Add offline-first task-master TUI with tickets, board lists, and undo.

Charm-based CLI with JSON persistence, status/list filters, external editor editing, command-history undo/redo, and glamour markdown without AutoStyle OSC hangs.

Co-authored-by: Cursor <cursoragent@cursor.com>

internal/command/executor.go

@@ -0,0 +1,124 @@
+package command
+
+import (
+	"context"
+	"fmt"
+	"sync"
+)
+
+// Executor runs commands and supports undo/redo of successful ones.
+type Executor interface {
+	Do(cmd Command) error
+	Undo() error
+	Redo() error
+	CanUndo() bool
+	CanRedo() bool
+	LastUndoName() string
+	LastRedoName() string
+}
+
+// History is an in-memory undo/redo stack for Command values.
+type History struct {
+	mu    sync.Mutex
+	undoS []Command
+	redoS []Command
+}
+
+// NewHistory creates an empty command history.
+func NewHistory() *History {
+	return &History{}
+}
+
+// Do executes cmd and pushes it onto the undo stack. The redo stack is cleared.
+func (h *History) Do(cmd Command) error {
+	if err := cmd.Execute(context.Background()); err != nil {
+		return err
+	}
+	h.mu.Lock()
+	defer h.mu.Unlock()
+	h.undoS = append(h.undoS, cmd)
+	h.redoS = nil
+	return nil
+}
+
+// Undo reverses the last successful command.
+func (h *History) Undo() error {
+	h.mu.Lock()
+	if len(h.undoS) == 0 {
+		h.mu.Unlock()
+		return fmt.Errorf("nothing to undo")
+	}
+	cmd := h.undoS[len(h.undoS)-1]
+	h.undoS = h.undoS[:len(h.undoS)-1]
+	h.mu.Unlock()
+
+	if err := cmd.Undo(context.Background()); err != nil {
+		h.mu.Lock()
+		h.undoS = append(h.undoS, cmd)
+		h.mu.Unlock()
+		return err
+	}
+
+	h.mu.Lock()
+	h.redoS = append(h.redoS, cmd)
+	h.mu.Unlock()
+	return nil
+}
+
+// Redo re-applies the last undone command.
+func (h *History) Redo() error {
+	h.mu.Lock()
+	if len(h.redoS) == 0 {
+		h.mu.Unlock()
+		return fmt.Errorf("nothing to redo")
+	}
+	cmd := h.redoS[len(h.redoS)-1]
+	h.redoS = h.redoS[:len(h.redoS)-1]
+	h.mu.Unlock()
+
+	if err := cmd.Execute(context.Background()); err != nil {
+		h.mu.Lock()
+		h.redoS = append(h.redoS, cmd)
+		h.mu.Unlock()
+		return err
+	}
+
+	h.mu.Lock()
+	h.undoS = append(h.undoS, cmd)
+	h.mu.Unlock()
+	return nil
+}
+
+// CanUndo reports whether Undo would succeed.
+func (h *History) CanUndo() bool {
+	h.mu.Lock()
+	defer h.mu.Unlock()
+	return len(h.undoS) > 0
+}
+
+// CanRedo reports whether Redo would succeed.
+func (h *History) CanRedo() bool {
+	h.mu.Lock()
+	defer h.mu.Unlock()
+	return len(h.redoS) > 0
+}
+
+// LastUndoName returns the name of the next undo command, or "".
+func (h *History) LastUndoName() string {
+	h.mu.Lock()
+	defer h.mu.Unlock()
+	if len(h.undoS) == 0 {
+		return ""
+	}
+	return h.undoS[len(h.undoS)-1].Name()
+}
+
+// LastRedoName returns the name of the next redo command, or "".
+func (h *History) LastRedoName() string {
+	h.mu.Lock()
+	defer h.mu.Unlock()
+	if len(h.redoS) == 0 {
+		return ""
+	}
+	return h.redoS[len(h.redoS)-1].Name()
+}