From ca6603a994d2f9ef61cf68eed99afe6ca2581657 Mon Sep 17 00:00:00 2001
From: DiheChen <michikawachin@outlook.com>
Date: Mon, 9 Nov 2026 21:26:41 +0800
Subject: [PATCH] feat: manage member playlists with server-side track metadata

---
 internal/app/playlist/playlist.go      | 164 +++++++++++++++++
 internal/app/playlist/playlist_test.go | 234 +++++++++++++++++++++++++
 2 files changed, 398 insertions(+)
 create mode 100644 internal/app/playlist/playlist.go
 create mode 100644 internal/app/playlist/playlist_test.go

diff --git a/internal/app/playlist/playlist.go b/internal/app/playlist/playlist.go
new file mode 100644
index 0000000..cf76620
--- /dev/null
+++ b/internal/app/playlist/playlist.go
@@ -0,0 +1,164 @@
+package playlist
+
+import (
+	"context"
+	"errors"
+	"strings"
+	"time"
+	"unicode"
+	"unicode/utf8"
+
+	"github.com/dihemoe/alisten/internal/app/catalog"
+	"github.com/dihemoe/alisten/internal/app/port"
+	"github.com/dihemoe/alisten/internal/domain/track"
+)
+
+const (
+	maxPlaylists  = 50
+	maxItems      = 1000
+	maxNameLength = 50
+	// 收藏可能要向音源查询元数据：额度防止批量请求让共用的音源账号被平台限流。
+	addBurst  = 30
+	addRefill = 2 * time.Second
+)
+
+var (
+	ErrNotRegistered    = errors.New("注册账号之后才能使用歌单")
+	ErrInvalidName      = errors.New("name：去掉首尾空白后应有 1 到 50 个字符，其中至少一个看得见，不能包含控制字符")
+	ErrTooManyPlaylists = errors.New("最多只能建 50 个歌单")
+	ErrPlaylistFull     = errors.New("一个歌单最多 1000 首歌")
+	ErrTrackNotReady    = errors.New("这首歌还在准备，准备好之后再保存")
+	ErrTooFast          = errors.New("操作太频繁，请稍后再试。")
+)
+
+type Service struct {
+	playlists port.Playlists
+	members   port.Members
+	tracks    port.Tracks
+	catalog   *catalog.Service
+	quota     port.AccountQuota
+}
+
+func New(playlists port.Playlists, members port.Members, tracks port.Tracks, catalog *catalog.Service, quota port.AccountQuota) *Service {
+	return &Service{playlists: playlists, members: members, tracks: tracks, catalog: catalog, quota: quota}
+}
+
+func (s *Service) List(ctx context.Context, memberID string) ([]port.PlaylistRecord, error) {
+	if err := s.registered(ctx, memberID); err != nil {
+		return nil, err
+	}
+	return s.playlists.MemberPlaylists(ctx, memberID)
+}
+
+func (s *Service) Create(ctx context.Context, memberID, name string) (port.PlaylistRecord, error) {
+	if err := s.registered(ctx, memberID); err != nil {
+		return port.PlaylistRecord{}, err
+	}
+	name, err := validName(name)
+	if err != nil {
+		return port.PlaylistRecord{}, err
+	}
+	p, err := s.playlists.CreatePlaylist(ctx, memberID, name, maxPlaylists)
+	if errors.Is(err, port.ErrPlaylistLimit) {
+		return port.PlaylistRecord{}, ErrTooManyPlaylists
+	}
+	return p, err
+}
+
+func (s *Service) Rename(ctx context.Context, memberID, id, name string) error {
+	if err := s.registered(ctx, memberID); err != nil {
+		return err
+	}
+	name, err := validName(name)
+	if err != nil {
+		return err
+	}
+	return s.playlists.RenamePlaylist(ctx, memberID, id, name)
+}
+
+func (s *Service) Delete(ctx context.Context, memberID, id string) error {
+	if err := s.registered(ctx, memberID); err != nil {
+		return err
+	}
+	return s.playlists.DeletePlaylist(ctx, memberID, id)
+}
+
+func (s *Service) Items(ctx context.Context, memberID, id string) ([]port.PlaylistItem, error) {
+	if err := s.registered(ctx, memberID); err != nil {
+		return nil, err
+	}
+	return s.playlists.PlaylistItems(ctx, memberID, id)
+}
+
+// 链接曲目的 t.ID 必须已经按 track.LinkID 规范化。
+func (s *Service) Add(ctx context.Context, memberID, id string, t track.Track) (port.PlaylistItem, error) {
+	if err := s.registered(ctx, memberID); err != nil {
+		return port.PlaylistItem{}, err
+	}
+	wait, err := s.quota.Take(ctx, "playlist:member:"+memberID, addBurst, addRefill)
+	if err != nil {
+		return port.PlaylistItem{}, err
+	}
+	if wait > 0 {
+		return port.PlaylistItem{}, ErrTooFast
+	}
+	meta, err := s.meta(ctx, t)
+	if err != nil {
+		return port.PlaylistItem{}, err
+	}
+	item := port.PlaylistItem{Track: t, Meta: meta}
