osamingo/indigo

/*
Package indigo generates a distributed unique ID generator of using Sonyflake and encoded by Base58.

More information: https://github.com/osamingo/indigo/blob/master/README.md
*/
package indigo

import (
    "fmt"
    "time"

    "github.com/osamingo/base58"
    "github.com/sony/sonyflake"
)

type (
    // An Encoder has Encode and Decode methods.
    Encoder interface {
        Encode(uint64) string
        Decode(string) (uint64, error)
    }
    // A Generator has sonyflake and encoder.
    Generator struct {
        sf  *sonyflake.Sonyflake
        enc Encoder
    }
)

// New settings new a indigo.Generator.
func New(enc Encoder, options ...func(*sonyflake.Settings)) *Generator {
    if enc == nil {
        enc = base58.MustNewEncoder(base58.StandardSource)
    }

    var settings sonyflake.Settings

    for i := range options {
        options[i](&settings)
    }

    return &Generator{
        sf:  sonyflake.NewSonyflake(settings),
        enc: enc,
    }
}

// StartTime is optional function for indigo.Generator.
func StartTime(t time.Time) func(*sonyflake.Settings) {
    return func(s *sonyflake.Settings) {
        s.StartTime = t
    }
}

// MachineID is optional function for indigo.Generator.
func MachineID(f func() (uint16, error)) func(*sonyflake.Settings) {
    return func(s *sonyflake.Settings) {
        s.MachineID = f
    }
}

// CheckMachineID is optional function for indigo.Generator.
func CheckMachineID(f func(uint16) bool) func(*sonyflake.Settings) {
    return func(s *sonyflake.Settings) {
        s.CheckMachineID = f
    }
}

// NextID generates a next unique ID.
func (g *Generator) NextID() (string, error) {
    n, err := g.sf.NextID()
    if err != nil {
        return "", fmt.Errorf("indigo: failed to generate next id: %w", err)
    }

    return g.enc.Encode(n), nil
}

// Decompose returns a set of sonyflake ID parts.
func (g *Generator) Decompose(id string) (map[string]uint64, error) {
    b, err := g.enc.Decode(id)
    if err != nil {
        return nil, fmt.Errorf("indigo: failed to decode, id = %s: %w", id, err)
    }

    return sonyflake.Decompose(b), nil
}