392 lines
13 KiB
Go
392 lines
13 KiB
Go
// Package service — social bits of the BFF.
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//
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// `social_service.go` bundles three lightweight services (Post, Bookmark,
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// Collection) because each is small (10–40 LOC of logic) and they share the
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// same R2 + UserRepo dependencies. Keeping them together keeps `server.go`'s
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// init-wiring tidy without sprawling into 4 separate files.
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package service
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import (
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"context"
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"crypto/rand"
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"encoding/hex"
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"errors"
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"fmt"
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"path"
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"strings"
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"time"
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"github.com/prabhupadasays/spsays-bff/internal/model"
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"github.com/prabhupadasays/spsays-bff/internal/repository"
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)
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// Sentinels surfaced to handlers.
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var (
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ErrForbidden = errors.New("forbidden")
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ErrNotFound = errors.New("not found")
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)
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// ---------------------------------------------------------------------------
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// PostService
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// ---------------------------------------------------------------------------
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type PostService struct {
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posts *repository.PostRepo
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r2 *repository.R2
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}
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func NewPostService(posts *repository.PostRepo, r2 *repository.R2) *PostService {
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return &PostService{posts: posts, r2: r2}
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}
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// Create persists a new post. The caption is treated as opaque — we trust
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// the frontend to send the exact text the user selected. Source URL must be
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// a same-origin path (e.g. /books/bg/1/1?hl=…) — we strip the host if one
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// was provided so links can't be hijacked.
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func (s *PostService) Create(ctx context.Context, userID, caption, sourceURL, sourceTitle string, imageURLs []string) (*model.Post, error) {
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caption = strings.TrimSpace(caption)
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if caption == "" {
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return nil, errors.New("caption is required")
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}
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if len(caption) > 4000 {
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return nil, errors.New("caption too long (max 4000)")
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}
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sourceURL = stripHost(strings.TrimSpace(sourceURL))
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if sourceURL == "" || !strings.HasPrefix(sourceURL, "/") {
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return nil, errors.New("source_url must be an absolute path starting with /")
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}
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if len(imageURLs) > 5 {
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return nil, errors.New("a post can hold up to 5 images")
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}
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return s.posts.Create(ctx, userID, caption, sourceURL, sourceTitle, imageURLs)
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}
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// Get returns one post (public).
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func (s *PostService) Get(ctx context.Context, id string) (*model.Post, error) {
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return s.posts.FindByID(ctx, id)
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}
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// Delete checks ownership and removes the post.
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func (s *PostService) Delete(ctx context.Context, postID, callerID string) error {
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return s.posts.Delete(ctx, postID, callerID)
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}
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// ReplaceImages swaps the image set on a post. The caller must own the
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// post. Returns the fresh post payload so the client can reconcile its
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// local state without a separate fetch.
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func (s *PostService) ReplaceImages(ctx context.Context, postID, callerID string, imageURLs []string) (*model.Post, error) {
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if err := s.posts.ReplaceImages(ctx, postID, callerID, imageURLs); err != nil {
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return nil, err
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}
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return s.posts.FindByID(ctx, postID)
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}
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// ListByHandle is the public feed view.
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func (s *PostService) ListByHandle(ctx context.Context, handle string, limit, offset int) ([]model.Post, int, error) {
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if limit <= 0 || limit > 50 {
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limit = 20
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}
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if offset < 0 {
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offset = 0
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}
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return s.posts.ListByHandle(ctx, handle, limit, offset)
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}
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// ListMine is the owner's view of their own posts (drafts feature isn't a
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// thing yet, so this is equivalent to ListByHandle minus the handle lookup).
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func (s *PostService) ListMine(ctx context.Context, userID string, limit, offset int) ([]model.Post, int, error) {
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if limit <= 0 || limit > 50 {
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limit = 20
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}
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if offset < 0 {
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offset = 0
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}
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return s.posts.ListByUser(ctx, userID, limit, offset)
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}
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// ImagePresign returns a one-shot R2 PUT URL for a post image.
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// The key is namespaced under post-images/<user_id>/<random>.<ext>. We
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// don't tie it to a post_id at presign time because the post might not
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// exist yet — the user uploads images first, then submits the post with
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// the public URLs.
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func (s *PostService) ImagePresign(ctx context.Context, userID, contentType string) (uploadURL, publicURL string, err error) {
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return presignImage(ctx, s.r2, "post-images", userID, contentType)
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}
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// ---------------------------------------------------------------------------
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// BookmarkService
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// ---------------------------------------------------------------------------
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type BookmarkService struct {
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users *repository.UserRepo
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bookmarks *repository.BookmarkRepo
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}
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func NewBookmarkService(users *repository.UserRepo, bookmarks *repository.BookmarkRepo) *BookmarkService {
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return &BookmarkService{users: users, bookmarks: bookmarks}
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}
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// Create enforces the plan cap and inserts a new bookmark.
