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 nallocFunc func() interface{}

type RegisteredTypes struct {
	NextId uint32
	types  map[uint32]Type
	names  map[string]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_INTERFACE    = 5
	ST_STRUCT_FIELD = 6
)

type StructField struct {
	Name string
	Tag  string
}

type NType struct {
	Name         string
	Id           uint32
	Indirection  int
	MainTypeId   uint32
	ValTypes     []uint32
	structFields []*StructField
	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
)

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

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

	uint8Type := &NType{
		"uint8", ST_UINT8, 0, ST_COMMON, []uint32{ST_UINT8},
		nil, func() interface{} { return new(uint8) },
	}
	cacheTypes.ntypes[ST_UINT8] = uint8Type
	cacheTypes.nnames["uint8"] = uint8Type

	uint16Type := &NType{
		"uint16", ST_UINT16, 0, ST_COMMON, []uint32{ST_UINT16},
		nil, func() interface{} { return new(uint16) },
	}
	cacheTypes.ntypes[ST_UINT16] = uint16Type
	cacheTypes.nnames["uint16"] = uint16Type

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

	uint64Type := &NType{
		"uint64", ST_UINT64, 0, ST_COMMON, []uint32{ST_UINT64},
		nil, func() interface{} { return new(uint64) },
	}
	cacheTypes.ntypes[ST_UINT64] = uint64Type
	cacheTypes.nnames["uint64"] = uint64Type

	int8Type := &NType{
		"int8", ST_INT8, 0, ST_COMMON, []uint32{ST_INT8},
		nil, func() interface{} { return new(int8) },
	}
	cacheTypes.ntypes[ST_INT8] = int8Type
	cacheTypes.nnames["int8"] = int8Type

	int16Type := &NType{
		"int16", ST_INT16, 0, ST_COMMON, []uint32{ST_INT16},
		nil, func() interface{} { return new(int16) },
	}
	cacheTypes.ntypes[ST_INT16] = int16Type
	cacheTypes.nnames["int16"] = int16Type

	int32Type := &NType{
		"int32", ST_INT32, 0, ST_COMMON, []uint32{ST_INT32},
		nil, func() interface{} { return new(int32) },
	}
	cacheTypes.ntypes[ST_INT32] = int32Type
	cacheTypes.nnames["int32"] = int32Type

	int64Type := &NType{
		"int64", ST_INT64, 0, ST_COMMON, []uint32{ST_INT64},
		nil, func() interface{} { return new(int64) },
	}
	cacheTypes.ntypes[ST_INT64] = int64Type
	cacheTypes.nnames["int64"] = int64Type

	float32Type := &NType{
		"float32", ST_FLOAT32, 0, ST_COMMON, []uint32{ST_FLOAT32},
		nil, func() interface{} { return new(float32) },
	}
	cacheTypes.ntypes[ST_FLOAT32] = float32Type
	cacheTypes.nnames["float32"] = float32Type

	float64Type := &NType{
		"float64", ST_FLOAT64, 0, ST_COMMON, []uint32{ST_FLOAT64},
		nil, func() interface{} { return new(float64) },
	}
	cacheTypes.ntypes[ST_FLOAT64] = float64Type
	cacheTypes.nnames["float64"] = float64Type

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

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

	cacheTypes.types[ST_BOOL] = Type{
		"bool", ST_BOOL,
		func(vals ...interface{}) interface{} { return new(bool) },
		baseTypeMarshaller,
		func(r io.Reader) (interface{}, error) { return baseTypeUnmarshaller(ST_BOOL, r) },
	}
	cacheTypes.names["bool"] = ST_BOOL

	cacheTypes.types[ST_UINT8] = Type{
		"uint8", ST_UINT8,
		func(vals ...interface{}) interface{} { return new(uint8) },
		baseTypeMarshaller,
		func(r io.Reader) (interface{}, error) { return baseTypeUnmarshaller(ST_UINT8, r) },
	}
	cacheTypes.names["uint8"] = ST_UINT8

	cacheTypes.types[ST_UINT16] = Type{
		"uint16", ST_UINT16,
		func(vals ...interface{}) interface{} { return new(uint16) },
		baseTypeMarshaller,
		func(r io.Reader) (interface{}, error) { return baseTypeUnmarshaller(ST_UINT16, r) },
	}
	cacheTypes.names["uint16"] = ST_UINT16

