gocommon/server.go

package gocommon

import (
	"bytes"
	"context"
	"encoding/gob"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"math"
	"net"
	"net/http"
	"net/url"
	"os"
	"os/signal"
	"path"
	"reflect"
	"runtime"
	"strconv"
	"strings"
	"sync"
	"sync/atomic"
	"syscall"
	"time"
	"unsafe"

	"repositories.action2quare.com/ayo/gocommon/flagx"
	"repositories.action2quare.com/ayo/gocommon/logger"

	"github.com/pires/go-proxyproto"
	"go.mongodb.org/mongo-driver/bson/primitive"
)

func init() {
	gob.Register(map[string]any{})
	gob.Register(primitive.A{})
	gob.Register(primitive.M{})
	gob.Register(primitive.D{})
	gob.Register(primitive.ObjectID{})
	gob.Register([]any{})
}

type ServerMuxInterface interface {
	http.Handler

	HandleFunc(pattern string, handler func(http.ResponseWriter, *http.Request))
	Handle(pattern string, handler http.Handler)
}

const (
	// HTTPStatusReloginRequired : http status를 이걸 받으면 클라이언트는 로그아웃하고 로그인 화면으로 돌아가야 한다.
	HTTPStatusReloginRequired = 599
	// HTTPStatusReloginRequiredDupID :
	HTTPStatusReloginRequiredDupID = 598
	// HTTPStatusPlayerBlocked :
	HTTPStatusPlayerBlocked = 597
)

type ShutdownFlag int32

const (
	ShutdownFlagRunning     = ShutdownFlag(0)
	ShutdownFlagTerminating = ShutdownFlag(1)
	ShutdownFlagRestarting  = ShutdownFlag(2)
	ShutdownFlagIdle        = ShutdownFlag(3)
)

type ErrorWithStatus struct {
	StatusCode int
}

func (e ErrorWithStatus) Error() string {
	return fmt.Sprintf("%d", e.StatusCode)
}

type RpcReturnTypeInterface interface {
	Value() any
	Error() error
	Serialize(http.ResponseWriter) error
}

type functionCallContext struct {
	Method string
	Args   []interface{}
}

// Server :
type Server struct {
	httpserver *http.Server
	interrupt  chan os.Signal
}

var healthcheckcounter = int64(0)

func healthCheckHandler(w http.ResponseWriter, r *http.Request) {
	defer func() {
		io.Copy(io.Discard, r.Body)
		r.Body.Close()
	}()

	// 한번이라도 들어오면 lb에 붙어있다는 뜻
	if t := atomic.AddInt64(&healthcheckcounter, 1); t < 0 {
		logger.Println("healthCheckHandler return StatusServiceUnavailable :", t)
		w.WriteHeader(http.StatusServiceUnavailable)
	}
}

func welcomeHandler(w http.ResponseWriter, r *http.Request) {
	defer func() {
		io.Copy(io.Discard, r.Body)
		r.Body.Close()
	}()
	w.Write([]byte("welcome"))
}

var tlsflag = flagx.String("tls", "", "")
var portptr = flagx.Int("port", 80, "")

func isTlsEnabled(fileout ...*string) bool {
	if len(*tlsflag) == 0 {
		return false
	}

	if strings.HasSuffix(*tlsflag, "/") {
		return false
	}

	crtfile := *tlsflag + ".crt"
	if _, err := os.Stat(crtfile); os.IsNotExist(err) {
		return false
	}

	keyfile := *tlsflag + ".key"
	if _, err := os.Stat(keyfile); os.IsNotExist(err) {
		return false
	}

	if len(fileout) > 0 {
		*fileout[0] = crtfile
	}

	if len(fileout) > 1 {
		*fileout[1] = keyfile
	}

	return true
}

func registUnhandledPattern(serveMux ServerMuxInterface) {
	defer func() {
		recover()
	}()

	serveMux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
		logger.Println("page not found :", r.URL.Path)
		w.WriteHeader(http.StatusNotFound)
	})
}

