feat: lobby join-by-code with J key and 4-char input

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

ui/lobby_view.go

@@ -2,16 +2,19 @@ package ui
 
 import (
 	"fmt"
+	"strings"
 
 	"github.com/charmbracelet/lipgloss"
 )
 
 type lobbyState struct {
-	rooms    []roomInfo
-	input    string
-	cursor   int
-	creating bool
-	roomName string
+	rooms     []roomInfo
+	input     string
+	cursor    int
+	creating  bool
+	roomName  string
+	joining   bool
+	codeInput string
 }
 
 type roomInfo struct {
@@ -31,7 +34,7 @@ func renderLobby(state lobbyState, width, height int) string {
 		Padding(0, 1)
 
 	header := headerStyle.Render("── Lobby ──")
-	menu := "[C] Create Room  [J] Join by Code  [Q] Back"
+	menu := "[C] Create Room  [J] Join by Code  [Up/Down] Select  [Enter] Join  [Q] Back"
 
 	roomList := ""
 	for i, r := range state.rooms {
@@ -45,6 +48,10 @@ func renderLobby(state lobbyState, width, height int) string {
 	if roomList == "" {
 		roomList = "  No rooms available. Create one!"
 	}
+	if state.joining {
+		inputStr := state.codeInput + strings.Repeat("_", 4-len(state.codeInput))
+		roomList += fmt.Sprintf("\n  Enter room code: [%s]  (Esc to cancel)\n", inputStr)
+	}
 
 	return lipgloss.JoinVertical(lipgloss.Left,
 		header,

ui/model.go

@@ -38,12 +38,13 @@ type Model struct {
 	store *store.DB
 
 	// Per-session state
-	session     *game.GameSession
-	roomCode    string
-	gameState   game.GameState
-	lobbyState  lobbyState
-	classState  classSelectState
-	inputBuffer string
+	session      *game.GameSession
+	roomCode     string
+	gameState    game.GameState
+	lobbyState   lobbyState
+	classState   classSelectState
+	inputBuffer  string
+	targetCursor int
 }
 
 func NewModel(width, height int, fingerprint string, lobby *game.Lobby, db *store.DB) Model {
@@ -113,7 +114,7 @@ func (m Model) View() string {
 	case screenClassSelect:
 		return renderClassSelect(m.classState, m.width, m.height)
 	case screenGame:
-		return renderGame(m.gameState, m.width, m.height)
+		return renderGame(m.gameState, m.width, m.height, m.targetCursor)
 	case screenShop:
 		return renderShop(m.gameState, m.width, m.height)
 	case screenResult:
@@ -179,6 +180,29 @@ func (m Model) updateTitle(msg tea.Msg) (tea.Model, tea.Cmd) {
 
 func (m Model) updateLobby(msg tea.Msg) (tea.Model, tea.Cmd) {
 	if key, ok := msg.(tea.KeyMsg); ok {
+		// Join-by-code input mode
+		if m.lobbyState.joining {
+			if isEnter(key) && len(m.lobbyState.codeInput) == 4 {
+				if m.lobby != nil {
+					if err := m.lobby.JoinRoom(m.lobbyState.codeInput, m.playerName); err == nil {
+						m.roomCode = m.lobbyState.codeInput
+						m.screen = screenClassSelect
+					}
+				}
+				m.lobbyState.joining = false
+				m.lobbyState.codeInput = ""
+			} else if isKey(key, "esc") || key.Type == tea.KeyEsc {
+				m.lobbyState.joining = false
+				m.lobbyState.codeInput = ""
+			} else if key.Type == tea.KeyBackspace && len(m.lobbyState.codeInput) > 0 {
+				m.lobbyState.codeInput = m.lobbyState.codeInput[:len(m.lobbyState.codeInput)-1]
+			} else if len(key.Runes) == 1 && len(m.lobbyState.codeInput) < 4 {
+				ch := strings.ToUpper(string(key.Runes))
+				m.lobbyState.codeInput += ch
+			}
+			return m, nil
+		}
+		// Normal lobby key handling
 		if isKey(key, "c") {
 			if m.lobby != nil {
 				code := m.lobby.CreateRoom(m.playerName + "'s Room")
@@ -186,6 +210,9 @@ func (m Model) updateLobby(msg tea.Msg) (tea.Model, tea.Cmd) {
 				m.roomCode = code
 				m.screen = screenClassSelect
 			}
+		} else if isKey(key, "j") {
+			m.lobbyState.joining = true
+			m.lobbyState.codeInput = ""
 		} else if isUp(key) {
 			if m.lobbyState.cursor > 0 {
 				m.lobbyState.cursor--
@@ -306,12 +333,18 @@ func (m Model) updateGame(msg tea.Msg) (tea.Model, tea.Cmd) {
 			if isPlayerDead {
 				return m, m.pollState()
 			}
+			if isKey(key, "tab") || key.Type == tea.KeyTab {
+				if len(m.gameState.Monsters) > 0 {
+					m.targetCursor = (m.targetCursor + 1) % len(m.gameState.Monsters)
+				}
+				return m, m.pollState()
+			}
 			if m.session != nil {
 				switch key.String() {
 				case "1":
-					m.session.SubmitAction(m.playerName, game.PlayerAction{Type: game.ActionAttack, TargetIdx: 0})
+					m.session.SubmitAction(m.playerName, game.PlayerAction{Type: game.ActionAttack, TargetIdx: m.targetCursor})
 				case "2":
-					m.session.SubmitAction(m.playerName, game.PlayerAction{Type: game.ActionSkill, TargetIdx: 0})
+					m.session.SubmitAction(m.playerName, game.PlayerAction{Type: game.ActionSkill, TargetIdx: m.targetCursor})
 				case "3":
 					m.session.SubmitAction(m.playerName, game.PlayerAction{Type: game.ActionItem})
 				case "4":