258 lines
8.1 KiB
Go
258 lines
8.1 KiB
Go
package repository
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import (
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"context"
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"errors"
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"fmt"
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"github.com/jackc/pgx/v5"
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"github.com/prabhupadasays/spsays-bff/internal/model"
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)
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// ErrPostNotFound is returned by lookup methods when no row matches.
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var ErrPostNotFound = errors.New("post not found")
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// PostRepo wraps Postgres access for posts + post_images.
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type PostRepo struct{ pg *Postgres }
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func NewPostRepo(pg *Postgres) *PostRepo { return &PostRepo{pg: pg} }
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// Create inserts a post + its images in a single transaction so we never
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// end up with orphan images.
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func (r *PostRepo) Create(ctx context.Context, userID, caption, sourceURL, sourceTitle string, imageURLs []string) (*model.Post, error) {
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tx, err := r.pg.Pool.Begin(ctx)
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if err != nil {
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return nil, fmt.Errorf("begin tx: %w", err)
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}
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defer func() { _ = tx.Rollback(ctx) }()
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p := &model.Post{}
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err = tx.QueryRow(ctx, `
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INSERT INTO posts (user_id, caption, source_url, source_title)
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VALUES ($1, $2, $3, $4)
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RETURNING id, user_id, caption, source_url, COALESCE(source_title, ''), created_at, updated_at`,
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userID, caption, sourceURL, sourceTitle,
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).Scan(&p.ID, &p.UserID, &p.Caption, &p.SourceURL, &p.SourceTitle, &p.CreatedAt, &p.UpdatedAt)
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if err != nil {
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return nil, fmt.Errorf("insert post: %w", err)
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}
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for i, url := range imageURLs {
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var img model.PostImage
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err = tx.QueryRow(ctx, `
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INSERT INTO post_images (post_id, url, position)
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VALUES ($1, $2, $3)
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RETURNING id, url, position`,
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p.ID, url, i,
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).Scan(&img.ID, &img.URL, &img.Position)
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if err != nil {
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return nil, fmt.Errorf("insert post image %d: %w", i, err)
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}
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p.Images = append(p.Images, img)
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}
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if err := tx.Commit(ctx); err != nil {
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return nil, fmt.Errorf("commit: %w", err)
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}
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return p, nil
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}
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// ReplaceImages atomically swaps a post's image set. Ownership is
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// enforced inside the tx by locking the post row and checking user_id —
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// non-owners get ErrPostNotFound (we don't distinguish "not yours" from
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// "doesn't exist" to non-owners). Existing rows are wiped, the new URLs
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// are inserted with sequential positions, and the post's `updated_at`
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// is touched so list views can sort by recency if needed later.
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func (r *PostRepo) ReplaceImages(ctx context.Context, postID, userID string, imageURLs []string) error {
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tx, err := r.pg.Pool.Begin(ctx)
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if err != nil {
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return fmt.Errorf("begin tx: %w", err)
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}
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defer func() { _ = tx.Rollback(ctx) }()
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var owner string
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if err := tx.QueryRow(ctx, `SELECT user_id FROM posts WHERE id = $1 FOR UPDATE`, postID).Scan(&owner); err != nil {
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if errors.Is(err, pgx.ErrNoRows) {
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return ErrPostNotFound
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}
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return fmt.Errorf("lock post: %w", err)
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}
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if owner != userID {
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return ErrPostNotFound
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}
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if _, err := tx.Exec(ctx, `DELETE FROM post_images WHERE post_id = $1`, postID); err != nil {
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return fmt.Errorf("delete images: %w", err)
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}
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for i, url := range imageURLs {
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if _, err := tx.Exec(ctx, `
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INSERT INTO post_images (post_id, url, position)
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VALUES ($1, $2, $3)`, postID, url, i,
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); err != nil {
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return fmt.Errorf("insert image %d: %w", i, err)
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}
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}
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if _, err := tx.Exec(ctx, `UPDATE posts SET updated_at = now() WHERE id = $1`, postID); err != nil {
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return fmt.Errorf("touch post: %w", err)
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}
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return tx.Commit(ctx)
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}
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// FindByID returns one post with its images and author info.
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func (r *PostRepo) FindByID(ctx context.Context, id string) (*model.Post, error) {
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const q = `
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SELECT p.id, p.user_id, p.caption, p.source_url, COALESCE(p.source_title, ''),
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p.created_at, p.updated_at, u.name, u.handle, u.avatar_url
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FROM posts p
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JOIN users u ON u.id = p.user_id
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WHERE p.id = $1`
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p := &model.Post{}
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err := r.pg.Pool.QueryRow(ctx, q, id).Scan(
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&p.ID, &p.UserID, &p.Caption, &p.SourceURL, &p.SourceTitle,
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&p.CreatedAt, &p.UpdatedAt,
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&p.AuthorName, &p.AuthorHandle, &p.AuthorAvatarURL,
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)
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if err != nil {
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if errors.Is(err, pgx.ErrNoRows) {
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return nil, ErrPostNotFound
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}
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return nil, fmt.Errorf("find post: %w", err)
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}
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imgs, err := r.imagesFor(ctx, []string{p.ID})
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if err != nil {
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return nil, err
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}
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p.Images = imgs[p.ID]
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return p, nil
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}
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// ListByHandle returns the public feed for a user, newest-first, paginated.