// NewHTTPServer :
func NewHTTPServerWithPort(serveMux ServerMuxInterface, port int) *Server {
	if isTlsEnabled() && port == 80 {
		port = 443
	}
	addr := fmt.Sprintf(":%d", port)
	serveMux.HandleFunc(MakeHttpHandlerPattern("welcome"), welcomeHandler)
	serveMux.HandleFunc(MakeHttpHandlerPattern("lb_health_chceck"), healthCheckHandler)
	serveMux.HandleFunc(MakeHttpHandlerPattern("lb_health_check"), healthCheckHandler)
	registUnhandledPattern(serveMux)

	server := &Server{
		httpserver: &http.Server{
			Addr:           addr,
			Handler:        serveMux,
			MaxHeaderBytes: 2 << 20, // 2 MB
		},
	}
	server.httpserver.SetKeepAlivesEnabled(true)

	return server
}

func NewHTTPServer(serveMux ServerMuxInterface) *Server {

	// 시작시 자동으로 enable됨
	if isTlsEnabled() && *portptr == 80 {
		*portptr = 443
	}
	return NewHTTPServerWithPort(serveMux, *portptr)
}

// Shutdown :
func (server *Server) shutdown() {
	logger.Println("server.shutdown()")

	signal.Stop(server.interrupt)

	if t := atomic.LoadInt64(&healthcheckcounter); t > 0 {
		logger.Println("http server shutdown. healthcheckcounter :", t)
		atomic.StoreInt64(&healthcheckcounter, math.MinInt64)

		for cnt := 0; cnt < 100; {
			next := atomic.LoadInt64(&healthcheckcounter)
			if next == t {
				cnt++
			} else {
				t = next
				cnt = 0
			}
			time.Sleep(100 * time.Millisecond)
		}
		logger.Println("http server shutdown. healthcheck completed")
	} else {
		logger.Println("http server shutdown. no lb")
	}

	if server.httpserver != nil {
		server.httpserver.Shutdown(context.Background())
		server.httpserver = nil
	}
}

func (server *Server) Stop() {
	if server.interrupt != nil {
		server.interrupt <- os.Interrupt
	} else {
		server.shutdown()
	}
}

// Start :
func (server *Server) Start(name ...string) error {
	if len(name) == 0 {
		exepath, _ := os.Executable()
		name = []string{path.Base(exepath)}
	}

	if server.httpserver != nil {
		ln, r := net.Listen("tcp", server.httpserver.Addr)
		if r != nil {
			return r
		}
		server.interrupt = make(chan os.Signal, 1)
		signal.Notify(server.interrupt, os.Interrupt, syscall.SIGINT, syscall.SIGTERM, syscall.SIGQUIT)

		go func() {
			c := <-server.interrupt
			logger.Println("interrupt!!!!!!!! :", c.String())
			server.shutdown()
		}()

		proxyListener := &proxyproto.Listener{
			Listener:          ln,
			ReadHeaderTimeout: 10 * time.Second,
		}
		defer proxyListener.Close()

		var err error
		var crtfile string
		var keyfile string
		if isTlsEnabled(&crtfile, &keyfile) {
			logger.Println("tls enabled :", crtfile, keyfile)
			err = server.httpserver.ServeTLS(proxyListener, crtfile, keyfile)
		} else {
			logger.Println("tls disabled")
			logger.Println(strings.Join(name, ", "), "started")
			err = server.httpserver.Serve(proxyListener)
		}

		if err != nil {
			if errors.Is(err, http.ErrServerClosed) {
				logger.Println("server.httpserver is closed normally")
				return nil
			}

			logger.Error("server.httpserver.Serve err :", err)
			return err
		}
	}
	return nil
}

