package signutil

import (
	"crypto/sha1"
	"encoding/hex"
	"sort"
	"strconv"
	"strings"
	"time"

	validation "github.com/go-ozzo/ozzo-validation/v4"
	"gogs.baozhida.cn/Cold_Logistic_libs/pkg/contrib/errors"
)

const (
	AppidKey     = "appid"
	NoncestrKey  = "noncestr"
	TimestampKey = "timestamp"
	SignKey      = "sign"
)

type GenSignFunc func(appid, secret, nonceStr, timestamp string) string

type IBINGLIDigest struct {
	AppId       string
	NonceStr    string
	Timestamp   string
	Sign        string
	TimeLimit   time.Duration
	genSignFunc GenSignFunc
}

type IBINGLIDigestOpt func(d *IBINGLIDigest)

func WithIBINGLIDigestTimeLimit(t time.Duration) IBINGLIDigestOpt {
	return func(d *IBINGLIDigest) {
		d.TimeLimit = t
	}
}

func WithIBINGLIDigestGenSignFunc(f GenSignFunc) IBINGLIDigestOpt {
	return func(d *IBINGLIDigest) {
		d.genSignFunc = f
	}
}

func NewIBINGLIDigestByParam(param map[string]string, opts ...IBINGLIDigestOpt) *IBINGLIDigest {
	d := &IBINGLIDigest{
		AppId:       param[AppidKey],
		NonceStr:    param[NoncestrKey],
		Timestamp:   param[TimestampKey],
		Sign:        param[SignKey],
		genSignFunc: defaultGenSign,
	}

	for _, opt := range opts {
		opt(d)
	}

	return d
}

func NewIBINGLIDigest(appId, nonceStr, timestamp, sign string, opts ...IBINGLIDigestOpt) *IBINGLIDigest {
	d := &IBINGLIDigest{
		AppId:       appId,
		NonceStr:    nonceStr,
		Timestamp:   timestamp,
		Sign:        sign,
		genSignFunc: defaultGenSign,
	}

	for _, opt := range opts {
		opt(d)
	}

	return d
}

func (v *IBINGLIDigest) Validate() error {
	err := validation.ValidateStruct(v,
		validation.Field(&v.AppId, validation.Required),
		validation.Field(&v.NonceStr, validation.Required),
		validation.Field(&v.Timestamp, validation.Required),
		validation.Field(&v.Sign, validation.Required),
	)
	if err != nil {
		return err
	}
	if v.TimeLimit > 0 {
		return v.ValidateTimestamp()
	}
	return nil
}

// 验证时效性
func (v *IBINGLIDigest) ValidateTimestamp() error {
	ts, err := strconv.Atoi(v.Timestamp)
	if err != nil {
		return errors.WithStackOnce(err)
	}
	if time.Now().Sub(time.UnixMilli(int64(ts))) > v.TimeLimit {
		return errors.New("timestamp invalid")
	}
	return nil
}

func defaultGenSign(appid, secret, nonceStr, timestamp string) string {
	// /*
	// 	  签名规则：
	// 	     1. 拼接appid和secret字符串
	// 	     2. 随机生成一个16位字符串，由[0~9a~zA~Z]组成
	// 	     3. 使用当前13位时间戳（毫秒值）
	// 	     4. 拼接123中的字符串
	// 	     5. 字典排序4中的字符串
	// 	     6. 计算字符串的SHA1校验和
	// 	*/
	target := appid + secret + nonceStr + timestamp
	targetStrArray := strings.Split(target, "")
	sort.Strings(targetStrArray)
	target = strings.Join(targetStrArray, "")
	h := sha1.New()
	h.Write([]byte(target))
	sum := h.Sum(nil)
	return hex.EncodeToString(sum)
}

// 生成签名
func (v *IBINGLIDigest) GenSign(secret string) string {
	return v.genSignFunc(v.AppId, secret, v.NonceStr, v.Timestamp)
}

// 比较签名
func (v *IBINGLIDigest) CompareSign(secret string) bool {
	return v.Sign == v.GenSign(secret)
}