	cacheTypes.types[ST_UINT32] = Type{
		"uint32", ST_UINT32,
		func(vals ...interface{}) interface{} { return new(uint32) },
		baseTypeMarshaller,
		func(r io.Reader) (interface{}, error) { return baseTypeUnmarshaller(ST_UINT32, r) },
	}
	cacheTypes.names["uint32"] = ST_UINT32

	cacheTypes.types[ST_UINT64] = Type{
		"uint64", ST_UINT64,
		func(vals ...interface{}) interface{} { return new(uint64) },
		baseTypeMarshaller,
		func(r io.Reader) (interface{}, error) { return baseTypeUnmarshaller(ST_UINT64, r) },
	}
	cacheTypes.names["uint64"] = ST_UINT64

	cacheTypes.types[ST_INT8] = Type{
		"int8", ST_INT8,
		func(vals ...interface{}) interface{} { return new(int8) },
		baseTypeMarshaller,
		func(r io.Reader) (interface{}, error) { return baseTypeUnmarshaller(ST_INT8, r) },
	}
	cacheTypes.names["int8"] = ST_UINT8

	cacheTypes.types[ST_INT16] = Type{
		"int16", ST_INT16,
		func(vals ...interface{}) interface{} { return new(int16) },
		baseTypeMarshaller,
		func(r io.Reader) (interface{}, error) { return baseTypeUnmarshaller(ST_INT16, r) },
	}
	cacheTypes.names["int16"] = ST_INT16

	cacheTypes.types[ST_INT32] = Type{
		"int32", ST_INT32,
		func(vals ...interface{}) interface{} { return new(int32) },
		baseTypeMarshaller,
		func(r io.Reader) (interface{}, error) { return baseTypeUnmarshaller(ST_INT32, r) },
	}
	cacheTypes.names["int32"] = ST_INT32

	cacheTypes.types[ST_INT64] = Type{
		"int64", ST_INT64,
		func(vals ...interface{}) interface{} { return new(int64) },
		baseTypeMarshaller,
		func(r io.Reader) (interface{}, error) { return baseTypeUnmarshaller(ST_INT64, r) },
	}
	cacheTypes.names["int64"] = ST_INT64

	cacheTypes.types[ST_FLOAT32] = Type{
		"float32", ST_FLOAT32,
		func(vals ...interface{}) interface{} { return new(float32) },
		baseTypeMarshaller,
		func(r io.Reader) (interface{}, error) { return baseTypeUnmarshaller(ST_FLOAT32, r) },
	}
	cacheTypes.names["float32"] = ST_FLOAT32

	cacheTypes.types[ST_FLOAT64] = Type{
		"float64", ST_FLOAT64,
		func(vals ...interface{}) interface{} { return new(float64) },
		baseTypeMarshaller,
		func(r io.Reader) (interface{}, error) { return baseTypeUnmarshaller(ST_FLOAT64, r) },
	}
	cacheTypes.names["float64"] = ST_FLOAT64

	cacheTypes.types[ST_STRING] = Type{
		"string", ST_STRING,
		func(vals ...interface{}) interface{} { return new(string) },
		baseTypeMarshaller,
		func(r io.Reader) (interface{}, error) { return baseTypeUnmarshaller(ST_STRING, r) },
	}
	cacheTypes.names["string"] = ST_STRING
}

func getTypeId(e interface{}, indirectLevel int) (id uint32, level int) {
	level = indirectLevel
	t := reflect.TypeOf(e)

	if t.Kind() == reflect.Invalid {
		return ST_INVALID, level
	}

	v := reflect.ValueOf(e)
	switch t.Kind() {
	case reflect.Ptr:
		if v.IsNil() {
			return ST_INVALID, level
		}
		p := reflect.Indirect(v)
		level += 1
		return getTypeId(p.Interface(), level)
	}

	if id, ok := cacheTypes.names[t.Kind().String()]; ok {
		return id, level
	}

	return ST_INVALID, level
}

func getIndirection(e interface{}, level int) (indirection int, maintype uint32, typ reflect.Type) {
	indirection = level
	maintype = ST_COMMON

