/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 main

import (
	"fmt"
	"os"
	"os/signal"
	"syscall"
	"time"
)

import (
	"github.com/alibaba/sentinel-golang/api"
	sentinelConf "github.com/alibaba/sentinel-golang/core/config"
	"github.com/alibaba/sentinel-golang/core/flow"

	hessian "github.com/apache/dubbo-go-hessian2"
	_ "github.com/apache/dubbo-go/cluster/cluster_impl"
	_ "github.com/apache/dubbo-go/cluster/loadbalance"
	"github.com/apache/dubbo-go/common/logger"
	_ "github.com/apache/dubbo-go/common/proxy/proxy_factory"
	"github.com/apache/dubbo-go/config"
	_ "github.com/apache/dubbo-go/filter/filter_impl"
	_ "github.com/apache/dubbo-go/protocol/dubbo"
	_ "github.com/apache/dubbo-go/registry/protocol"
	_ "github.com/apache/dubbo-go/registry/zookeeper"
)

import (
	"github.com/apache/dubbo-go-samples/filter/sentinel/go-server/pkg"
)

var (
	survivalTimeout = int(3e9)
)

// need to setup environment variable "CONF_PROVIDER_FILE_PATH" to "conf/server.yml" before run
func main() {
	hessian.RegisterPOJO(&pkg.User{})
	config.Load()

	if err := initSentinel(); err != nil {
		panic(err)
	}
	_, err := flow.LoadRules([]*flow.Rule{
		{
			// protocol:consumer:interfaceName:group:version:method
			Resource:               "dubbo:provider:org.apache.dubbo.UserProvider:::GetUser()",
			TokenCalculateStrategy: flow.Direct,
			ControlBehavior:        flow.Reject,
			Threshold:              1,
			StatIntervalInMs:       1000,
		},
	})
	if err != nil {
		panic(err)
	}

	initSignal()
}

func initSentinel() error {
	// custom changes configs
	conf := sentinelConf.NewDefaultConfig()
	return api.InitWithConfig(conf)
}

func initSignal() {
	signals := make(chan os.Signal, 1)
	// It is not possible to block SIGKILL or syscall.SIGSTOP
	signal.Notify(signals, os.Interrupt, os.Kill, syscall.SIGHUP, syscall.SIGQUIT, syscall.SIGTERM, syscall.SIGINT)
	for {
		sig := <-signals
		logger.Infof("get signal %s", sig.String())
		switch sig {
		case syscall.SIGHUP:
			// reload()
		default:
			time.AfterFunc(time.Duration(survivalTimeout), func() {
				logger.Warnf("app exit now by force...")
				os.Exit(1)
			})

			// The program exits normally or timeout forcibly exits.
			fmt.Println("provider app exit now...")
			return
		}
	}
}