// Package main is the main package.
package main

import (
	"flag"
	"fmt"
	"log"
	"math/rand"
	"net/http"
	_ "net/http/pprof"
	"os"
	"runtime"
	"runtime/pprof"
	"time"

	"github.com/eiannone/keyboard"
	metrics "github.com/tevjef/go-runtime-metrics"
	qpcl "gitlab-app.eng.qops.net/golang/qmp"
	qsl "gitlab-app.eng.qops.net/golang/qmp/qsl"
)

// Log logs stuff.
func Log(a ...interface{}) {
	s := fmt.Sprintf("%v", a)
	fmt.Fprintln(os.Stderr, s[1:len(s)-1])
}

func main() {
	if _, ok := os.LookupEnv("SCHEMA_REGISTRY_URL"); !ok {
		log.Println("setting schema_registry_url")
		os.Setenv("SCHEMA_REGISTRY_URL", "localhost:8081")
		os.Setenv("SCHEMA_REGISTRY_URL", "qmp-schema-registry.service.b1-prv.consul:8081")
	}
	if _, ok := os.LookupEnv("QPL_BULK_BOOTSTRAP_SERVERS"); !ok {
		log.Println("setting qpl_bulk_bootstrap_servers")
		os.Setenv("QPL_BULK_BOOTSTRAP_SERVERS", "localhost:9092")
		os.Setenv("QPL_BULK_BOOTSTRAP_SERVERS", "core-kafka.service.b1-prv.consul:9092")
	}
	os.Setenv("QPL_DURABLE_BOOTSTRAP_SERVERS", os.Getenv("QPL_BULK_BOOTSTRAP_SERVERS"))
	os.Setenv("QCL_BULK_BOOTSTRAP_SERVERS", os.Getenv("QPL_BULK_BOOTSTRAP_SERVERS"))
	os.Setenv("QCL_RECORD_STATE_BOOTSTRAP_SERVERS", os.Getenv("QPL_BULK_BOOTSTRAP_SERVERS"))
	os.Setenv("QCL_BACKGROUND_JOB_BOOTSTRAP_SERVERS", os.Getenv("QPL_BULK_BOOTSTRAP_SERVERS"))
	os.Setenv("QCL_IDEMPOTENT_BACKGROUND_JOB_BOOTSTRAP_SERVERS", os.Getenv("QPL_BULK_BOOTSTRAP_SERVERS"))
	fmt.Println("\n---")
	fmt.Println("HELLO AND WELCOME. Ctrl-C won't save you now.")
	fmt.Println("* p  create another producer")
	fmt.Println("* o  delete a producer")
	fmt.Println("* c  create another consumer")
	fmt.Println("* x  delete a consumer")
	fmt.Println("* u  queue a configuration update")
	fmt.Println("* q  quit")
	fmt.Println("---\n")
	fmt.Println("--consumers n   // start with n consumers")
	fmt.Println("--producers n   // start with n producers")
	fmt.Println("--lag n         // wait n seconds between messages produced")
	fmt.Println("--group x       // consume as group x")
	fmt.Println("--topic x       // producer/consume from topic x")
	fmt.Println("\n---\n")

	// attempt influxDB/grafana but don't care if it fails
	metrics.DefaultConfig.CollectionInterval = time.Millisecond * 100
	metrics.DefaultConfig.BatchInterval = time.Second * 1
	if err := metrics.RunCollector(metrics.DefaultConfig); err != nil {
		Log(err)
	}

	rand.Seed(time.Now().UTC().UnixNano())

	// configuration
	conCnt := 1
	proCnt := 1
	lag := 1
	group := "gogroup"
	topic := "my-topic-1"
	mylogger := false

	flag.IntVar(&conCnt, "consumers", conCnt, "how many consumers to start")
	flag.IntVar(&proCnt, "producers", proCnt, "how many producers to start")
	flag.IntVar(&lag, "lag", lag, "seconds between prdoucer put()s")
	flag.StringVar(&group, "group", group, "group name")
	flag.StringVar(&topic, "topic", topic, "topic name")
	flag.BoolVar(&mylogger, "pychart", mylogger, "print stats to stdout")
	cpuprofile := flag.String("cpuprofile", "", "write cpu profile to file")
	memprofile := flag.String("memprofile", "", "write memory profile to file")
	flag.Parse()

