package command

import (
	"bufio"
	"context"
	"fmt"
	"io"
	"math"
	"math/rand"
	"os"
	"runtime"
	"runtime/pprof"
	"sort"
	"sync"
	"time"

	"github.com/seaweedfs/seaweedfs/weed/glog"
	"github.com/seaweedfs/seaweedfs/weed/operation"
	"github.com/seaweedfs/seaweedfs/weed/pb"
	"github.com/seaweedfs/seaweedfs/weed/security"
	"github.com/seaweedfs/seaweedfs/weed/util"
	util_http "github.com/seaweedfs/seaweedfs/weed/util/http"
	"github.com/seaweedfs/seaweedfs/weed/util/version"
	"github.com/seaweedfs/seaweedfs/weed/wdclient"
	"google.golang.org/grpc"
)

type BenchmarkOptions struct {
	masters          *string
	concurrency      *int
	numberOfFiles    *int
	fileSize         *int
	idListFile       *string
	deletePercentage *int
	readOnly         *bool
	writeOnly        *bool
	sequentialRead   *bool
	collection       *string
	replication      *string
	diskType         *string
	cpuprofile       *string
	maxCpu           *int
	grpcDialOption   grpc.DialOption
	masterClient     *wdclient.MasterClient
	fsync            *bool
}

var (
	b           BenchmarkOptions
	sharedBytes []byte
	isSecure    bool
)

func init() {
	cmdBenchmark.Run = runBenchmark // break init cycle
	cmdBenchmark.IsDebug = cmdBenchmark.Flag.Bool("debug", false, "verbose debug information")
	b.masters = cmdBenchmark.Flag.String("master", "localhost:9333", "SeaweedFS master location")
	b.concurrency = cmdBenchmark.Flag.Int("c", 16, "number of concurrent write or read processes")
	b.fileSize = cmdBenchmark.Flag.Int("size", 1024, "simulated file size in bytes, with random(0~63) bytes padding")
	b.numberOfFiles = cmdBenchmark.Flag.Int("n", 1024*1024, "number of files to write for each thread")
	b.idListFile = cmdBenchmark.Flag.String("list", os.TempDir()+"/benchmark_list.txt", "list of uploaded file ids")
	b.deletePercentage = cmdBenchmark.Flag.Int("deletePercent", 0, "the percent of writes that are deletes")
	b.readOnly = cmdBenchmark.Flag.Bool("readOnly", false, "only benchmark read operations")
	b.writeOnly = cmdBenchmark.Flag.Bool("writeOnly", false, "only benchmark write operations")
	b.sequentialRead = cmdBenchmark.Flag.Bool("readSequentially", false, "randomly read by ids from \"-list\" specified file")
	b.collection = cmdBenchmark.Flag.String("collection", "benchmark", "write data to this collection")
	b.replication = cmdBenchmark.Flag.String("replication", "000", "replication type")
	b.diskType = cmdBenchmark.Flag.String("disk", "", "[hdd|ssd|<tag>] hard drive or solid state drive or any tag")
	b.cpuprofile = cmdBenchmark.Flag.String("cpuprofile", "", "cpu profile output file")
	b.maxCpu = cmdBenchmark.Flag.Int("maxCpu", 0, "maximum number of CPUs. 0 means all available CPUs")
	b.fsync = cmdBenchmark.Flag.Bool("fsync", false, "flush data to disk after write")
	sharedBytes = make([]byte, 1024)
}

var cmdBenchmark = &Command{
	UsageLine: "benchmark -master=localhost:9333 -c=10 -n=100000",
	Short:     "benchmark by writing millions of files and reading them out",
	Long: `benchmark on an empty SeaweedFS file system.

  Two tests during benchmark:
  1) write lots of small files to the system
  2) read the files out

  The file content is mostly zeros, but no compression is done.

  You can choose to only benchmark read or write:
    -readOnly   only benchmark read operations
    -writeOnly  only benchmark write operations

  During write, the list of uploaded file ids is stored in "-list" specified file.
  You can also use your own list of file ids to run read test.

  Write speed and read speed will be collected.
  The numbers are used to get a sense of the system.
  Usually your network or the hard drive is the real bottleneck.

