package jwt

import (
	"context"
	"fmt"
	"pro2d/src/common"
	"pro2d/src/components/logger"
	"time"

	jwt "github.com/dgrijalva/jwt-go"
	"google.golang.org/grpc/metadata"
)

func CreateToken(uid string) (tokenString string) {
	token := jwt.NewWithClaims(jwt.SigningMethodHS256, jwt.MapClaims{
		"iss":      "pro2d-app-server",
		"aud":      "pro2d-app-server",
		"nbf":      time.Now().Unix(),
		"exp":      time.Now().Add(time.Hour).Unix(),
		"sub":      "pro2d",
		"uid": uid,
	})
	tokenString, err := token.SignedString([]byte(common.Pro2DTokenSignedString))
	if err != nil {
		panic(err)
	}
	return tokenString
}

func ParseToken(tokenStr string) string {
	var clientClaims Claims
	token, err := jwt.ParseWithClaims(tokenStr, &clientClaims, func(token *jwt.Token) (interface{}, error) {
		if token.Header["alg"] != "HS256" {
			//panic("ErrInvalidAlgorithm")
			logger.Error("ErrInvalidAlgorithm")
			return nil, nil
		}
		return []byte(common.Pro2DTokenSignedString), nil
	})
	if err != nil {
		logger.Error("jwt parse error")
		return ""
	}

	if !token.Valid {
		logger.Error("ErrInvalidToken")
		return ""
	}
	return clientClaims.Uid
}


// Claims defines the struct containing the token claims.
type Claims struct {
	jwt.StandardClaims
	Uid string
}

// 从 context 的 metadata 中，取出 token
func getTokenFromContext(ctx context.Context) (string, error) {
	md, ok := metadata.FromIncomingContext(ctx)
	if !ok {
		return "", fmt.Errorf("ErrNoMetadataInContext")
	}
	// md 的类型是 type MD map[string][]string
	token, ok := md["authorization"]
	if !ok || len(token) == 0 {
		return "", fmt.Errorf("ErrNoAuthorizationInMetadata")
	}
	// 因此，token 是一个字符串数组，我们只用了 token[0]
	return token[0], nil
}

func CheckAuth(ctx context.Context) string {
	tokenStr, err := getTokenFromContext(ctx)
	if err != nil {
		logger.Error("get token from context error")
		return ""
	}
	return ParseToken(tokenStr)
}

// AuthToken 自定义认证 客户端使用
type AuthToken struct {
	Token string
}

func (c AuthToken) GetRequestMetadata(ctx context.Context, uri ...string) (map[string]string, error) {
	return map[string]string{
		"authorization": c.Token,
	}, nil
}

func (c AuthToken) RequireTransportSecurity() bool {
	return false
}