From 2852097b2619b20ab5a92899a835ed991af3616a Mon Sep 17 00:00:00 2001
From: Fendy <xingfen.fendy@outlook.com>
Date: Wed, 26 Aug 2026 23:04:13 +0800
Subject: [PATCH] feat: scanner for directory reconciliation

---
 internal/scanner/scanner.go      | 109 +++++++++++++++++++++++++++++++
 internal/scanner/scanner_test.go |  44 +++++++++++++
 2 files changed, 153 insertions(+)
 create mode 100644 internal/scanner/scanner.go
 create mode 100644 internal/scanner/scanner_test.go

diff --git a/internal/scanner/scanner.go b/internal/scanner/scanner.go
new file mode 100644
index 0000000..5d56c34
--- /dev/null
+++ b/internal/scanner/scanner.go
@@ -0,0 +1,109 @@
+package scanner
+
+import (
+	"crypto/rand"
+	"encoding/hex"
+	"os"
+	"path/filepath"
+	"time"
+	"yoresee_dropbox/internal/store"
+)
+
+type Scanner struct {
+	store     *store.Store
+	workspace string
+	interval  time.Duration
+	stopCh    chan struct{}
+}
+
+func New(s *store.Store, workspace string, interval time.Duration) *Scanner {
+	return &Scanner{
+		store:     s,
+		workspace: workspace,
+		interval:  interval,
+		stopCh:    make(chan struct{}),
+	}
+}
+
+func (sc *Scanner) Start() {
+	go sc.run()
+}
+
+func (sc *Scanner) Stop() {
+	close(sc.stopCh)
+}
+
+func (sc *Scanner) run() {
+	ticker := time.NewTicker(sc.interval)
+	defer ticker.Stop()
+
+	sc.scan()
+	for {
+		select {
+		case <-sc.stopCh:
+			return
+		case <-ticker.C:
+			sc.scan()
+		}
+	}
+}
+
+func (sc *Scanner) scan() {
+	sc.scanDir("inbox")
+	sc.scanDir("outbox")
+}
+
+func (sc *Scanner) scanDir(dir string) {
+	dirPath := filepath.Join(sc.workspace, dir)
+	entries, err := os.ReadDir(dirPath)
+	if err != nil {
+		return
+	}
+
+	dbFiles, err := sc.store.FileList(dir)
+	if err != nil {
+		return
+	}
+
+	dbMap := make(map[string]*store.File)
+	for _, f := range dbFiles {
+		dbMap[f.StorageName] = f
+	}
+
+	diskMap := make(map[string]bool)
+	for _, entry := range entries {
+		if entry.IsDir() {
+			continue
+		}
+		info, err := entry.Info()
+		if err != nil {
+			continue
+		}
+		diskMap[entry.Name()] = true
+
+		if _, exists := dbMap[entry.Name()]; !exists {
+			id := generateUUID()
+			f := &store.File{
+				ID:           id,
+				OriginalName: entry.Name(),
+				StorageName:  entry.Name(),
+				Dir:          dir,
+				Size:         info.Size(),
+				CreatedAt:    time.Now().Unix(),
+			}
+			sc.store.FileCreate(f)
+		}
+	}
+
+	for name, f := range dbMap {
+		if !diskMap[name] {
+			sc.store.FileDelete(f.ID)
+		}
+	}
+}
+
+func generateUUID() string {
+	b := make([]byte, 16)
+	rand.Read(b)
+	return hex.EncodeToString(b)
+}
diff --git a/internal/scanner/scanner_test.go b/internal/scanner/scanner_test.go
new file mode 100644
index 0000000..0f99914
--- /dev/null
+++ b/internal/scanner/scanner_test.go
@@ -0,0 +1,44 @@
+package scanner
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+	"time"
+	"yoresee_dropbox/internal/store"
+)
+
+func TestScannerReconciles(t *testing.T) {
+	dir := t.TempDir()
+	inbox := filepath.Join(dir, "inbox")
+	outbox := filepath.Join(dir, "outbox")
+	os.MkdirAll(inbox, 0755)
+	os.MkdirAll(outbox, 0755)
+
+	dbPath := filepath.Join(dir, "test.db")
+	s, err := store.Open(dbPath)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer s.Close()
+
+	// Create a file on disk
+	testFile := filepath.Join(inbox, "test.txt")
+	os.WriteFile(testFile, []byte("hello"), 0644)
+
+	sc := New(s, dir, 100*time.Millisecond)
+	sc.Start()
+	time.Sleep(300 * time.Millisecond)
+	sc.Stop()
+
+	files, err := s.FileList("inbox")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(files) != 1 {
+		t.Errorf("Expected 1 file, got %d", len(files))
+	}
+	if files[0].OriginalName != "test.txt" {
+		t.Errorf("OriginalName = %q, want %q", files[0].OriginalName, "test.txt")
+	}
+}