fix: unify handler errors

internal/anime/handler/handler.go

@@ -7,6 +7,7 @@ import (
 	"mal/internal/db"
 	"mal/internal/domain"
 	"mal/internal/observability"
+	"mal/internal/server"
 	"net/http"
 	"net/url"
 	"strconv"
@@ -75,11 +76,19 @@ func (h *AnimeHandler) Register(r *gin.Engine) {
 
 func (h *AnimeHandler) HandleProducers(c *gin.Context) {
 	q := strings.TrimSpace(c.Query("q"))
-	page, _ := strconv.Atoi(c.DefaultQuery("page", "1"))
+	page, err := strconv.Atoi(c.DefaultQuery("page", "1"))
+	if err != nil {
+		server.RespondHTMLOrJSONError(c, http.StatusBadRequest, "invalid page")
+		return
+	}
 	if page < 1 {
 		page = 1
 	}
-	limit, _ := strconv.Atoi(c.DefaultQuery("limit", "50"))
+	limit, err := strconv.Atoi(c.DefaultQuery("limit", "50"))
+	if err != nil {
+		server.RespondHTMLOrJSONError(c, http.StatusBadRequest, "invalid limit")
+		return
+	}
 	if limit < 1 {
 		limit = 12
 	}
@@ -113,7 +122,15 @@ func (h *AnimeHandler) HandleProducers(c *gin.Context) {
 			return
 		}
 
-		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		server.RespondError(
+			c,
+			http.StatusInternalServerError,
+			"producers_fetch_failed",
+			"anime",
+			"failed to load producers",
+			map[string]any{"q": q, "page": page, "limit": limit},
+			err,
+		)
 		return
 	}
 
@@ -329,27 +346,57 @@ func (h *AnimeHandler) HandleBrowse(c *gin.Context) {
 	orderBy := c.Query("order_by")
 	sort := c.Query("sort")
 	sfw := c.Query("sfw") != "false"
-	studioID, _ := strconv.Atoi(c.Query("studio"))
+	studioID := 0
-	if studioID < 0 {
+	if raw := strings.TrimSpace(c.Query("studio")); raw != "" {
-		studioID = 0
+		id, err := strconv.Atoi(raw)
+		if err != nil || id < 0 {
+			server.RespondHTMLOrJSONError(c, http.StatusBadRequest, "invalid studio id")
+			return
+		}
+		studioID = id
 	}
 
 	var genres []int
 	for _, g := range c.QueryArray("genres") {
-		id, _ := strconv.Atoi(g)
+		id, err := strconv.Atoi(g)
+		if err != nil {
+			server.RespondHTMLOrJSONError(c, http.StatusBadRequest, "invalid genre id")
+			return
+		}
 		if id > 0 {
 			genres = append(genres, id)
 		}
 	}
 
-	page, _ := strconv.Atoi(c.DefaultQuery("page", "1"))
+	page, err := strconv.Atoi(c.DefaultQuery("page", "1"))
+	if err != nil {
+		server.RespondHTMLOrJSONError(c, http.StatusBadRequest, "invalid page")
+		return
+	}
 	if page < 1 {
 		page = 1
 	}
 
 	res, err := h.svc.SearchAdvanced(c.Request.Context(), q, animeType, status, orderBy, sort, genres, studioID, sfw, page, 24)
 	if err != nil {
-		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		server.RespondError(
+			c,
+			http.StatusInternalServerError,
+			"browse_search_failed",
+			"anime",
+			"failed to load browse results",
+			map[string]any{
+				"q":        q,
+				"type":     animeType,
+				"status":   status,
+				"order_by": orderBy,
+				"sort":     sort,
+				"studio":   studioID,
+				"sfw":      sfw,
+				"page":     page,
+			},
+			err,
+		)
 		return
 	}
 
@@ -434,9 +481,9 @@ func (h *AnimeHandler) HandleBrowse(c *gin.Context) {
 }
 
 func (h *AnimeHandler) HandleAnimeDetails(c *gin.Context) {
-	id, _ := strconv.Atoi(c.Param("id"))
+	id, err := strconv.Atoi(c.Param("id"))
-	if id <= 0 {
+	if err != nil || id <= 0 {
-		c.Status(http.StatusNotFound)
+		server.RespondHTMLOrJSONError(c, http.StatusBadRequest, "invalid anime id")
 		return
 	}
 
@@ -523,9 +570,9 @@ func (h *AnimeHandler) HandleAnimeDetails(c *gin.Context) {
 }
 
 func (h *AnimeHandler) HandleHTMLWatchOrder(c *gin.Context) {
-	id, _ := strconv.Atoi(c.Query("animeId"))
+	id, err := strconv.Atoi(c.Query("animeId"))
-	if id <= 0 {
+	if err != nil || id <= 0 {
-		c.Status(http.StatusBadRequest)
+		server.RespondHTMLOrJSONError(c, http.StatusBadRequest, "invalid anime id")
 		return
 	}
 
@@ -802,11 +849,19 @@ func (h *AnimeHandler) HandleRandomAnime(c *gin.Context) {
 
 	anime, err := h.svc.GetRandomAnime(ctx)
 	if err != nil {
-		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to fetch random anime"})
+		server.RespondError(
+			c,
+			http.StatusInternalServerError,
+			"random_anime_fetch_failed",
+			"anime",
+			"failed to fetch random anime",
+			nil,
+			err,
+		)
 		return
 	}
 	if anime.MalID == 0 {
-		c.JSON(http.StatusBadGateway, gin.H{"error": "Random anime unavailable"})
+		server.RespondHTMLOrJSONError(c, http.StatusBadGateway, "random anime unavailable")
 		return
 	}
 
