feat(repo): enhance MoveToArchive functionality to handle duplicates and improve error handling

backend/internal/repo/episode_repo.go

@@ -3,6 +3,7 @@ package repo
 import (
 	"context"
 	"errors"
+	"time"
 
 	"watch-party-backend/internal/core/episode"
 
@@ -140,68 +141,89 @@ func (r *pgxEpisodeRepo) MoveToArchive(ctx context.Context, ids []int64) (episod
 		return res, nil
 	}
 
+	requested := make(map[int64]struct{}, len(ids))
+	for _, id := range ids {
+		requested[id] = struct{}{}
+	}
+
 	tx, err := r.pool.Begin(ctx)
 	if err != nil {
 		return res, err
 	}
 	defer func() { _ = tx.Rollback(ctx) }()
 
-	// 1) Insert into archive from current (skip duplicates by id)
+	// Grab the rows we need to archive.
-	insRows, err := tx.Query(ctx, `
+	rows, err := tx.Query(ctx, `
-		INSERT INTO current_archive (
-			id, ep_num, ep_title, season_name, start_time, playback_length, current_ep, date_created
-		)
 		SELECT id, ep_num, ep_title, season_name, start_time, playback_length, current_ep, date_created
 		FROM current
 		WHERE id = ANY($1::bigint[])
-		ON CONFLICT (id) DO NOTHING
-		RETURNING id
 	`, ids)
 	if err != nil {
 		return res, err
 	}
-	for insRows.Next() {
+	defer rows.Close()
-		var id int64
+
-		if err := insRows.Scan(&id); err != nil {
+	for rows.Next() {
+		var (
+			id          int64
+			epNum       int
+			epTitle     string
+			seasonName  string
+			startTime   string
+			playback    string
+			currentEp   bool
+			dateCreated time.Time
+			archivedID  int64
+			inserted    bool
+		)
+		if err := rows.Scan(&id, &epNum, &epTitle, &seasonName, &startTime, &playback, &currentEp, &dateCreated); err != nil {
 			return res, err
 		}
+
+		// First try to insert with the same id; on conflict, insert with a new id.
+		err = tx.QueryRow(ctx, `
+			INSERT INTO current_archive (
+				id, ep_num, ep_title, season_name, start_time, playback_length, current_ep, date_created
+			)
+			VALUES ($1, $2, $3, $4, $5, $6, $7, $8)
+			ON CONFLICT (id) DO NOTHING
+			RETURNING id
+		`, id, epNum, epTitle, seasonName, startTime, playback, currentEp, dateCreated).Scan(&archivedID)
+		if err != nil && !errors.Is(err, pgx.ErrNoRows) {
+			return res, err
+		}
+		if err == nil {
+			inserted = true
+		}
+
+		if !inserted {
+			if err := tx.QueryRow(ctx, `
+				INSERT INTO current_archive (
+					id, ep_num, ep_title, season_name, start_time, playback_length, current_ep, date_created
+				)
+				VALUES (nextval(pg_get_serial_sequence('current','id')), $1, $2, $3, $4, $5, $6, $7)
+				RETURNING id
+			`, epNum, epTitle, seasonName, startTime, playback, currentEp, dateCreated).Scan(&archivedID); err != nil {
+				return res, err
+			}
+		}
+
+		// Delete from current using the original id.
+		if _, err := tx.Exec(ctx, `DELETE FROM current WHERE id = $1`, id); err != nil {
+			return res, err
+		}
+
 		res.MovedIDs = append(res.MovedIDs, id)
+		res.DeletedIDs = append(res.DeletedIDs, id)
+		delete(requested, id)
 	}
-	if err := insRows.Err(); err != nil {
+	if err := rows.Err(); err != nil {
 		return res, err
 	}
 
-	// 2) Delete from current only those actually inserted to archive
+	// Any ids not found are treated as skipped.
-	if len(res.MovedIDs) > 0 {
+	for id := range requested {
-		delRows, err := tx.Query(ctx, `
+		res.SkippedIDs = append(res.SkippedIDs, id)
-			DELETE FROM current
-			WHERE id = ANY($1::bigint[])
-			RETURNING id
-		`, res.MovedIDs)
-		if err != nil {
-			return res, err
-		}
-		for delRows.Next() {
-			var id int64
-			if err := delRows.Scan(&id); err != nil {
-				return res, err
-			}
-			res.DeletedIDs = append(res.DeletedIDs, id)
-		}
-		if err := delRows.Err(); err != nil {
-			return res, err
-		}
-	}
-
-	// 3) Compute skipped = requested - moved
-	sel := make(map[int64]struct{}, len(res.MovedIDs))
-	for _, id := range res.MovedIDs {
-		sel[id] = struct{}{}
-	}
-	for _, id := range ids {
-		if _, ok := sel[id]; !ok {
-			res.SkippedIDs = append(res.SkippedIDs, id)
-		}
 	}
 
 	if err := tx.Commit(ctx); err != nil {