// Copyright 2015 PingCAP, Inc.
//
// 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,
// See the License for the specific language governing permissions and
// limitations under the License.

package main

import (
	"flag"
	"fmt"
	"net"
	"os"
	"os/signal"
	"runtime"
	"strconv"
	"strings"
	"syscall"
	"time"

	"github.com/juju/errors"
	"github.com/opentracing/opentracing-go"
	"github.com/pingcap/tidb/config"
	"github.com/pingcap/tidb/ddl"
	"github.com/pingcap/tidb/domain"
	"github.com/pingcap/tidb/kv"
	"github.com/pingcap/tidb/metrics"
	"github.com/pingcap/tidb/plan"
	"github.com/pingcap/tidb/privilege/privileges"
	"github.com/pingcap/tidb/server"
	"github.com/pingcap/tidb/session"
	"github.com/pingcap/tidb/sessionctx/binloginfo"
	"github.com/pingcap/tidb/sessionctx/variable"
	"github.com/pingcap/tidb/statistics"
	"github.com/pingcap/tidb/store/mockstore"
	"github.com/pingcap/tidb/store/tikv"
	"github.com/pingcap/tidb/store/tikv/gcworker"
	"github.com/pingcap/tidb/terror"
	"github.com/pingcap/tidb/util"
	"github.com/pingcap/tidb/util/kvcache"
	"github.com/pingcap/tidb/util/logutil"
	"github.com/pingcap/tidb/util/printer"
	"github.com/pingcap/tidb/util/systimemon"
	"github.com/pingcap/tidb/x-server"
	binlog "github.com/pingcap/tipb/go-binlog"
	"github.com/prometheus/client_golang/prometheus"
	"github.com/prometheus/client_golang/prometheus/push"
	log "github.com/sirupsen/logrus"
	"google.golang.org/grpc"
)

// Flag Names
const (
	nmVersion         = "V"
	nmConfig          = "config"
	nmStore           = "store"
	nmStorePath       = "path"
	nmHost            = "host"
	nmPort            = "P"
	nmSocket          = "socket"
	nmBinlogSocket    = "binlog-socket"
	nmRunDDL          = "run-ddl"
	nmLogLevel        = "L"
	nmLogFile         = "log-file"
	nmLogSlowQuery    = "log-slow-query"
	nmReportStatus    = "report-status"
	nmStatusPort      = "status"
	nmMetricsAddr     = "metrics-addr"
	nmMetricsInterval = "metrics-interval"
	nmDdlLease        = "lease"
	nmTokenLimit      = "token-limit"

	nmProxyProtocolNetworks      = "proxy-protocol-networks"
	nmProxyProtocolHeaderTimeout = "proxy-protocol-header-timeout"
)

var (
	version    = flagBoolean(nmVersion, false, "print version information and exit")
	configPath = flag.String(nmConfig, "", "config file path")

	// Base
	store        = flag.String(nmStore, "mocktikv", "registered store name, [tikv, mocktikv]")
	storePath    = flag.String(nmStorePath, "/tmp/tidb", "tidb storage path")
	host         = flag.String(nmHost, "0.0.0.0", "tidb server host")
	port         = flag.String(nmPort, "4000", "tidb server port")
	socket       = flag.String(nmSocket, "", "The socket file to use for connection.")
	binlogSocket = flag.String(nmBinlogSocket, "", "socket file to write binlog")
	runDDL       = flagBoolean(nmRunDDL, true, "run ddl worker on this tidb-server")
	ddlLease     = flag.String(nmDdlLease, "45s", "schema lease duration, very dangerous to change only if you know what you do")
	tokenLimit   = flag.Int(nmTokenLimit, 1000, "the limit of concurrent executed sessions")

	// Log
	logLevel     = flag.String(nmLogLevel, "info", "log level: info, debug, warn, error, fatal")
	logFile      = flag.String(nmLogFile, "", "log file path")
	logSlowQuery = flag.String(nmLogSlowQuery, "", "slow query file path")

	// Status
	reportStatus    = flagBoolean(nmReportStatus, true, "If enable status report HTTP service.")
	statusPort      = flag.String(nmStatusPort, "10080", "tidb server status port")
	metricsAddr     = flag.String(nmMetricsAddr, "", "prometheus pushgateway address, leaves it empty will disable prometheus push.")
	metricsInterval = flag.Uint(nmMetricsInterval, 15, "prometheus client push interval in second, set \"0\" to disable prometheus push.")