@@ -824,20 +879,32 @@ func (h *AnimeHandler) HandleRandomAnime(c *gin.Context) {
 }
 
 func (h *AnimeHandler) HandleAnimeReviews(c *gin.Context) {
-	id, _ := strconv.Atoi(c.Param("id"))
+	id, err := strconv.Atoi(c.Param("id"))
-	if id <= 0 {
+	if err != nil || id <= 0 {
-		c.Status(http.StatusNotFound)
+		server.RespondHTMLOrJSONError(c, http.StatusBadRequest, "invalid anime id")
 		return
 	}
 
-	page, _ := strconv.Atoi(c.DefaultQuery("page", "1"))
+	page, err := strconv.Atoi(c.DefaultQuery("page", "1"))
+	if err != nil {
+		server.RespondHTMLOrJSONError(c, http.StatusBadRequest, "invalid page")
+		return
+	}
 	if page < 1 {
 		page = 1
 	}
 
 	reviews, hasNextPage, err := h.svc.GetReviews(c.Request.Context(), id, page)
 	if err != nil {
-		c.Status(http.StatusInternalServerError)
+		server.RespondError(
+			c,
+			http.StatusInternalServerError,
+			"anime_reviews_fetch_failed",
+			"anime",
+			"failed to load reviews",
+			map[string]any{"anime_id": id, "page": page},
+			err,
+		)
 		return
 	}
 

internal/watchlist/handler/handler.go

@@ -2,6 +2,7 @@ package handler
 
 import (
 	"mal/internal/domain"
+	"mal/internal/server"
 	"net/http"
 	"strconv"
 
@@ -35,13 +36,21 @@ func (h *WatchlistHandler) HandleUpdateWatchlist(c *gin.Context) {
 		Status  string `json:"status"`
 	}
 	if err := c.ShouldBindJSON(&body); err != nil || body.AnimeID <= 0 || body.Status == "" {
-		c.Status(http.StatusBadRequest)
+		server.RespondHTMLOrJSONError(c, http.StatusBadRequest, "invalid request body")
 		return
 	}
 
 	err := h.svc.UpdateEntry(c.Request.Context(), userID, body.AnimeID, body.Status)
 	if err != nil {
-		c.Status(http.StatusInternalServerError)
+		server.RespondError(
+			c,
+			http.StatusInternalServerError,
+			"watchlist_update_failed",
+			"watchlist",
+			"failed to update watchlist entry",
+			map[string]any{"user_id": userID, "anime_id": body.AnimeID, "status": body.Status},
+			err,
+		)
 		return
 	}
 
@@ -55,16 +64,24 @@ func (h *WatchlistHandler) HandleDeleteWatchlist(c *gin.Context) {
 		userID = u.ID
 	}
 
-	animeID, _ := strconv.ParseInt(c.Param("id"), 10, 64)
+	animeID, err := strconv.ParseInt(c.Param("id"), 10, 64)
 
-	if animeID <= 0 {
+	if err != nil || animeID <= 0 {
-		c.Status(http.StatusBadRequest)
+		server.RespondHTMLOrJSONError(c, http.StatusBadRequest, "invalid anime id")
 		return
 	}
 
-	err := h.svc.RemoveEntry(c.Request.Context(), userID, animeID)
+	err = h.svc.RemoveEntry(c.Request.Context(), userID, animeID)
 	if err != nil {
-		c.Status(http.StatusInternalServerError)
+		server.RespondError(
+			c,
+			http.StatusInternalServerError,
+			"watchlist_remove_failed",
+			"watchlist",
+			"failed to remove watchlist entry",
+			map[string]any{"user_id": userID, "anime_id": animeID},
+			err,
+		)
 		return
 	}
 
@@ -78,16 +95,24 @@ func (h *WatchlistHandler) HandleDeleteContinueWatching(c *gin.Context) {
 		userID = u.ID
 	}
 
-	animeID, _ := strconv.ParseInt(c.Param("id"), 10, 64)
+	animeID, err := strconv.ParseInt(c.Param("id"), 10, 64)
 
-	if animeID <= 0 {
+	if err != nil || animeID <= 0 {
-		c.Status(http.StatusBadRequest)
+		server.RespondHTMLOrJSONError(c, http.StatusBadRequest, "invalid anime id")
 		return
 	}
 
-	err := h.svc.DeleteContinueWatching(c.Request.Context(), userID, animeID)
+	err = h.svc.DeleteContinueWatching(c.Request.Context(), userID, animeID)
 	if err != nil {
-		c.Status(http.StatusInternalServerError)
+		server.RespondError(
+			c,
+			http.StatusInternalServerError,
+			"continue_watching_delete_failed",
+			"watchlist",
+			"failed to delete continue watching entry",
+			map[string]any{"user_id": userID, "anime_id": animeID},
+			err,
+		)
 		return
 	}
 
@@ -103,7 +128,15 @@ func (h *WatchlistHandler) HandleGetWatchlist(c *gin.Context) {
 
 	entries, err := h.svc.GetWatchlist(c.Request.Context(), userID)
 	if err != nil {
-		c.Status(http.StatusInternalServerError)
+		server.RespondError(
+			c,
+			http.StatusInternalServerError,
+			"watchlist_load_failed",
+			"watchlist",
+			"failed to load watchlist",
+			map[string]any{"user_id": userID},
+			err,
+		)
 		return
 	}