	t := reflect.TypeOf(e)
	v := reflect.ValueOf(e)

	switch t.Kind() {
	case reflect.Ptr:
		if v.IsNil() {
			return indirection, maintype, t
		}
		p := reflect.Indirect(v)
		indirection += 1
		return getIndirection(p.Interface(), indirection)
	case reflect.Slice:
		maintype = ST_SLICE
	case reflect.Array:
		maintype = ST_ARRAY
	case reflect.Struct:
		maintype = ST_STRUCT
	}

	return indirection, maintype, t
}

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, valTypes []uint32, base bool, sfields []*StructField, 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.Interface()
	}

	valTypes = []uint32{}
	sfields = []*StructField{}
	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
			slog.LOG_DEBUGFLN("Indirection: %d", indirection)
		} else {
			slog.LOG_DEBUGFLN("ELSE: %v", t)

			switch val.Kind() {
			case reflect.Slice:
				typ := reflect.TypeOf(val.Interface())
				slog.LOG_DEBUGFLN("typ.Kind(): %s", typ.Kind())
				slog.LOG_DEBUGFLN("val.Type(): %s", typ.Elem())
				vt, err := getTypeByNameRegister(typ.Elem().String(), typ.Elem())
				slog.LOG_DEBUGFLN("vt: %v", vt)
				if err != nil {
					return ret, mainTypeId, indirection, valTypes, base, sfields, fmt.Errorf("ssob: Failed receiving type '%s': %w", typ.Elem(), err)
				}
				valTypes = append(valTypes, vt.Id)
				base = false
				mainTypeId = ST_SLICE
			case reflect.Array:
				typ := reflect.TypeOf(val.Interface())
				slog.LOG_DEBUGFLN("typ.Kind(): %s", typ.Kind())
				slog.LOG_DEBUGFLN("val.Type(): %s", typ.Elem())
				vt, err := getTypeByNameRegister(typ.Elem().String(), typ.Elem())
				slog.LOG_DEBUGFLN("vt: %v", vt)
				if err != nil {
					return ret, mainTypeId, indirection, valTypes, base, sfields, fmt.Errorf("ssob: Failed receiving type '%s': %w", typ.Elem(), err)
				}
				valTypes = append(valTypes, uint32(val.Len()))
				valTypes = append(valTypes, vt.Id)
				base = false
				mainTypeId = ST_ARRAY
			case reflect.Interface:
				typ := reflect.TypeOf(nval.Interface())
				slog.LOG_DEBUGFLN("val.Type(): %s", typ.Elem())
				slog.LOG_DEBUGFLN("INTERFACE")
				if !base {
					vt, err := getTypeByNameRegister(typ.Elem().String(), typ.Elem())
					slog.LOG_DEBUGFLN("vt: %v", vt)
					if err != nil {
						return ret, mainTypeId, indirection, valTypes, base, sfields, fmt.Errorf("ssob: Failed receiving type '%s': %w", typ.Elem(), err)
					}
					valTypes = append(valTypes, vt.Id)
				}
				mainTypeId = ST_INTERFACE
			case reflect.Struct:
				typ := reflect.TypeOf(val.Interface())
				slog.LOG_DEBUGFLN("typ.Kind(): %s", typ.String())
				slog.LOG_DEBUGFLN("STRUCT")
				if !base {
					vt, err := getTypeByNameRegister(typ.String(), typ)
					slog.LOG_DEBUGFLN("vt: %v", vt)
					if err != nil {
						return ret, mainTypeId, indirection, valTypes, base, sfields, fmt.Errorf("ssob: Failed receiving type '%s': %w", typ.Elem(), err)
					}
					valTypes = append(valTypes, vt.Id)
				} else {
					sl := val.NumField()
					for i := 0; i < sl; i++ {
						if val.Field(i).CanSet() {
							slog.LOG_DEBUGFLN("Struct '%s': Field '%d' '%s' -> '%v'", typ.String(), i, val.Type().Field(i).Name, val.Field(i).Type())
							sfield := new(StructField)
							sfield.Name = val.Type().Field(i).Name
							sfield.Tag = string(val.Type().Field(i).Tag)
							sfields = append(sfields, sfield)
							vt, err := getTypeByNameRegister(val.Field(i).Type().String(), val.Field(i).Type())
							if err != nil {
								return ret, mainTypeId, indirection, valTypes, base, sfields, fmt.Errorf("ssob: Failed receiving type '%s': %w", typ.Elem(), err)
							}
							valTypes = append(valTypes, vt.Id)
						}
					}
					base = false
				}
				mainTypeId = ST_STRUCT
			case reflect.Map:
				typ := reflect.TypeOf(val.Interface())
				slog.LOG_DEBUGFLN("typ.Kind(): %s", typ.String())
				slog.LOG_DEBUGFLN("MAP")
				slog.LOG_DEBUGFLN("key: %s", typ.Key())
				slog.LOG_DEBUGFLN("val: %s", typ.Elem())
				if !base {
					vt, err := getTypeByNameRegister(typ.String(), typ)
					slog.LOG_DEBUGFLN("vt: %v", vt)
					if err != nil {
						return ret, mainTypeId, indirection, valTypes, base, sfields, fmt.Errorf("ssob: Failed receiving type '%s': %w", typ.Elem(), err)
					}
					valTypes = append(valTypes, vt.Id)
				} else {
					// Key
					vt, err := getTypeByNameRegister(typ.Key().String(), typ.Key())
					slog.LOG_DEBUGFLN("vt: %v", vt)
					if err != nil {
						return ret, mainTypeId, indirection, valTypes, base, sfields, fmt.Errorf("ssob: Failed receiving type '%s': %w", typ.Elem(), err)
					}
					valTypes = append(valTypes, vt.Id)

