main.go

package main

import (
	"bufio"
	"flag"
	"fmt"
	"os"
	"strings"
	"sync"

	"github.com/gautamrege/gochat/api"
)

const helpStr = `Commands
1. /users :- Get list of live users
2. @{user} message :- send message to specified user
3. /exit :- Exit the Chat
4. /all :- Send message to all the users [TODO]`

var (
	name      = flag.String("name", "", "The name you want to chat as")
	port      = flag.Int("port", 12345, "Port that your server will run on.")
	host      = flag.String("host", "", "Host IP that your server is running on.")
	preload   = flag.Bool("preload", false, "Preload users from users.json")
	stdReader = bufio.NewReader(os.Stdin)
)

var MyHandle api.Handle
var USERS = PeerHandleMapSync{
	PeerHandleMap: make(map[string]api.Handle),
}

func main() {
	// Parse flags for host, port and name
	flag.Parse()

	// TODO-WORKSHOP-STEP-1: If the name and host are empty, return an error with help message

	// TODO-WORKSHOP-STEP-2: Initialize global MyHandle of type api.Handle

	var wg sync.WaitGroup
	wg.Add(3)

	if *preload {
		preloadUsers()
	} else {
		// Broadcast for is-alive on 33333 with own UserHandle.
		go broadcastOwnHandle(&wg)

		// Listener for is-alive broadcasts from other hosts. Listening on 33333
		go listenAndRegisterUsers(&wg)
	}

	// gRPC listener
	go startServer(&wg)

	for {
		fmt.Printf("> ")
		textInput, _ := stdReader.ReadString('\n')
		// convert CRLF to LF
		textInput = strings.Replace(textInput, "\n", "", -1)
		parseAndExecInput(textInput)
	}

	wg.Wait()
}

// Handle the input chat messages as well as help commands
func parseAndExecInput(input string) {
	// Split the line into 2 tokens (cmd and message)
	tokens := strings.SplitN(input, " ", 2)
	cmd := tokens[0]

	switch {
	case cmd == "":
		break
	case cmd == "?":
		fmt.Printf(helpStr)
		break
	case strings.ToLower(cmd) == "/users":
		fmt.Println(USERS)
		break
	case strings.ToLower(cmd) == "/exit":
		os.Exit(1)
		break
	case cmd[0] == '@':
		// TODO-WORKSHOP-STEP-9: Write code to sendChat. Example
		// "@gautam hello golang" should send a message to handle with name "gautam" and message "hello golang"
		// Invoke sendChat to send the  message
		break
	case strings.ToLower(cmd) == "/help":
		fmt.Println(helpStr)
		break
	default:
		fmt.Println(helpStr)
	}
}