REFACTOR: Optimized Catagory IDs

cms/internal/handlers/videos.go

@@ -1,6 +1,7 @@
 package handlers
 
 import (
+	"context"
 	"crypto/rand"
 	"encoding/hex"
 	"encoding/json"
@@ -8,6 +9,7 @@ import (
 	"log"
 	"net/http"
 	"path/filepath"
+	"strconv"
 	"strings"
 	"thamanyah/cms/v2/internal/api"
 	"thamanyah/cms/v2/internal/services"
@@ -23,7 +25,7 @@ const (
 // ListCategories returns the categories a video may be assigned to.
 //
 //	@Summary		List video categories
-//	@Description	Returns the fixed lookup set of categories a video can belong to. Values from this list are the only ones accepted in the `categories` field of POST /api/videos.
+//	@Description	Returns the fixed lookup set of categories a video can belong to, each with the id used to reference it. The `id` values from this list are the only ones accepted in the `categoryIds` field of POST /api/videos.
 //	@Tags			categories
 //	@Produce		json
 //	@Success		200	{object}	api.CategoriesResponse
@@ -38,10 +40,11 @@ func ListCategories(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	if categories == nil {
-		categories = []string{}
+	body := make([]api.Category, 0, len(categories))
+	for _, category := range categories {
+		body = append(body, api.Category{ID: category.ID, Name: category.Name})
 	}
-	writeJSON(w, http.StatusOK, api.CategoriesResponse{Categories: categories})
+	writeJSON(w, http.StatusOK, api.CategoriesResponse{Categories: body})
 }
 
 // allowedUploadContentTypes is the set of media types accepted for upload,
@@ -108,11 +111,11 @@ func PresignVideoUpload(w http.ResponseWriter, r *http.Request) {
 //	@Tags			videos
 //	@Accept			json
 //	@Produce		json
-//	@Param			request	body		api.CompleteRequest	true	"Video metadata plus the storage key from the presign step. title and key are required; categories must be values from GET /api/categories."
-//	@Success		201		{object}	api.VideoResponse
+//	@Param			request	body		api.CompleteRequest	true	"Video metadata plus the storage key from the presign step. title, key and categoryIds are required; categoryIds must hold at least one id from GET /api/categories."
+//	@Success		201		{object}	api.CompleteResponse
 //	@Failure		400		{object}	api.ProblemDetails	"Request body was not valid JSON"
-//	@Failure		422		{object}	api.ProblemDetails	"title was empty, or key was missing or not a key issued by this API"
-//	@Failure		500		{object}	api.ProblemDetails	"Transcoding job could not be queued, or the video record could not be saved"
+//	@Failure		422		{object}	api.ProblemDetails	"title was empty, key was missing or not a key issued by this API, or categoryIds was empty or contained an id that does not exist"
+//	@Failure		500		{object}	api.ProblemDetails	"Categories could not be read, the transcoding job could not be queued, or the video record could not be saved"
 //	@Router			/api/videos [post]
 func CompleteVideoUpload(w http.ResponseWriter, r *http.Request) {
 	r.Body = http.MaxBytesReader(w, r.Body, maxJSONBodySize)
@@ -138,11 +141,23 @@ func CompleteVideoUpload(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	categories := make([]string, 0, len(req.Categories))
-	for _, category := range req.Categories {
-		if category = strings.TrimSpace(category); category != "" {
-			categories = append(categories, category)
-		}
+	if len(req.CategoryIDs) == 0 {
+		writeProblem(w, http.StatusUnprocessableEntity, "At least one category is required.",
+			"The 'categoryIds' field was absent or empty. Every video belongs to at least one category; send ids taken from the 'id' field of GET /api/categories.")
+		return
+	}
+
+	categoryIDs, unknown, err := resolveCategoryIDs(r.Context(), req.CategoryIDs)
+	if err != nil {
+		log.Printf("Something Went Wrong Loading Categories: %s", err)
+		writeProblem(w, http.StatusInternalServerError, "Something Went Wrong Loading Categories",
+			"The submitted category ids could not be checked against the database, so no video record was created. This is a server-side fault; the uploaded file is still in storage, so retry this request with the same 'key'.")
+		return
+	}
+	if len(unknown) > 0 {
+		writeProblem(w, http.StatusUnprocessableEntity, "Unknown category.",
+			fmt.Sprintf("The 'categoryIds' field referenced %s, which do not exist. Send ids taken from the 'id' field of GET /api/categories.", formatCategoryIDs(unknown)))
+		return
 	}
 
 	jobID, err := services.MediaConvertClient.QueueEncodingJob(r.Context(), key)
@@ -156,7 +171,7 @@ func CompleteVideoUpload(w http.ResponseWriter, r *http.Request) {
 	video, err := services.DB.CreateVideo(r.Context(), services.Video{
 		Title:             title,
 		Description:       strings.TrimSpace(req.Description),
-		Categories:        categories,
+		CategoryIDs:       categoryIDs,
 		Tags:              strings.TrimSpace(req.Tags),
 		FileName:          strings.TrimSpace(req.FileName),
 		StorageKey:        key,
@@ -175,7 +190,7 @@ func CompleteVideoUpload(w http.ResponseWriter, r *http.Request) {
 		ID:                video.ID,
 		Title:             video.Title,
 		Description:       video.Description,
-		Categories:        video.Categories,
+		CategoryIDs:       video.CategoryIDs,
 		Tags:              video.Tags,
 		FileName:          video.FileName,
 		StorageKey:        video.StorageKey,
@@ -187,6 +202,53 @@ func CompleteVideoUpload(w http.ResponseWriter, r *http.Request) {
 	})
 }
 
+// resolveCategoryIDs deduplicates the submitted category ids, preserving the
+// order they arrived in, and splits them into ids that exist and ids that do
+// not. Checking them here rather than leaning on the video_categories foreign
+// key keeps an unknown id from surfacing only after a transcoding job has
+// already been queued — and the duplicate pass keeps a repeated id from
+// tripping the join table's composite primary key. Callers reject an empty
+// list before calling, so a non-empty submitted list always yields either at
+// least one known id or at least one unknown one.
+func resolveCategoryIDs(ctx context.Context, submitted []int16) (known, unknown []int16, err error) {
+	known = make([]int16, 0, len(submitted))
+
+	categories, err := services.DB.ListCategories(ctx)
+	if err != nil {
+		return nil, nil, err
+	}
+	exists := make(map[int16]struct{}, len(categories))
+	for _, category := range categories {
+		exists[category.ID] = struct{}{}
+	}
+
+	seen := make(map[int16]struct{}, len(submitted))
+	for _, id := range submitted {
+		if _, duplicate := seen[id]; duplicate {
+			continue
+		}
+		seen[id] = struct{}{}
+
+		if _, ok := exists[id]; ok {
+			known = append(known, id)
+		} else {
+			unknown = append(unknown, id)
+		}
+	}
+	return known, unknown, nil
+}
+
+func formatCategoryIDs(ids []int16) string {
+	formatted := make([]string, 0, len(ids))
+	for _, id := range ids {
+		formatted = append(formatted, strconv.Itoa(int(id)))
+	}
+	if len(formatted) == 1 {
+		return "id " + formatted[0]
+	}
+	return "ids " + strings.Join(formatted, ", ")
+}
+
 func randomFilename(original string) (string, error) {
 	ext := filepath.Ext(filepath.Base(original))
 	buf := make([]byte, 16)