package main

import (
	"log"
	"net/http"
	"os"
	"time"

	jwt "github.com/appleboy/gin-jwt/v2"
	"github.com/gin-gonic/gin"
)

type login struct {
	Username string `form:"username" json:"username" binding:"required"`
	Password string `form:"password" json:"password" binding:"required"`
}

var identityKey = "id"

func helloHandler(c *gin.Context) {
	claims := jwt.ExtractClaims(c)
	user, _ := c.Get(identityKey)
	c.JSON(200, gin.H{
		"userID":  claims[identityKey],
		"userName": user.(*User).UserName,
		"text":   "Hello World.",
	})
}

type User struct {
	UserName string
	FirstName string
	LastName string
}

func main() {
	port := os.Getenv("PORT")
	r := gin.New()
	r.Use(gin.Logger())
	r.Use(gin.Recovery())

	if port == "" {
		port = "8000"
	}

	authMiddleware, err := jwt.New(&jwt.GinJWTMiddleware{
		Realm:    "test zone",
		Key:     []byte("secret key"),
		Timeout:   time.Hour,
		MaxRefresh: time.Hour,
		IdentityKey: identityKey,
		PayloadFunc: func(data interface{}) jwt.MapClaims {
			if v, ok := data.(*User); ok {
				return jwt.MapClaims{
					identityKey: v.UserName,
				}
			}
			return jwt.MapClaims{}
		},
		IdentityHandler: func(c *gin.Context) interface{} {
			claims := jwt.ExtractClaims(c)
			return &User{
				UserName: claims[identityKey].(string),
			}
		},
		Authenticator: func(c *gin.Context) (interface{}, error) {
			var loginVals login
			if err := c.ShouldBind(&loginVals); err != nil {
				return "", jwt.ErrMissingLoginValues
			}
			userID := loginVals.Username
			password := loginVals.Password

			if (userID == "admin" && password == "admin") || (userID == "test" && password == "test") {
				return &User{
					UserName: userID,
					LastName: "Bo-Yi",
					FirstName: "Wu",
				}, nil
			}

			return nil, jwt.ErrFailedAuthentication
		},
		Authorizator: func(data interface{}, c *gin.Context) bool {
			if v, ok := data.(*User); ok && v.UserName == "admin" {
				return true
			}

			return false
		},
		Unauthorized: func(c *gin.Context, code int, message string) {
			c.JSON(code, gin.H{
				"code":  code,
				"message": message,
			})
		},

		TokenLookup: "header: Authorization, query: token, cookie: jwt",
		TokenHeadName: "Bearer",
		TimeFunc: time.Now,
	})

	if err != nil {
		log.Fatal("JWT Error:" + err.Error())
	}

	errInit := authMiddleware.MiddlewareInit()

	if errInit != nil {
		log.Fatal("authMiddleware.MiddlewareInit() Error:" + errInit.Error())
	}

	r.POST("/login", authMiddleware.LoginHandler)

	r.NoRoute(authMiddleware.MiddlewareFunc(), func(c *gin.Context) {
		claims := jwt.ExtractClaims(c)
		log.Printf("NoRoute claims: %#v\n", claims)
		c.JSON(404, gin.H{"code": "PAGE_NOT_FOUND", "message": "Page not found"})
	})

	auth := r.Group("/auth")
	auth.GET("/refresh_token", authMiddleware.RefreshHandler)
	auth.Use(authMiddleware.MiddlewareFunc())
	{
		auth.GET("/hello", helloHandler)
	}

	if err := http.ListenAndServe(":"+port, r); err != nil {
		log.Fatal(err)
	}
}

func (mw *GinJWTMiddleware) LoginHandler(c *gin.Context) {
	if mw.Authenticator == nil {
		mw.unauthorized(c, http.StatusInternalServerError, mw.HTTPStatusMessageFunc(ErrMissingAuthenticatorFunc, c))
		return
	}

	data, err := mw.Authenticator(c)

	if err != nil {
		mw.unauthorized(c, http.StatusUnauthorized, mw.HTTPStatusMessageFunc(err, c))
		return
	}

	// Create the token
	token := jwt.New(jwt.GetSigningMethod(mw.SigningAlgorithm))
	claims := token.Claims.(jwt.MapClaims)

	if mw.PayloadFunc != nil {
		for key, value := range mw.PayloadFunc(data) {
			claims[key] = value
		}
	}

	expire := mw.TimeFunc().Add(mw.Timeout)
	claims["exp"] = expire.Unix()
	claims["orig_iat"] = mw.TimeFunc().Unix()
	tokenString, err := mw.signedString(token)

	if err != nil {
		mw.unauthorized(c, http.StatusUnauthorized, mw.HTTPStatusMessageFunc(ErrFailedTokenCreation, c))
		return
	}

	// set cookie
	if mw.SendCookie {
		expireCookie := mw.TimeFunc().Add(mw.CookieMaxAge)
		maxage := int(expireCookie.Unix() - mw.TimeFunc().Unix())

		if mw.CookieSameSite != 0 {
			c.SetSameSite(mw.CookieSameSite)
		}

		c.SetCookie(
			mw.CookieName,
			tokenString,
			maxage,
			"/",
			mw.CookieDomain,
			mw.SecureCookie,
			mw.CookieHTTPOnly,
		)
	}

	mw.LoginResponse(c, http.StatusOK, tokenString, expire)
}

func (mw *GinJWTMiddleware) MiddlewareFunc() gin.HandlerFunc {
	return func(c *gin.Context) {
		mw.middlewareImpl(c)
	}
}

func (mw *GinJWTMiddleware) middlewareImpl(c *gin.Context) {
	claims, err := mw.GetClaimsFromJWT(c)
	if err != nil {
		mw.unauthorized(c, http.StatusUnauthorized, mw.HTTPStatusMessageFunc(err, c))
		return
	}

	if claims["exp"] == nil {
		mw.unauthorized(c, http.StatusBadRequest, mw.HTTPStatusMessageFunc(ErrMissingExpField, c))
		return
	}

	if _, ok := claims["exp"].(float64); !ok {
		mw.unauthorized(c, http.StatusBadRequest, mw.HTTPStatusMessageFunc(ErrWrongFormatOfExp, c))
		return
	}

	if int64(claims["exp"].(float64)) < mw.TimeFunc().Unix() {
		mw.unauthorized(c, http.StatusUnauthorized, mw.HTTPStatusMessageFunc(ErrExpiredToken, c))
		return
	}

	c.Set("JWT_PAYLOAD", claims)
	identity := mw.IdentityHandler(c)

	if identity != nil {
		c.Set(mw.IdentityKey, identity)
	}

	if !mw.Authorizator(identity, c) {
		mw.unauthorized(c, http.StatusForbidden, mw.HTTPStatusMessageFunc(ErrForbidden, c))
		return
	}

	c.Next()
}