package captcha

import (
	"context"
	"gitee.com/neuro-netw0rk/server-golib/errors"
	dcaptcha "github.com/dchest/captcha"
	"github.com/gin-gonic/gin"
	"github.com/go-redis/redis/v7"
)

type Value struct {
	ID   string `json:"id,omitempty"`
	Code string `json:"code,omitempty"`
	Img  string `json:"img,omitempty"`
	Len  int    `json:"len,omitempty"`
}

type Captcha struct {
	enabled bool
	options Options
	imgExt  string
}

type Options struct {
	Enabled   bool
	StoreMode int8
	Len       int
	Width     int
	Height    int
	Rds       *redis.Client
}

type StoreMode int8

const (
	defaultStoreMode = storeModeMem
	storeModeMem     = 0
	storeModeRedis   = 1
)

const defaultImgExt = ".png"
const defaultLen = 4

var (
	ErrNotEnabled = errors.New("captcha: not enabled")
	ErrIDEmpty    = errors.New("captcha: id is empty")
)

var C *Captcha

func Init(opts *Options) {
	if opts == nil {
		return
	}
	if !opts.Enabled {
		return
	}
	if opts.Rds == nil {
		opts.StoreMode = defaultStoreMode
	}
	if opts.StoreMode != storeModeMem && opts.StoreMode != storeModeRedis {
		opts.StoreMode = defaultStoreMode
	}
	if opts.StoreMode == storeModeRedis {
		dcaptcha.SetCustomStore(newRedisMode(context.Background(), opts.Rds))
	}
	if opts.Width <= 0 {
		opts.Width = dcaptcha.StdWidth
	}
	if opts.Height <= 0 {
		opts.Height = dcaptcha.StdHeight
	}
	if opts.Len <= 0 {
		opts.Len = defaultLen
	}
	C = &Captcha{
		enabled: true,
		options: *opts,
		imgExt:  defaultImgExt,
	}
}

func (c *Captcha) GetEnabled() bool {
	if c == nil {
		return false
	}
	return c.enabled
}

// Get 获取验证码
func (c *Captcha) Get() *Value {
	if !c.GetEnabled() {
		return &Value{}
	}
	id := dcaptcha.NewLen(c.options.Len)
	return &Value{
		ID:   id,
		Code: "",
		Img:  id + c.imgExt,
		Len:  c.options.Len,
	}
}

// Verify 验证验证码
func (c *Captcha) Verify(val *Value) bool {
	if !c.GetEnabled() {
		return true
	}
	if val == nil {
		return false
	}
	if val.ID == "" || val.Code == "" {
		return false
	}
	return dcaptcha.VerifyString(val.ID, val.Code)
}

// Show 展示验证码
func (c *Captcha) Show(ctx *gin.Context, id string) error {
	if !c.GetEnabled() {
		return ErrNotEnabled
	}
	if id == "" {
		return ErrIDEmpty
	}
	err := dcaptcha.WriteImage(ctx.Writer, id, c.options.Width, c.options.Height)
	if err != nil {
		return err
	}
	return nil
}