  Another thing to watch is whether the volumes are evenly distributed
  to each volume server. Because the 7 more benchmark volumes are randomly distributed
  to servers with free slots, it's highly possible some servers have uneven amount of
  benchmark volumes. To remedy this, you can use this to grow the benchmark volumes
  before starting the benchmark command:
    http://localhost:9333/vol/grow?collection=benchmark&count=5

  After benchmarking, you can clean up the written data by deleting the benchmark collection
    http://localhost:9333/col/delete?collection=benchmark

  `,
}

var (
	wait       sync.WaitGroup
	writeStats *stats
	readStats  *stats
)

func runBenchmark(cmd *Command, args []string) bool {

	util.LoadSecurityConfiguration()
	b.grpcDialOption = security.LoadClientTLS(util.GetViper(), "grpc.client")

	fmt.Printf("This is SeaweedFS version %s %s %s\n", version.Version(), runtime.GOOS, runtime.GOARCH)
	if *b.maxCpu < 1 {
		*b.maxCpu = runtime.NumCPU()
	}
	runtime.GOMAXPROCS(*b.maxCpu)
	*b.cpuprofile = util.ResolvePath(*b.cpuprofile)
	*b.idListFile = util.ResolvePath(*b.idListFile)
	if *b.cpuprofile != "" {
		f, err := os.Create(*b.cpuprofile)
		if err != nil {
			glog.Fatal(err)
		}
		pprof.StartCPUProfile(f)
		defer func() {
			pprof.StopCPUProfile()
			f.Close()
		}()
	}

	// Determine what operations to perform
	// Default: both write and read
	// -readOnly: only read
	// -writeOnly: only write
	if *b.readOnly && *b.writeOnly {
		fmt.Fprintln(os.Stderr, "Error: -readOnly and -writeOnly are mutually exclusive.")
		return false
	}

	doWrite := true
	doRead := true
	if *b.readOnly {
		doWrite = false
	} else if *b.writeOnly {
		doRead = false
	}

	b.masterClient = wdclient.NewMasterClient(b.grpcDialOption, "", "client", "", "", "", *pb.ServerAddresses(*b.masters).ToServiceDiscovery())
	ctx := context.Background()
	go b.masterClient.KeepConnectedToMaster(ctx)
	b.masterClient.WaitUntilConnected(ctx)

	if doWrite {
		benchWrite()
	}

	if doRead {
		benchRead()
	}

	return true
}

func benchWrite() {
	fileIdLineChan := make(chan string)
	finishChan := make(chan bool)
	writeStats = newStats(*b.concurrency)
	idChan := make(chan int)
	go writeFileIds(*b.idListFile, fileIdLineChan, finishChan)
	for i := 0; i < *b.concurrency; i++ {
		wait.Add(1)
		go writeFiles(idChan, fileIdLineChan, &writeStats.localStats[i])
	}
	writeStats.start = time.Now()
	writeStats.total = *b.numberOfFiles
	go writeStats.checkProgress("Writing Benchmark", finishChan)
	for i := 0; i < *b.numberOfFiles; i++ {
		idChan <- i
	}
	close(idChan)
	wait.Wait()
	writeStats.end = time.Now()
	wait.Add(2)
	finishChan <- true
	finishChan <- true
	wait.Wait()
	close(finishChan)
	writeStats.printStats()
}

func benchRead() {
	fileIdLineChan := make(chan string)
	finishChan := make(chan bool)
	readStats = newStats(*b.concurrency)
	go readFileIds(*b.idListFile, fileIdLineChan)
	readStats.start = time.Now()
	readStats.total = *b.numberOfFiles
	go readStats.checkProgress("Randomly Reading Benchmark", finishChan)
	for i := 0; i < *b.concurrency; i++ {
		wait.Add(1)
		go readFiles(fileIdLineChan, &readStats.localStats[i])
	}
	wait.Wait()
	wait.Add(1)
	finishChan <- true
	wait.Wait()
	close(finishChan)
	readStats.end = time.Now()
	readStats.printStats()
}

