feat: add terminal UI with Bubble Tea v2 (#12)

* feat: add terminal UI with Bubble Tea v2

Implement `yantra tui` — a polished terminal chat UI that connects to
the gateway server via WebSocket. The TUI starts the gateway in-process
(goroutine), then renders streaming responses, tool progress, and
session management in an alternate-screen Bubble Tea app.

New files in internal/tui/:
- app.go: root Model composing header, chat viewport, input, status bar
- chat.go: message rendering with streaming cursor, tool spinners, glamour markdown
- client.go: WebSocket client with reconnect and exponential backoff
- commands.go: slash command parser (/new, /sessions, /switch, /cancel, /clear, /help, /quit)
- input.go: textarea wrapper with Enter-to-send and dynamic height
- markdown.go: glamour wrapper for completed assistant messages
- messages.go: tea.Msg types bridging server frames into Bubble Tea
- styles.go: adaptive dark/light lipgloss styles with purple branding

Dependencies: bubbletea v2, bubbles v2, lipgloss v2, glamour.


* fix: address PR review — nil program, conn race, reconnect, health timeout, DB leak

1. nil Program: Connect() no longer takes a program arg; AttachProgram()
   wires it before Run(). readLoop now receives frames correctly.
2. conn race: readLoop takes the conn as a local argument so it never
   races with Close/Reconnect mutating c.conn. sessionID reads also
   protected by mutex.
3. Reconnect never triggered: DisconnectedMsg handler now returns
   a.client.Reconnect() cmd for automatic exponential-backoff reconnect.
4. Health poll timeout: waitForHealth uses http.Client{Timeout: 1s} so a
   stalled request can't block past the overall deadline.
5. DB leak: startGatewayInProcess returns a cleanup func that closes all
   opened SQLite databases; runTUI defers it.


* fix: Gemini array items bug + TUI visual redesign

- Fix Gemini provider: jsonPropToGeminiSchema now parses the 'items'
  field for array-type parameters, fixing 400 errors with tools like
  memory_save that have array properties (tags).

- Redesign TUI visuals for a cleaner, modern look:
  - Replace heavy purple header bar with subtle bordered title line
  - Use ❯/◆ indicators for user/assistant messages instead of labels
  - Indented message bodies with 4-space padding
  - Softer color palette (Monokai-inspired: soft purple, cyan, yellow)
  - Streaming shows 'thinking...' placeholder then text with ▍ cursor
  - Tool progress: spinner + yellow name + dimmed status
  - Errors: ✗ prefix with pink-red text
  - Remove mouse capture so text selection/copy works natively
  - Minimal status bar with accent-colored session ID


* fix: detect dark mode before tea.Program to prevent ANSI escape leak

Move lipgloss.HasDarkBackground() call to runTUI before creating the
Bubble Tea program. The terminal query response was arriving after
Bubble Tea took over stdin, leaking raw escape sequences into the
textarea input.

Author: hackertron

cmd/yantra/main.go

@@ -4,16 +4,20 @@ import (
 	"context"
 	"fmt"
 	"log/slog"
+	"net/http"
 	"os"
 	"os/signal"
 	"path/filepath"
 	"syscall"
+	"time"
 
+	tea "charm.land/bubbletea/v2"
 	"github.com/hackertron/Yantra/internal/gateway"
 	"github.com/hackertron/Yantra/internal/memory"
 	"github.com/hackertron/Yantra/internal/provider"
 	"github.com/hackertron/Yantra/internal/runtime"
 	"github.com/hackertron/Yantra/internal/tool"
+	"github.com/hackertron/Yantra/internal/tui"
 	"github.com/hackertron/Yantra/internal/types"
 	"github.com/spf13/cobra"
 )
@@ -302,9 +306,160 @@ func runStart(cmd *cobra.Command, args []string) error {
 }
 
