Do not add to collection a movies that is already here

collection.go

@@ -24,6 +24,10 @@ func Import(filename string) (*Collection, error) {
 		return nil, err
 	}
 
+	for _, m := range c.Movies {
+		m.FillFromOMDB()
+	}
+
 	return &c, nil
 }
 
@@ -49,6 +53,12 @@ func (c *Collection) Add(m *Movie) {
 	c.mutex.Lock()
 	defer c.mutex.Unlock()
 
+	for _, present := range c.Movies {
+		if m.IMDBID == present.IMDBID {
+			return
+		}
+	}
+
 	c.Movies = append(c.Movies, m)
 	c.hasChanged = true
 }

movies.go

@@ -11,7 +11,8 @@ type Movie struct {
 	Title    string
 	Director string
 	Poster   string
-	Rating   Rating
+	Rating   *Rating
+	IMDBID   string
 
 	OMDB OMDBMovie
 }
@@ -59,24 +60,47 @@ func Unmarshal(b []byte) (*Movie, error) {
 		return nil, err
 	}
 
-	note, err := strconv.ParseFloat(omdb.IMDBRating, 64)
-	if err != nil {
-		return nil, fmt.Errorf("cannot convert %q to float64: %w", omdb.IMDBRating, err)
+	m := &Movie{
+		OMDB: omdb,
+	}
+
+	if err := m.FillFromOMDB(); err != nil {
+		return nil, err
 	}
 
-	votes, err := strconv.ParseInt(strings.ReplaceAll(omdb.IMDBVotes, ",", ""), 10, 64)
-	if err != nil {
-		return nil, fmt.Errorf("cannot convert %q to int: %w", omdb.IMDBVotes, err)
+	return m, nil
+}
+
+func (m *Movie) FillFromOMDB() error {
+	if m.Title == "" {
+		m.Title = m.OMDB.Title
+	}
+	if m.Director == "" {
+		m.Director = m.OMDB.Director
 	}
+	if m.Poster == "" {
+		m.Poster = m.OMDB.Poster
+	}
+	if m.IMDBID == "" {
+		m.IMDBID = m.OMDB.IMDBID
+	}
+
+	if m.Rating == nil {
+		note, err := strconv.ParseFloat(m.OMDB.IMDBRating, 64)
+		if err != nil {
+			return fmt.Errorf("cannot convert %q to float64: %w", m.OMDB.IMDBRating, err)
+		}
+
+		votes, err := strconv.ParseInt(strings.ReplaceAll(m.OMDB.IMDBVotes, ",", ""), 10, 64)
+		if err != nil {
+			return fmt.Errorf("cannot convert %q to int: %w", m.OMDB.IMDBVotes, err)
+		}
 
-	return &Movie{
-		Title:    omdb.Title,
-		Director: omdb.Director,
-		Poster:   omdb.Poster,
-		Rating: Rating{
+		m.Rating = &Rating{
 			Note:  note,
 			Votes: votes,
-		},
-		OMDB: omdb,
-	}, nil
+		}
+	}
+
+	return nil
 }