// package client_bus_http -- клиент HTTP-шины.
package client_bus_http

import (
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"strings"

	"github.com/google/uuid"

	mL0 "gitp78su.ipnodns.ru/svi/kern/v4/lev0"
	mKa "gitp78su.ipnodns.ru/svi/kern/v4/lev0/alias"
	mKt "gitp78su.ipnodns.ru/svi/kern/v4/lev0/ktypes"
	mL1 "gitp78su.ipnodns.ru/svi/kern/v4/lev1"
	"gitp78su.ipnodns.ru/svi/kern/v4/lev1/kbus_msg/msg_pub"
	"gitp78su.ipnodns.ru/svi/kern/v4/lev1/kbus_msg/msg_serve"
	"gitp78su.ipnodns.ru/svi/kern/v4/lev1/kbus_msg/msg_sub"
	"gitp78su.ipnodns.ru/svi/kern/v4/lev1/kbus_msg/msg_unsub"
	"gitp78su.ipnodns.ru/svi/kern/v4/lev1/safe_string"
	"gitp78su.ipnodns.ru/svi/kern/v4/lev2/kbus_http"
	"gitp78su.ipnodns.ru/svi/kern/v4/lev2/kctx"
)

// ClientBusHttp -- клиент HTTP-шины.
type ClientBusHttp struct {
	bus       mKt.IKernelBus
	ctx       mKt.ILocalCtx
	log       mKt.ILogBuf
	isWork    mKt.ISafeBool
	urlRemote string // URL дистанционной шины
	urlLocal  string // URL локальной шины для веб-хуков
}

// NewClientBusHttp - -возвращает новый клиент HTTP-шины.
func NewClientBusHttp(urlRemote string) *mL0.Result[mKt.IBusClient] {
	log := mL1.NewLogBuf(mL1.OptIsTerm(true), mL1.OptPrefix("ClientBusHttp"))
	log.Debug("NewClientBusHttp()")
	if urlRemote == "" {
		err := fmt.Errorf("NewClientBusHttp(): urlRemote is empty")
		return mL0.NewErr[mKt.IBusClient](err)
	}
	resKernCtx := kctx.GetKernelCtx()
	if resKernCtx.IsErr() {
		err := fmt.Errorf("NewClientBusHttp(): in get ctx, err=\n\t%w", resKernCtx.Err())
		return mL0.NewErr[mKt.IBusClient](err)
	}
	kCtx := resKernCtx.Val()
	resLocal := safe_string.NewSafeStringGetenv("LOCAL_HTTP_URL")
	if resLocal.IsErr() {
		err := fmt.Errorf("NewClientBusHttp(): in get env LOCAL_HTTP_URL, err=\n\t%w", resLocal.Err())
		return mL0.NewErr[mKt.IBusClient](err)
	}
	urlLocal := resLocal.Val()
	resBus := kbus_http.GetKernelBusHttp()
	if resBus.IsErr() {
		err := fmt.Errorf("NewClientBusHttp(): in get bus, err=\n\t%w", resBus.Err())
		return mL0.NewErr[mKt.IBusClient](err)
	}
	kBusHttp := resBus.Val()
	lCtx := mL1.NewLocalCtx(kCtx.Ctx())
	sf := &ClientBusHttp{
		ctx:       lCtx.Val(),
		log:       log,
		bus:       kBusHttp,
		isWork:    mL1.NewSafeBool(),
		urlRemote: strings.TrimSuffix(urlRemote, "/"),
		urlLocal:  strings.TrimSuffix(urlLocal.Get(), "/"),
	}
	return mL0.NewRes(mKt.IBusClient(sf))
}

// Unsubscribe -- отписывается от топика в дистанционной шине.
func (sf *ClientBusHttp) Unsubscribe(handler mKt.IBusHandlerSubscribe) {
	_uuid, err := uuid.NewV6()
	mL1.Hassert()(err == nil, "ClientBusHttp.Unsubscribe(): in generate UUID v6, err=\n\t%v", err)

	req := &msg_unsub.UnsubReq{
		Name_: handler.Name(),
		Uuid_: _uuid.String(),
	}
	req.SelfCheck()
	binReq, err := json.MarshalIndent(req, "", "  ")
	mL1.Hassert()(err == nil, "ClientBusHttp.Unsubscribe(): in marshal to JSON unsubscribe request, err=\n\t%v", err)
	reader := strings.NewReader(string(binReq))

