fix(subscription): prevent duplicate qb downloads

internal/service/downloads_test.go

@@ -2,10 +2,19 @@ package service
 
 import (
 	"encoding/json"
+	"errors"
+	"net/http"
+	"net/http/httptest"
 	"strings"
+	"sync/atomic"
 	"testing"
 
+	"github.com/glebarez/sqlite"
+	"go.uber.org/zap"
+	"gorm.io/gorm"
+
 	"github.com/ShukeBta/MediaStationGo/internal/model"
+	"github.com/ShukeBta/MediaStationGo/internal/repository"
 )
 
 func TestDownloadViewsDoNotExposePrivateURL(t *testing.T) {
@@ -41,3 +50,57 @@ func TestPublicDownloadTitleUsesMagnetDisplayName(t *testing.T) {
 		t.Fatalf("publicDownloadTitle = %q, want %q", got, "测试影片")
 	}
 }
+
+func TestAddDownloadWithMetaSkipsExistingTaskBeforeQBAdd(t *testing.T) {
+	var addCalls int32
+	qb := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		switch r.URL.Path {
+		case "/api/v2/auth/login":
+			_, _ = w.Write([]byte("Ok."))
+		case "/api/v2/torrents/info":
+			_, _ = w.Write([]byte(`[]`))
+		case "/api/v2/torrents/add":
+			atomic.AddInt32(&addCalls, 1)
+			_, _ = w.Write([]byte("Ok."))
+		default:
+			http.NotFound(w, r)
+		}
+	}))
+	defer qb.Close()
+
+	db, err := gorm.Open(sqlite.Open(":memory:"), &gorm.Config{})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err := db.AutoMigrate(&model.DownloadTask{}, &model.Setting{}); err != nil {
+		t.Fatal(err)
+	}
+	repos := repository.New(db)
+	existing := &model.DownloadTask{
+		UserID:   "u1",
+		Source:   "qbittorrent",
+		URL:      "https://pt.example/download?id=old&passkey=old",
+		Title:    "Some Show S01E01 1080p",
+		SavePath: "/downloads/tv",
+		Status:   "completed",
+		Progress: 1,
+	}
+	if err := repos.Download.Create(t.Context(), existing); err != nil {
+		t.Fatal(err)
+	}
+
+	svc := NewDownloadService(zap.NewNop(), repos, NewHub(zap.NewNop()), nil)
+	svc.qb.Configure(QBitConfig{BaseURL: qb.URL, Username: "admin", Password: "admin"})
+	task, err := svc.AddDownloadWithMeta(t.Context(), "u1", "https://pt.example/download?id=new&passkey=new", "/downloads/tv", DownloadTaskMeta{
+		Title: "Some Show S01E01 1080p",
+	})
+	if !errors.Is(err, ErrDownloadAlreadyExists) {
+		t.Fatalf("err = %v, want ErrDownloadAlreadyExists", err)
+	}
+	if task == nil || task.ID != existing.ID {
+		t.Fatalf("task = %#v, want existing task %#v", task, existing)
+	}
+	if got := atomic.LoadInt32(&addCalls); got != 0 {
+		t.Fatalf("qb add calls = %d, want 0", got)
+	}
+}