TUI: create and interact with shared terminal tabs

go.mod

@@ -7,6 +7,7 @@ require (
 	github.com/charmbracelet/bubbletea v1.3.10
 	github.com/charmbracelet/lipgloss v1.1.0
 	github.com/charmbracelet/x/ansi v0.11.8
+	github.com/charmbracelet/x/term v0.2.2
 	github.com/coder/websocket v1.8.15
 	github.com/creack/pty v1.1.24
 	github.com/hashicorp/yamux v0.1.2
@@ -19,7 +20,6 @@ require (
 	github.com/aymanbagabas/go-osc52/v2 v2.0.1 // indirect
 	github.com/charmbracelet/colorprofile v0.4.1 // indirect
 	github.com/charmbracelet/x/cellbuf v0.0.15 // indirect
-	github.com/charmbracelet/x/term v0.2.2 // indirect
 	github.com/clipperhouse/displaywidth v0.11.0 // indirect
 	github.com/clipperhouse/uax29/v2 v2.7.0 // indirect
 	github.com/erikgeiser/coninput v0.0.0-20211004153227-1c3628e74d0f // indirect

internal/system/system.go

@@ -6,7 +6,10 @@ import (
 	"bytes"
 	"context"
 	"crypto/ecdh"
+	"crypto/rand"
+	"encoding/base64"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io"
 	"net"
@@ -19,6 +22,17 @@ import (
 	"github.com/nicodes/ormos/relay"
 )
 
+var terminalSessionRandom = rand.Read
+
+const terminalSessionCreateAttempts = 8
+
+type relayHTTPError struct {
+	statusCode int
+	message    string
+}
+
+func (e *relayHTTPError) Error() string { return e.message }
+
 // PortStatus is one configured exposed port for this system, with whether it
 // is currently being served (a local process is listening on it).
 type PortStatus struct {
@@ -428,9 +442,9 @@ func (d *system) relayDo(ctx context.Context, method, path string, body any) ([]
 			Error string `json:"error"`
 		}
 		if json.Unmarshal(data, &e) == nil && e.Error != "" {
-			return nil, fmt.Errorf("%s", e.Error)
+			return nil, &relayHTTPError{statusCode: resp.StatusCode, message: e.Error}
 		}
-		return nil, fmt.Errorf("relay returned %s", resp.Status)
+		return nil, &relayHTTPError{statusCode: resp.StatusCode, message: fmt.Sprintf("relay returned %s", resp.Status)}
 	}
 	return data, nil
 }
@@ -469,6 +483,58 @@ func (d *system) fetchProjects(ctx context.Context) ([]relay.ProjectInfo, error)
 	return out.Projects, nil
 }
 
+// fetchTerminalSessions lists the persisted terminal tabs for this system.
+func (d *system) fetchTerminalSessions(ctx context.Context) ([]relay.TerminalSessionInfo, error) {
+	data, err := d.relayDo(ctx, http.MethodGet, "/system/terminal-sessions", nil)
+	if err != nil {
+		return nil, err
+	}
+	var out struct {
+		Sessions []relay.TerminalSessionInfo `json:"sessions"`
+	}
+	if err := json.Unmarshal(data, &out); err != nil {
+		return nil, err
+	}
+	return out.Sessions, nil
+}
+
+// createTerminalSession persists a new terminal tab before any local PTY is
+// attached. A transport failure is deliberately not retried: the relay may
+// have committed the record before the connection failed. Only an explicit
+// duplicate response proves that generating a fresh id is safe.
+func (d *system) createTerminalSession(ctx context.Context, projectID string) (string, error) {
+	for range terminalSessionCreateAttempts {
+		sessionID, err := newTerminalSessionID()
+		if err != nil {
+			return "", fmt.Errorf("generate terminal session id: %w", err)
+		}
+		_, err = d.relayDo(ctx, http.MethodPost, "/system/terminal-sessions", struct {
+			ProjectID string `json:"project_id"`
+			SessionID string `json:"session_id"`
+		}{ProjectID: projectID, SessionID: sessionID})
+		if err == nil {
+			return sessionID, nil
+		}
+		var httpErr *relayHTTPError
+		if !errors.As(err, &httpErr) || httpErr.statusCode != http.StatusConflict {
+			return "", err
+		}
+	}
+	return "", fmt.Errorf("could not allocate a unique terminal session id")
+}
+
+func newTerminalSessionID() (string, error) {
+	var raw [18]byte // 144 random bits; base64url encodes without punctuation or padding.
+	n, err := terminalSessionRandom(raw[:])
+	if err != nil {
+		return "", err
+	}
+	if n != len(raw) {
+		return "", io.ErrUnexpectedEOF
+	}
+	return base64.RawURLEncoding.EncodeToString(raw[:]), nil
+}
+
 // createProject creates a project and returns nothing but an error.
 func (d *system) createProject(ctx context.Context, name, rootDir string) error {
 	_, err := d.relayDo(ctx, http.MethodPost, "/system/projects",