package common

import (
	"context"
	"crypto/aes"
	"crypto/cipher"
	"crypto/md5"
	"encoding/hex"
	"fmt"
	"time"
)

import (
	"github.com/gin-gonic/gin"
	"github.com/golang-jwt/jwt/v5"
	"github.com/spf13/cast"
	grpcmd "google.golang.org/grpc/metadata"
)

var CstSh, _ = time.LoadLocation("Asia/Shanghai")

const (
	LocateDateFormat  = "2006-01-02"
	LocateTimeFormat  = "2006-01-02 15:04:05"
	LocateMilliFormat = "2006-01-02 15:04:05.9999"
)

func Date() string {
	return time.Now().In(CstSh).Format(LocateDateFormat)
}

func Now() string {
	return time.Now().In(CstSh).Format(LocateTimeFormat)
}

func NowMilli() string {
	return time.Now().In(CstSh).Format(LocateMilliFormat)
}

func NewToken(userId uint, name string) (string, int64, error) {
	expire := time.Now().AddDate(0, 1, 0)
	hmacSampleSecret := []byte(BasicConfig.Jwt)
	token := jwt.NewWithClaims(jwt.SigningMethodHS256, jwt.MapClaims{
		"id":   userId,
		"name": name,
		"exp":  expire.Unix(),
	})
	str, err := token.SignedString(hmacSampleSecret)
	return str, expire.Unix(), err
}

func ParseToken(tokenString string) (uint, string, error) {
	token, err := jwt.Parse(tokenString, 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(BasicConfig.Jwt), nil
	})
	if err != nil {
		return 0, "", err
	}
	claims := token.Claims.(jwt.MapClaims)
	return cast.ToUint(claims["id"]), claims["name"].(string), nil
}

func GC2GM(c *gin.Context) context.Context {
	md := grpcmd.New(map[string]string{
		"uid":      cast.ToString(c.GetInt("uid")),
		"username": c.GetString("username"),
		"language": c.GetString("language"),
		"source":   c.GetString("source"),
		"product":  c.GetString("product"),
	},
	)
	return grpcmd.NewOutgoingContext(context.Background(), md)
}

func GetQueryString(c *gin.Context, key string) *string {
	if t, ok := c.GetQuery(key); ok {
		return &t
	}
	return nil
}

func IsEnabled(c *gin.Context) *bool {
	if isEnabled, ok := c.GetQuery("is_enabled"); ok {
		if r, e := cast.ToBoolE(isEnabled); e == nil {
			return &r
		}
	}
	return nil
}

func MD5(v []byte) string {
	h := md5.New()
	h.Write(v)
	re := h.Sum(nil)
	return hex.EncodeToString(re)
}

var dbPwKey = []byte("X3O6wVF&6*&lSVk0*504V~q7>\"k]6S'*") // 32 bytes for AES-256
var dbPwNonceHex = "1962a6f6f9999447632c8a34"

func EncryptGCM(key []byte, nonce []byte, plaintext []byte) ([]byte, error) {
	block, err := aes.NewCipher(key)
	if err != nil {
		return nil, err
	}

	gcm, err := cipher.NewGCM(block)
	if err != nil {
		return nil, err
	}

	ciphertext := gcm.Seal(nil, nonce, plaintext, nonce)

	return ciphertext, nil
}

func DecryptGCM(key []byte, nonce []byte, ciphertext []byte) ([]byte, error) {
	block, err := aes.NewCipher(key)
	if err != nil {
		return nil, err
	}

	gcm, err := cipher.NewGCM(block)
	if err != nil {
		return nil, err
	}

	plaintext, err := gcm.Open(nil, nonce, ciphertext, nonce)
	if err != nil {
		return nil, err
	}

	return plaintext, nil
}

func DBPwdEncrypt(ciphertext []byte) ([]byte, error) {
	nonce, _ := hex.DecodeString(dbPwNonceHex)
	return EncryptGCM(dbPwKey, nonce, ciphertext)
}

func DBPwdDecrypt(ciphertext []byte) ([]byte, error) {
	nonce, _ := hex.DecodeString(dbPwNonceHex)
	return DecryptGCM(dbPwKey, nonce, ciphertext)
}