Better modularize clipboard code (add "clip" package; break up TOTP code

clip/copyTERMUX.go

@@ -0,0 +1,31 @@
+//go:build android && termux
+
+package clip
+
+import (
+	"errors"
+	"os/exec"
+
+	"github.com/rwinkhart/go-boilerplate/back"
+)
+
+// CopyString copies a string to the clipboard.
+func CopyString(continuous bool, copySubject string) error {
+	cmd := exec.Command("termux-clipboard-set")
+	_ = back.WriteToStdin(cmd, copySubject)
+	err := cmd.Run()
+	if err != nil {
+		return errors.New("unable to copy to clipboard: " + err.Error())
+	}
+	if !continuous {
+		LaunchClipClearProcess(copySubject)
+	}
+	return nil
+}
+
+// getClipCommands returns the commands for pasting and clearing the clipboard contents.
+func getClipCommands() (*exec.Cmd, *exec.Cmd) {
+	cmdClear := exec.Command("termux-clipboard-set")
+	_ = back.WriteToStdin(cmdClear, "")
+	return exec.Command("termux-clipboard-get"), cmdClear
+}