package ledis

import (
	"encoding/binary"
	"errors"
	"strconv"

	"github.com/siddontang/go/hack"
)

var errIntNumber = errors.New("invalid integer")

/*
	Below I forget why I use little endian to store int.
	Maybe I was foolish at that time.
*/

// Int64 gets 64 integer with the little endian format.
func Int64(v []byte, err error) (int64, error) {
	if err != nil {
		return 0, err
	} else if v == nil || len(v) == 0 {
		return 0, nil
	} else if len(v) != 8 {
		return 0, errIntNumber
	}

	return int64(binary.LittleEndian.Uint64(v)), nil
}

// Uint64 gets unsigned 64 integer.
func Uint64(v []byte, err error) (uint64, error) {
	if err != nil {
		return 0, err
	} else if v == nil || len(v) == 0 {
		return 0, nil
	} else if len(v) != 8 {
		return 0, errIntNumber
	}

	return binary.LittleEndian.Uint64(v), nil
}

// PutInt64 puts the 64 integer.
func PutInt64(v int64) []byte {
	b := make([]byte, 8)
	binary.LittleEndian.PutUint64(b, uint64(v))
	return b
}

// StrInt64 gets the 64 integer with string format.
func StrInt64(v []byte, err error) (int64, error) {
	if err != nil {
		return 0, err
	} else if v == nil {
		return 0, nil
	} else {
		return strconv.ParseInt(hack.String(v), 10, 64)
	}
}

// StrUint64 gets the unsigned 64 integer with string format.
func StrUint64(v []byte, err error) (uint64, error) {
	if err != nil {
		return 0, err
	} else if v == nil {
		return 0, nil
	} else {
		return strconv.ParseUint(hack.String(v), 10, 64)
	}
}

// StrInt32 gets the 32 integer with string format.
func StrInt32(v []byte, err error) (int32, error) {
	if err != nil {
		return 0, err
	} else if v == nil {
		return 0, nil
	} else {
		res, err := strconv.ParseInt(hack.String(v), 10, 32)
		return int32(res), err
	}
}

// StrInt8 ets the 8 integer with string format.
func StrInt8(v []byte, err error) (int8, error) {
	if err != nil {
		return 0, err
	} else if v == nil {
		return 0, nil
	} else {
		res, err := strconv.ParseInt(hack.String(v), 10, 8)
		return int8(res), err
	}
}

// AsyncNotify notices the channel.
func AsyncNotify(ch chan struct{}) {
	select {
	case ch <- struct{}{}:
	default:
	}
}