package main

import (
	"encoding/json"
	"fmt"
	"log"
	"net"
)

const (
	MESSAGE      = "message"
	AUTHENTICATE = "authenticate"
	RENAME       = "rename"
)

const (
	SUCCESS = "success"
	FAILURE = "failure"
)

type Message struct {
	Type string
	Data string
	User string
}

type Response struct {
	Status string
	Data   string
}

func parseMessage(data []byte) Message {
	var m Message
	// TODO(andrew): Добавить обработку ошибок
	json.Unmarshal(data, &m)
	return m
}

func handleConnection(conn net.Conn) {
	defer conn.Close()

	maxAuthAttempts := 5
	authAttempts := 0
	authenticated := false
	buf := make([]byte, 4096)

	for {
		if authAttempts >= maxAuthAttempts {
			resp, _ := json.Marshal(Response{
				Status: FAILURE,
				Data:   "Превышено количество неавторизованных запросов",
			})
			_, _ = conn.Write(resp)
			break
		}

		readLen, err := conn.Read(buf)
		if err != nil {
			break
		}

		message := parseMessage(buf[:readLen])
		if message.Type == AUTHENTICATE {
			// TODO(andrew): Добавить процесс аутентификации
			if true {
				authenticated = true
			}
		}

		if !authenticated {
			resp, _ := json.Marshal(Response{
				Status: FAILURE,
				Data:   "Для работы с сервером необходима аутентификация",
			})
			_, err = conn.Write(resp)
			if err != nil {
				conn.Close()
				break
			} else {
				authAttempts += 1
				continue
			}
		}

		if message.Data == "exit" {
			break
		}

		fmt.Println(message.Data)
		resp, _ := json.Marshal(Response{
			Status: SUCCESS,
			Data:   "some data",
		})
		_, err = conn.Write(resp)
		if err != nil {
			err = conn.Close()
			break
		}
	}
}

func main() {
	sock, err := net.Listen("tcp", "localhost:8080")
	handleError(err)

	for {
		conn, err := sock.Accept()
		if err == nil {
			go handleConnection(conn)
		} else {
			break
		}
	}
}

func handleError(err error) {
	if err != nil {
		log.Fatal(err)
	}
}