package controller

import (
    "gopkg.in/go-playground/validator.v9"
    "github.com/gravitl/netmaker/models"
    "github.com/gravitl/netmaker/functions"
    "github.com/gravitl/netmaker/mongoconn"
    "golang.org/x/crypto/bcrypt"
    "time"
    "strings"
    "fmt"
    "context"
    "encoding/json"
    "net/http"
    "github.com/gorilla/mux"
    "go.mongodb.org/mongo-driver/bson"
    "go.mongodb.org/mongo-driver/mongo/options"
    "go.mongodb.org/mongo-driver/mongo"
)


func userHandlers(r *mux.Router) {

    r.HandleFunc("/users/hasadmin", hasAdmin).Methods("GET")
    r.HandleFunc("/users/createadmin", createAdmin).Methods("POST")
    r.HandleFunc("/users/{username}", authorizeUser(http.HandlerFunc(updateUser))).Methods("PUT")
    r.HandleFunc("/users/{username}", authorizeUser(http.HandlerFunc(deleteUser))).Methods("DELETE")
    r.HandleFunc("/users/{username}", authorizeUser(http.HandlerFunc(getUser))).Methods("GET")
    r.HandleFunc("/users/authenticate", authenticateUser).Methods("POST")
}

//Node authenticates using its password and retrieves a JWT for authorization.
func authenticateUser(response http.ResponseWriter, request *http.Request) {

    //Auth request consists of Mac Address and Password (from node that is authorizing
    //in case of Master, auth is ignored and mac is set to "mastermac"
    var authRequest models.UserAuthParams
    var result models.User
    var errorResponse = models.ErrorResponse{
	    Code: http.StatusInternalServerError, Message: "W1R3: It's not you it's me.",
    }

    decoder := json.NewDecoder(request.Body)
    decoderErr := decoder.Decode(&authRequest)
    defer request.Body.Close()

    if decoderErr != nil {
        returnErrorResponse(response, request, errorResponse)
	return
    } else {
        errorResponse.Code = http.StatusBadRequest
        if authRequest.UserName == "" {
            errorResponse.Message = "W1R3: Username can't be empty"
            returnErrorResponse(response, request, errorResponse)
	    return
        } else if authRequest.Password == "" {
            errorResponse.Message = "W1R3: Password can't be empty"
            returnErrorResponse(response, request, errorResponse)
	    return
        } else {

            //Search DB for node with Mac Address. Ignore pending nodes (they should not be able to authenticate with API untill approved).
            collection := mongoconn.Client.Database("netmaker").Collection("users")
            ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
	    var err = collection.FindOne(ctx, bson.M{ "username": authRequest.UserName }).Decode(&result)

            defer cancel()

            if err != nil {
		errorResponse.Message = "W1R3: User " + authRequest.UserName + " not found."
                returnErrorResponse(response, request, errorResponse)
		return
            }

	   //compare password from request to stored password in database
	   //might be able to have a common hash (certificates?) and compare those so that a password isn't passed in in plain text...
	   //TODO: Consider a way of hashing the password client side before sending, or using certificates
	   err = bcrypt.CompareHashAndPassword([]byte(result.Password), []byte(authRequest.Password))
	   if err != nil {
                        errorResponse = models.ErrorResponse{
                                Code: http.StatusUnauthorized, Message: "W1R3: Wrong Password.",
                        }
		   returnErrorResponse(response, request, errorResponse)
		   return
	   } else {
		//Create a new JWT for the node
                tokenString, _ := functions.CreateUserJWT(authRequest.UserName, result.IsAdmin)

                if tokenString == "" {
                    returnErrorResponse(response, request, errorResponse)
		    return
                }

                var successResponse = models.SuccessResponse{
                    Code:    http.StatusOK,
                    Message: "W1R3: Device " + authRequest.UserName + " Authorized",
                    Response: models.SuccessfulUserLoginResponse{
                        AuthToken: tokenString,
                        UserName:     authRequest.UserName,
                    },
                }
                //Send back the JWT
                successJSONResponse, jsonError := json.Marshal(successResponse)

                if jsonError != nil {
                    returnErrorResponse(response, request, errorResponse)
		    return
                }
                response.Header().Set("Content-Type", "application/json")
                response.Write(successJSONResponse)
            }
	}
    }
}

