Resolve race condition issues

internal/torrent/manager.go

@@ -16,33 +16,41 @@ import (
 )
 
 type TorrentManager struct {
-	requiredVersion       string
-	torrents              []Torrent
-	inProgress            []string
-	checksum              string
-	config                config.ConfigInterface
-	cache                 *expirable.LRU[string, string]
-	workerPool            chan bool
-	TorrentDirectoriesMap map[string][]string
-	processedTorrents     map[string][]string
+	requiredVersion   string
+	torrents          []Torrent
+	inProgress        []string
+	checksum          string
+	config            config.ConfigInterface
+	cache             *expirable.LRU[string, string]
+	workerPool        chan bool
+	directoryMap      map[string][]string
+	processedTorrents map[string][]string
+	mu                *sync.Mutex
 }
 
 // NewTorrentManager creates a new torrent manager
 // it will fetch all torrents and their info in the background
-// and store them in-memory
+// and store them in-memory; it is called only once at startup
 func NewTorrentManager(config config.ConfigInterface, cache *expirable.LRU[string, string]) *TorrentManager {
 	t := &TorrentManager{
-		requiredVersion:       "28.10.2023",
-		config:                config,
-		cache:                 cache,
-		workerPool:            make(chan bool, config.GetNumOfWorkers()),
-		TorrentDirectoriesMap: make(map[string][]string),
-		processedTorrents:     make(map[string][]string),
+		requiredVersion:   "4.11.2023",
+		config:            config,
+		cache:             cache,
+		workerPool:        make(chan bool, config.GetNumOfWorkers()),
+		directoryMap:      make(map[string][]string),
+		processedTorrents: make(map[string][]string),
+		mu:                &sync.Mutex{},
 	}
 
 	// Initialize torrents for the first time
+	log.Println("Initializing torrents")
+	t.mu.Lock()
+	log.Println("Fetching torrents")
 	t.torrents = t.getFreshListFromAPI()
 	t.checksum = t.getChecksum()
+	t.mu.Unlock()
+	log.Println("Finished fetching torrents")
+
 	// log.Println("First checksum", t.checksum)
 
 	var wg sync.WaitGroup
@@ -72,7 +80,7 @@ func NewTorrentManager(config config.ConfigInterface, cache *expirable.LRU[strin
 func (t *TorrentManager) GetByDirectory(directory string) []Torrent {
 	var torrents []Torrent
 	for i := range t.torrents {
-		for _, dir := range t.TorrentDirectoriesMap[t.torrents[i].Name] {
+		for _, dir := range t.directoryMap[t.torrents[i].Name] {
 			if dir == directory {
 				torrents = append(torrents, t.torrents[i])
 			}
@@ -195,8 +203,11 @@ func (t *TorrentManager) startRefreshJob() {
 		wg.Wait()
 
 		// apply side effects
+		t.mu.Lock()
 		t.torrents = newTorrents
 		t.checksum = t.getChecksum()
+		t.mu.Unlock()
+
 		// log.Println("Checksum changed", t.checksum)
 		if t.config.EnableRepair() {
 			go t.repairAll(&wg)
@@ -223,6 +234,8 @@ func (t *TorrentManager) getFreshListFromAPI() []Torrent {
 		torrentV2 := Torrent{
 			Torrent:       torrent,
 			SelectedFiles: nil,
+			ForRepair:     false,
+			lock:          &sync.Mutex{},
 		}
 		torrentsV2 = append(torrentsV2, torrentV2)
 
@@ -361,7 +374,7 @@ func (t *TorrentManager) mapToDirectories() {
 					if configV1.MeetsConditions(directory, t.torrents[i].ID, t.torrents[i].Name, filenames) {
 						found := false
 						// check if it is already mapped to this directory
-						for _, dir := range t.TorrentDirectoriesMap[t.torrents[i].Name] {
+						for _, dir := range t.directoryMap[t.torrents[i].Name] {
 							if dir == directory {
 								found = true
 								break // it is already mapped to this directory
@@ -369,12 +382,16 @@ func (t *TorrentManager) mapToDirectories() {
 						}
 						if !found {
 							counter[directory]++
-							t.TorrentDirectoriesMap[t.torrents[i].Name] = append(t.TorrentDirectoriesMap[t.torrents[i].Name], directory)
+							t.mu.Lock()
+							t.directoryMap[t.torrents[i].Name] = append(t.directoryMap[t.torrents[i].Name], directory)
+							t.mu.Unlock()
 							break // we found a directory for this torrent, so we can stop looking for more
 						}
 					}
 				}
+				t.mu.Lock()
 				t.processedTorrents[t.torrents[i].Name] = append(t.processedTorrents[t.torrents[i].Name], group)
+				t.mu.Unlock()
 			}
 			sum := 0
 			for _, count := range counter {
@@ -439,7 +456,6 @@ func (t *TorrentManager) readFromFile(torrentID string) *Torrent {
 	dataDecoder := gob.NewDecoder(file)
 	err = dataDecoder.Decode(&torrent)
 	if err != nil {
-		log.Fatalf("Failed decoding file: %s", err)
 		return nil
 	}
 	if torrent.Version != t.requiredVersion {