feat(mal): add comprehensive error handling

MALFunctions.go:
- Update MALHelper to return (json.RawMessage, string, error)
- Add network error handling and proper request error checking
- Update GetMyAnimeList to return (MALWatchlist, error)
- Update MyAnimeListUpdate to return (MalListStatus, error)
- Update GetMyAnimeListAnime to return (MALAnime, error)
- Update DeleteMyAnimeListEntry to return (bool, error)

MALUserFunctions.go:
- Replace log.Fatalf with log.Printf in server error handling
- Prevent server shutdown on OAuth callback errors

All MAL API calls now properly propagate errors to frontend.

MALFunctions.go

@@ -11,10 +11,19 @@ import (
 	"strings"
 )
 
-func MALHelper(method string, malUrl string, body url.Values) (json.RawMessage, string) {
+func MALHelper(method string, malUrl string, body url.Values) (json.RawMessage, string, error) {
 	client := &http.Client{}
 
-	req, _ := http.NewRequest(method, malUrl, strings.NewReader(body.Encode()))
+	req, err := http.NewRequest(method, malUrl, strings.NewReader(body.Encode()))
+
+	if err != nil {
+		message, _ := json.Marshal(struct {
+			Message string `json:"message"`
+		}{
+			Message: "Failed to create request: " + err.Error(),
+		})
+		return message, "", fmt.Errorf("failed to create request: %w", err)
+	}
 
 	req.Header.Add("Content-Type", "application/x-www-form-urlencoded")
 	req.Header.Add("Authorization", "Bearer "+myAnimeListJwt.AccessToken)
@@ -22,47 +31,57 @@ func MALHelper(method string, malUrl string, body url.Values) (json.RawMessage,
 	resp, err := client.Do(req)
 
 	if err != nil {
-		fmt.Println("Errored when sending request to the server")
 		message, _ := json.Marshal(struct {
-			Message string `json:"message" ts_type:"message"`
+			Message string `json:"message"`
 		}{
-			Message: "Errored when sending request to the server" + err.Error(),
+			Message: "Network error: " + err.Error(),
 		})
-
-		return message, resp.Status
+		return message, "", fmt.Errorf("network error: %w", err)
 	}
 
 	defer resp.Body.Close()
-	respBody, _ := io.ReadAll(resp.Body)
+	respBody, err := io.ReadAll(resp.Body)
+
+	if err != nil {
+		return nil, resp.Status, fmt.Errorf("failed to read response: %w", err)
+	}
 
 	if resp.Status == "401 Unauthorized" {
 		refreshMyAnimeListAuthorizationToken()
-		MALHelper(method, malUrl, body)
+		return MALHelper(method, malUrl, body)
 	}
 
-	return respBody, resp.Status
+	if resp.Status != "200 OK" && resp.Status != "201 Created" && resp.Status != "202 Accepted" {
+		return respBody, resp.Status, fmt.Errorf("API returned status: %s", resp.Status)
+	}
+	return respBody, resp.Status, nil
 }
 
-func (a *App) GetMyAnimeList(count int) MALWatchlist {
+func (a *App) GetMyAnimeList(count int) (MALWatchlist, error) {
 	limit := strconv.Itoa(count)
 	user := a.GetMyAnimeListLoggedInUser()
 	malUrl := "https://api.myanimelist.net/v2/users/" + user.Name + "/animelist?fields=list_status&status=watching&limit=" + limit
 
 	var malList MALWatchlist
 
-	respBody, resStatus := MALHelper("GET", malUrl, nil)
+	respBody, resStatus, err := MALHelper("GET", malUrl, nil)
+
+	if err != nil {
+		return malList, fmt.Errorf("failed to get MAL watchlist: %w", err)
+	}
 
 	if resStatus == "200 OK" {
 		err := json.Unmarshal(respBody, &malList)
 		if err != nil {
 			log.Printf("Failed to unmarshal json response, %s\n", err)
+			return malList, fmt.Errorf("failed to parse response: %w", err)
 		}
 	}
 
-	return malList
+	return malList, nil
 }
 
-func (a *App) MyAnimeListUpdate(anime MALAnime, update MALUploadStatus) MalListStatus {
+func (a *App) MyAnimeListUpdate(anime MALAnime, update MALUploadStatus) (MalListStatus, error) {
 	if update.NumTimesRewatched >= 1 {
 		update.IsRewatching = true
 	} else {
@@ -78,39 +97,52 @@ func (a *App) MyAnimeListUpdate(anime MALAnime, update MALUploadStatus) MalListS
 
 	malUrl := "https://api.myanimelist.net/v2/anime/" + strconv.Itoa(anime.Id) + "/my_list_status"
 	var status MalListStatus
-	respBody, respStatus := MALHelper("PATCH", malUrl, body)
+	respBody, respStatus, err := MALHelper("PATCH", malUrl, body)
+
+	if err != nil {
+		return status, fmt.Errorf("failed to update MAL entry: %w", err)
+	}
 
 	if respStatus == "200 OK" {
 		err := json.Unmarshal(respBody, &status)
 		if err != nil {
 			log.Printf("Failed to unmarshal json response, %s\n", err)
+			return status, fmt.Errorf("failed to parse response: %w", err)
 		}
 	}
-
-	return status
+	return status, nil
 }
 
-func (a *App) GetMyAnimeListAnime(id int) MALAnime {
+func (a *App) GetMyAnimeListAnime(id int) (MALAnime, error) {
 	malUrl := "https://api.myanimelist.net/v2/anime/" + strconv.Itoa(id) + "?fields=id,title,main_picture,alternative_titles,start_date,end_date,synopsis,mean,rank,popularity,num_list_users,num_scoring_users,nsfw,genres,created_at,updated_at,media_type,status,my_list_status,num_episodes,start_season,broadcast,source,average_episode_duration,rating,pictures,background,related_anime,recommendations,studios,statistics"
-	respBody, respStatus := MALHelper("GET", malUrl, nil)
 	var malAnime MALAnime
+	respBody, respStatus, err := MALHelper("GET", malUrl, nil)
+
+	if err != nil {
+		return malAnime, fmt.Errorf("failed to get MAL anime: %w", err)
+	}
 
 	if respStatus == "200 OK" {
 		err := json.Unmarshal(respBody, &malAnime)
 		if err != nil {
 			log.Printf("Failed to unmarshal json response, %s\n", err)
+			return malAnime, fmt.Errorf("failed to parse response: %w", err)
 		}
 	}
-
-	return malAnime
+	return malAnime, nil
 }
 
-func (a *App) DeleteMyAnimeListEntry(id int) bool {
+func (a *App) DeleteMyAnimeListEntry(id int) (bool, error) {
 	malUrl := "https://api.myanimelist.net/v2/anime/" + strconv.Itoa(id) + "/my_list_status"
-	_, respStatus := MALHelper("DELETE", malUrl, nil)
+	_, respStatus, err := MALHelper("DELETE", malUrl, nil)
+
+	if err != nil {
+		return false, fmt.Errorf("failed to delete MAL entry: %w", err)
+	}
+
 	if respStatus == "200 OK" {
-		return true
+		return true, nil
 	} else {
-		return false
+		return false, fmt.Errorf("delete failed with status: %s", respStatus)
 	}
 }