type delayedFile struct {
	enterTime time.Time
	fp        *operation.FilePart
}

func writeFiles(idChan chan int, fileIdLineChan chan string, s *stat) {
	defer wait.Done()
	delayedDeleteChan := make(chan *delayedFile, 100)
	var waitForDeletions sync.WaitGroup

	for i := 0; i < 7; i++ {
		waitForDeletions.Add(1)
		go func() {
			defer waitForDeletions.Done()
			for df := range delayedDeleteChan {
				if df.enterTime.After(time.Now()) {
					time.Sleep(df.enterTime.Sub(time.Now()))
				}
				var jwtAuthorization security.EncodedJwt
				if isSecure {
					jwtAuthorization = operation.LookupJwt(b.masterClient.GetMaster(context.Background()), b.grpcDialOption, df.fp.Fid)
				}
				if e := util_http.Delete(fmt.Sprintf("http://%s/%s", df.fp.Server, df.fp.Fid), string(jwtAuthorization)); e == nil {
					s.completed++
				} else {
					s.failed++
				}
			}
		}()
	}

	random := rand.New(rand.NewSource(time.Now().UnixNano()))

	for id := range idChan {
		start := time.Now()
		fileSize := int64(*b.fileSize + random.Intn(64))
		fp := &operation.FilePart{
			Reader:   &FakeReader{id: uint64(id), size: fileSize, random: random},
			FileSize: fileSize,
			MimeType: "image/bench", // prevent gzip benchmark content
			Fsync:    *b.fsync,
		}
		ar := &operation.VolumeAssignRequest{
			Count:            1,
			Collection:       *b.collection,
			Replication:      *b.replication,
			DiskType:         *b.diskType,
			ExpectedDataSize: uint64(fileSize),
		}
		if assignResult, err := operation.Assign(context.Background(), b.masterClient.GetMaster, b.grpcDialOption, ar); err == nil {
			fp.Server, fp.Fid, fp.Pref.Collection = assignResult.Url, assignResult.Fid, *b.collection
			if !isSecure && assignResult.Auth != "" {
				isSecure = true
			}
			if _, err := fp.Upload(0, b.masterClient.GetMaster, false, assignResult.Auth, b.grpcDialOption); err == nil {
				if random.Intn(100) < *b.deletePercentage {
					s.total++
					delayedDeleteChan <- &delayedFile{time.Now().Add(time.Second), fp}
				} else {
					fileIdLineChan <- fp.Fid
				}
				s.completed++
				s.transferred += fileSize
			} else {
				s.failed++
				fmt.Printf("Failed to write with error:%v\n", err)
			}
			writeStats.addSample(time.Now().Sub(start))
			if *cmdBenchmark.IsDebug {
				fmt.Printf("writing %d file %s\n", id, fp.Fid)
			}
		} else {
			s.failed++
			println("writing file error:", err.Error())
		}
	}
	close(delayedDeleteChan)
	waitForDeletions.Wait()
}

func readFiles(fileIdLineChan chan string, s *stat) {
	defer wait.Done()

	for fid := range fileIdLineChan {
		if len(fid) == 0 {
			continue
		}
		if fid[0] == '#' {
			continue
		}
		if *cmdBenchmark.IsDebug {
			fmt.Printf("reading file %s\n", fid)
		}
		start := time.Now()
		var bytesRead int
		var err error
		urls, err := b.masterClient.LookupFileId(context.Background(), fid)
		if err != nil {
			s.failed++
			println("!!!! ", fid, " location not found!!!!!")
			continue
		}
		var bytes []byte
		for _, url := range urls {
			bytes, _, err = util_http.Get(url)
			if err == nil {
				break
			}
		}
		bytesRead = len(bytes)
		if err == nil {
			s.completed++
			s.transferred += int64(bytesRead)
			readStats.addSample(time.Now().Sub(start))
		} else {
			s.failed++
			fmt.Printf("Failed to read %s error:%v\n", fid, err)
		}
	}
}

func writeFileIds(fileName string, fileIdLineChan chan string, finishChan chan bool) {
	file, err := os.OpenFile(fileName, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0644)
	if err != nil {
		glog.Fatalf("File to create file %s: %s\n", fileName, err)
	}
	defer file.Close()

