// Package concerns provides functionality.
package concerns

import (
	"bytes"
	"crypto/rand"
	"encoding/base64"
)

// HasToken provides functionality.
type HasToken struct {
	Token string `json:"-" gorm:"unique_index"`
}

// SetToken provides functionality.
func (m *HasToken) SetToken() {
	tk := RandomToken(32)
	m.Token = base64.RawURLEncoding.EncodeToString(tk)
	if m.Token == "" {
		panic("RandomToken failed: token not set")
	}
	if len(m.Token) < 32 {
		panic("RandomToken failed: token too short")
	}
}

// RandomToken provides functionality.
func RandomToken(tokenLen int) []byte {
	b := make([]byte, tokenLen)
	n, err := rand.Read(b)
	if err != nil {
		panic(err)
	}
	if n != tokenLen {
		panic("RandomToken failed: bad len")
	}
	if bytes.Equal(b, make([]byte, tokenLen)) {
		panic("RandomToken failed: generated empty token")
	}
	return b
}