package main

import (
        "encoding/csv"
        "fmt"
        "github.com/fsouza/gokabinet/kc"
        "log"
        "math/rand"
        "os"
        "runtime"
        "time"
)

const chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890 abcdefghijklmnopqrstuvwxyz" +
        "~!@#$%^&*()-_+={}[]\\|<,>.?/\"';:`"

const Maxlen = 1024

func RandStrings(N int) []string {
        r := make([]string, N)
        ri := 0
        buf := make([]byte, Maxlen)
        known := map[string]bool{}

        for i := 0; i < N; i++ {
        retry:
                l := rand.Intn(Maxlen)
                for j := 0; j < l; j++ {
                        buf[j] = chars[rand.Intn(len(chars))]
                }
                s := string(buf[0:l])
                if known[s] {
                        goto retry
                }
                known[s] = true
                r[ri] = s
                ri++
        }
        return r
}

func save_csv(num int, sec float64, dbtype string) {
        file, _ := os.OpenFile(fmt.Sprintf("bench_%s.csv", dbtype), os.O_CREATE|os.O_APPEND|os.O_RDWR, 0664)
        defer file.Close()
        writer := csv.NewWriter(file)
        record := []string{fmt.Sprintf("%d", num), fmt.Sprintf("%f", sec), dbtype}
        writer.Write(record)
        writer.Flush()
}

func timeTrack(start time.Time, name string, num int, dbtype string) {
        elapsed := time.Since(start)
        fmt.Println(name, elapsed, "throughput:", int64(float64(num)/(elapsed.Seconds())), "/sec\n")
        save_csv(num, elapsed.Seconds(), dbtype)
}

func runbench(t string, n int) {
        p := fmt.Sprintf("./cache_%d.kc%s", n, t)
        fmt.Println(p)
        defer timeTrack(time.Now(), fmt.Sprintf("%d records, type %s", n, t), n, t)
        db, err := kc.Open(p, kc.WRITE)
        if err != nil {
                log.Fatal(err)
        }
        defer db.Close()
        for i := 0; i < n; i++ {
                r := RandStrings(2)
                k := r[0]
                v := r[1]
                db.Set(k, v)
        }
        os.Remove(p)
}

func main() {
        fmt.Println("Generated string length:", Maxlen)
        iter := 64000000
        incr := 1000

        for i := incr; i < iter+1; i = incr {
                //runbench("h", i)
                runbench("t", i)
                runtime.GC()
                incr = 2 * i
        }
}