String(), typ)
					if err != nil {
						return ret, mainTypeId, indirection, valType, base, sfields, arrayLen, err
					}
					valType = vt.Id
				}
				mainTypeId = ST_COMMON
			}
			break
		}
	}

	return ret, mainTypeId, indirection, valType, base, sfields, arrayLen, err
}

func getTypeByNameRegister(name string, t reflect.Type) (ret *NType, err error) {
	if ret = getTypeByName(name); ret != nil {
		return ret, err
	}

	if err = registerType(t); err != nil {
		return ret, err
	}

	if ret = getTypeByName(name); ret == nil {
		return ret, fmt.Errorf("ssob: Failed registering type '%s'", name)
	}

	return ret, err
}

func createType(t reflect.Type) (ret *NType, base bool, err error) {
	if t == nil {
		return ret, base, fmt.Errorf("ssob: Cannot create Type from nil: %w", ErrTypeInvalid)
	}

	ret = new(NType)
	ret.Name = t.String()
	ret.alloc, ret.MainTypeId, ret.Indirection, ret.ValType, base, ret.structFields, ret.arrayLen, err = parseType(t)

	return ret, base, err
}

func registerType(t reflect.Type) (err error) {
	if t == nil || t.Kind() == reflect.Invalid {
		return ErrTypeInvalid
	}

	if getTypeByName(t.String()) != nil {
		return nil
	}

	var base bool
	ntype, base, err := createType(t)
	if err != nil {
		return err
	}
	ntype.Id = cacheTypes.NextId
	if base {
		ntype.ValType = ntype.Id
	}
	cacheTypes.ntypes[ntype.Id] = ntype
	cacheTypes.nnames[ntype.Name] = ntype
	cacheTypes.NextId += 1

	return err
}

func splitType(e interface{}) (t reflect.Type, v reflect.Value, err error) {
	t = reflect.TypeOf(e)
	if t == nil || t.Kind() != reflect.Ptr {
		return t, v, ErrTypeInvalid
	}

	v = reflect.ValueOf(e)
	if v.IsNil() {
		return t, v, ErrValueInvalid
	}

	return t, v, err
}

func indirectType(e interface{}) (ret interface{}, ntype *NType, nilLevel uint16, err error) {
	nilLevel = 0

	t, v, err := splitType(e)
	if err != nil {
		return nil, nil, nilLevel, err
	}

	ntype, err = getTypeByNameRegister(t.Elem().String(), t.Elem())
	if err != nil {
		return nil, nil, nilLevel, err
	}

	for i := 0; i < ntype.Indirection; i++ {
		if v, err = indirectValue(v); err != nil {
			return nil, ntype, nilLevel, ErrValueInvalid
		}
		if v.IsValid() && v.IsNil() {
			nilLevel += uint16(i)
			return nil, ntype, nilLevel, err
		}
	}

	if v, err = indirectValue(v); err != nil {
		return nil, ntype, nilLevel, err
	}

	return v.Interface(), ntype, nilLevel, err
}

func setTypeNil(e interface{}, indirection int) (err error) {
	var v reflect.Value

	if v, err = getValPtr(e); err != nil {
		return err
	}

	if v, err = indirectValue(v); err != nil {
		if indirection > 0 {
			return ErrValueInvalid
		}
	}

	for i := 0; i < indirection; i++ {
		if v, err = indirectValue(v); err != nil {
			return err
		}
	}

	if v.IsValid() && !v.IsNil() {
		v.Set(reflect.Zero(reflect.TypeOf(v.Interface())))
	}

	return err
}

func setTypeVal(e interface{}, val interface{}, ntype *NType) (err error) {
	var v reflect.Value

	if v, err = getValPtr(e); err != nil {
		return err
	}
	if v, err = indirectValue(v); err != nil {
		return err
	}
	for i := 0; i < ntype.Indirection; i++ {
		if v, err = indirectValue(v); err != nil {
			return err
		}
	}

	v.Set(reflect.ValueOf(val))
	return err
}

func getValPtr(e interface{}) (ret reflect.Value, err error) {
	v := reflect.ValueOf(e)

	if !v.IsValid() || v.Kind() != reflect.Ptr || v.IsNil() {
		err = ErrValueInvalid
	}

	return v, err
}

func getVal(e interface{}) (ret reflect.Value) {
	v := reflect.ValueOf(e)

	if !v.IsValid() || v.Kind() != reflect.Ptr || v.IsNil() {
		return v
	}
	return reflect.Indirect(v)
}

func indirectValue(v reflect.Value) (ret reflect.Value, err error) {
	if !v.IsValid() || v.Kind() != reflect.Ptr {
		return v, ErrValueInvalid
	}

	ret = reflect.Indirect(v)
	return ret, err
}

func valueIsNil(v reflect.Value) (ret bool) {
	ret = false

	if !v.IsValid() || v.Kind() == reflect.Invalid || (v.Kind() == reflect.Ptr && v.IsNil()) {
		ret = true
	}
	return ret
}

func traverseValuePtr(v reflect.Value) (ret reflect.Value) {
	ret = v
	if !ret.IsValid() || ret.Kind() != reflect.Ptr {
		return ret
	} else {
		ret = reflect.Indirect(ret)
		return traverseValuePtr(ret)
	}
}

func parseInterface(e interface{}) (rett reflect.Type, retv reflect.Value, err error) {
	t := reflect.TypeOf(e)

	if t == nil || t.Kind() != reflect.Ptr {
		return nil, reflect.ValueOf(e), ErrTypeInvalid
	}

	if t.Elem().Kind() == reflect.Interface {
		rett = reflect.TypeOf(reflect.Indirect(reflect.ValueOf(e)).Interface())

		retv = reflect.New(rett)
		retv.Elem().Set(reflect.ValueOf(reflect.Indirect(reflect.ValueOf(e)).Interface()))
		slog.LOG_DEBUGFLN("rett: %v", rett)
		slog.LOG_DEBUGFLN("retv: %v", retv)
		return rett, retv, nil
	}

	slog.LOG_DEBUGFLN("t: %v", t)
	slog.LOG_DEBUGFLN("v: %v", reflect.ValueOf(e))
	return t, reflect.ValueOf(e), nil
}

func RegisterType(e interface{}) (err error) {
	//t := reflect.TypeOf(e)
	t, _, err := parseInterface(e)
	if err != nil {
		return err
	}

	if t == nil || t.Kind() != reflect.Ptr {
		return fmt.Errorf("ssob: Interface is not a valid address: %w", ErrTypeInvalid)
	}

	if err = registerType(t.Elem()); err != nil {
		return err
	}

	return nil
}