package captcha

import (
	"math/rand"
	"time"

	"github.com/mojocn/base64Captcha"
)

func init() {
	//init rand seed
	rand.Seed(time.Now().UnixNano())
}

// Captcha captcha basic information.
type Captcha struct {
	Driver base64Captcha.Driver
	Store  base64Captcha.Store
	Config *configJsonBody
}

// NewCaptcha creates a captcha instance from driver and store
func NewCaptcha() *Captcha {
	config := &configJsonBody{
		DriverAudio:   audioConfig(),
		DriverDigit:   digitConfig(),
		DriverString:  stringConfig(),
		DriverMath:    mathConfig(),
		DriverChinese: chineseConfig(),
	}
	driver := config.DriverMath
	return &Captcha{
		Driver: driver,
		Store:  base64Captcha.DefaultMemStore,
		Config: config,
	}
}

func (c *Captcha) SetDriver(captchaType string) *Captcha {
	var driver base64Captcha.Driver
	//create base64 encoding captcha
	switch captchaType {
	case "audio":
		driver = c.Config.DriverAudio
	case "string":
		driver = c.Config.DriverString
	case "math":
		driver = c.Config.DriverMath
	case "chinese":
		driver = c.Config.DriverChinese
	default:
		driver = c.Config.DriverDigit
	}
	c.Driver = driver
	return c
}

// Generate generates a random id, base64 image string or an error if any
func (c *Captcha) Generate() (id, b64s string, err error) {
	id, content, answer := c.Driver.GenerateIdQuestionAnswer()
	item, err := c.Driver.DrawCaptcha(content)
	if err != nil {
		return "", "", err
	}
	c.Store.Set(id, answer)
	b64s = item.EncodeB64string()
	return
}

// Verify by a given id key and remove the captcha value in store,
// return boolean value.
// if you has multiple captcha instances which share a same store.
// You may want to call `store.Verify` method instead.
func (c *Captcha) Verify(id, answer string, clear bool) (match bool) {
	match = c.Store.Get(id, clear) == answer
	return
}