Files
TermorServer/internal/playlist/service.go

358 lines
10 KiB
Go

package playlist
import (
"context"
"crypto/sha1"
"database/sql"
"encoding/hex"
"errors"
"fmt"
"slices"
"strconv"
"strings"
"time"
)
var ErrNotFound = errors.New("playlist not found")
type Summary struct {
ID string `json:"id"`
Name string `json:"name"`
Comment string `json:"comment"`
Public bool `json:"public"`
SongCount int `json:"songCount"`
Duration int `json:"durationSeconds"`
CreatedAt time.Time `json:"createdAt"`
UpdatedAt time.Time `json:"updatedAt"`
}
type Track struct {
ID string `json:"id"`
AlbumID string `json:"albumId"`
ArtistID string `json:"artistId"`
Title string `json:"title"`
ArtistName string `json:"artistName"`
AlbumTitle string `json:"albumTitle"`
TrackNumber int `json:"trackNumber"`
DurationSeconds int `json:"durationSeconds"`
CoverArtID string `json:"coverArtId"`
}
type Detail struct {
Summary
Tracks []Track `json:"tracks"`
}
type CreateInput struct {
Name string `json:"name"`
Comment string `json:"comment"`
Public bool `json:"public"`
TrackIDs []string `json:"trackIds"`
}
type UpdateInput struct {
Name *string `json:"name"`
Comment *string `json:"comment"`
Public *bool `json:"public"`
AddTrackIDs []string `json:"addTrackIds"`
RemoveTrackIDs []string `json:"removeTrackIds"`
RemovePositions []int `json:"removePositions"`
}
type Service struct {
db *sql.DB
}
func NewService(db *sql.DB) *Service {
return &Service{db: db}
}
func (s *Service) List(ctx context.Context, userID string) ([]Summary, error) {
rows, err := s.db.QueryContext(
ctx,
`SELECT p.id, p.name, COALESCE(p.comment, ''), p.public, COALESCE(COUNT(pt.track_id), 0), COALESCE(SUM(t.duration_seconds), 0), p.created_at, p.updated_at
FROM playlists p
LEFT JOIN playlist_tracks pt ON pt.playlist_id = p.id
LEFT JOIN tracks t ON t.id = pt.track_id
WHERE p.user_id = ?
GROUP BY p.id, p.name, p.comment, p.public, p.created_at, p.updated_at
ORDER BY p.updated_at DESC, p.name ASC`,
userID,
)
if err != nil {
return nil, fmt.Errorf("query playlists: %w", err)
}
defer rows.Close()
var items []Summary
for rows.Next() {
var item Summary
var createdAt string
var updatedAt string
var public int
if err := rows.Scan(&item.ID, &item.Name, &item.Comment, &public, &item.SongCount, &item.Duration, &createdAt, &updatedAt); err != nil {
return nil, fmt.Errorf("scan playlists: %w", err)
}
item.Public = public == 1
item.CreatedAt = parseTime(createdAt)
item.UpdatedAt = parseTime(updatedAt)
items = append(items, item)
}
return items, rows.Err()
}
func (s *Service) ByID(ctx context.Context, userID, playlistID string) (Detail, error) {
summary, err := s.loadSummary(ctx, userID, playlistID)
if err != nil {
return Detail{}, err
}
rows, err := s.db.QueryContext(
ctx,
`SELECT t.id, t.album_id, t.artist_id, t.title, a.name, al.title, COALESCE(t.track_number, 0), COALESCE(t.duration_seconds, 0), COALESCE(al.cover_art_id, '')
FROM playlist_tracks pt
JOIN tracks t ON t.id = pt.track_id
JOIN artists a ON a.id = t.artist_id
JOIN albums al ON al.id = t.album_id
WHERE pt.playlist_id = ?
