feat: support wand file shell completion

cmd/completion.go

@@ -0,0 +1,49 @@
+package cmd
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/spf13/cobra"
+)
+
+func newCompletionCmd(rootCmd *cobra.Command) *cobra.Command {
+	cmd := &cobra.Command{
+		Use:   "completion [bash|zsh|fish|powershell]",
+		Short: "Generate shell completion script",
+		Long: `Generate a shell completion script for wand.
+Use --name to generate completions for an alias:
+
+  # Source completions for an alias directly
+  source <(wand --wand-file ~/.config/wand/nextcloud.yml completion --name wand-nc zsh)
+
+  # Or write to a file
+  wand --wand-file ~/.config/wand/nextcloud.yml completion --name wand-nc zsh > _wand-nc`,
+		ValidArgs:             []string{"bash", "zsh", "fish", "powershell"},
+		Args:                  cobra.MatchAll(cobra.ExactArgs(1), cobra.OnlyValidArgs),
+		DisableFlagsInUseLine: true,
+		RunE: func(cmd *cobra.Command, args []string) error {
+			name, _ := cmd.Flags().GetString("name")
+			if name != "" {
+				rootCmd.Use = name
+			}
+
+			switch args[0] {
+			case "bash":
+				return rootCmd.GenBashCompletion(os.Stdout)
+			case "zsh":
+				return rootCmd.GenZshCompletion(os.Stdout)
+			case "fish":
+				return rootCmd.GenFishCompletion(os.Stdout, true)
+			case "powershell":
+				return rootCmd.GenPowerShellCompletionWithDesc(os.Stdout)
+			default:
+				return fmt.Errorf("unsupported shell: %s", args[0])
+			}
+		},
+	}
+
+	cmd.Flags().String("name", "", "command name to use in the completion script (for aliases)")
+
+	return cmd
+}

cmd/root.go

@@ -40,6 +40,8 @@ func Execute() error {
 		},
 	)
 
+	rootCmd.AddCommand(newCompletionCmd(rootCmd))
+
 	return rootCmd.Execute()
 }