refactor: extract core logic to a plain Go package

commands/commands.go

@@ -0,0 +1,39 @@
+package commands
+
+import "github.com/spf13/cobra"
+
+type runEFunc func(cmd *cobra.Command, _ []string) error
+
+type validArgsFunc func(
+	cmd *cobra.Command,
+	args []string,
+	toComplete string,
+) ([]string, cobra.ShellCompDirective)
+
+func noValidArgs(
+	_ *cobra.Command,
+	_ []string,
+	_ string,
+) ([]string, cobra.ShellCompDirective) {
+	return nil, cobra.ShellCompDirectiveNoFileComp
+}
+
+func flagString(cmd *cobra.Command, name string) string {
+	var r string
+
+	if f := cmd.Flag(name); f != nil {
+		r = f.Value.String()
+	}
+
+	return r
+}
+
+func stringsContains(haystack []string, needle string) bool {
+	for _, s := range haystack {
+		if s == needle {
+			return true
+		}
+	}
+
+	return false
+}