package utils

import (
	"errors"
	"fmt"
	"strconv"
	"time"

	"github.com/golang-jwt/jwt/v4"
)

const (
	TokenTypeAccess  = "access"
	TokenTypeRefresh = "refresh"
)

type JWT struct {
	Secret string
	TTL    int
	Issuer string
}

func NewJWT(secret, issuer string, ttlSeconds int) (*JWT, error) {
	if secret == "" {
		return nil, errors.New("jwt secret empty")
	}
	if ttlSeconds < 1 {
		return nil, errors.New("jwt ttl invalid")
	}
	return &JWT{
		Secret: secret,
		TTL:    ttlSeconds,
		Issuer: issuer,
	}, nil
}

type Claims struct {
	UserID     int64  `json:"user_id"`
	Name       string `json:"name"`
	Avatar     string `json:"avatar"`
	Mobile     string `json:"mobile"`
	Gender     uint8  `json:"gender"`
	Birthday   string `json:"birthday"`
	Type       uint8  `json:"type"` // 1销售 2门店 3普通用户
	ClientCode string `json:"client_code"`
	SaleId     int64  `json:"sale_id,omitempty"`
	StoreId    int64  `json:"store_id,omitempty"`
	TokenType  string `json:"token_type"` // access | refresh
	jwt.RegisteredClaims
}

func (j *JWT) Sign(claims Claims) (string, error) {
	if j == nil {
		return "", errors.New("jwt not initialized")
	}
	now := time.Now()
	claims.Issuer = j.Issuer
	claims.IssuedAt = jwt.NewNumericDate(now)
	claims.ExpiresAt = jwt.NewNumericDate(now.Add(time.Duration(j.TTL) * time.Second))
	claims.ID = strconv.FormatInt(claims.UserID, NumberTen)

	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
	return token.SignedString([]byte(j.Secret))
}

func (j *JWT) Parse(tokenString string) (*Claims, error) {
	if j == nil {
		return nil, errors.New("jwt not initialized")
	}
	token, err := jwt.ParseWithClaims(tokenString, &Claims{}, func(token *jwt.Token) (interface{}, error) {
		if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
			return nil, fmt.Errorf("unexpected signing method: %v", token.Header["alg"])
		}
		return []byte(j.Secret), nil
	})
	if err != nil {
		return nil, err
	}
	claims, ok := token.Claims.(*Claims)
	if !ok || !token.Valid {
		return nil, errors.New("invalid token")
	}
	return claims, nil
}

func (j *JWT) ParseExpect(tokenString, expectType string) (*Claims, error) {
	claims, err := j.Parse(tokenString)
	if err != nil {
		return nil, err
	}
	if claims.TokenType != expectType {
		return nil, fmt.Errorf("unexpected token type: %s", claims.TokenType)
	}
	return claims, nil
}