	// PROXY Protocol
	proxyProtocolNetworks      = flag.String(nmProxyProtocolNetworks, "", "proxy protocol networks allowed IP or *, empty mean disable proxy protocol support")
	proxyProtocolHeaderTimeout = flag.Uint(nmProxyProtocolHeaderTimeout, 5, "proxy protocol header read timeout, unit is second.")
)

var (
	cfg      *config.Config
	storage  kv.Storage
	dom      *domain.Domain
	svr      *server.Server
	xsvr     *xserver.Server
	graceful bool
)

func main() {
	flag.Parse()
	if *version {
		printer.PrintRawTiDBInfo()
		os.Exit(0)
	}

	registerStores()
	loadConfig()
	overrideConfig()
	validateConfig()
	setGlobalVars()
	setupLog()
	setupTracing() // Should before createServer and after setup config.
	printInfo()
	setupBinlogClient()
	createStoreAndDomain()
	createServer()
	setupSignalHandler()
	setupMetrics()
	runServer()
	cleanup()
	os.Exit(0)
}

func registerStores() {
	err := session.RegisterStore("tikv", tikv.Driver{})
	terror.MustNil(err)
	tikv.NewGCHandlerFunc = gcworker.NewGCWorker
	err = session.RegisterStore("mocktikv", mockstore.MockDriver{})
	terror.MustNil(err)
}

func createStoreAndDomain() {
	fullPath := fmt.Sprintf("%s://%s", cfg.Store, cfg.Path)
	var err error
	storage, err = session.NewStore(fullPath)
	terror.MustNil(err)
	// Bootstrap a session to load information schema.
	dom, err = session.BootstrapSession(storage)
	terror.MustNil(err)
}

func setupBinlogClient() {
	if cfg.Binlog.BinlogSocket == "" {
		return
	}
	dialerOpt := grpc.WithDialer(func(addr string, timeout time.Duration) (net.Conn, error) {
		return net.DialTimeout("unix", addr, timeout)
	})
	clientConn, err := session.DialPumpClientWithRetry(cfg.Binlog.BinlogSocket, util.DefaultMaxRetries, dialerOpt)
	terror.MustNil(err)
	if cfg.Binlog.IgnoreError {
		binloginfo.SetIgnoreError(true)
	}
	binloginfo.SetPumpClient(binlog.NewPumpClient(clientConn))
	log.Infof("created binlog client at %s, ignore error %v", cfg.Binlog.BinlogSocket, cfg.Binlog.IgnoreError)
}

// Prometheus push.
const zeroDuration = time.Duration(0)

// pushMetric pushs metircs in background.
func pushMetric(addr string, interval time.Duration) {
	if interval == zeroDuration || len(addr) == 0 {
		log.Info("disable Prometheus push client")
		return
	}
	log.Infof("start Prometheus push client with server addr %s and interval %s", addr, interval)
	go prometheusPushClient(addr, interval)
}

// prometheusPushClient pushs metrics to Prometheus Pushgateway.
func prometheusPushClient(addr string, interval time.Duration) {
	// TODO: TiDB do not have uniq name, so we use host+port to compose a name.
	job := "tidb"
	for {
		err := push.AddFromGatherer(
			job,
			map[string]string{"instance": instanceName()},
			addr,
			prometheus.DefaultGatherer,
		)
		if err != nil {
			log.Errorf("could not push metrics to Prometheus Pushgateway: %v", err)
		}
		time.Sleep(interval)
	}
}

func instanceName() string {
	hostname, err := os.Hostname()
	if err != nil {
		return "unknown"
	}
	return fmt.Sprintf("%s_%d", hostname, cfg.Port)
}

// parseDuration parses lease argument string.
func parseDuration(lease string) time.Duration {
	dur, err := time.ParseDuration(lease)
	if err != nil {
		dur, err = time.ParseDuration(lease + "s")
	}
	if err != nil || dur < 0 {
		log.Fatalf("invalid lease duration %s", lease)
	}
	return dur
}

func hasRootPrivilege() bool {
	return os.Geteuid() == 0
}

func flagBoolean(name string, defaultVal bool, usage string) *bool {
	if defaultVal == false {
		// Fix #4125, golang do not print default false value in usage, so we append it.
		usage = fmt.Sprintf("%s (default false)", usage)
		return flag.Bool(name, defaultVal, usage)
	}
	return flag.Bool(name, defaultVal, usage)
}

func loadConfig() {
	cfg = config.GetGlobalConfig()
	if *configPath != "" {
		err := cfg.Load(*configPath)
		terror.MustNil(err)
	}
}

func overrideConfig() {
	actualFlags := make(map[string]bool)
	flag.Visit(func(f *flag.Flag) {
		actualFlags[f.Name] = true
	})