ORDER BY pt.position ASC`,
playlistID,
)
if err != nil {
return Detail{}, fmt.Errorf("query playlist tracks: %w", err)
}
defer rows.Close()
detail := Detail{Summary: summary}
for rows.Next() {
var track Track
if err := rows.Scan(&track.ID, &track.AlbumID, &track.ArtistID, &track.Title, &track.ArtistName, &track.AlbumTitle, &track.TrackNumber, &track.DurationSeconds, &track.CoverArtID); err != nil {
return Detail{}, fmt.Errorf("scan playlist track: %w", err)
}
detail.Tracks = append(detail.Tracks, track)
}
return detail, rows.Err()
}
func (s *Service) Create(ctx context.Context, userID string, input CreateInput) (Detail, error) {
name := strings.TrimSpace(input.Name)
if name == "" {
name = "Новый плейлист"
}
now := time.Now().UTC().Format(time.RFC3339)
playlistID := hashID("playlist", userID, name, now)
tx, err := s.db.BeginTx(ctx, nil)
if err != nil {
return Detail{}, fmt.Errorf("begin create playlist: %w", err)
}
if _, err := tx.ExecContext(ctx, `INSERT INTO playlists (id, user_id, name, comment, public, created_at, updated_at) VALUES (?, ?, ?, ?, ?, ?, ?)`, playlistID, userID, name, strings.TrimSpace(input.Comment), boolToInt(input.Public), now, now); err != nil {
_ = tx.Rollback()
return Detail{}, fmt.Errorf("insert playlist: %w", err)
}
if err := s.replaceTracksTx(ctx, tx, playlistID, input.TrackIDs); err != nil {
_ = tx.Rollback()
return Detail{}, err
}
if err := tx.Commit(); err != nil {
return Detail{}, fmt.Errorf("commit create playlist: %w", err)
}
return s.ByID(ctx, userID, playlistID)
}
func (s *Service) Update(ctx context.Context, userID, playlistID string, input UpdateInput) (Detail, error) {
detail, err := s.ByID(ctx, userID, playlistID)
if err != nil {
return Detail{}, err
}
nextTrackIDs := make([]string, 0, len(detail.Tracks))
for _, track := range detail.Tracks {
nextTrackIDs = append(nextTrackIDs, track.ID)
}
if len(input.RemovePositions) > 0 {
slices.Sort(input.RemovePositions)
for index := len(input.RemovePositions) - 1; index >= 0; index -= 1 {
position := input.RemovePositions[index]
if position < 0 || position >= len(nextTrackIDs) {
continue
}
nextTrackIDs = append(nextTrackIDs[:position], nextTrackIDs[position+1:]...)
}
}
if len(input.RemoveTrackIDs) > 0 {
removeSet := map[string]struct{}{}
for _, id := range input.RemoveTrackIDs {
removeSet[id] = struct{}{}
}
filtered := nextTrackIDs[:0]
for _, id := range nextTrackIDs {
if _, found := removeSet[id]; !found {
filtered = append(filtered, id)
}
}
nextTrackIDs = filtered
}
nextTrackIDs = append(nextTrackIDs, input.AddTrackIDs...)