	hReq, err := http.NewRequest(http.MethodPost, sf.urlRemote+"/bus/unsub", reader)
	mL1.Hassert()(err == nil, "ClientBusHttp.Unsubscribe(): in new request, err=\n\t%v", err)

	binBody, err := sf.makePost(hReq)
	if err != nil {
		sf.log.Err("Unsubscribe(): in make request, err=\n\t%v", err)
		return
	}
	resp := &msg_unsub.UnsubResp{}
	err = json.Unmarshal(binBody, resp)
	if err != nil {
		sf.log.Err("Unsubscribe(): in unmarshal response, err=\n\t%v", err)
		return
	}
	if resp.Status_ != "ok" {
		sf.log.Err("Unsubscribe(): resp!='ok', err=\n\t%v", resp.Status_)
	}
	if resp.Uuid_ != req.Uuid_ {
		sf.log.Err("Unsubscribe(): resp uuid(%v) bad", resp.Uuid_)
	}
}

// Subscribe -- подписывается на топик в дистанционной шине.
func (sf *ClientBusHttp) Subscribe(handler mKt.IBusHandlerSubscribe) *mL0.Result[bool] {
	_uuid, err := uuid.NewV6()
	mL1.Hassert()(err == nil, "ClientBusHttp.Subscribe(): in generate UUID v6, err=\n\t%v", err)
	req := &msg_sub.SubscribeReq{
		Topic_:   handler.Topic(),
		Uuid_:    _uuid.String(),
		WebHook_: sf.urlLocal + "/bus/pub", // Веб-хук всегда на своей стороне
	}
	req.SelfCheck()
	binReq, _ := json.MarshalIndent(req, "", "  ")
	body := strings.NewReader(string(binReq))

	hReq, err := http.NewRequest(http.MethodPost, sf.urlRemote+"/bus/sub", body)
	mL1.Hassert()(err == nil, "ClientBusHttp.Subscribe(): in new request, err=\n\t%v")

	binBody, err := sf.makePost(hReq)
	if err != nil {
		err := fmt.Errorf("ClientBusHttp.Subscribe(): in make request, err=\n\t%w", err)
		return mL0.NewErr[bool](err)
	}
	resp := &msg_sub.SubscribeResp{}
	err = json.Unmarshal(binBody, resp)
	if err != nil {
		err := fmt.Errorf("ClientBusHttp.Subscribe(): in unmarshal response, err=\n\t%v", err)
		return mL0.NewErr[bool](err)
	}
	if resp.Status_ != "ok" {
		err := fmt.Errorf("ClientBusHttp.Subscribe(): resp!='ok', err=\n\t%v", resp.Status_)
		return mL0.NewErr[bool](err)
	}
	if resp.Uuid_ != req.Uuid_ {
		err := fmt.Errorf("ClientBusHttp.Subscribe(): resp uuid(%v) bad", resp.Uuid_)
		return mL0.NewErr[bool](err)
	}
	res := sf.bus.Subscribe(handler)
	return res
}

// SendRequest -- отправляет в дистанционную шину запрос.
func (sf *ClientBusHttp) SendRequest(topic *mKa.ATopic, binReq []byte) *mL0.Result[[]byte] {
	_uuid, err := uuid.NewV6()
	mL1.Hassert()(err == nil, "ClientBusHttp.SendRequest(): in generate UUID v6, err=\n\t%v", err)
	req := &msg_serve.ServeReq{
		Topic_:  topic,
		Uuid_:   _uuid.String(),
		BinReq_: binReq,
	}
	req.SelfCheck()
	_binReq, _ := json.MarshalIndent(req, "", "  ")
	body := strings.NewReader(string(_binReq))

	hReq, err := http.NewRequest(http.MethodPost, sf.urlRemote+"/bus/request", body)
	mL1.Hassert()(err == nil, "ClientBusHttp.SendRequest(): in new request, err=\n\t%v")