	for {
		select {
		case <-finishChan:
			wait.Done()
			return
		case line := <-fileIdLineChan:
			file.Write([]byte(line))
			file.Write([]byte("\n"))
		}
	}
}

func readFileIds(fileName string, fileIdLineChan chan string) {
	file, err := os.Open(fileName) // For read access.
	if err != nil {
		glog.Fatalf("File to read file %s: %s\n", fileName, err)
	}
	defer file.Close()

	random := rand.New(rand.NewSource(time.Now().UnixNano()))

	r := bufio.NewReader(file)
	if *b.sequentialRead {
		for {
			if line, err := Readln(r); err == nil {
				fileIdLineChan <- string(line)
			} else {
				break
			}
		}
	} else {
		lines := make([]string, 0, readStats.total)
		for {
			if line, err := Readln(r); err == nil {
				lines = append(lines, string(line))
			} else {
				break
			}
		}
		if len(lines) > 0 {
			for i := 0; i < readStats.total; i++ {
				fileIdLineChan <- lines[random.Intn(len(lines))]
			}
		}
	}

	close(fileIdLineChan)
}

const (
	benchResolution = 10000 // 0.1 microsecond
	benchBucket     = 1000000000 / benchResolution
)

// An efficient statistics collecting and rendering
type stats struct {
	data       []int
	overflow   []int
	localStats []stat
	start      time.Time
	end        time.Time
	total      int
}
type stat struct {
	completed   int
	failed      int
	total       int
	transferred int64
}

var percentages = []int{50, 66, 75, 80, 90, 95, 98, 99, 100}

func newStats(n int) *stats {
	return &stats{
		data:       make([]int, benchResolution),
		overflow:   make([]int, 0),
		localStats: make([]stat, n),
	}
}

func (s *stats) addSample(d time.Duration) {
	index := int(d / benchBucket)
	if index < 0 {
		fmt.Printf("This request takes %3.1f seconds, skipping!\n", float64(index)/10000)
	} else if index < len(s.data) {
		s.data[int(d/benchBucket)]++
	} else {
		s.overflow = append(s.overflow, index)
	}
}

func (s *stats) checkProgress(testName string, finishChan chan bool) {
	fmt.Printf("\n------------ %s ----------\n", testName)
	ticker := time.Tick(time.Second)
	lastCompleted, lastTransferred, lastTime := 0, int64(0), time.Now()
	for {
		select {
		case <-finishChan:
			wait.Done()
			return
		case t := <-ticker:
			completed, transferred, taken, total := 0, int64(0), t.Sub(lastTime), s.total
			for _, localStat := range s.localStats {
				completed += localStat.completed
				transferred += localStat.transferred
				total += localStat.total
			}
			fmt.Printf("Completed %d of %d requests, %3.1f%% %3.1f/s %3.1fMB/s\n",
				completed, total, float64(completed)*100/float64(total),
				float64(completed-lastCompleted)*float64(int64(time.Second))/float64(int64(taken)),
				float64(transferred-lastTransferred)*float64(int64(time.Second))/float64(int64(taken))/float64(1024*1024),
			)
			lastCompleted, lastTransferred, lastTime = completed, transferred, t
		}
	}
}