tx, err := s.db.BeginTx(ctx, nil)
if err != nil {
return Detail{}, fmt.Errorf("begin update playlist: %w", err)
}
name := detail.Name
if input.Name != nil && strings.TrimSpace(*input.Name) != "" {
name = strings.TrimSpace(*input.Name)
}
comment := detail.Comment
if input.Comment != nil {
comment = strings.TrimSpace(*input.Comment)
}
publicValue := detail.Public
if input.Public != nil {
publicValue = *input.Public
}
if _, err := tx.ExecContext(ctx, `UPDATE playlists SET name = ?, comment = ?, public = ?, updated_at = ? WHERE id = ? AND user_id = ?`, name, comment, boolToInt(publicValue), time.Now().UTC().Format(time.RFC3339), playlistID, userID); err != nil {
_ = tx.Rollback()
return Detail{}, fmt.Errorf("update playlist metadata: %w", err)
}
if err := s.replaceTracksTx(ctx, tx, playlistID, nextTrackIDs); err != nil {
_ = tx.Rollback()
return Detail{}, err
}
if err := tx.Commit(); err != nil {
return Detail{}, fmt.Errorf("commit update playlist: %w", err)
}
return s.ByID(ctx, userID, playlistID)
}
func (s *Service) Delete(ctx context.Context, userID, playlistID string) error {
tx, err := s.db.BeginTx(ctx, nil)
if err != nil {
return fmt.Errorf("begin delete playlist: %w", err)
}
result, err := tx.ExecContext(ctx, `DELETE FROM playlists WHERE id = ? AND user_id = ?`, playlistID, userID)
if err != nil {
_ = tx.Rollback()
return fmt.Errorf("delete playlist: %w", err)
}
rows, err := result.RowsAffected()
if err != nil {
_ = tx.Rollback()
return fmt.Errorf("playlist rows affected: %w", err)
}
if rows == 0 {
_ = tx.Rollback()
return ErrNotFound
}
if _, err := tx.ExecContext(ctx, `DELETE FROM playlist_tracks WHERE playlist_id = ?`, playlistID); err != nil {
_ = tx.Rollback()
return fmt.Errorf("delete playlist tracks: %w", err)
}
if err := tx.Commit(); err != nil {
return fmt.Errorf("commit delete playlist: %w", err)
}
return nil
}
func (s *Service) loadSummary(ctx context.Context, userID, playlistID string) (Summary, error) {
var summary Summary
var createdAt string
var updatedAt string
var public int
err := s.db.QueryRowContext(
ctx,
`SELECT p.id, p.name, COALESCE(p.comment, ''), p.public, COALESCE(COUNT(pt.track_id), 0), COALESCE(SUM(t.duration_seconds), 0), p.created_at, p.updated_at
FROM playlists p
LEFT JOIN playlist_tracks pt ON pt.playlist_id = p.id
LEFT JOIN tracks t ON t.id = pt.track_id
WHERE p.id = ? AND p.user_id = ?
GROUP BY p.id, p.name, p.comment, p.public, p.created_at, p.updated_at`,
playlistID,
userID,
).Scan(&summary.ID, &summary.Name, &summary.Comment, &public, &summary.SongCount, &summary.Duration, &createdAt, &updatedAt)
if err != nil {
if errors.Is(err, sql.ErrNoRows) {
return Summary{}, ErrNotFound
}
return Summary{}, fmt.Errorf("load playlist summary: %w", err)
}
summary.Public = public == 1
summary.CreatedAt = parseTime(createdAt)
summary.UpdatedAt = parseTime(updatedAt)
return summary, nil
}
func (s *Service) replaceTracksTx(ctx context.Context, tx *sql.Tx, playlistID string, trackIDs []string) error {
if _, err := tx.ExecContext(ctx, `DELETE FROM playlist_tracks WHERE playlist_id = ?`, playlistID); err != nil {
return fmt.Errorf("clear playlist tracks: %w", err)
}
position := 0
for _, trackID := range trackIDs {
if strings.TrimSpace(trackID) == "" {
continue
}
var exists int
if err := tx.QueryRowContext(ctx, `SELECT COUNT(*) FROM tracks WHERE id = ?`, trackID).Scan(&exists); err != nil {
return fmt.Errorf("check playlist track: %w", err)
}
if exists == 0 {
continue
}
if _, err := tx.ExecContext(ctx, `INSERT INTO playlist_tracks (playlist_id, track_id, position) VALUES (?, ?, ?)`, playlistID, trackID, position); err != nil {
return fmt.Errorf("insert playlist track: %w", err)
}
position += 1
}
return nil
}
func parseTime(raw string) time.Time {
parsed, err := time.Parse(time.RFC3339, raw)
if err != nil {
return time.Time{}
}
return parsed
}
func boolToInt(value bool) int {
if value {
return 1
}
return 0
}
func hashID(parts ...string) string {
sum := sha1.Sum([]byte(strings.Join(parts, "::")))
return hex.EncodeToString(sum[:])
}
func ParseIndices(values []string) []int {
var parsed []int
for _, value := range values {
index, err := strconv.Atoi(strings.TrimSpace(value))
if err == nil {
parsed = append(parsed, index)
}
}
return parsed
}