	// if profiling
	if *cpuprofile != "" {
		f, err := os.Create(*cpuprofile)
		if err != nil {
			panic(err)
		}
		go func() {
			Log(http.ListenAndServe("localhost:6060", nil))
		}()
		pprof.StartCPUProfile(f)
		defer pprof.StopCPUProfile()
	}

	// channels
	conStop := make(chan rune)
	proStop := make(chan rune)
	confirmation := make(chan error, 10)
	consumed := make(chan int, 1000)
	produced := make(chan int, 1000)
	doUpdate := make(chan bool, 1)

	// Register App
	for err := qsl.RegisterApplication("qsl-go"); err != nil; err = qsl.RegisterApplication("qsl-go") {
		Log("QSL Register failed with:", err)
		time.Sleep(time.Second)
		Log("Trying QSL.RegisterApplication() again")
	}
	for err := qpcl.RegisterApplication("qsl-go"); err != nil; err = qpcl.RegisterApplication("qsl-go") {
		Log("QPCL Register failed with:", err)
		time.Sleep(time.Second)
		Log("Trying QPCL.RegisterApplication() again")
	}

	globalStart := time.Now()

	// Launch
	for i := 0; i < proCnt; i++ {
		go oneProducer(confirmation, proStop, produced, topic, lag)
	}
	for i := 0; i < conCnt; i++ {
		go oneConsumer(confirmation, conStop, consumed, topic, group)
	}

	go updateProducer(doUpdate)

	// Listen and report
	cntP := uint64(0)
	cntC := uint64(0)
	keys := keyChannel()
	/*
		go func() {
			rotation := []rune{'p', 'o', 'c', 'x'}
			cur := 0
			for {
				time.Sleep(time.Duration(lag) * time.Second)
				cur = (cur + 1) % len(rotation)
				keys <- rotation[cur]
			}
		}()
	*/
	go func() {
		for {
			select {
			case c := <-produced:
				cntP += uint64(c)
			case c := <-consumed:
				cntC += uint64(c)
			}
		}
	}()
	for {
		select {
		case b := <-keys:
			globalStop := time.Now()
			if keyHandler(b, topic, group, lag, &proCnt, proStop, produced, &conCnt, conStop, consumed, confirmation, doUpdate) {
				seconds := globalStop.Sub(globalStart).Seconds()
				fmt.Fprintf(os.Stderr, "Produced %d in %.1f seconds, that's %.1f/second\n", cntP, seconds, float64(cntP)/seconds)
				if *memprofile != "" {
					f, err := os.Create(*memprofile)
					if err != nil {
						panic(err)
					}
					runtime.GC()
					if err := pprof.WriteHeapProfile(f); err != nil {
						panic(err)
					}
					f.Close()
				}
				return
			}
		case <-time.After(time.Second):
		}
		report(proCnt, conCnt, cntP, cntC)
	}
}

func updateProducer(doUpdate chan bool) {
	qw, err := qsl.NewWriter("qmp.configuration.v1")
	if err != nil {
		Log("Cannot queue an update:", err)
		return
	}
	qp, err := qpcl.NewProducer(qpcl.PBulk, "qmp.state.config")
	if err != nil {
		panic(err)
	}
	for {
		<-doUpdate

		t := time.Now().Second() % 2
		key := "bulk"
		typeS := "consumer"
		conf := map[string]interface{}{
			"consumer": map[string]interface{}{
				"enable_auto_commit": false,
				"max_poll_records":   map[string]interface{}{"int": 1},
			},
			"qmp": map[string]interface{}{},
		}
		if t == 0 {
			key = "bulk"
			conf = map[string]interface{}{
				"producer": map[string]interface{}{},
			}
			typeS = "producer"
		}

		msg, err := qw.NewMessage()
		if err != nil {
			fmt.Printf("\n%v\n", err)
			continue
		}
		msg.Set(key+"_"+typeS, qsl.Union("qmp.envelope."+typeS, conf))

		err = qp.Put(msg, nil)
		if err != nil {
			fmt.Printf("\n%v\n", err)
			continue
		}
	}
}

