chance.go

// Package chance is a random generator in Go
package chance

import "math/rand"

// Chance is interface of chance
type Chance interface {
	Bool(options ...BoolOption) bool
	String(options ...StringOption) string
	Int(options ...IntOption) int
	Int8(options ...Int8Option) int8
	Int16(options ...Int16Option) int16
	Int32(options ...Int32Option) int32
	Int64(options ...Int64Option) int64
	UInt(options ...UIntOption) uint
	UInt8(options ...UInt8Option) uint8
	UInt16(options ...UInt16Option) uint16
	UInt32(options ...UInt32Option) uint32
	Byte(options ...ByteOption) byte
	Rune(options ...RuneOption) rune
	UInt64(options ...UInt64Option) uint64
	Float32(options ...Float32Option) float32
}

type chance struct {
	r    *rand.Rand
	seed int64
}

// Option is a type
type Option func(Chance)

var defaultChance Chance

func init() {
	defaultChance = New()
}

// New returns new instance of chance
//  chance.New(chance.SetSeed(time.Now().UnixNano()))
func New(options ...Option) Chance {
	ch := new(chance)

	// defaults
	ResetSeed()(ch)
	ch.r = rand.New(rand.NewSource(ch.seed))

	for i := range options {
		options[i](ch)
	}
	return ch
}

// SetSeed sets seed option of instance
func SetSeed(seed int64) Option {
	return func(ich Chance) {
		ch := ich.(*chance)
		ch.seed = seed
	}
}

// ResetSeed resets seed option of instance
func ResetSeed() Option {
	return func(ich Chance) {
		ch := ich.(*chance)
		ch.seed = 1
	}
}