//The middleware for most requests to the API
//They all pass  through here first
//This will validate the JWT (or check for master token)
//This will also check against the authGroup and make sure the node should be accessing that endpoint,
//even if it's technically ok
//This is kind of a poor man's RBAC. There's probably a better/smarter way.
//TODO: Consider better RBAC implementations
func authorizeUser(next http.Handler) http.HandlerFunc {
        return func(w http.ResponseWriter, r *http.Request) {

                var errorResponse = models.ErrorResponse{
                        Code: http.StatusInternalServerError, Message: "W1R3: It's not you it's me.",
                }

	        w.Header().Set("Content-Type", "application/json")

		//get the auth token
		bearerToken := r.Header.Get("Authorization")

                var tokenSplit = strings.Split(bearerToken, " ")

		//I put this in in case the user doesn't put in a token at all (in which case it's empty)
		//There's probably a smarter way of handling this.
                var authToken = "928rt238tghgwe@TY@$Y@#WQAEGB2FC#@HG#@$Hddd"

                if len(tokenSplit) > 1 {
                        authToken = tokenSplit[1]
                } else {
                        errorResponse = models.ErrorResponse{
                                Code: http.StatusUnauthorized, Message: "W1R3: Missing Auth Token.",
                        }
                        returnErrorResponse(w, r, errorResponse)
			return
		}

		//This checks if
		//A: the token is the master password
		//B: the token corresponds to a mac address, and if so, which one
		//TODO: There's probably a better way of dealing with the "master token"/master password. Plz Halp.
		username, _, err := functions.VerifyUserToken(authToken)

		if err != nil {
                        errorResponse = models.ErrorResponse{
                                Code: http.StatusUnauthorized, Message: "W1R3: Error Verifying Auth Token.",
                        }
                        returnErrorResponse(w, r, errorResponse)
			return
		}

		isAuthorized := username != ""

		if !isAuthorized {
			errorResponse = models.ErrorResponse{
				Code: http.StatusUnauthorized, Message: "W1R3: You are unauthorized to access this endpoint.",
			}
			returnErrorResponse(w, r, errorResponse)
			return
		} else {
			//If authorized, this function passes along it's request and output to the appropriate route function.
			next.ServeHTTP(w, r)
		}
	}
}

func HasAdmin() (bool, error){

        collection := mongoconn.Client.Database("netmaker").Collection("users")

        ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)

        filter := bson.M{"isadmin": true}

        //Filtering out the ID field cuz Dillon doesn't like it. May want to filter out other fields in the future
        var result bson.M

	err := collection.FindOne(ctx, filter).Decode(&result)

        defer cancel()

        if err != nil {
		if err == mongo.ErrNoDocuments {
			return false, err
		}
		fmt.Println(err)
	}
	return true, err
}

func hasAdmin(w http.ResponseWriter, r *http.Request) {

	w.Header().Set("Content-Type", "application/json")

	hasadmin, _ := HasAdmin()

	//Returns all the nodes in JSON format

	json.NewEncoder(w).Encode(hasadmin)

}

func GetUser(username string) (models.User, error) {

        var user models.User

        collection := mongoconn.Client.Database("netmaker").Collection("users")

        ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)

        filter := bson.M{"username": username}
        err := collection.FindOne(ctx, filter, options.FindOne().SetProjection(bson.M{"_id": 0})).Decode(&user)

        defer cancel()

        return user, err
}

//Get an individual node. Nothin fancy here folks.
func getUser(w http.ResponseWriter, r *http.Request) {
	// set header.
	w.Header().Set("Content-Type", "application/json")

        var params = mux.Vars(r)

	user, err := GetUser(params["username"])

	if err != nil {
		mongoconn.GetError(err, w)
		return
	}

	json.NewEncoder(w).Encode(user)
}

func CreateUser(user models.User) (models.User, error) {

        //encrypt that password so we never see it again
        hash, err := bcrypt.GenerateFromPassword([]byte(user.Password), 5)

        if err != nil {
                return user, err
        }
        //set password to encrypted password
        user.Password = string(hash)

        tokenString, _ := functions.CreateUserJWT(user.UserName, user.IsAdmin)

        if tokenString == "" {
                //returnErrorResponse(w, r, errorResponse)
                return user, err
        }

        // connect db
        collection := mongoconn.Client.Database("netmaker").Collection("users")
        ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)