// ConvertInterface :
func ConvertInterface(from interface{}, toType reflect.Type) reflect.Value {
	fromrv := reflect.ValueOf(from)
	fromtype := reflect.TypeOf(from)

	if fromtype == toType {
		return fromrv
	}

	switch fromtype.Kind() {
	case reflect.Map:
		frommap := from.(map[string]interface{})
		if frommap == nil {
			// map[string]interface{}가 아니고 뭐란말인가
			return reflect.Zero(toType)
		}

		needAddr := false
		if toType.Kind() == reflect.Pointer {
			toType = toType.Elem()
			needAddr = true
		}

		out := reflect.New(toType)
		switch toType.Kind() {
		case reflect.Struct:
			for i := 0; i < toType.NumField(); i++ {
				field := toType.FieldByIndex([]int{i})
				if field.Anonymous {
					fieldval := out.Elem().FieldByIndex([]int{i})
					fieldval.Set(ConvertInterface(from, field.Type))
				} else if v, ok := frommap[strings.ToLower(field.Name)]; ok {
					fieldval := out.Elem().FieldByIndex([]int{i})
					fieldval.Set(ConvertInterface(v, fieldval.Type()))
				}
			}

		case reflect.Map:
			out.Elem().Set(reflect.MakeMap(toType))

			if toType.Key().Kind() != reflect.String {
				for k, v := range frommap {
					tok := reflect.ValueOf(k).Convert(toType.Key())
					tov := ConvertInterface(v, toType.Elem())
					out.Elem().SetMapIndex(tok, tov)
				}
			} else {
				for k, v := range frommap {
					tov := ConvertInterface(v, toType.Elem())
					out.Elem().SetMapIndex(reflect.ValueOf(k), tov)
				}
			}
		default:
			logger.Println("ConvertInterface failed : map ->", toType.Kind().String())
		}

		if needAddr {
			return out
		}

		return out.Elem()

	case reflect.Slice:
		convslice := reflect.MakeSlice(toType, 0, fromrv.Len())
		for i := 0; i < fromrv.Len(); i++ {
			convslice = reflect.Append(convslice, ConvertInterface(fromrv.Index(i).Interface(), toType.Elem()))
		}

		return convslice

	case reflect.Bool:
		val, _ := strconv.ParseBool(from.(string))
		return reflect.ValueOf(val)

	case reflect.String:
		if toType == reflect.TypeOf(primitive.ObjectID{}) {
			objid, _ := primitive.ObjectIDFromHex(from.(string))
			return reflect.ValueOf(objid)
		}
	}

	return fromrv.Convert(toType)
}

// ErrUnmarshalRequestFailed :
var ErrUnmarshalRequestFailed = errors.New("unmarshal failed at rpc handler")
var ErrWithStatusCode = errors.New("custom error with status code")
var ErrSecondReturnShouldBeErrorType = errors.New("second return type should be error")

type methodCacheType struct {
	sync.Mutex
	toIndex map[reflect.Type]map[string]int
}

var methodCache = methodCacheType{
	toIndex: make(map[reflect.Type]map[string]int),
}

func (mc *methodCacheType) method(receiver any, method string) (reflect.Value, bool) {
	mc.Lock()
	defer mc.Unlock()

	t := reflect.TypeOf(receiver)
	table, ok := mc.toIndex[t]
	if !ok {
		table = make(map[string]int)
		mc.toIndex[t] = table
	}

	idx, ok := table[method]
	if !ok {
		m, ok := t.MethodByName(method)
		if !ok {
			return reflect.Value{}, false
		}

		table[method] = m.Index
		idx = m.Index
	}

	return reflect.ValueOf(receiver).Method(idx), true
}

// CallMethodInternal :
func CallMethodInternal(receiver interface{}, context functionCallContext) (result RpcReturnTypeInterface, err error) {
	fn, ok := methodCache.method(receiver, context.Method)
	if !ok {
		return nil, errors.New(fmt.Sprint("method is missing :", receiver, context.Method))
	}
	if len(context.Args) != fn.Type().NumIn() {
		return nil, errors.New(fmt.Sprint("argument is not matching :", context.Method))
	}

