go-nwaku/examples/chat2/ui.go

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2021-04-04 17:06:17 +00:00
package main
import (
"chat2/pb"
"fmt"
"io"
"strings"
"time"
"github.com/gdamore/tcell/v2"
"github.com/rivo/tview"
"github.com/status-im/go-waku/waku/v2/node"
)
// ChatUI is a Text User Interface (TUI) for a ChatRoom.
// The Run method will draw the UI to the terminal in "fullscreen"
// mode. You can quit with Ctrl-C, or by typing "/quit" into the
// chat prompt.
type ChatUI struct {
app *tview.Application
chat *Chat
msgW io.Writer
inputCh chan string
doneCh chan struct{}
}
// NewChatUI returns a new ChatUI struct that controls the text UI.
// It won't actually do anything until you call Run().
func NewChatUI(chat *Chat) *ChatUI {
chatUI := new(ChatUI)
app := tview.NewApplication()
// make a NewChatUI text view to contain our chat messages
msgBox := tview.NewTextView()
msgBox.SetDynamicColors(true)
msgBox.SetBorder(true)
msgBox.SetTitle("chat2 example")
// text views are io.Writers, but they don't automatically refresh.
// this sets a change handler to force the app to redraw when we get
// new messages to display.
msgBox.SetChangedFunc(func() {
app.Draw()
})
// an input field for typing messages into
inputCh := make(chan string, 32)
input := tview.NewInputField().
SetLabel(chat.nick + " > ").
SetFieldWidth(0).
SetFieldBackgroundColor(tcell.ColorBlack)
// the done func is called when the user hits enter, or tabs out of the field
input.SetDoneFunc(func(key tcell.Key) {
if key != tcell.KeyEnter {
// we don't want to do anything if they just tabbed away
return
}
line := input.GetText()
if len(line) == 0 {
// ignore blank lines
return
}
input.SetText("")
// bail if requested
if line == "/quit" {
app.Stop()
return
}
// add peer
if strings.HasPrefix(line, "/connect ") {
peer := strings.TrimPrefix(line, "/connect ")
go func(peer string) {
chatUI.displayMessage("Connecting to peer...")
err := chat.node.DialPeer(peer)
if err != nil {
chatUI.displayMessage(err.Error())
} else {
chatUI.displayMessage("Peer connected succesfully")
}
}(peer)
return
}
// list peers
if line == "/peers" {
peers := chat.node.PubSub().ListPeers(string(node.DefaultWakuTopic))
if len(peers) == 0 {
chatUI.displayMessage("No peers available")
}
for _, p := range peers {
chatUI.displayMessage("- " + p.Pretty())
}
return
}
// change nick
if strings.HasPrefix(line, "/nick ") {
newNick := strings.TrimSpace(strings.TrimPrefix(line, "/nick "))
chat.nick = newNick
input.SetLabel(chat.nick + " > ")
return
}
if line == "/help" {
chatUI.displayMessage(`
Available commands:
/connect multiaddress - dials a node adding it to the list of connected peers
/peers - list of peers connected to this node
/nick newNick - change the user's nickname
/quit - closes the app
`)
return
}
// send the line onto the input chan and reset the field text
inputCh <- line
})
chatPanel := tview.NewFlex().
AddItem(msgBox, 0, 1, false)
// flex is a vertical box with the chatPanel on top and the input field at the bottom.
flex := tview.NewFlex().
SetDirection(tview.FlexRow).
AddItem(chatPanel, 0, 1, false).
AddItem(input, 1, 1, true)
app.SetRoot(flex, true)
chatUI.app = app
chatUI.msgW = msgBox
chatUI.chat = chat
chatUI.inputCh = inputCh
chatUI.doneCh = make(chan struct{}, 1)
for _, addr := range chat.node.ListenAddresses() {
chatUI.displayMessage(fmt.Sprintf("Listening on %s", addr))
}
return chatUI
}
// Run starts the chat event loop in the background, then starts
// the event loop for the text UI.
func (ui *ChatUI) Run() error {
ui.displayMessage("\nWelcome, " + ui.chat.nick)
ui.displayMessage("type /help to see available commands \n")
go ui.handleEvents()
defer ui.end()
return ui.app.Run()
}
// end signals the event loop to exit gracefully
func (ui *ChatUI) end() {
ui.doneCh <- struct{}{}
}
// displayChatMessage writes a ChatMessage from the room to the message window,
// with the sender's nick highlighted in green.
func (ui *ChatUI) displayChatMessage(cm *pb.Chat2Message) {
t := time.Unix(int64(cm.Timestamp), 0)
prompt := withColor("green", fmt.Sprintf("<%s> %s:", t.Format("Jan 02, 15:04"), cm.Nick))
fmt.Fprintf(ui.msgW, "%s %s\n", prompt, cm.Payload)
}
// displayMessage writes a blue message to output
func (ui *ChatUI) displayMessage(msg string) {
fmt.Fprintf(ui.msgW, "%s\n", withColor("grey", msg))
}
// handleEvents runs an event loop that sends user input to the chat room
// and displays messages received from the chat room. It also periodically
// refreshes the list of peers in the UI.
func (ui *ChatUI) handleEvents() {
for {
select {
case input := <-ui.inputCh:
err := ui.chat.Publish(input)
if err != nil {
printErr("publish error: %s", err)
}
case m := <-ui.chat.Messages:
// when we receive a message from the chat room, print it to the message window
ui.displayChatMessage(m)
case <-ui.chat.ctx.Done():
return
case <-ui.doneCh:
return
}
}
}
// withColor wraps a string with color tags for display in the messages text box.
func withColor(color, msg string) string {
return fmt.Sprintf("[%s]%s[-]", color, msg)
}