feat(cli): add apply subcommand

internal/cli/show.go

@@ -0,0 +1,120 @@
+package cli
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"github.com/spf13/cobra"
+
+	"github.com/lukaszraczylo/harness-sync/internal/adapter"
+	"github.com/lukaszraczylo/harness-sync/internal/canonical"
+)
+
+// NewShow returns the `show` subcommand which prints the files each adapter
+// would manage if `apply` were run now. Useful for auditing what harness-sync
+// will write to your system before committing to it.
+func NewShow(reg *adapter.Registry) *cobra.Command {
+	var (
+		root string
+		all  bool
+	)
+	cmd := &cobra.Command{
+		Use:   "show [harness...]",
+		Short: "List files harness-sync manages for each harness",
+		Long: `Renders the canonical bundle through each adapter and prints
+the resulting targets without writing anything. By default, shows only detected
+harnesses; pass --all to include adapters whose harness is not installed, or
+positional args to select specific harnesses.`,
+		RunE: func(cmd *cobra.Command, args []string) error {
+			r, err := resolveRoot(root)
+			if err != nil {
+				return err
+			}
+			b, err := canonical.Load(r)
+			if err != nil {
+				return err
+			}
+
+			var selected []adapter.Adapter
+			switch {
+			case len(args) > 0:
+				for _, name := range args {
+					a, ok := reg.Get(name)
+					if !ok {
+						return fmt.Errorf("unknown adapter %q", name)
+					}
+					selected = append(selected, a)
+				}
+			case all:
+				selected = reg.All()
+			default:
+				for _, a := range reg.All() {
+					if a.Detect() {
+						selected = append(selected, a)
+					}
+				}
+			}
+
+			w := cmd.OutOrStdout()
+			for _, a := range selected {
+				fs, err := a.Render(b)
+				if err != nil {
+					if _, werr := fmt.Fprintf(w, "%s: render error: %v\n", a.Name(), err); werr != nil {
+						return werr
+					}
+					continue
+				}
+				if _, werr := fmt.Fprintf(w, "%s (%s)\n", a.Name(), detectLabel(a)); werr != nil {
+					return werr
+				}
+				var iterErr error
+				fs.ForEach(func(f adapter.File) {
+					if iterErr != nil {
+						return
+					}
+					switch f.Kind {
+					case adapter.SymlinkDir, adapter.SymlinkFile:
+						_, iterErr = fmt.Fprintf(w, "  %-12s %s -> %s\n",
+							f.Kind.String(), short(f.Dest), short(f.SymlinkTarget))
+					case adapter.RenderedFile:
+						_, iterErr = fmt.Fprintf(w, "  %-12s %s (%d bytes)\n",
+							f.Kind.String(), short(f.Dest), len(f.Content))
+					}
+				})
+				if iterErr != nil {
+					return iterErr
+				}
+				if _, werr := fmt.Fprintln(w); werr != nil {
+					return werr
+				}
+			}
+			return nil
+		},
+	}
+	cmd.Flags().StringVar(&root, "root", "", "canonical root (default ~/.config/harness-sync)")
+	cmd.Flags().BoolVar(&all, "all", false, "include adapters whose harness is not detected")
+	return cmd
+}
+
+func detectLabel(a adapter.Adapter) string {
+	if a.Detect() {
+		return "detected"
+	}
+	return "not detected"
+}
+
+// short collapses the user's home dir to "~" for cleaner output.
+func short(p string) string {
+	home, err := os.UserHomeDir()
+	if err != nil || home == "" {
+		return p
+	}
+	if p == home {
+		return "~"
+	}
+	if len(p) > len(home) && p[:len(home)+1] == home+string(filepath.Separator) {
+		return "~" + p[len(home):]
+	}
+	return p
+}