	// Base
	if actualFlags[nmHost] {
		cfg.Host = *host
	}
	var err error
	if actualFlags[nmPort] {
		var p int
		p, err = strconv.Atoi(*port)
		terror.MustNil(err)
		cfg.Port = uint(p)
	}
	if actualFlags[nmStore] {
		cfg.Store = *store
	}
	if actualFlags[nmStorePath] {
		cfg.Path = *storePath
	}
	if actualFlags[nmSocket] {
		cfg.Socket = *socket
	}
	if actualFlags[nmBinlogSocket] {
		cfg.Binlog.BinlogSocket = *binlogSocket
	}
	if actualFlags[nmRunDDL] {
		cfg.RunDDL = *runDDL
	}
	if actualFlags[nmDdlLease] {
		cfg.Lease = *ddlLease
	}
	if actualFlags[nmTokenLimit] {
		cfg.TokenLimit = uint(*tokenLimit)
	}

	// Log
	if actualFlags[nmLogLevel] {
		cfg.Log.Level = *logLevel
	}
	if actualFlags[nmLogFile] {
		cfg.Log.File.Filename = *logFile
	}
	if actualFlags[nmLogSlowQuery] {
		cfg.Log.SlowQueryFile = *logSlowQuery
	}

	// Status
	if actualFlags[nmReportStatus] {
		cfg.Status.ReportStatus = *reportStatus
	}
	if actualFlags[nmStatusPort] {
		var p int
		p, err = strconv.Atoi(*statusPort)
		terror.MustNil(err)
		cfg.Status.StatusPort = uint(p)
	}
	if actualFlags[nmMetricsAddr] {
		cfg.Status.MetricsAddr = *metricsAddr
	}
	if actualFlags[nmMetricsInterval] {
		cfg.Status.MetricsInterval = *metricsInterval
	}

	// PROXY Protocol
	if actualFlags[nmProxyProtocolNetworks] {
		cfg.ProxyProtocol.Networks = *proxyProtocolNetworks
	}
	if actualFlags[nmProxyProtocolHeaderTimeout] {
		cfg.ProxyProtocol.HeaderTimeout = *proxyProtocolHeaderTimeout
	}
}

func validateConfig() {
	if cfg.Security.SkipGrantTable && !hasRootPrivilege() {
		log.Error("TiDB run with skip-grant-table need root privilege.")
		os.Exit(-1)
	}
	if _, ok := config.ValidStorage[cfg.Store]; !ok {
		nameList := make([]string, 0, len(config.ValidStorage))
		for k, v := range config.ValidStorage {
			if v {
				nameList = append(nameList, k)
			}
		}
		log.Errorf("\"store\" should be in [%s] only", strings.Join(nameList, ", "))
		os.Exit(-1)
	}
	if cfg.Log.File.MaxSize > config.MaxLogFileSize {
		log.Errorf("log max-size should not be larger than %d MB", config.MaxLogFileSize)
		os.Exit(-1)
	}
	if cfg.XProtocol.XServer {
		log.Error("X Server is not available")
		os.Exit(-1)
	}
	cfg.OOMAction = strings.ToLower(cfg.OOMAction)

	// lower_case_table_names is allowed to be 0, 1, 2
	if cfg.LowerCaseTableNames < 0 || cfg.LowerCaseTableNames > 2 {
		log.Errorf("lower-case-table-names should be 0 or 1 or 2.")
		os.Exit(-1)
	}
}