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//
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// If the same URL is already bookmarked (UNIQUE constraint), we return the
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// existing row as a 200 idempotent response instead of an error — clicking
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// "Bookmark" twice on the same passage should feel like a no-op.
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func (s *BookmarkService) Create(ctx context.Context, userID, sourceURL, sourceTitle string, excerpt, note *string) (*model.Bookmark, error) {
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u, err := s.users.FindByID(ctx, userID)
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if err != nil {
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return nil, err
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}
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current, err := s.bookmarks.CountByUser(ctx, userID)
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if err != nil {
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return nil, err
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}
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if err := EnforceBookmarkLimit(u.Plan, current); err != nil {
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return nil, err
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}
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b, err := s.bookmarks.Create(ctx, userID, stripHost(sourceURL), sourceTitle, excerpt, note)
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if err == nil {
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return b, nil
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}
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if errors.Is(err, repository.ErrBookmarkExists) {
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// Idempotent: return whatever is already there.
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list, lerr := s.bookmarks.ListByUser(ctx, userID)
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if lerr != nil {
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return nil, lerr
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}
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for _, existing := range list {
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if existing.SourceURL == stripHost(sourceURL) {
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return &existing, nil
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}
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}
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}
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return nil, err
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}
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// List returns the caller's bookmarks.
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func (s *BookmarkService) List(ctx context.Context, userID string) ([]model.Bookmark, error) {
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return s.bookmarks.ListByUser(ctx, userID)
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}
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// Delete removes a bookmark belonging to the caller.
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func (s *BookmarkService) Delete(ctx context.Context, id, userID string) error {
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return s.bookmarks.Delete(ctx, id, userID)
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}
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// ---------------------------------------------------------------------------
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// CollectionService
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// ---------------------------------------------------------------------------
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type CollectionService struct {
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users *repository.UserRepo
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collections *repository.CollectionRepo
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posts *repository.PostRepo
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r2 *repository.R2
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}
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func NewCollectionService(users *repository.UserRepo, collections *repository.CollectionRepo, posts *repository.PostRepo, r2 *repository.R2) *CollectionService {
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return &CollectionService{users: users, collections: collections, posts: posts, r2: r2}
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}
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// Create enforces per-visibility plan caps and inserts.
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func (s *CollectionService) Create(ctx context.Context, userID, title string, description, coverURL *string, isPublic bool) (*model.CollectionRecord, error) {
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if title = strings.TrimSpace(title); title == "" {
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return nil, errors.New("title is required")
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}
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if len(title) > 120 {
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return nil, errors.New("title too long (max 120)")
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}
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u, err := s.users.FindByID(ctx, userID)
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if err != nil {
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return nil, err
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}
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current, err := s.collections.CountByUserAndVisibility(ctx, userID, isPublic)
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if err != nil {
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return nil, err
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}
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if err := EnforceCollectionLimit(u.Plan, isPublic, current); err != nil {
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return nil, err
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}
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return s.collections.Create(ctx, userID, title, description, coverURL, isPublic)
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}
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// Update — only the owner may edit. Visibility changes that would exceed
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// the plan cap are blocked.
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func (s *CollectionService) Update(ctx context.Context, id, userID string, title, description, coverURL *string, isPublic *bool) (*model.CollectionRecord, error) {
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c, err := s.collections.FindByID(ctx, id)
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if err != nil {
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return nil, err
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}
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if c.UserID != userID {
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return nil, ErrForbidden
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}
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// If the caller is flipping visibility, make sure they wouldn't blow the cap.
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if isPublic != nil && *isPublic != c.IsPublic {
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u, err := s.users.FindByID(ctx, userID)
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if err != nil {
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return nil, err
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}
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current, err := s.collections.CountByUserAndVisibility(ctx, userID, *isPublic)
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if err != nil {
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return nil, err
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}
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if err := EnforceCollectionLimit(u.Plan, *isPublic, current); err != nil {
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return nil, err
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}
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}
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return s.collections.Update(ctx, id, userID, title, description, coverURL, isPublic)
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}
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// Delete — only the owner may delete.
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func (s *CollectionService) Delete(ctx context.Context, id, userID string) error {
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c, err := s.collections.FindByID(ctx, id)
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if err != nil {
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return err
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}
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if c.UserID != userID {
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return ErrForbidden
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}
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return s.collections.Delete(ctx, id, userID)
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}
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// ListMine returns the caller's collections (both public and private).
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func (s *CollectionService) ListMine(ctx context.Context, userID string) ([]model.CollectionRecord, error) {
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return s.collections.ListByUser(ctx, userID)
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}
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// AddItem inserts a post into a collection. Caller must own the collection.