	binBody, err := sf.makePost(hReq)
	if err != nil {
		err := fmt.Errorf("ClientBusHttp.SendRequest(): in make request, err=\n\t%w", err)
		return mL0.NewErr[[]byte](err)
	}
	resp := &msg_serve.ServeResp{}
	err = json.Unmarshal(binBody, resp)
	if err != nil {
		err := fmt.Errorf("ClientBusHttp.SendRequest(): in unmarshal response, err=\n\t%v", err)
		return mL0.NewErr[[]byte](err)
	}
	if resp.Status_ != "ok" {
		err := fmt.Errorf("ClientBusHttp.SendRequest(): resp!='ok', err=\n\t%v", resp.Status_)
		return mL0.NewErr[[]byte](err)
	}
	if resp.Uuid_ != req.Uuid_ {
		err := fmt.Errorf("ClientBusHttp.SendRequest(): resp uuid(%v) bad", resp.Uuid_)
		return mL0.NewErr[[]byte](err)
	}
	return mL0.NewRes(resp.BinResp_)
}

// RegisterServe -- регистрирует в локальной шине обработчик.
func (sf *ClientBusHttp) RegisterServe(handler mKt.IBusHandlerServe) *mL0.Result[bool] {
	if handler == nil {
		return mL0.NewErr[bool](fmt.Errorf("ClientBusHttp.RegisterServe(): handler==nil"))
	}
	res := sf.bus.RegisterServe(handler)
	if res.IsErr() {
		err := fmt.Errorf("ClientBusHttp.RegisterServe(): in register serve to bus, err=\n\t%v", res.Err())
		return mL0.NewErr[bool](err)
	}
	return mL0.NewRes(true)
}

// Publish -- публикует сообщение в дистанционной шину.
func (sf *ClientBusHttp) Publish(topic *mKa.ATopic, binMsg []byte) *mL0.Result[bool] {
	_uuid, err := uuid.NewV6()
	mL1.Hassert()(err == nil, "ClientBusHttp.Publish(): in generate UUID v6, err=\n\t%v", err)
	req := &msg_pub.PublishReq{
		Topic_:  topic,
		Uuid_:   _uuid.String(),
		BinMsg_: binMsg,
	}
	req.SelfCheck()
	binReq, _ := json.MarshalIndent(req, "", "  ")
	body := strings.NewReader(string(binReq))

	hReq, err := http.NewRequest(http.MethodPost, sf.urlRemote+"/bus/pub", body)
	mL1.Hassert()(err == nil, "ClientBusHttp.Publish(): in new request, err=\n\t%v")

	binBody, err := sf.makePost(hReq)
	if err != nil {
		err := fmt.Errorf("ClientBusHttp.Publish(): in make request, err=\n\t%w", err)
		return mL0.NewErr[bool](err)
	}
	resp := &msg_pub.PublishResp{}
	err = json.Unmarshal(binBody, resp)
	if err != nil {
		err := fmt.Errorf("ClientBusHttp.Publish(): in unmarshal response, err=\n\t%v", err)
		return mL0.NewErr[bool](err)
	}
	if resp.Status_ != "ok" {
		err := fmt.Errorf("ClientBusHttp.Publish(): resp!='ok', err=\n\t%v", resp.Status_)
		return mL0.NewErr[bool](err)
	}
	if resp.Uuid_ != req.Uuid_ {
		err := fmt.Errorf("ClientBusHttp.Publish(): resp uuid(%v) bad", resp.Uuid_)
		return mL0.NewErr[bool](err)
	}
	return mL0.NewRes(true)
}

// Единый обработчик запросов.
func (sf *ClientBusHttp) makePost(hReq *http.Request) ([]byte, error) {
	hReq.Header.Add("Content-Type", "application/json")
	_resp, err := http.DefaultClient.Do(hReq)
	if err != nil {
		err := fmt.Errorf("ClientBusHttp.makePost(): after request, err=\n\t%w", err)
		return nil, err
	}
	defer func() {
		_ = _resp.Body.Close()
	}()
	if _resp.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("ClientBusHttp.makePost(): url=%q, status=%q", hReq.URL, _resp.Status)
	}
	binBody, err := io.ReadAll(_resp.Body)
	return binBody, err
}

// Log -- возвращает локальный лог клиента.
func (sf *ClientBusHttp) Log() mKt.ILogBuf {
	return sf.log
}

// IsWork -- возвращает признак работы.
func (sf *ClientBusHttp) IsWork() bool {
	return sf.bus.IsWork()
}