					// Val
					vt, err = getTypeByNameRegister(typ.Elem().String(), typ.Elem())
					slog.LOG_DEBUGFLN("vt: %v", vt)
					if err != nil {
						return ret, mainTypeId, indirection, valTypes, base, sfields, fmt.Errorf("ssob: Failed receiving type '%s': %w", typ.Elem(), err)
					}
					valTypes = append(valTypes, vt.Id)
					base = false
				}
				mainTypeId = ST_MAP
			default:
				typ := reflect.TypeOf(val.Interface())
				slog.LOG_DEBUGFLN("typ.Kind(): %s", typ.Kind())
				slog.LOG_DEBUGFLN("COMMON")
				if !base {
					vt, err := getTypeByNameRegister(typ.Kind().String(), typ)
					slog.LOG_DEBUGFLN("vt: %v", vt)
					if err != nil {
						return ret, mainTypeId, indirection, valTypes, base, sfields, fmt.Errorf("ssob: Failed receiving type '%s': %w", typ.Elem(), err)
					}
					valTypes = append(valTypes, vt.Id)
				}
				mainTypeId = ST_COMMON
			}
			break
		}
	}

	return ret, mainTypeId, indirection, valTypes, base, sfields, 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()
	slog.LOG_DEBUGFLN("t.Name(): %s", t)
	ret.alloc, ret.MainTypeId, ret.Indirection, ret.ValTypes, base, ret.structFields, err = parseType(t)

	return ret, base, err
}

func registerType(t reflect.Type) (err error) {
	if t == nil || t.Kind() == reflect.Invalid {
		return fmt.Errorf("ssob: Cannot register nil: %w", ErrTypeInvalid)
	}

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

	var base bool
	ntype, base, err := createType(t)
	if err != nil {
		return fmt.Errorf("ssob: Cannot register type '%s': %w", t, err)
	}
	ntype.Id = cacheTypes.NextId
	if base {
		ntype.ValTypes = []uint32{ntype.Id}
	}
	cacheTypes.ntypes[ntype.Id] = ntype
	cacheTypes.nnames[ntype.Name] = ntype
	cacheTypes.NextId += 1

	slog.LOG_DEBUGFLN("Registered type: %v", ntype)
	if ntype.MainTypeId == ST_STRUCT {
		for _, f := range ntype.structFields {
			slog.LOG_DEBUGFLN("  Field: %v", f)
		}
	}

	return err
}

func RegisterType(e interface{}) (err error) {
	t := reflect.TypeOf(e)
	return registerType(t)
}