 func runTUI(cmd *cobra.Command, args []string) error {
-	fmt.Println("Launching Yantra TUI...")
-	// TODO: implement TUI launch
-	return fmt.Errorf("not yet implemented")
+	cfg, err := types.LoadConfig(configPath)
+	if err != nil {
+		return fmt.Errorf("loading config: %w", err)
+	}
+
+	// Redirect slog to a temp file so logs don't corrupt the TUI.
+	logFile, err := os.CreateTemp("", "yantra-tui-*.log")
+	if err != nil {
+		return fmt.Errorf("creating log file: %w", err)
+	}
+	defer logFile.Close()
+	logger := slog.New(slog.NewTextHandler(logFile, nil))
+
+	// Build the provider label for the header.
+	providerLabel := fmt.Sprintf("%s/%s", cfg.Selection.Provider, cfg.Selection.Model)
+
+	// Start the gateway server in-process.
+	gwCtx, gwCancel := context.WithCancel(cmd.Context())
+	defer gwCancel()
+
+	addr, errCh, gwCleanup, err := startGatewayInProcess(gwCtx, cfg, logger)
+	if err != nil {
+		return fmt.Errorf("starting gateway: %w", err)
+	}
+	defer gwCleanup()
+
+	// Wait for the gateway to be healthy.
+	if err := waitForHealth(addr, 10*time.Second); err != nil {
+		return fmt.Errorf("gateway not ready: %w (check logs: %s)", err, logFile.Name())
+	}
+
+	// Create the TUI client and app.
+	client := tui.NewClient(addr, cfg.Gateway.APIKey)
+	hasDark := tui.DetectDarkMode()
+	app := tui.NewApp(client, providerLabel, version, hasDark)
+
+	p := tea.NewProgram(app)
+	client.AttachProgram(p)
+	if _, err := p.Run(); err != nil {
+		return fmt.Errorf("TUI error: %w", err)
+	}
+
+	// Clean up.
+	client.Close()
+	gwCancel()
+
+	// Drain any gateway error.
+	select {
+	case gwErr := <-errCh:
+		if gwErr != nil {
+			logger.Warn("gateway exited with error", "error", gwErr)
+		}
+	default:
+	}
+
+	fmt.Fprintf(os.Stderr, "Logs written to: %s\n", logFile.Name())
+	return nil
+}
+
+// startGatewayInProcess boots the gateway server in a goroutine.
+// It mirrors the setup in runServe but returns immediately.
+// The returned cleanup function closes any opened databases.
+func startGatewayInProcess(ctx context.Context, cfg *types.YantraConfig, logger *slog.Logger) (addr string, errCh <-chan error, cleanup func(), err error) {
+	p, err := provider.BuildFromConfig(cfg)
+	if err != nil {
+		return "", nil, nil, fmt.Errorf("building provider: %w", err)
+	}
+	p = provider.NewReliable(p, provider.DefaultReliableConfig())
+
+	absWorkspace, err := filepath.Abs(".")
+	if err != nil {
+		return "", nil, nil, fmt.Errorf("resolving workspace: %w", err)
+	}
+
+	var mem types.MemoryRetrieval
+	var sessStore types.SessionStore
+	var closers []func() // DB close functions
+
+	if cfg.Memory.Enabled {
+		dbPath := cfg.Memory.DBPath
+		if dbPath == "" {
+			dbPath = ".yantra/memory.db"
+		}
+		if !filepath.IsAbs(dbPath) {
+			dbPath = filepath.Join(absWorkspace, dbPath)
+		}
+
+		memDB, dbErr := memory.OpenDB(dbPath)
+		if dbErr != nil {
+			logger.Warn("failed to open memory DB, continuing without memory", "error", dbErr)
+		} else {
+			closers = append(closers, func() { memDB.Close() })
+			embedder, embErr := memory.NewEmbeddingBackend(cfg.Memory)
+			if embErr != nil {
+				logger.Warn("failed to create embedding backend", "error", embErr)
+			}
+			mem = memory.NewStore(memDB, embedder, cfg.Memory.Retrieval)
+			sessStore = memory.NewSessionStore(memDB)
+		}
+	}
+
+	if sessStore == nil {
+		sessDB, dbErr := memory.OpenDB(":memory:")
+		if dbErr != nil {
+			return "", nil, nil, fmt.Errorf("opening session DB: %w", dbErr)
+		}
+		closers = append(closers, func() { sessDB.Close() })
+		sessStore = memory.NewSessionStore(sessDB)
+	}
+
+	policy := tool.NewWorkspacePolicy(cfg.Tools.Shell)
+	reg := tool.NewRegistry(policy)
+	if err := tool.RegisterBuiltins(reg, cfg.Tools, mem); err != nil {
+		return "", nil, nil, fmt.Errorf("registering tools: %w", err)
+	}
+
+	addr = cfg.Gateway.Listen
+	if addr == "" {
+		addr = "127.0.0.1:7700"
+	}
+
+	srv := gateway.NewServer(cfg.Gateway, cfg, p, reg, mem, sessStore, absWorkspace, logger)
+
+	ch := make(chan error, 1)
+	go func() {
+		ch <- srv.ListenAndServe(ctx)
+	}()
+
+	cleanupFn := func() {
+		for _, c := range closers {
+			c()
+		}
+	}
+
+	return addr, ch, cleanupFn, nil
+}
+
+// waitForHealth polls the gateway /health endpoint until it responds 200.
+func waitForHealth(addr string, timeout time.Duration) error {
+	deadline := time.Now().Add(timeout)
+	url := fmt.Sprintf("http://%s/health", addr)
+	client := &http.Client{Timeout: time.Second}
+
+	for time.Now().Before(deadline) {
+		resp, err := client.Get(url)
+		if err == nil {
+			resp.Body.Close()
+			if resp.StatusCode == http.StatusOK {
+				return nil
+			}
+		}
+		time.Sleep(100 * time.Millisecond)
+	}
+	return fmt.Errorf("timeout waiting for gateway at %s", addr)
 }
 