	var argv []reflect.Value
	for i := 0; i < len(context.Args); i++ {
		argv = append(argv, ConvertInterface(context.Args[i], fn.Type().In(i)))
	}
	returnVals := fn.Call(argv)

	if len(returnVals) == 0 {
		return nil, ErrSecondReturnShouldBeErrorType
	}

	result = nil
	err = nil
	if result, ok = returnVals[0].Interface().(RpcReturnTypeInterface); !ok {
		return nil, ErrSecondReturnShouldBeErrorType
	}

	if len(returnVals) > 1 {
		if err, ok = returnVals[1].Interface().(error); !ok {
			return nil, ErrSecondReturnShouldBeErrorType
		}
	}

	return
}

// CallMethod :
func CallMethod(receiver interface{}, context []byte) (RpcReturnTypeInterface, error) {
	defer func() {
		r := recover()
		if r != nil {
			logger.Error(r)
		}
	}()

	var meta functionCallContext
	if err := json.Unmarshal(context, &meta); err != nil {
		return nil, ErrUnmarshalRequestFailed
	}

	return CallMethodInternal(receiver, meta)
}

func ReadIntegerFormValue(r url.Values, key string) (int64, bool) {
	strval := r.Get(key)
	if len(strval) == 0 {
		return 0, false
	}
	temp, err := strconv.ParseInt(strval, 10, 0)
	if err != nil {
		logger.Error("common.ReadFloatFormValue failed :", key, err)
		return 0, false
	}

	return temp, true

}

func ReadFloatFormValue(r url.Values, key string) (float64, bool) {
	var inst float64
	strval := r.Get(key)
	if len(strval) == 0 {
		return inst, false
	}
	temp, err := strconv.ParseFloat(strval, 64)
	if err != nil {
		logger.Error("common.ReadFloatFormValue failed :", key, err)
		return inst, false
	}

	return temp, true
}

func ReadObjectIDFormValue(r url.Values, key string) (primitive.ObjectID, bool) {
	strval := r.Get(key)
	if len(strval) == 0 {
		return primitive.NilObjectID, false
	}
	id, err := primitive.ObjectIDFromHex(strval)
	if err != nil {
		logger.Error("common.ReadObjectIDFormValue failed :", key, err)
		return primitive.NilObjectID, false
	}
	return id, true
}

func ReadBoolFormValue(r url.Values, key string) (bool, bool) {
	strval := r.Get(key)
	if len(strval) == 0 {
		return false, false
	}
	ret, err := strconv.ParseBool(strval)
	if err != nil {
		logger.Error("common.ReadBoolFormValue failed :", key, err)
		return false, false
	}
	return ret, true
}

func ReadStringFormValue(r url.Values, key string) (string, bool) {
	strval := r.Get(key)
	return strval, len(strval) > 0
}

func ReadStringsFormValue(r url.Values, key string) ([]string, bool) {
	if r.Has(key) {
		return (map[string][]string)(r)[key], true
	}
	return nil, false
}

type encoder interface {
	Encode(any) error
}

type nilEncoder struct{}

func (ne *nilEncoder) Encode(any) error { return nil }

type decoder interface {
	Decode(any) error
}

type nilDecoder struct{}

func (nd *nilDecoder) Decode(any) error { return nil }

func MakeDecoder(r *http.Request) decoder {
	ct := r.Header.Get("Content-Type")
	if ct == "application/gob" {
		return gob.NewDecoder(r.Body)
	} else if ct == "application/json" {
		return json.NewDecoder(r.Body)
	}

	logger.Error("Content-Type is not supported :", ct)
	return &nilDecoder{}
}

func MakeEncoder(w http.ResponseWriter, r *http.Request) encoder {
	ct := r.Header.Get("Content-Type")
	if ct == "application/gob" {
		return gob.NewEncoder(w)
	} else if ct == "application/json" {
		return json.NewEncoder(w)
	}

