package main

import (
	"fmt"
	//	"bytes"
	//	"encoding/json"
	//	"io/ioutil"
	"log"
	"net/http"
	"strings"
	"time"

	jwt "github.com/dgrijalva/jwt-go"
	"github.com/go-macaron/binding"
	"gopkg.in/macaron.v1"
)

const (
	JWT_Secret   = "jwt-Dashoo-1705"
	JWT_Issuer   = "dashoo.cn"
	JWT_Audience = "dashoo"
	JWT_Expires  = 24 * 60 * 60 // 24h
)

type MyCustomClaims struct {
	// This will hold a users username after authenticating.
	// Ignore `json:"username"` it's required by JSON
	Username string `json:"username"`

	// This will hold claims that are recommended having (Expiration, issuer)
	jwt.StandardClaims
}

func main() {
	m := macaron.Classic()
	m.Use(macaron.Recovery())
	m.Use(macaron.Renderer())
	m.Use(macaron.Static("front_end"))
	m.Get("/", defaultGet)

	//前端框架使用的API
	m.Post("/api/auth/login", binding.Json(User{}), loginPost)
	m.Post("/api/tokens", binding.Json(User{}), genTokenPost) // 生成JWT token
	m.Get("/api/tokens", checkTokenGet)                       // 检验JWT token是否有效
	m.Get("/api/users/me", getCurUserGet)                     // 获取登录用户信息

	log.Println("Server is running...")
	log.Println(http.ListenAndServe("0.0.0.0:4000", m))
}

// 返回的json body 映射结构
type User struct {
	Username string `json:"username"`
	Password string `json:"password"`
}

type ResultUser struct {
	Name     string `json:"name"`
	UserName string `json:"username"`
	Slug     string `json:"slug"`
}
type ResponseUser struct {
	User ResultUser `json:"user"`
}

// 用户登录处理
func loginPost(ctx *macaron.Context, user User) {
	// request data body 通过binding自动解析到映射结构
	username := user.Username

	// todo 处理登录验证

	// 返回json数据
	ctx.JSON(200, map[string]interface{}{
		"user": username,
		"role": "admin",
	})

}

// 生成JWT token
func genTokenPost(ctx *macaron.Context, user User) {
	fmt.Println("un=", user.Username)
	claims := MyCustomClaims{
		user.Username,
		jwt.StandardClaims{
			NotBefore: int64(time.Now().Unix()),
			ExpiresAt: int64(time.Now().Unix() + JWT_Expires),
			Issuer:    JWT_Issuer,
		},
	}
	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
	signedToken, err := token.SignedString([]byte(JWT_Secret))
	if err != nil {
		log.Println(err)
		//		return 401
	}

	ctx.JSON(201, map[string]interface{}{
		"token": signedToken,
	})

}

// 检验JWT token是否有效
func checkTokenGet(ctx *macaron.Context) {
	//	fmt.Println(ctx.Req.Request.Header["Authorization"])

	authString := ctx.Req.Request.Header["Authorization"][0]
	auths := strings.Split(authString, " ")
	if len(auths) != 2 || auths[0] != "Bearer" {
		log.Println("AuthString invalid:", authString)
		//		return 401
	}
	signedToken := auths[1]
	fmt.Println("signedToken=", signedToken)

	token, err := jwt.ParseWithClaims(signedToken, &MyCustomClaims{}, func(token *jwt.Token) (interface{}, error) {
		return []byte(JWT_Secret), nil
	})

	if claims, ok := token.Claims.(*MyCustomClaims); ok && token.Valid {
		fmt.Printf("%v %v", claims.Username, claims.StandardClaims.ExpiresAt)
		ctx.JSON(200, map[string]interface{}{
			"msg": "Token is validated.",
		})
	} else {
		fmt.Println(err)
		//		return 401
	}

	//	ctx.JSON(200, map[string]interface{}{
	//		"user": username,
	//		"role": "admin",
	//	})
}

func getCurUserGet(ctx *macaron.Context) ResponseUser {
	authString := ctx.Req.Request.Header["Authorization"][0]
	auths := strings.Split(authString, " ")
	if len(auths) != 2 || auths[0] != "Bearer" {
		log.Println("AuthString invalid:", authString)
		//		return 401
	}
	signedToken := auths[1]
	fmt.Println("signedToken=", signedToken)

	token, err := jwt.ParseWithClaims(signedToken, &MyCustomClaims{}, func(token *jwt.Token) (interface{}, error) {
		return []byte(JWT_Secret), nil
	})

	if claims, ok := token.Claims.(*MyCustomClaims); ok && token.Valid {
		fmt.Printf("%v %v", claims.Username, claims.StandardClaims.ExpiresAt)

		//to do get user
		user := ResultUser{}
		user.Name = claims.Username
		user.UserName = claims.Username
		user.Slug = "dashoo"

		responseUser := ResponseUser{}
		responseUser.User = user

		return responseUser
		//		ctx.JSON(200, map[string]interface{}{
		//			"username": claims.Username,
		//		})
	} else {
		fmt.Println(err)
		return ResponseUser{}
		//		return 401
	}
}

func defaultGet(ctx *macaron.Context) {
	ctx.Data["method"] = "(Get)"
	ctx.HTML(200, "default")
}