/*
 * 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 syncdb

import (
	"fmt"
	"net"
	"os"
	"strconv"
	"strings"

	//"github.com/apache/servicecomb-service-center/syncer/pkg/utils"
	"github.com/hashicorp/memberlist"
	"github.com/hashicorp/serf/cmd/serf/command/agent"
	"github.com/hashicorp/serf/serf"
)

const (
	DefaultBindPort    = 30190
	DefaultRPCPort     = 30191
	DefaultClusterPort = 30192
	ModeSingle         = "single"
	ModeCluster        = "cluster"
	retryMaxAttempts   = 3
	groupExpect        = 3
	DefaultEncryptKey  = "bjbasic@aiotlink"
	tagKeyClusterID    = "syncer-cluster-name"
	TagKeyClusterPort  = "syncer-cluster-port"
	TagKeyRPCPort      = "syncer-rpc-port"
	BroadcastIP        = "255.255.255.255"
	BroadcastPort      = 30193
	BroadcastInterval  = 5
	MaxQueryRespSize   = 50 * 1024 * 1024
	MaxQuerySize       = 50 * 1024 * 1024
	MaxUserEventSize   = 9 * 1024
	ReplayOnJoinDefault = false
	SnapshotPathDefault = "/sdcard/serfSnapShot"
	MaxEventBufferCount = 2048

	TcpTransportPort = 30194 //tcp传输大数据量接口
)

// DefaultConfig default config
func DefaultConfig() *Config {
	agentConf := agent.DefaultConfig()
	agentConf.QueryResponseSizeLimit = MaxQueryRespSize
	agentConf.QuerySizeLimit = MaxQuerySize
	agentConf.UserEventSizeLimit = MaxUserEventSize
	agentConf.BindAddr = fmt.Sprintf("0.0.0.0:%d", DefaultBindPort)
	agentConf.RPCAddr = fmt.Sprintf("0.0.0.0:%d", DefaultRPCPort)
	return &Config{
		Mode:        ModeSingle,
		Config:      agentConf,
		ClusterPort: DefaultClusterPort,
	}
}

// Config struct
type Config struct {
	// config from serf agent
	*agent.Config
	Mode string `json:"mode"`

	// name to group members into cluster
	ClusterID string `json:"cluster_name"`

	// port to communicate between cluster members
	ClusterPort int `yaml:"cluster_port"`
	RPCPort     int `yaml:"-"`
}

// readConfigFile reads configuration from config file
func (c *Config) readConfigFile(filepath string) error {
	if filepath != "" {
		// todo:
	}
	return nil
}

func isFileRightful(filePath string) bool {
	if filePath != "" {
		_, err := os.Stat(filePath)
		if err != nil && os.IsNotExist(err) {
			pos := strings.LastIndex(filePath, "/")
			if pos != -1 {
				filePath = filePath[0:pos]
			}

			_, err = os.Stat(filePath)
			if err == nil || !os.IsNotExist(err) {
				return true
			} else {
				return false
			}
		} else {
			return false
		}
	}
	return false
}

// convertToSerf convert Config to serf.Config
func (c *Config) convertToSerf(snapshotPath string) (*serf.Config, error) {
	serfConf := serf.DefaultConfig()

	bindIP, bindPort, err := SplitHostPort(c.BindAddr, DefaultBindPort)
	if err != nil {
		return nil, fmt.Errorf("invalid bind address: %s", err)
	}

	switch c.Profile {
	case "lan":
		serfConf.MemberlistConfig = memberlist.DefaultLANConfig()
	case "wan":
		serfConf.MemberlistConfig = memberlist.DefaultWANConfig()
	case "local":
		serfConf.MemberlistConfig = memberlist.DefaultLocalConfig()
	default:
		serfConf.MemberlistConfig = memberlist.DefaultLANConfig()
	}

	serfConf.MemberlistConfig.BindAddr = bindIP
	serfConf.MemberlistConfig.BindPort = bindPort
	serfConf.NodeName = c.NodeName

	serfConf.Tags = map[string]string{TagKeyRPCPort: strconv.Itoa(c.RPCPort)}

	if c.ClusterID != "" {
		serfConf.Tags[tagKeyClusterID] = c.ClusterID
		serfConf.Tags[TagKeyClusterPort] = strconv.Itoa(c.ClusterPort)
	}

	if c.Mode == ModeCluster && c.RetryMaxAttempts <= 0 {
		c.RetryMaxAttempts = retryMaxAttempts
	}

	c.SnapshotPath = SnapshotPathDefault
	if isFileRightful(snapshotPath) {
		c.SnapshotPath = snapshotPath
	}

	c.ReplayOnJoin = ReplayOnJoinDefault

	serfConf.QueryResponseSizeLimit = c.QueryResponseSizeLimit
	serfConf.QuerySizeLimit = c.QuerySizeLimit
	serfConf.UserEventSizeLimit = c.UserEventSizeLimit
	serfConf.SnapshotPath = c.SnapshotPath
	serfConf.EventBuffer = MaxEventBufferCount

	return serfConf, nil
}

// SplitHostPort returns the parts of the address and port. If the port does not exist, use defaultPort.
func SplitHostPort(address string, defaultPort int) (string, int, error) {
	_, _, err := net.SplitHostPort(address)
	if ae, ok := err.(*net.AddrError); ok && ae.Err == "missing port in address" {
		address = fmt.Sprintf("%s:%d", address, defaultPort)
		_, _, err = net.SplitHostPort(address)
	}
	if err != nil {
		return "", 0, err
	}

	addr, err := net.ResolveTCPAddr("tcp", address)
	if err != nil {
		return "", 0, err
	}

	return addr.IP.String(), addr.Port, nil
}