        // insert our node to the node db.
        result, err := collection.InsertOne(ctx, user)
        _ = result

        defer cancel()

        return user, err
}

func createAdmin(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json")

	var errorResponse = models.ErrorResponse{
	        Code: http.StatusInternalServerError, Message: "W1R3: It's not you it's me.",
	}

	hasadmin, err := HasAdmin()

        if hasadmin {
                errorResponse = models.ErrorResponse{
                        Code: http.StatusUnauthorized, Message: "W1R3: Admin already exists! ",
                }
                returnErrorResponse(w, r, errorResponse)
                return
        }

	var admin models.User

	//get node from body of request
	_ = json.NewDecoder(r.Body).Decode(&admin)

	admin.IsAdmin = true

	err =  ValidateUser("create", admin)
        if err != nil {
		json.NewEncoder(w).Encode(err)
		return
        }

        admin, err = CreateUser(admin)
        if err != nil {
		json.NewEncoder(w).Encode(err)
                return
        }

	json.NewEncoder(w).Encode(admin)
}

func UpdateUser(userchange models.User, user models.User) (models.User, error) {

    queryUser := user.UserName

    if userchange.UserName != "" {
        user.UserName = userchange.UserName
    }
    if userchange.Password != "" {
        //encrypt that password so we never see it again
        hash, err := bcrypt.GenerateFromPassword([]byte(userchange.Password), 5)

        if err != nil {
                return userchange, err
        }
        //set password to encrypted password
        userchange.Password = string(hash)

        user.Password = userchange.Password
    }
        //collection := mongoconn.ConnectDB()
        collection := mongoconn.Client.Database("netmaker").Collection("users")

        ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)

        // Create filter
        filter := bson.M{"username": queryUser}

        fmt.Println("Updating User " + user.UserName)


        // prepare update model.
        update := bson.D{
                {"$set", bson.D{
                        {"username", user.UserName},
                        {"password", user.Password},
                        {"isadmin", user.IsAdmin},
                }},
        }
        var userupdate models.User

        errN := collection.FindOneAndUpdate(ctx, filter, update).Decode(&userupdate)
	if errN != nil {
               fmt.Println("Could not update: ")
               fmt.Println(errN)
        }  else {
		fmt.Println("User updated  successfully.")
	}

        defer cancel()

        return userupdate, errN
}

func updateUser(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json")

	var params = mux.Vars(r)

	var user models.User

	//start here
	user, err := GetUser(params["username"])
        if err != nil {
                json.NewEncoder(w).Encode(err)
                return
        }


        var userchange models.User

        // we decode our body request params
        err = json.NewDecoder(r.Body).Decode(&userchange)
	if err != nil {
                json.NewEncoder(w).Encode(err)
                return
        }

	userchange.IsAdmin = true

        err = ValidateUser("update", userchange)

        if err != nil {
                json.NewEncoder(w).Encode(err)
                return
        }

	user, err = UpdateUser(userchange, user)

	if err != nil {
                json.NewEncoder(w).Encode(err)
		return
	}

	json.NewEncoder(w).Encode(user)
}

func DeleteUser(user string) (bool, error)  {

        deleted := false

        collection := mongoconn.Client.Database("netmaker").Collection("users")

        filter := bson.M{"username": user}

        ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)

        result, err := collection.DeleteOne(ctx, filter)

        deletecount := result.DeletedCount

        if deletecount > 0 {
                deleted = true
        }

        defer cancel()

        return deleted, err
}

func deleteUser(w http.ResponseWriter, r *http.Request) {
	// Set header
	w.Header().Set("Content-Type", "application/json")

	// get params
	var params = mux.Vars(r)

	success, err := DeleteUser(params["username"])

	if err != nil || !success {
		http.Error(w, err.Error(), 400)
		json.NewEncoder(w).Encode("Could not delete user " + params["username"])
		return
	}

	json.NewEncoder(w).Encode(params["username"] + " deleted.")
}

func ValidateUser(operation string, user models.User) error {

        v := validator.New()

        _ = v.RegisterValidation("username_unique", func(fl validator.FieldLevel) bool {
		_, err := GetUser(user.UserName)
		return err == nil || operation == "update"
        })

        _ = v.RegisterValidation("username_valid", func(fl validator.FieldLevel) bool {
                isvalid := functions.NameInNodeCharSet(user.UserName)
                return isvalid
        })

        _ = v.RegisterValidation("password_check", func(fl validator.FieldLevel) bool {
                notEmptyCheck := user.Password != ""
                goodLength := len(user.Password) > 5
                return (notEmptyCheck && goodLength) || operation == "update"
        })

        err := v.Struct(user)

        if err != nil {
                for _, e := range err.(validator.ValidationErrors) {
                        fmt.Println(e)
                }
        }
        return err
}