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func (r *PostRepo) ListByHandle(ctx context.Context, handle string, limit, offset int) ([]model.Post, int, error) {
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var total int
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if err := r.pg.Pool.QueryRow(ctx, `
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SELECT COUNT(*) FROM posts p
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JOIN users u ON u.id = p.user_id
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WHERE u.handle = $1`, handle,
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).Scan(&total); err != nil {
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return nil, 0, fmt.Errorf("count posts: %w", err)
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}
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const q = `
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SELECT p.id, p.user_id, p.caption, p.source_url, COALESCE(p.source_title, ''),
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p.created_at, p.updated_at, u.name, u.handle, u.avatar_url
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FROM posts p
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JOIN users u ON u.id = p.user_id
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WHERE u.handle = $1
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ORDER BY p.created_at DESC
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LIMIT $2 OFFSET $3`
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return r.collectPosts(ctx, total, q, handle, limit, offset)
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}
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// ListByUser returns the user's own posts (private listing — same shape).
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func (r *PostRepo) ListByUser(ctx context.Context, userID string, limit, offset int) ([]model.Post, int, error) {
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var total int
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if err := r.pg.Pool.QueryRow(ctx, `SELECT COUNT(*) FROM posts WHERE user_id = $1`, userID).Scan(&total); err != nil {
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return nil, 0, fmt.Errorf("count posts: %w", err)
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}
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const q = `
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SELECT p.id, p.user_id, p.caption, p.source_url, COALESCE(p.source_title, ''),
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p.created_at, p.updated_at, u.name, u.handle, u.avatar_url
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FROM posts p
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JOIN users u ON u.id = p.user_id
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WHERE p.user_id = $1
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ORDER BY p.created_at DESC
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LIMIT $2 OFFSET $3`
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return r.collectPosts(ctx, total, q, userID, limit, offset)
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}
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// Delete removes a post only if it belongs to the caller.
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func (r *PostRepo) Delete(ctx context.Context, postID, userID string) error {
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tag, err := r.pg.Pool.Exec(ctx,
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`DELETE FROM posts WHERE id = $1 AND user_id = $2`, postID, userID)
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if err != nil {
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return fmt.Errorf("delete post: %w", err)
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}
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if tag.RowsAffected() == 0 {
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return ErrPostNotFound
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}
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return nil
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}
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// CountByUser is used by services that need to know how many posts a user
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// has — currently the public-profile endpoint only.
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func (r *PostRepo) CountByUser(ctx context.Context, userID string) (int, error) {
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var n int
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err := r.pg.Pool.QueryRow(ctx, `SELECT COUNT(*) FROM posts WHERE user_id = $1`, userID).Scan(&n)
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if err != nil {
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return 0, fmt.Errorf("count user posts: %w", err)
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}
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return n, nil
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}
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// --- internal helpers ---
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func (r *PostRepo) collectPosts(ctx context.Context, total int, query string, args ...any) ([]model.Post, int, error) {
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rows, err := r.pg.Pool.Query(ctx, query, args...)
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if err != nil {
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return nil, 0, fmt.Errorf("query posts: %w", err)
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}
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defer rows.Close()
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posts := []model.Post{}
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ids := []string{}
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for rows.Next() {
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var p model.Post
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if err := rows.Scan(
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&p.ID, &p.UserID, &p.Caption, &p.SourceURL, &p.SourceTitle,
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&p.CreatedAt, &p.UpdatedAt,
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&p.AuthorName, &p.AuthorHandle, &p.AuthorAvatarURL,
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); err != nil {
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return nil, 0, fmt.Errorf("scan post: %w", err)
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}
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posts = append(posts, p)
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ids = append(ids, p.ID)
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}
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if err := rows.Err(); err != nil {
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return nil, 0, fmt.Errorf("iterate posts: %w", err)
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}
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if len(ids) > 0 {
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imgs, err := r.imagesFor(ctx, ids)
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if err != nil {
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return nil, 0, err
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}
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for i := range posts {
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posts[i].Images = imgs[posts[i].ID]
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}
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}
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return posts, total, nil
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}
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// imagesFor returns a map post_id → [images...] for a batch of post IDs in
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// a single query so we don't N+1 the feed endpoint.
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func (r *PostRepo) imagesFor(ctx context.Context, postIDs []string) (map[string][]model.PostImage, error) {
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out := make(map[string][]model.PostImage, len(postIDs))
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if len(postIDs) == 0 {
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return out, nil
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}
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rows, err := r.pg.Pool.Query(ctx, `
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SELECT post_id, id, url, position
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FROM post_images
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WHERE post_id = ANY($1)
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ORDER BY post_id, position`, postIDs,
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)
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if err != nil {
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return nil, fmt.Errorf("query post images: %w", err)
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}
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defer rows.Close()
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for rows.Next() {
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var postID string
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var img model.PostImage
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if err := rows.Scan(&postID, &img.ID, &img.URL, &img.Position); err != nil {
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return nil, fmt.Errorf("scan post image: %w", err)
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}
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out[postID] = append(out[postID], img)
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}
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return out, rows.Err()
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}
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