manager.go

package main

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

	"github.com/gorilla/websocket"
)

var (
	webSocketUpgrader = websocket.Upgrader{
		CheckOrigin:     checkOrigin,
		ReadBufferSize:  1024,
		WriteBufferSize: 1024,
	}
)

type Manager struct {
	client ClientList
	sync.RWMutex
	otps     RetentionMap
	handlers map[string]EventHandler
}

func NewManager(ctx context.Context) *Manager {
	return &Manager{
		client:   make(ClientList),
		handlers: make(map[string]EventHandler),
		otps:     NewRetentionMap(ctx, 5*time.Second),
	}
}

func (m *Manager) setupEventHandlers() {
	m.handlers[EventSendMessage] = SendMessage
}
func SendMessage(event Event, c *Client) error {
	fmt.Println(event)
	message, err := event.Payload.MarshalJSON()
	if err != nil {
		log.Println(err)
	}
	c.connection.WriteMessage(websocket.TextMessage, message)
	return nil
}
func (m *Manager) routeEvent(event Event, c *Client) error {
	if handler, ok := m.handlers[event.Type]; ok {
		if err := handler(event, c); err != nil {
			return err
		}
		return nil
	} else {
		return errors.New("there is no such event")
	}
}
func (m *Manager) serveWs(w http.ResponseWriter, r *http.Request) {
	otp := r.URL.Query().Get("otp")
	if otp == "" {
		w.WriteHeader(http.StatusUnauthorized)
		return
	}
	if !m.otps.VerifyOTP(otp) {
		w.WriteHeader(http.StatusUnauthorized)
		return
	}

	log.Println("New Connection")
	//Upgrade Regular HTTP to Websocket
	conn, err := webSocketUpgrader.Upgrade(w, r, nil)
	if err != nil {
		log.Println(err)
		return
	}
	client := NewClient(conn, m)
	m.addClient(client)

	//start client messages
	go client.readMessages()
	go client.writeMessages()
}

func (m *Manager) loginHandler(w http.ResponseWriter, r *http.Request) {
	type userLoginRequest struct {
		UserName string `json:"username"`
		Password string `json:"password"`
	}
	var req userLoginRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)
	}
	if req.UserName == "vacaramin" && req.Password == "password" {
		type response struct {
			OTP string `json:"otp"`
		}
		otp := m.otps.NewOTP()
		resp := response{
			OTP: otp.Key,
		}
		data, err := json.Marshal(resp)
		if err != nil {
			log.Println(err)
		}
		w.WriteHeader(http.StatusOK)
		w.Write(data)
		return
	}
	w.WriteHeader(http.StatusUnauthorized)
}

func (m *Manager) addClient(client *Client) {
	m.Lock()
	defer m.Unlock()
	m.client[client] = true
}

func (m *Manager) removeClient(client *Client) {
	m.Lock()
	defer m.Unlock()
	if _, ok := m.client[client]; ok {
		client.connection.Close()
		delete(m.client, client)
	}
	m.client[client] = false
}
func checkOrigin(r *http.Request) bool {
	origin := r.Header.Get("Origin")
	switch origin {
	case "http://localhost:8080":
		return true
	default:
		return false
	}
}