// Copyright 2015 The etcd Authors
//
// 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,
// 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 cmd

import (
	"encoding/binary"
	"fmt"
	"math/rand"
	"os"
	"time"

	v3 "github.com/coreos/etcd/clientv3"
	"github.com/spf13/cobra"
	"golang.org/x/net/context"
	"gopkg.in/cheggaaa/pb.v1"
)

// putCmd represents the put command
var putCmd = &cobra.Command{
	Use:   "put",
	Short: "Benchmark put",

	Run: putFunc,
}

var (
	keySize int
	valSize int

	putTotal int

	keySpaceSize int
	seqKeys      bool

	compactInterval   time.Duration
	compactIndexDelta int64
)

func init() {
	RootCmd.AddCommand(putCmd)
	putCmd.Flags().IntVar(&keySize, "key-size", 8, "Key size of put request")
	putCmd.Flags().IntVar(&valSize, "val-size", 8, "Value size of put request")
	putCmd.Flags().IntVar(&putTotal, "total", 10000, "Total number of put requests")
	putCmd.Flags().IntVar(&keySpaceSize, "key-space-size", 1, "Maximum possible keys")
	putCmd.Flags().BoolVar(&seqKeys, "sequential-keys", false, "Use sequential keys")
	putCmd.Flags().DurationVar(&compactInterval, "compact-interval", 0, `Interval to compact database (do not duplicate this with etcd's 'auto-compaction-retention' flag) (e.g. --compact-interval=5m compacts every 5-minute)`)
	putCmd.Flags().Int64Var(&compactIndexDelta, "compact-index-delta", 1000, "Delta between current revision and compact revision (e.g. current revision 10000, compact at 9000)")
}

func putFunc(cmd *cobra.Command, args []string) {
	if keySpaceSize <= 0 {
		fmt.Fprintf(os.Stderr, "expected positive --key-space-size, got (%v)", keySpaceSize)
		os.Exit(1)
	}

	results = make(chan result)
	requests := make(chan v3.Op, totalClients)
	bar = pb.New(putTotal)

	k, v := make([]byte, keySize), string(mustRandBytes(valSize))

	clients := mustCreateClients(totalClients, totalConns)

	bar.Format("Bom !")
	bar.Start()

	for i := range clients {
		wg.Add(1)
		go doPut(context.Background(), clients[i], requests)
	}

	pdoneC := printReport(results)

	go func() {
		for i := 0; i < putTotal; i++ {
			if seqKeys {
				binary.PutVarint(k, int64(i%keySpaceSize))
			} else {
				binary.PutVarint(k, int64(rand.Intn(keySpaceSize)))
			}
			requests <- v3.OpPut(string(k), v)
		}
		close(requests)
	}()

	if compactInterval > 0 {
		go func() {
			for {
				time.Sleep(compactInterval)
				compactKV(clients)
			}
		}()
	}

	wg.Wait()

	bar.Finish()

	close(results)
	<-pdoneC
}

func doPut(ctx context.Context, client v3.KV, requests <-chan v3.Op) {
	defer wg.Done()

	for op := range requests {
		st := time.Now()
		_, err := client.Do(ctx, op)

		var errStr string
		if err != nil {
			errStr = err.Error()
		}
		results <- result{errStr: errStr, duration: time.Since(st), happened: time.Now()}
		bar.Increment()
	}
}

func compactKV(clients []*v3.Client) {
	var curRev int64
	for _, c := range clients {
		ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
		resp, err := c.KV.Get(ctx, "foo")
		cancel()
		if err != nil {
			panic(err)
		}
		curRev = resp.Header.Revision
		break
	}
	revToCompact := max(0, curRev-compactIndexDelta)
	for _, c := range clients {
		ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
		_, err := c.KV.Compact(ctx, revToCompact)
		cancel()
		if err != nil {
			panic(err)
		}
		break
	}
}

func max(n1, n2 int64) int64 {
	if n1 > n2 {
		return n1
	}
	return n2
}