func setGlobalVars() {
	ddlLeaseDuration := parseDuration(cfg.Lease)
	session.SetSchemaLease(ddlLeaseDuration)
	runtime.GOMAXPROCS(int(cfg.Performance.MaxProcs))
	statsLeaseDuration := parseDuration(cfg.Performance.StatsLease)
	session.SetStatsLease(statsLeaseDuration)
	domain.RunAutoAnalyze = cfg.Performance.RunAutoAnalyze
	statistics.FeedbackProbability = cfg.Performance.FeedbackProbability
	statistics.MaxQueryFeedbackCount = int(cfg.Performance.QueryFeedbackLimit)
	plan.RatioOfPseudoEstimate = cfg.Performance.PseudoEstimateRatio
	ddl.RunWorker = cfg.RunDDL
	ddl.EnableSplitTableRegion = cfg.SplitTable
	session.SetCommitRetryLimit(cfg.Performance.RetryLimit)
	plan.AllowCartesianProduct = cfg.Performance.CrossJoin
	privileges.SkipWithGrant = cfg.Security.SkipGrantTable

	if cfg.PlanCache.Enabled {
		plan.GlobalPlanCache = kvcache.NewShardedLRUCache(cfg.PlanCache.Capacity, cfg.PlanCache.Shards)
	}

	plan.PreparedPlanCacheEnabled = cfg.PreparedPlanCache.Enabled
	if plan.PreparedPlanCacheEnabled {
		plan.PreparedPlanCacheCapacity = cfg.PreparedPlanCache.Capacity
	}

	if cfg.TiKVClient.GrpcConnectionCount > 0 {
		tikv.MaxConnectionCount = cfg.TiKVClient.GrpcConnectionCount
	}

	// set lower_case_table_names
	variable.SysVars["lower_case_table_names"].Value = strconv.Itoa(cfg.LowerCaseTableNames)

	tikv.CommitMaxBackoff = int(parseDuration(cfg.TiKVClient.CommitTimeout).Seconds() * 1000)
}

func setupLog() {
	err := logutil.InitLogger(cfg.Log.ToLogConfig())
	terror.MustNil(err)
}

func printInfo() {
	// Make sure the TiDB info is always printed.
	level := log.GetLevel()
	log.SetLevel(log.InfoLevel)
	printer.PrintTiDBInfo()
	log.SetLevel(level)
}

func createServer() {
	var driver server.IDriver
	driver = server.NewTiDBDriver(storage)
	var err error
	svr, err = server.NewServer(cfg, driver)
	terror.MustNil(err)
	if cfg.XProtocol.XServer {
		xcfg := &xserver.Config{
			Addr:       fmt.Sprintf("%s:%d", cfg.XProtocol.XHost, cfg.XProtocol.XPort),
			Socket:     cfg.XProtocol.XSocket,
			TokenLimit: cfg.TokenLimit,
		}
		xsvr, err = xserver.NewServer(xcfg)
		terror.MustNil(err)
	}
}

func setupSignalHandler() {
	sc := make(chan os.Signal, 1)
	signal.Notify(sc,
		syscall.SIGHUP,
		syscall.SIGINT,
		syscall.SIGTERM,
		syscall.SIGQUIT)

	go func() {
		sig := <-sc
		log.Infof("Got signal [%s] to exit.", sig)
		if sig == syscall.SIGQUIT {
			graceful = true
		}

		if xsvr != nil {
			xsvr.Close() // Should close xserver before server.
		}
		svr.Close()
	}()
}

func setupMetrics() {
	systimeErrHandler := func() {
		metrics.TimeJumpBackCounter.Inc()
	}
	callBackCount := 0
	sucessCallBack := func() {
		callBackCount++
		// It is callback by monitor per second, we increase metrics.KeepAliveCounter per 5s.
		if callBackCount >= 5 {
			callBackCount = 0
			metrics.KeepAliveCounter.Inc()
		}
	}
	go systimemon.StartMonitor(time.Now, systimeErrHandler, sucessCallBack)

	pushMetric(cfg.Status.MetricsAddr, time.Duration(cfg.Status.MetricsInterval)*time.Second)
}

func setupTracing() {
	tracingCfg := cfg.OpenTracing.ToTracingConfig()
	tracer, _, err := tracingCfg.New("TiDB")
	if err != nil {
		log.Fatal("cannot initialize Jaeger Tracer", err)
	}
	opentracing.SetGlobalTracer(tracer)
}

func runServer() {
	err := svr.Run()
	terror.MustNil(err)
	if cfg.XProtocol.XServer {
		err := xsvr.Run()
		terror.MustNil(err)
	}
}

func cleanup() {
	if graceful {
		svr.GracefulDown()
	}
	dom.Close()
	err := storage.Close()
	terror.Log(errors.Trace(err))
}