	logger.Error("Content-Type is not supported :", ct)
	return &nilEncoder{}
}

func DotStringToTimestamp(tv string) primitive.Timestamp {
	if len(tv) == 0 {
		return primitive.Timestamp{T: 0, I: 0}
	}

	ti := strings.Split(tv, ".")
	t, _ := strconv.ParseUint(ti[0], 10, 0)
	if len(ti) > 1 {
		i, _ := strconv.ParseUint(ti[1], 10, 0)
		return primitive.Timestamp{T: uint32(t), I: uint32(i)}
	}

	return primitive.Timestamp{T: uint32(t), I: 0}
}

type RpcReturnSimple struct {
	value any
}

func (rt *RpcReturnSimple) Value() any {
	return rt.value
}

func (rt *RpcReturnSimple) Error() error {
	return nil
}

func (rt *RpcReturnSimple) Serialize(w http.ResponseWriter) error {
	err := SerializeInterface(w, rt.value)
	if err == nil {
		w.Write([]byte{0, 0})
	}
	return err
}

type RpcReturnError struct {
	err  error
	code int
	h    map[string]any
}

func (rt *RpcReturnError) Value() any {
	return nil
}

var errDefaultError = errors.New("unknown error")

func (rt *RpcReturnError) Error() error {
	if rt.err != nil {
		return rt.err
	}

	if rt.code != 0 {
		if rt.h == nil {
			return fmt.Errorf("http status code %d error", rt.code)
		}
		return fmt.Errorf("http status code %d error with header %v", rt.code, rt.h)
	}

	return errDefaultError
}

func (rt *RpcReturnError) Serialize(w http.ResponseWriter) error {
	if rt.h != nil {
		bt, _ := json.Marshal(rt.h)
		w.Header().Add("As-X-Err", string(bt))
	}

	w.WriteHeader(rt.code)
	if rt.err != nil {
		logger.Error(rt.err)
	}

	if rt.code >= http.StatusInternalServerError {
		logger.Println("rpc return error :", rt.code, rt.h)
	}

	return nil
}

func (rt *RpcReturnError) WithCode(code int) *RpcReturnError {
	rt.code = code
	return rt
}

func (rt *RpcReturnError) WithError(err error) *RpcReturnError {
	if err2, ok := err.(*ErrorWithStatus); ok {
		rt.WithCode(err2.StatusCode)
	} else {
		rt.err = err
	}
	return rt
}

func (rt *RpcReturnError) WithHeader(k string, v any) *RpcReturnError {
	if rt.h == nil {
		rt.h = make(map[string]any)
	}
	rt.h[k] = v
	return rt
}

func (rt *RpcReturnError) WithHeaders(h map[string]any) *RpcReturnError {
	if rt.h == nil {
		rt.h = h
	} else {
		for k, v := range h {
			rt.h[k] = v
		}
	}
	return rt
}

// MakeRPCReturn :
func MakeRPCReturn(value interface{}) *RpcReturnSimple {
	return &RpcReturnSimple{
		value: value,
	}
}

func MakeRPCFail() *RpcReturnError {
	return &RpcReturnError{
		err:  nil,
		code: http.StatusInternalServerError,
		h:    nil,
	}
}

func MakeRPCError() *RpcReturnError {
	pc, _, _, ok := runtime.Caller(1)
	if ok {
		frames := runtime.CallersFrames([]uintptr{pc})
		frame, _ := frames.Next()
		logger.Printf("rpc error. func=%s, file=%s, line=%d", frame.Function, frame.File, frame.Line)
	}

	return &RpcReturnError{
		err:  nil,
		code: http.StatusInternalServerError,
		h:    nil,
	}
}

type indirectBody struct {
	inner  io.ReadCloser
	dump   []byte
	closer func()
}

func (ib *indirectBody) Read(p []byte) (n int, err error) {
	n, err = ib.inner.Read(p)
	if n > 0 {
		ib.dump = append(ib.dump, p...)
	}
	return
}

