package dsync

import (
	"math/rand"
	"time"
)

func backoffWait(min, unit, cap time.Duration) func(*rand.Rand, uint) time.Duration {
	if unit > time.Hour {
		// Protect against integer overflow
		panic("unit cannot exceed one hour")
	}
	return func(r *rand.Rand, attempt uint) time.Duration {
		sleep := min
		sleep += unit * time.Duration(attempt)
		if sleep > cap {
			sleep = cap
		}

| Entry           | Encoding                    | Content
| ----------------|-----------------------------|----------------------------------------
| xlHeaderVersion | msgp uint                   | header version identifier
| xlMetaVersion   | msgp uint                   | metadata version identifier
| versions        | msgp int                    | Number of versions following
| header_1        | msgp bin array              | Header of version 1

		// Call back.
		fn(string(key), val)
	}
	return nil
}

const (
	xlHeaderVersion = 3
	xlMetaVersion   = 2
)

type xlHeaders struct {
	versions           int
	headerVer, metaVer uint
}

func decodeXLHeaders(buf []byte) (x xlHeaders, b []byte, err error) {
	x.headerVer, buf, err = msgp.ReadUintBytes(buf)
	if err != nil {
		return x, buf, err
	}

// https://www.awsarchitectureblog.com/2015/03/backoff.html
func exponentialBackoffWait(r *rand.Rand, unit, cap time.Duration) func(uint) time.Duration {
	if unit > time.Hour {
		// Protect against integer overflow
		panic("unit cannot exceed one hour")
	}
	return func(attempt uint) time.Duration {
		if attempt > 16 {
			// Protect against integer overflow
			attempt = 16
		}

		exp             interface{}
		expectedFailure bool
	}{
		{"", true},
		{"-1", true},
		{"1574812326", false},
		{1574812326, false},
		{int64(1574812326), false},
		{int(1574812326), false},
		{uint(1574812326), false},
		{uint64(1574812326), false},
		{json.Number("1574812326"), false},
		{1574812326.000, false},
		{time.Duration(3) * time.Minute, false},
	}

	for _, testCase := range testCases {

	}{
		{"", "", true},
		{"-1", "0", true},
		{"-1", "900", true},
		{"1574812326", "900", false},
		{1574812326, "900", false},
		{int64(1574812326), "900", false},
		{int(1574812326), "900", false},
		{uint(1574812326), "900", false},
		{uint64(1574812326), "900", false},
		{json.Number("1574812326"), "900", false},
		{1574812326.000, "900", false},
		{time.Duration(3) * time.Minute, "900", false},
	}

func (z *BitrotAlgorithm) DecodeMsg(dc *msgp.Reader) (err error) {
	{
		var zb0001 uint
		zb0001, err = dc.ReadUint()
		if err != nil {
			err = msgp.WrapError(err)
			return
		}
		(*z) = BitrotAlgorithm(zb0001)
	}
	return
}

// EncodeMsg implements msgp.Encodable
func (z BitrotAlgorithm) EncodeMsg(en *msgp.Writer) (err error) {
	err = en.WriteUint(uint(z))
	if err != nil {
		err = msgp.WrapError(err)
		return
	}

	if b {
		*t |= other
	}
}

// Mask returns the mask as a uint64.
func (t Mask) Mask() uint64 {
	return uint64(t)
}

// Maskable implementations must return their mask as a 64 bit uint.
type Maskable interface {
	Mask() uint64

	"github.com/minio/pkg/v2/env"
)

// Indicator if logging is enabled.
var dsyncLog bool

// Retry unit interval
var lockRetryMinInterval time.Duration

var lockRetryBackOff func(*rand.Rand, uint) time.Duration

func init() {
	// Check for MINIO_DSYNC_TRACE env variable, if set logging will be enabled for failed REST operations.
	dsyncLog = env.Get("_MINIO_DSYNC_TRACE", "0") == "1"

		if ecindex != nei.Distribution[i] {
			return false
		}
	}
	return true
}

// BitrotAlgorithm specifies a algorithm used for bitrot protection.
type BitrotAlgorithm uint

const (
	// SHA256 represents the SHA-256 hash function
	SHA256 BitrotAlgorithm = 1 + iota
	// HighwayHash256 represents the HighwayHash-256 hash function
	HighwayHash256