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// We don't require ownership of the *post* — collections can curate other
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// users' public posts in a future iteration; for v1 the toolbar always
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// creates a fresh post owned by the caller before calling this.
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func (s *CollectionService) AddItem(ctx context.Context, collectionID, postID, callerID string) error {
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c, err := s.collections.FindByID(ctx, collectionID)
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if err != nil {
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return err
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}
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if c.UserID != callerID {
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return ErrForbidden
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}
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if _, err := s.posts.FindByID(ctx, postID); err != nil {
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return err
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}
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return s.collections.AddItem(ctx, collectionID, postID)
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}
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// SetItemOrder updates positions for the given post ids so the new order
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// matches the input array. Owner-only.
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func (s *CollectionService) SetItemOrder(ctx context.Context, collectionID, callerID string, postIDs []string) error {
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c, err := s.collections.FindByID(ctx, collectionID)
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if err != nil {
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return err
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}
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if c.UserID != callerID {
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return ErrForbidden
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}
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return s.collections.SetItemOrder(ctx, collectionID, postIDs)
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}
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// CollectionsContaining returns the ids of the caller's collections
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// that already include the given post. Used by the save-to-collection
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// drawer to disable rows the post is already in.
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func (s *CollectionService) CollectionsContaining(ctx context.Context, postID, callerID string) ([]string, error) {
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return s.collections.CollectionsContaining(ctx, postID, callerID)
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}
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// RemoveItem detaches a post from a collection (owner only).
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func (s *CollectionService) RemoveItem(ctx context.Context, collectionID, postID, callerID string) error {
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c, err := s.collections.FindByID(ctx, collectionID)
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if err != nil {
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return err
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}
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if c.UserID != callerID {
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return ErrForbidden
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}
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return s.collections.RemoveItem(ctx, collectionID, postID)
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}
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// Get returns one collection. Visibility is enforced by the caller —
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// `viewerID` is the calling user id ("" if anonymous). If the collection is
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// private and the viewer isn't the owner, returns ErrForbidden.
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func (s *CollectionService) Get(ctx context.Context, id, viewerID string) (*model.CollectionRecord, []model.Post, error) {
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c, err := s.collections.FindByID(ctx, id)
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if err != nil {
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return nil, nil, err
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}
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if !c.IsPublic && c.UserID != viewerID {
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return nil, nil, ErrForbidden
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}
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posts, err := s.collections.PostsIn(ctx, id)
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if err != nil {
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return nil, nil, err
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}
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return c, posts, nil
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}
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// CoverPresign returns a one-shot R2 PUT URL for a collection cover image.
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func (s *CollectionService) CoverPresign(ctx context.Context, userID, contentType string) (uploadURL, publicURL string, err error) {
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return presignImage(ctx, s.r2, "collection-covers", userID, contentType)
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}
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// ---------------------------------------------------------------------------
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// shared helpers
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// ---------------------------------------------------------------------------
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// presignImage builds an R2 presign for a user-scoped media key under the
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// given prefix. The random suffix invalidates browser caches when the image
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// is replaced.
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func presignImage(ctx context.Context, r2 *repository.R2, prefix, userID, contentType string) (uploadURL, publicURL string, err error) {
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if r2 == nil {
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return "", "", errors.New("media uploads are not configured")
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}
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ext, ok := imageExtensionFor(contentType)
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if !ok {
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return "", "", fmt.Errorf("unsupported content type: %s", contentType)
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}
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suffix := make([]byte, 8)
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if _, err := rand.Read(suffix); err != nil {
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return "", "", err
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}
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key := path.Join(prefix, userID, hex.EncodeToString(suffix)+ext)
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return r2.PresignPut(ctx, key, contentType, 5*time.Minute)
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}
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func imageExtensionFor(ct string) (string, bool) {
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switch ct {
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case "image/png":
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return ".png", true
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case "image/jpeg":
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return ".jpg", true
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case "image/webp":
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return ".webp", true
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case "image/gif":
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return ".gif", true
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default:
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return "", false
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}
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}
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// stripHost reduces "https://prabhupadasays.org/books/bg/1/1?hl=x" to
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// "/books/bg/1/1?hl=x" so we never store arbitrary external URLs.
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// Anything that doesn't parse cleanly is returned unchanged (and rejected
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// later by the prefix-check in the service).
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func stripHost(u string) string {
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u = strings.TrimSpace(u)
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if u == "" {
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return u
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}
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if strings.HasPrefix(u, "/") {
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return u
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}
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for _, prefix := range []string{"http://", "https://"} {
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if strings.HasPrefix(u, prefix) {
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rest := u[len(prefix):]
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if i := strings.IndexByte(rest, '/'); i >= 0 {
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return rest[i:]
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}
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return "/"
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}
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}
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return u
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}
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