func (ib *indirectBody) Close() error {
	if ib.closer != nil {
		ib.closer()
		ib.closer = nil
	}
	return ib.inner.Close()
}

func MakeHttpRequestForLogging(r *http.Request) *http.Request {
	ib := &indirectBody{
		inner: r.Body,
	}

	closer := func() {
		var uv url.Values

		if r.Form != nil {
			uv = r.Form
		} else {
			uv = r.URL.Query()
		}

		logger.Println("request :")
		logger.Println("    header :", r.Header)
		logger.Println("    values :", uv)
		logger.Println("    body   :", string(ib.dump))
	}

	ib.closer = closer

	r.Body = ib
	return r
}

type apiFuncType func(http.ResponseWriter, *http.Request)
type HttpApiHandler struct {
	methods              map[string]apiFuncType
	originalReceiverName string
}

func MakeHttpApiHandler[T any](receiver *T, receiverName string) HttpApiHandler {
	methods := make(map[string]apiFuncType)

	tp := reflect.TypeOf(receiver)
	if len(receiverName) == 0 {
		receiverName = tp.Elem().Name()
	}
	writerType := reflect.TypeOf((*http.ResponseWriter)(nil)).Elem()
	for i := 0; i < tp.NumMethod(); i++ {
		method := tp.Method(i)
		if method.Type.NumIn() != 3 {
			continue
		}

		if method.Type.In(0) != tp {
			continue
		}

		if !method.Type.In(1).Implements(writerType) {
			continue
		}

		var r http.Request
		if method.Type.In(2) != reflect.TypeOf(&r) {
			continue
		}

		if method.Name == "ServeHTTP" {
			continue
		}

		funcptr := method.Func.Pointer()
		p1 := unsafe.Pointer(&funcptr)
		p2 := unsafe.Pointer(&p1)
		testfunc := (*func(*T, http.ResponseWriter, *http.Request))(p2)
		methods[receiverName+"."+method.Name] = func(w http.ResponseWriter, r *http.Request) {
			(*testfunc)(receiver, w, r)
		}
	}

	return HttpApiHandler{
		methods:              methods,
		originalReceiverName: tp.Elem().Name(),
	}
}

type HttpApiBroker struct {
	methods     map[string]apiFuncType
	methods_dup map[string][]apiFuncType
}

type bufferReadCloser struct {
	*bytes.Reader
}

func (buff *bufferReadCloser) Close() error { return nil }

type readOnlyResponseWriter struct {
	inner      http.ResponseWriter
	statusCode int
}

func (w *readOnlyResponseWriter) Header() http.Header {
	return w.inner.Header()
}

func (w *readOnlyResponseWriter) Write(in []byte) (int, error) {
	logger.Println("readOnlyResponseWriter cannot write")
	return len(in), nil
}

func (w *readOnlyResponseWriter) WriteHeader(statusCode int) {
	w.statusCode = statusCode
}

func (hc *HttpApiBroker) AddHandler(receiver HttpApiHandler) {
	if hc.methods == nil {
		hc.methods = make(map[string]apiFuncType)
		hc.methods_dup = make(map[string][]apiFuncType)
	}

	for k, v := range receiver.methods {
		ab := strings.Split(k, ".")
		logger.Printf("http api registered : %s.%s -> %s\n", receiver.originalReceiverName, ab[1], k)

		hc.methods_dup[k] = append(hc.methods_dup[k], v)
		if len(hc.methods_dup[k]) > 1 {
			chain := hc.methods_dup[k]
			hc.methods[k] = func(w http.ResponseWriter, r *http.Request) {
				body, _ := io.ReadAll(r.Body)
				defer r.Body.Close()

				wrap := &readOnlyResponseWriter{inner: w, statusCode: 200}
				for _, f := range chain {
					r.Body = &bufferReadCloser{bytes.NewReader(body)}
					f(wrap, r)
				}

