stepwriter: Add DryRun

installer/stepwriter/dryrun.go

@@ -0,0 +1,78 @@
+// SPDX-FileCopyrightText: Fabio Forni <development@redaril.me>
+// SPDX-License-Identifier: MPL-2.0
+
+package stepwriter
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"os"
+	"strings"
+
+	"github.com/livingsilver94/backee/installer"
+	"github.com/livingsilver94/backee/service"
+)
+
+var (
+	buf = &strings.Builder{}
+)
+
+type DryRun struct{}
+
+func (DryRun) Setup(script string) error {
+	return printMultiline(strings.NewReader(script))
+}
+
+func (DryRun) InstallPackages(fullCmd []string) error {
+	return printf("Will run %q", strings.Join(fullCmd, " "))
+}
+
+func (DryRun) SymlinkFile(dst service.FilePath, src string) error {
+	defer buf.Reset()
+	fmt.Fprintf(buf, "%s → %s", src, dst.Path)
+	if dst.Mode != 0 {
+		fmt.Fprintf(buf, " with permission %o", dst.Mode)
+	}
+	return printLine(buf.String())
+}
+
+func (DryRun) CopyFile(dst service.FilePath, src installer.FileCopy) error {
+	defer buf.Reset()
+	fmt.Fprintf(buf, "Will write %s", dst.Path)
+	if dst.Mode != 0 {
+		fmt.Fprintf(buf, " with permission %o", dst.Mode)
+	}
+	buf.WriteString(" with the following content:")
+	err := printLine(buf.String())
+	if err != nil {
+		return err
+	}
+	_, err = src.WriteTo(os.Stdout)
+	return err
+}
+
+func (DryRun) Finalize(script string) error {
+	return printMultiline(strings.NewReader(script))
+}
+
+func printLine(str string) error {
+	_, err := fmt.Println("\t" + str)
+	return err
+}
+
+func printMultiline(read io.Reader) error {
+	lines := bufio.NewScanner(read)
+	for lines.Scan() {
+		err := printLine(lines.Text())
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func printf(format string, args ...any) error {
+	_, err := fmt.Printf("\t"+format+"\n", args)
+	return err
+}