// Copyright © 2023 OpenIM. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package msgtransfer

import (
	"context"
	"errors"
	"fmt"

	"github.com/OpenIMSDK/tools/errs"

	util "github.com/openimsdk/open-im-server/v3/pkg/util/genutil"

	"net/http"
	"os"
	"os/signal"
	"syscall"

	"github.com/OpenIMSDK/tools/mw"
	"github.com/prometheus/client_golang/prometheus"
	"github.com/prometheus/client_golang/prometheus/collectors"
	"github.com/prometheus/client_golang/prometheus/promhttp"
	"google.golang.org/grpc"
	"google.golang.org/grpc/credentials/insecure"

	"github.com/openimsdk/open-im-server/v3/pkg/common/config"
	"github.com/openimsdk/open-im-server/v3/pkg/common/db/cache"
	"github.com/openimsdk/open-im-server/v3/pkg/common/db/controller"
	"github.com/openimsdk/open-im-server/v3/pkg/common/db/unrelation"
	kdisc "github.com/openimsdk/open-im-server/v3/pkg/common/discoveryregister"
	"github.com/openimsdk/open-im-server/v3/pkg/common/prommetrics"
	"github.com/openimsdk/open-im-server/v3/pkg/rpcclient"
)

type MsgTransfer struct {
	historyCH      *OnlineHistoryRedisConsumerHandler // 这个消费者聚合消息, 订阅的topic：ws2ms_chat, 修改通知发往msg_to_modify topic, 消息存入redis后Incr Redis, 再发消息到ms2pschat topic推送， 发消息到msg_to_mongo topic持久化
	historyMongoCH *OnlineHistoryMongoConsumerHandler // mongoDB批量插入, 成功后删除redis中消息，以及处理删除通知消息删除的 订阅的topic: msg_to_mongo
	ctx            context.Context
	cancel         context.CancelFunc
}

func StartTransfer(prometheusPort int) error {
	rdb, err := cache.NewRedis()
	if err != nil {
		return err
	}

	mongo, err := unrelation.NewMongo()
	if err != nil {
		return err
	}

	if err = mongo.CreateMsgIndex(); err != nil {
		return err
	}
	client, err := kdisc.NewDiscoveryRegister(config.Config.Envs.Discovery)
	if err != nil {
		return err
	}

	if err2 := client.CreateRpcRootNodes(config.Config.GetServiceNames()); err2 != nil {
		return err
	}
	client.AddOption(mw.GrpcClient(), grpc.WithTransportCredentials(insecure.NewCredentials()), grpc.WithDefaultServiceConfig(fmt.Sprintf(`{"LoadBalancingPolicy": "%s"}`, "round_robin")))
	msgModel := cache.NewMsgCacheModel(rdb)
	msgDocModel := unrelation.NewMsgMongoDriver(mongo.GetDatabase())
	msgDatabase, err := controller.NewCommonMsgDatabase(msgDocModel, msgModel)
	if err != nil {
		return err
	}
	conversationRpcClient := rpcclient.NewConversationRpcClient(client)
	groupRpcClient := rpcclient.NewGroupRpcClient(client)
	msgTransfer, err := NewMsgTransfer(msgDatabase, &conversationRpcClient, &groupRpcClient)
	if err != nil {
		return err
	}
	return msgTransfer.Start(prometheusPort)
}

func NewMsgTransfer(msgDatabase controller.CommonMsgDatabase, conversationRpcClient *rpcclient.ConversationRpcClient, groupRpcClient *rpcclient.GroupRpcClient) (*MsgTransfer, error) {
	historyCH, err := NewOnlineHistoryRedisConsumerHandler(msgDatabase, conversationRpcClient, groupRpcClient)
	if err != nil {
		return nil, err
	}
	historyMongoCH, err := NewOnlineHistoryMongoConsumerHandler(msgDatabase)
	if err != nil {
		return nil, err
	}

	return &MsgTransfer{
		historyCH:      historyCH,
		historyMongoCH: historyMongoCH,
	}, nil
}

func (m *MsgTransfer) Start(prometheusPort int) error {
	fmt.Println("start msg transfer", "prometheusPort:", prometheusPort)
	if prometheusPort <= 0 {
		return errs.Wrap(errors.New("prometheusPort not correct"))
	}
	m.ctx, m.cancel = context.WithCancel(context.Background())

	var (
		netDone = make(chan struct{}, 1)
		netErr  error
	)

	go m.historyCH.historyConsumerGroup.RegisterHandleAndConsumer(m.ctx, m.historyCH)
	go m.historyMongoCH.historyConsumerGroup.RegisterHandleAndConsumer(m.ctx, m.historyMongoCH)

	if config.Config.Prometheus.Enable {
		go func() {
			proreg := prometheus.NewRegistry()
			proreg.MustRegister(
				collectors.NewGoCollector(),
			)
			proreg.MustRegister(prommetrics.GetGrpcCusMetrics("Transfer")...)
			http.Handle("/metrics", promhttp.HandlerFor(proreg, promhttp.HandlerOpts{Registry: proreg}))
			err := http.ListenAndServe(fmt.Sprintf(":%d", prometheusPort), nil)
			if err != nil && err != http.ErrServerClosed {
				netErr = errs.Wrap(err, fmt.Sprintf("prometheus start err: %d", prometheusPort))
				netDone <- struct{}{}
			}
		}()
	}

	sigs := make(chan os.Signal, 1)
	signal.Notify(sigs, syscall.SIGTERM)
	select {
	case <-sigs:
		util.SIGTERMExit()
		// graceful close kafka client.
		m.cancel()
		m.historyCH.historyConsumerGroup.Close()
		m.historyMongoCH.historyConsumerGroup.Close()
		return nil
	case <-netDone:
		m.cancel()
		m.historyCH.historyConsumerGroup.Close()
		m.historyMongoCH.historyConsumerGroup.Close()
		close(netDone)
		return netErr
	}
}