				if wrap.statusCode != 200 {
					w.WriteHeader(wrap.statusCode)
				}
			}
		} else {
			hc.methods[k] = v
		}
	}
}

func (hc *HttpApiBroker) AllMethodNames() (out []string) {
	out = make([]string, 0, len(hc.methods))
	for name := range hc.methods {
		out = append(out, name)
	}
	return
}

func (hc *HttpApiBroker) CallByHeader(w http.ResponseWriter, r *http.Request) {
	funcname := r.Header.Get("AS-X-CALL")
	if len(funcname) == 0 {
		logger.Println("as-x-call header is missing")
		w.WriteHeader(http.StatusBadRequest)
		return
	}

	hc.call(funcname, w, r)
}

func (hc *HttpApiBroker) Call(w http.ResponseWriter, r *http.Request) {
	funcname := r.URL.Query().Get("call")
	if len(funcname) == 0 {
		logger.Println("query param 'call' is missing")
		w.WriteHeader(http.StatusBadRequest)
		return

	}
	hc.call(funcname, w, r)
}

func (hc *HttpApiBroker) call(funcname string, w http.ResponseWriter, r *http.Request) {
	if found := hc.methods[funcname]; found != nil {
		found(w, r)
	} else {
		logger.Println("api is not found :", funcname)
	}
}

func CallInternalServiceAPI[T any](url string, apitoken string, method string, data T, headers ...string) error {
	tempHeader := make(http.Header)
	tempHeader.Set("MG-X-API-TOKEN", apitoken)
	tempHeader.Set("Content-Type", "application/gob")

	for i := 1; i < len(headers); i += 2 {
		tempHeader.Set(headers[i-1], headers[i])
	}

	buff := new(bytes.Buffer)
	ct := tempHeader.Get("Content-Type")
	if ct == "application/gob" {
		enc := gob.NewEncoder(buff)
		enc.Encode(data)
	} else if ct == "application/json" {
		enc := json.NewEncoder(buff)
		enc.Encode(data)
	}

	reqURL := fmt.Sprintf("%s/api?call=%s", url, method)
	req, err := http.NewRequest("POST", reqURL, buff)
	if err != nil {
		return err
	}

	req.Header = tempHeader
	resp, err := http.DefaultClient.Do(req)

	defer func() {
		if resp != nil && resp.Body != nil {
			resp.Body.Close()
		}
	}()

	if err == nil {
		if resp.StatusCode != http.StatusOK {
			return &ErrorWithStatus{StatusCode: resp.StatusCode}
		}
	}

	return err
}

func CallInternalServiceAPIAs[Tin any, Tout any](url string, apitoken string, method string, data Tin, out *Tout, headers ...string) error {
	tempHeader := make(http.Header)
	tempHeader.Set("MG-X-API-TOKEN", apitoken)
	tempHeader.Set("Content-Type", "application/gob")

	for i := 1; i < len(headers); i += 2 {
		tempHeader.Set(headers[i-1], headers[i])
	}

	buff := new(bytes.Buffer)
	ct := tempHeader.Get("Content-Type")
	if ct == "application/gob" {
		enc := gob.NewEncoder(buff)
		enc.Encode(data)
	} else if ct == "application/json" {
		enc := json.NewEncoder(buff)
		enc.Encode(data)
	}

	reqURL := fmt.Sprintf("%s/api?call=%s", url, method)
	req, err := http.NewRequest("POST", reqURL, buff)
	if err != nil {
		return err
	}

	req.Header = tempHeader
	resp, err := http.DefaultClient.Do(req)
	if err != nil {
		return err
	}

	if resp.StatusCode != http.StatusOK {
		return &ErrorWithStatus{StatusCode: resp.StatusCode}
	}

	defer func() {
		if resp != nil && resp.Body != nil {
			resp.Body.Close()
		}
	}()

	if out != nil && resp.Body != nil {
		dec := gob.NewDecoder(resp.Body)
		return dec.Decode(out)
	}
	return nil
}