func (s *stats) printStats() {
	completed, failed, transferred, total := 0, 0, int64(0), s.total
	for _, localStat := range s.localStats {
		completed += localStat.completed
		failed += localStat.failed
		transferred += localStat.transferred
		total += localStat.total
	}
	timeTaken := float64(int64(s.end.Sub(s.start))) / 1000000000
	fmt.Printf("\nConcurrency Level:      %d\n", *b.concurrency)
	fmt.Printf("Time taken for tests:   %.3f seconds\n", timeTaken)
	fmt.Printf("Completed requests:      %d\n", completed)
	fmt.Printf("Failed requests:        %d\n", failed)
	fmt.Printf("Total transferred:      %d bytes\n", transferred)
	fmt.Printf("Requests per second:    %.2f [#/sec]\n", float64(completed)/timeTaken)
	fmt.Printf("Transfer rate:          %.2f [Kbytes/sec]\n", float64(transferred)/1024/timeTaken)
	n, sum := 0, 0
	min, max := 10000000, 0
	for i := 0; i < len(s.data); i++ {
		n += s.data[i]
		sum += s.data[i] * i
		if s.data[i] > 0 {
			if min > i {
				min = i
			}
			if max < i {
				max = i
			}
		}
	}
	n += len(s.overflow)
	for i := 0; i < len(s.overflow); i++ {
		sum += s.overflow[i]
		if min > s.overflow[i] {
			min = s.overflow[i]
		}
		if max < s.overflow[i] {
			max = s.overflow[i]
		}
	}
	avg := float64(sum) / float64(n)
	varianceSum := 0.0
	for i := 0; i < len(s.data); i++ {
		if s.data[i] > 0 {
			d := float64(i) - avg
			varianceSum += d * d * float64(s.data[i])
		}
	}
	for i := 0; i < len(s.overflow); i++ {
		d := float64(s.overflow[i]) - avg
		varianceSum += d * d
	}
	std := math.Sqrt(varianceSum / float64(n))
	fmt.Printf("\nConnection Times (ms)\n")
	fmt.Printf("              min      avg        max      std\n")
	fmt.Printf("Total:        %2.1f      %3.1f       %3.1f      %3.1f\n", float32(min)/10, float32(avg)/10, float32(max)/10, std/10)
	// printing percentiles
	fmt.Printf("\nPercentage of the requests served within a certain time (ms)\n")
	percentiles := make([]int, len(percentages))
	for i := 0; i < len(percentages); i++ {
		percentiles[i] = n * percentages[i] / 100
	}
	percentiles[len(percentiles)-1] = n
	percentileIndex := 0
	currentSum := 0
	for i := 0; i < len(s.data); i++ {
		currentSum += s.data[i]
		if s.data[i] > 0 && percentileIndex < len(percentiles) && currentSum >= percentiles[percentileIndex] {
			fmt.Printf("  %3d%%    %5.1f ms\n", percentages[percentileIndex], float32(i)/10.0)
			percentileIndex++
			for percentileIndex < len(percentiles) && currentSum >= percentiles[percentileIndex] {
				percentileIndex++
			}
		}
	}
	sort.Ints(s.overflow)
	for i := 0; i < len(s.overflow); i++ {
		currentSum++
		if percentileIndex < len(percentiles) && currentSum >= percentiles[percentileIndex] {
			fmt.Printf("  %3d%%    %5.1f ms\n", percentages[percentileIndex], float32(s.overflow[i])/10.0)
			percentileIndex++
			for percentileIndex < len(percentiles) && currentSum >= percentiles[percentileIndex] {
				percentileIndex++
			}
		}
	}
}

// a fake reader to generate content to upload
type FakeReader struct {
	id     uint64 // an id number
	size   int64  // max bytes
	random *rand.Rand
}

func (l *FakeReader) Read(p []byte) (n int, err error) {
	if l.size <= 0 {
		return 0, io.EOF
	}
	if int64(len(p)) > l.size {
		n = int(l.size)
	} else {
		n = len(p)
	}
	if n >= 8 {
		for i := 0; i < 8; i++ {
			p[i] = byte(l.id >> uint(i*8))
		}
		l.random.Read(p[8:])
	}
	l.size -= int64(n)
	return
}

func (l *FakeReader) WriteTo(w io.Writer) (n int64, err error) {
	size := int(l.size)
	bufferSize := len(sharedBytes)
	for size > 0 {
		tempBuffer := sharedBytes
		if size < bufferSize {
			tempBuffer = sharedBytes[0:size]
		}
		count, e := w.Write(tempBuffer)
		if e != nil {
			return int64(size), e
		}
		size -= count
	}
	return l.size, nil
}

func Readln(r *bufio.Reader) ([]byte, error) {
	var (
		isPrefix = true
		err      error
		line, ln []byte
	)
	for isPrefix && err == nil {
		line, isPrefix, err = r.ReadLine()
		ln = append(ln, line...)
	}
	return ln, err
}
