package main

import (
	"encoding/hex"
	"fmt"
	"sort"
	"testing"
	"time"

	"roseh.moe/cmd/roseh.moe/internal/pwhash"
)

func mustHex(s string) []byte {
	b, err := hex.DecodeString(s)
	if err != nil {
		panic(err)
	}
	return b
}

var salt = mustHex("34539b5dd2591415")

func benchmarkHashIter(iter int) time.Duration {
	const password = "wavy upend 4z jk linda k zing four atop pi"
	return time.Duration(testing.Benchmark(func(b *testing.B) {
		for b.Loop() {
			pwhash.HashIter(password, salt, iter)
		}
	}).NsPerOp())
}

func main() {
	const targetTime = 5 * time.Second
	iter := 8192
	for ; benchmarkHashIter(iter) < targetTime; iter *= 2 {
	}
	lo := iter / 2
	hi := iter
	fmt.Println(lo + sort.Search(hi-lo, func(n int) bool {
		return benchmarkHashIter(lo+n) > targetTime
	}))
}