2 files changed, 73 insertions, 8 deletions
diff --git a/main.go b/main.go
index f8a38ae..f70faa4 100644
--- a/main.go
+++ b/main.go
@@ -1,19 +1,20 @@
 package main
 
 import (
+	"fmt"
 	"os"
 )
 
 func main() {
-	path := "."
 
-	if len(os.Args) > 1 {
-		path = os.Args[1]
+	if len(os.Args) != 3 {
+		fmt.Println("usage: dna-backup <source> <dest>")
+		os.Exit(1)
 	}
 
-	files := make(chan File)
-	chunks := make(chan []byte)
-	go ListFiles(path, files)
-	go ReadFiles(files, chunks)
-	StoreChunks(".", chunks)
+	source := os.Args[1]
+	dest := os.Args[2]
+
+	os.MkdirAll(dest, 0775)
+	Commit(source, dest)
 }
diff --git a/repo.go b/repo.go
index 17ad8f3..22c323f 100644
--- a/repo.go
+++ b/repo.go
@@ -1,13 +1,39 @@
+/*
+Manage a deduplicated versionned backups repository.
+
+Sample repository:
+
+```
+repo/
+├── 00000/
+│   ├── chunks/
+│   │   ├── 000000000000000
+│   │   ├── 000000000000001
+│   │   ├── 000000000000002
+│   │   ├── 000000000000003
+│   ├── dentries
+│   └── recipe
+└── 00001/
+    ├── chunks/
+    │   ├── 000000000000000
+    │   ├── 000000000000001
+    ├── dentries
+    └── recipe
+```
+*/
+
 package main
 
 import (
 	"fmt"
 	"io"
 	"io/fs"
+	"io/ioutil"
 	"log"
 	"os"
 	"path"
 	"path/filepath"
+	"strconv"
 )
 
 const (
@@ -19,6 +45,44 @@ type File struct {
 	Size int64
 }
 
+func Commit(source string, repo string) {
+	latest := GetLastVersion(repo)
+	new := latest + 1
+	newPath := path.Join(repo, fmt.Sprintf("%05d", new))
+	newChunkPath := path.Join(newPath, "chunks")
+	os.Mkdir(newPath, 0775)
+	os.Mkdir(newChunkPath, 0775)
+	files := make(chan File)
+	newChunks := make(chan []byte)
+	oldChunks := make(chan []byte)
+	go LoadChunks(repo, oldChunks)
+	go ListFiles(source, files)
+	go ReadFiles(files, newChunks)
+	StoreChunks(newChunkPath, newChunks)
+}
+
+func GetLastVersion(repo string) int {
+	v := -1
+	files, err := ioutil.ReadDir(repo)
+	if err != nil {
+		log.Fatalln(err)
+	}
+	for _, f := range files {
+		if !f.IsDir() {
+			continue
+		}
+		num, err := strconv.Atoi(f.Name())
+		if err != nil {
+			log.Println(err)
+			continue
+		}
+		if num > v {
+			v = num
+		}
+	}
+	return v
+}
+
 func ListFiles(path string, files chan<- File) {
 	err := filepath.Walk(path,
 		func(p string, i fs.FileInfo, err error) error {