func keyHandler(key rune, topic, group string, lag int, proCnt *int, proStop chan rune, proCounter chan int, conCnt *int, conStop chan rune, conCounter chan int, confirm chan error, doUpdate chan bool) bool {
	switch key {
	case 'q':
		fmt.Fprintf(os.Stderr, "\n")
		for i := 0; i < *proCnt; i++ {
			fmt.Fprintf(os.Stderr, "\tpro %d/%d\n", i+1, *proCnt)
			proStop <- 'q'
		}
		for i := 0; i < *conCnt; i++ {
			fmt.Fprintf(os.Stderr, "\tcon %d/%d\n", i+1, *conCnt)
			conStop <- 'q'
		}
		for i := 0; i < *proCnt+*conCnt; i++ {
			<-confirm
		}
		return true
	case 'u':
		doUpdate <- true
	case 'c':
		go oneConsumer(confirm, conStop, conCounter, topic, group)
		*conCnt++
	case 'x':
		if *conCnt > 0 {
			conStop <- 'x'
			*conCnt--
			<-confirm
		}
	case 'p':
		go oneProducer(confirm, proStop, proCounter, topic, lag)
		*proCnt++
	case 'o':
		if *proCnt > 0 {
			proStop <- 'o'
			*proCnt--
			<-confirm
		}
	case 'g':
		runtime.GC()
	}
	return false
}

func report(producers, consumers int, produced, consumed uint64) {
	plen := len(fmt.Sprintf("%d", produced))
	plen += plen % 3
	clen := len(fmt.Sprintf("%d", consumed))
	clen += clen % 3
	template := fmt.Sprintf("\rProduced (%%3d): %%%dd  \t\tConsumed (%%3d): %%%dd  ", plen, clen)
	fmt.Fprintf(os.Stdout, template, producers, produced, consumers, consumed)
}

func oneConsumer(confirm chan<- error, stop <-chan rune, count chan int, topic, group string) {
	//qr, err := qsl.NewReader("qmp.payload.v1")
	//qr, err := qsl.NewReader("isolation-service.key-rotation.v1")
	qr, err := qsl.NewReader("qds.record.v1")
	if err != nil {
		panic(err)
	}
	qc, err := qpcl.NewConsumer(qpcl.CBulk, topic, group, qr, 1)
	if err != nil {
		panic(err)
	}
	err = qc.Start(func(qm qsl.Message) {
		fmt.Printf("\n%v\n", qm.GetAvroObject()["payload"])
		select {
		case prev := <-count:
			count <- prev + 1
		case count <- 1:
		}
	})
	if err != nil {
		panic(err)
	}
	<-stop
	confirm <- qc.Stop()
	return
}

func oneProducer(confirm chan<- error, stop <-chan rune, count chan int, topic string, lag int) {
	qw, err := qsl.NewWriter("qmp.payload.v1")
	if err != nil {
		panic(err)
	}
	qp, err := qpcl.NewProducer(qpcl.PBulk, topic)
	if err != nil {
		panic(err)
	}
	for {
		msg, err := qw.NewMessage()
		if err != nil {
			panic(err)
		}
		if err := msg.Set("brandId", "Go"); err != nil {
			panic(err)
		}
		err = qp.Put(msg, func(e error, q qsl.Message) {
			if e != nil {
				fmt.Println("Cannot produce:", e)
			} else {
				select {
				case prev := <-count:
					count <- prev + 1
				case count <- 1:
				}
			}
		})
		if err != nil {
			panic(err)
		}
		select {
		case <-stop:
			err := qp.Close()
			confirm <- err
			return
		case <-time.After(time.Duration(lag) * time.Second):
		}
	}
}

func keyChannel() chan rune {
	ch := make(chan rune, 20)
	go func() {
		time.Sleep(time.Second * 5)
		if err := keyboard.Open(); err != nil {
			panic(err)
		}
		for {
			b, _, err := keyboard.GetKey()
			if err != nil {
				panic(err)
			}
			by := rune(b)
			if by == 'q' {
				keyboard.Close()
				ch <- by
				return
			}
			ch <- by
		}
	}()
	return ch
}