add CLI with subcommands

1 files changed, 68 insertions, 10 deletions

diff --git a/main.go b/main.go
index c0e55d8..cf208c9 100644
--- a/main.go
+++ b/main.go
@@ -8,32 +8,90 @@ import (
 	"github.com/n-peugnet/dna-backup/logger"
 )
 
+type command struct {
+	Flag  *flag.FlagSet
+	Usage string
+	Help  string
+	Run   func([]string) error
+}
+
 const (
-	usage = "usage: dna-backup [<options>] [--] <source> <dest>\n\noptions:\n"
+	name         = "dna-backup"
+	baseUsage    = "<command> [<options>] [--] <args>"
+	commitUsage  = "[<options>] [--] <source> <dest>"
+	commitHelp   = "Create a new version of folder <source> into repo <dest>"
+	restoreUsage = "[<options>] [--] <source> <dest>"
+	restoreHelp  = "Restore the last version from repo <source> into folder <dest>"
 )
 
 var (
-	logLevel int
+	logLevel    int
+	commitCmd   = flag.NewFlagSet("commit", flag.ExitOnError)
+	restoreCmd  = flag.NewFlagSet("restore", flag.ExitOnError)
+	subcommands = map[string]command{
+		commitCmd.Name():  {commitCmd, commitUsage, commitHelp, commitMain},
+		restoreCmd.Name(): {restoreCmd, restoreUsage, restoreHelp, restoreMain},
+	}
 )
 
 func init() {
-	flag.IntVar(&logLevel, "v", 3, "log verbosity level (0-4)")
+	// init default help message
+	flag.Usage = func() {
+		fmt.Fprintf(flag.CommandLine.Output(), "usage: %s %s\n\ncommands:\n", name, baseUsage)
+		for _, s := range subcommands {
+			fmt.Printf("  %s	%s\n", s.Flag.Name(), s.Help)
+		}
+		os.Exit(1)
+	}
+	// setup subcommands
+	for _, s := range subcommands {
+		s.Flag.IntVar(&logLevel, "v", 3, "log verbosity level (0-4)")
+	}
 }
 
 func main() {
-	flag.Usage = func() {
-		fmt.Fprintf(flag.CommandLine.Output(), usage)
-		flag.PrintDefaults()
-	}
 	flag.Parse()
-	logger.Init(logLevel)
-	if len(flag.Args()) != 2 {
+
+	args := flag.Args()
+	if len(args) < 1 {
+		flag.Usage()
+	}
+	cmd, exists := subcommands[args[0]]
+	if !exists {
+		fmt.Fprintf(flag.CommandLine.Output(), "error: unknown command %s\n\n", args[0])
 		flag.Usage()
+	}
+	cmd.Flag.Usage = func() {
+		fmt.Fprintf(cmd.Flag.Output(), "usage: %s %s %s\n\noptions:\n", name, cmd.Flag.Name(), cmd.Usage)
+		cmd.Flag.PrintDefaults()
 		os.Exit(1)
 	}
-	args := flag.Args()
+	cmd.Flag.Parse(args[1:])
+	logger.Init(logLevel)
+	if err := cmd.Run(cmd.Flag.Args()); err != nil {
+		fmt.Fprintf(cmd.Flag.Output(), "error: %s\n\n", err)
+		cmd.Flag.Usage()
+	}
+}
+
+func commitMain(args []string) error {
+	if len(args) != 2 {
+		return fmt.Errorf("wrong number of args")
+	}
 	source := args[0]
 	dest := args[1]
 	repo := NewRepo(dest)
 	repo.Commit(source)
+	return nil
+}
+
+func restoreMain(args []string) error {
+	if len(args) != 2 {
+		return fmt.Errorf("wrong number args")
+	}
+	source := args[0]
+	dest := args[1]
+	repo := NewRepo(source)
+	repo.Restore(dest)
+	return nil
 }