 func runServe(cmd *cobra.Command, args []string) error {

go.mod

@@ -3,7 +3,11 @@ module github.com/hackertron/Yantra
 go 1.26
 
 require (
+	charm.land/bubbles/v2 v2.0.0
+	charm.land/bubbletea/v2 v2.0.1
+	charm.land/lipgloss/v2 v2.0.0
 	github.com/anthropics/anthropic-sdk-go v1.26.0
+	github.com/charmbracelet/glamour v0.10.0
 	github.com/gorilla/websocket v1.5.3
 	github.com/knadh/koanf/parsers/toml v0.1.0
 	github.com/knadh/koanf/providers/env v1.1.0
@@ -20,6 +24,22 @@ require (
 	cloud.google.com/go v0.116.0 // indirect
 	cloud.google.com/go/auth v0.9.3 // indirect
 	cloud.google.com/go/compute/metadata v0.5.0 // indirect
+	github.com/alecthomas/chroma/v2 v2.14.0 // indirect
+	github.com/atotto/clipboard v0.1.4 // indirect
+	github.com/aymanbagabas/go-osc52/v2 v2.0.1 // indirect
+	github.com/aymerick/douceur v0.2.0 // indirect
+	github.com/charmbracelet/colorprofile v0.4.2 // indirect
+	github.com/charmbracelet/lipgloss v1.1.1-0.20250404203927-76690c660834 // indirect
+	github.com/charmbracelet/ultraviolet v0.0.0-20260205113103-524a6607adb8 // indirect
+	github.com/charmbracelet/x/ansi v0.11.6 // indirect
+	github.com/charmbracelet/x/cellbuf v0.0.15 // indirect
+	github.com/charmbracelet/x/exp/slice v0.0.0-20250327172914-2fdc97757edf // indirect
+	github.com/charmbracelet/x/term v0.2.2 // indirect
+	github.com/charmbracelet/x/termios v0.1.1 // indirect
+	github.com/charmbracelet/x/windows v0.2.2 // indirect
+	github.com/clipperhouse/displaywidth v0.11.0 // indirect
+	github.com/clipperhouse/uax29/v2 v2.7.0 // indirect
+	github.com/dlclark/regexp2 v1.11.0 // indirect
 	github.com/dustin/go-humanize v1.0.1 // indirect
 	github.com/fatih/structs v1.1.0 // indirect
 	github.com/fsnotify/fsnotify v1.9.0 // indirect
@@ -29,25 +49,37 @@ require (
 	github.com/google/s2a-go v0.1.8 // indirect
 	github.com/google/uuid v1.6.0 // indirect
 	github.com/googleapis/enterprise-certificate-proxy v0.3.4 // indirect
+	github.com/gorilla/css v1.0.1 // indirect
 	github.com/inconshreveable/mousetrap v1.1.0 // indirect
 	github.com/knadh/koanf/maps v0.1.2 // indirect
+	github.com/lucasb-eyer/go-colorful v1.3.0 // indirect
 	github.com/mattn/go-isatty v0.0.20 // indirect
+	github.com/mattn/go-runewidth v0.0.20 // indirect
+	github.com/microcosm-cc/bluemonday v1.0.27 // indirect
 	github.com/mitchellh/copystructure v1.2.0 // indirect
 	github.com/mitchellh/reflectwalk v1.0.2 // indirect
+	github.com/muesli/cancelreader v0.2.2 // indirect
+	github.com/muesli/reflow v0.3.0 // indirect
+	github.com/muesli/termenv v0.16.0 // indirect
 	github.com/ncruces/go-strftime v1.0.0 // indirect
 	github.com/pelletier/go-toml v1.9.5 // indirect
 	github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec // indirect
+	github.com/rivo/uniseg v0.4.7 // indirect
 	github.com/spf13/pflag v1.0.9 // indirect
 	github.com/tidwall/gjson v1.18.0 // indirect
 	github.com/tidwall/match v1.1.1 // indirect
 	github.com/tidwall/pretty v1.2.1 // indirect
 	github.com/tidwall/sjson v1.2.5 // indirect
+	github.com/xo/terminfo v0.0.0-20220910002029-abceb7e1c41e // indirect
+	github.com/yuin/goldmark v1.7.8 // indirect
+	github.com/yuin/goldmark-emoji v1.0.5 // indirect
 	go.opencensus.io v0.24.0 // indirect
 	golang.org/x/crypto v0.40.0 // indirect
 	golang.org/x/exp v0.0.0-20251023183803-a4bb9ffd2546 // indirect
 	golang.org/x/net v0.41.0 // indirect
-	golang.org/x/sync v0.17.0 // indirect
-	golang.org/x/sys v0.37.0 // indirect
+	golang.org/x/sync v0.19.0 // indirect
+	golang.org/x/sys v0.41.0 // indirect
+	golang.org/x/term v0.33.0 // indirect
 	golang.org/x/text v0.27.0 // indirect
 	google.golang.org/genproto/googleapis/rpc v0.0.0-20240903143218-8af14fe29dc1 // indirect
 	google.golang.org/grpc v1.66.2 // indirect