package controller

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"net/http"
	"strings"
	"time"

	"github.com/go-playground/validator/v10"
	"github.com/gorilla/mux"
	"github.com/gravitl/netmaker/functions"
	"github.com/gravitl/netmaker/models"
	"github.com/gravitl/netmaker/mongoconn"
	"go.mongodb.org/mongo-driver/bson"
	"go.mongodb.org/mongo-driver/mongo"
	"go.mongodb.org/mongo-driver/mongo/options"
	"golang.org/x/crypto/bcrypt"
)

func userHandlers(r *mux.Router) {

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

//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 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
	}

	jwt, err := VerifyAuthRequest(authRequest)
	if err != nil {
		returnErrorResponse(response, request, formatError(err, "badrequest"))
		return
	}

	if jwt == "" {
		//very unlikely that err is !nil and no jwt returned, but handle it anyways.
		returnErrorResponse(response, request, formatError(errors.New("No token returned"), "internal"))
		return
	}

	var successResponse = models.SuccessResponse{
		Code:    http.StatusOK,
		Message: "W1R3: Device " + authRequest.UserName + " Authorized",
		Response: models.SuccessfulUserLoginResponse{
			AuthToken: jwt,
			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)
}

func VerifyAuthRequest(authRequest models.UserAuthParams) (string, error) {
	var result models.User
	if authRequest.UserName == "" {
		return "", errors.New("Username can't be empty")
	} else if authRequest.Password == "" {
		return "", errors.New("Password can't be empty")
	}
	//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 {
		return "", errors.New("User " + authRequest.UserName + " not found")
	}
	// This is a a useless test as cannot create user that is not an an admin
	//if !result.IsAdmin {
	//	return "", errors.New("User is not an admin")
	//}

	//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 {
		return "", errors.New("Wrong Password")
	}

	//Create a new JWT for the node
	tokenString, _ := functions.CreateUserJWT(authRequest.UserName, result.Networks,  result.IsAdmin)
	return tokenString, nil
}

//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 authNetwork 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) {
		w.Header().Set("Content-Type", "application/json")
	        var params = mux.Vars(r)

		//get the auth token
		bearerToken := r.Header.Get("Authorization")
		err := ValidateUserToken(bearerToken, params["username"], false)
		if err != nil {
			returnErrorResponse(w, r, formatError(err, "unauthorized"))
			return
		}
		next.ServeHTTP(w, r)
	}
}

func authorizeUserAdm(next http.Handler) http.HandlerFunc {
        return func(w http.ResponseWriter, r *http.Request) {
                w.Header().Set("Content-Type", "application/json")
	        var params = mux.Vars(r)

                //get the auth token
                bearerToken := r.Header.Get("Authorization")
                err := ValidateUserToken(bearerToken, params["username"], true)
                if err != nil {
                        returnErrorResponse(w, r, formatError(err, "unauthorized"))
                        return
                }
                next.ServeHTTP(w, r)
        }
}


func ValidateUserToken(token string, user string, adminonly bool) error {
	var tokenSplit = strings.Split(token, " ")

	//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 {
		return errors.New("Missing Auth Token.")
	}

	username, _, isadmin, err := functions.VerifyUserToken(authToken)
	if err != nil {
		return errors.New("Error Verifying Auth Token")
	}
	isAuthorized := false
	if adminonly {
		isAuthorized = isadmin
	} else {
		isAuthorized = username == user || isadmin
	}
	if !isAuthorized {
		return errors.New("You are unauthorized to access this endpoint.")
	}

	return nil
}

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, nil
		}
		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
}

func GetUsers() ([]models.User, error) {

        var users []models.User

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

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

        cur, err := collection.Find(ctx, bson.M{}, options.Find().SetProjection(bson.M{"_id": 0}))

        if err != nil {
                return users, err
        }

        defer cancel()

        for cur.Next(context.TODO()) {

                var user models.User
                err := cur.Decode(&user)
                if err != nil {
                        return users, err
                }

                // add network our array
                users = append(users, user)
        }

        if err := cur.Err(); err != nil {
                return users, err
        }

        return users, 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 {
		returnErrorResponse(w, r, formatError(err, "internal"))
		return
	}

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

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

        users, err := GetUsers()

        if err != nil {
                returnErrorResponse(w, r, formatError(err, "internal"))
                return
        }

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


func CreateUser(user models.User) (models.User, error) {
	hasadmin, err := HasAdmin()
	if hasadmin && user.IsAdmin {
		return models.User{}, errors.New("Admin already Exists")
	}
	err = ValidateUser("create", user)
	if err != nil {
		return models.User{}, err
	}

	//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.Networks, 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.
	_, err = collection.InsertOne(ctx, user)
	defer cancel()

	return user, err
}

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

	var admin models.User
	//get node from body of request
	_ = json.NewDecoder(r.Body).Decode(&admin)
        admin.IsAdmin = true
	admin, err := CreateUser(admin)

	if err != nil {
		returnErrorResponse(w, r, formatError(err, "badrequest"))
		return
	}

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

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

        var user models.User
        //get node from body of request
        _ = json.NewDecoder(r.Body).Decode(&user)

        user, err := CreateUser(user)

        if err != nil {
                returnErrorResponse(w, r, formatError(err, "badrequest"))
                return
        }

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


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

	err := ValidateUser("update", userchange)
	if err != nil {
		return models.User{}, err
	}

	queryUser := user.UserName

	if userchange.UserName != "" {
		user.UserName = userchange.UserName
	}
        if len(userchange.Networks) > 0  {
                user.Networks = userchange.Networks
        }
	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},
			{"networks", user.Networks},
			{"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 user, 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 {
		returnErrorResponse(w, r, formatError(err, "internal"))
		return
	}
	var userchange models.User
	// we decode our body request params
	err = json.NewDecoder(r.Body).Decode(&userchange)
	if err != nil {
		returnErrorResponse(w, r, formatError(err, "internal"))
		return
	}
	userchange.Networks = nil
	user, err = UpdateUser(userchange, user)
	if err != nil {
		returnErrorResponse(w, r, formatError(err, "badrequest"))
		return
	}
	json.NewEncoder(w).Encode(user)
}

func updateUserAdm(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 {
                returnErrorResponse(w, r, formatError(err, "internal"))
                return
        }
        var userchange models.User
        // we decode our body request params
        err = json.NewDecoder(r.Body).Decode(&userchange)
        if err != nil {
                returnErrorResponse(w, r, formatError(err, "internal"))
                return
        }
	user, err = UpdateUser(userchange, user)
        if err != nil {
                returnErrorResponse(w, r, formatError(err, "badrequest"))
                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 {
		returnErrorResponse(w, r, formatError(err, "internal"))
		return
	} else if !success {
		returnErrorResponse(w, r, formatError(errors.New("Delete unsuccessful."), "badrequest"))
		return
	}

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

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

	v := validator.New()
	err := v.Struct(user)

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