+	err = s.playlists.AddPlaylistItem(ctx, memberID, id, item, maxItems)
+	if errors.Is(err, port.ErrPlaylistLimit) {
+		return port.PlaylistItem{}, ErrPlaylistFull
+	}
+	if err != nil {
+		return port.PlaylistItem{}, err
+	}
+	return item, nil
+}
+
+func (s *Service) Remove(ctx context.Context, memberID, id string, t track.Track) error {
+	if err := s.registered(ctx, memberID); err != nil {
+		return err
+	}
+	return s.playlists.RemovePlaylistItem(ctx, memberID, id, t)
+}
+
+func (s *Service) registered(ctx context.Context, memberID string) error {
+	profile, err := s.members.AccountProfile(ctx, memberID)
+	if err != nil {
+		return err
+	}
+	if profile.Username == "" {
+		return ErrNotRegistered
+	}
+	return nil
+}
+
+// 链接曲目准备好之前没有元数据，音源也查不到。
+func (s *Service) meta(ctx context.Context, t track.Track) (track.Meta, error) {
+	if t.Source != track.Link {
+		return s.catalog.TrackMeta(ctx, t)
+	}
+	p, ok, err := s.tracks.PreparedTrack(ctx, t)
+	if err != nil {
+		return track.Meta{}, err
+	}
+	if !ok {
+		return track.Meta{}, ErrTrackNotReady
+	}
+	return p.Meta, nil
+}
+
+func validName(name string) (string, error) {
+	name = strings.TrimSpace(name)
+	if utf8.RuneCountInString(name) > maxNameLength || strings.ContainsFunc(name, unicode.IsControl) || !strings.ContainsFunc(name, visible) {
+		return "", ErrInvalidName
+	}
+	return name, nil
+}
+
+// unicode.IsGraphic 把 Zs 类的空白也算作 graphic。
+func visible(r rune) bool {
+	return unicode.IsGraphic(r) && !unicode.IsSpace(r)
+}
diff --git a/internal/app/playlist/playlist_test.go b/internal/app/playlist/playlist_test.go
new file mode 100644
index 0000000..471454a
--- /dev/null
+++ b/internal/app/playlist/playlist_test.go
@@ -0,0 +1,234 @@
+package playlist
+
+import (
+	"context"
+	"crypto/sha256"
+	"errors"
+	"slices"
+	"strconv"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/dihemoe/alisten/internal/app/catalog"
+	"github.com/dihemoe/alisten/internal/app/port"
+	"github.com/dihemoe/alisten/internal/app/port/porttest"
+	"github.com/dihemoe/alisten/internal/domain/member"
+	"github.com/dihemoe/alisten/internal/domain/track"
+)
+
+var (
+	sunny     = track.Track{Source: track.NetEase, ID: "186016"}
+	sunnyMeta = track.Meta{Title: "晴天", Artist: "周杰伦", Album: "叶惠美", CoverURL: "https://p1.music.126.net/a.jpg", PageURL: "https://music.163.com/#/song?id=186016", Duration: 269 * time.Second}
+	clip      = track.Track{Source: track.Link, ID: "https://example.com/a.mp3"}
+)
+
+type tracksTable map[track.Track]port.PreparedTrack
+
+func (t tracksTable) PreparedTrack(_ context.Context, k track.Track) (port.PreparedTrack, bool, error) {
+	p, ok := t[k]
+	return p, ok, nil
+}
+
+func (tracksTable) SavePreparedTrack(context.Context, track.Track, port.PreparedTrack) error {
+	return nil
+}
+
+type noHistory struct{}
+
+func (noHistory) AutoDJSeeds(context.Context, string, bool) ([]track.Track, error) { return nil, nil }
+
+func (noHistory) AutoDJExclusions(context.Context, string) ([]track.Track, error) { return nil, nil }
+
+type roomQuota struct{}
+
+func (roomQuota) TakeSearch(context.Context, string, int, time.Duration) (time.Duration, error) {
+	return 0, nil
+}
+
+func (roomQuota) TakePick(context.Context, string, int, time.Duration) (time.Duration, error) {
+	return 0, nil
+}
+
+type accountQuota struct {
+	exhausted bool
+	keys      []string
+}
+
+func (q *accountQuota) Take(_ context.Context, key string, _ int, _ time.Duration) (time.Duration, error) {
+	q.keys = append(q.keys, key)
+	if q.exhausted {
+		return time.Second, nil
+	}
+	return 0, nil
+}
+
+type fixture struct {
+	svc    *Service
+	store  *porttest.Store
+	tracks tracksTable
+	quota  *accountQuota
+}
+
+func newFixture(t *testing.T) fixture {
+	t.Helper()
+	store := porttest.New()
+	netease := porttest.NewSource(track.NetEase)
+	netease.Add(sunny.ID, sunnyMeta, "", nil)
+	bilibili := porttest.NewBilibili()
+	tracks := tracksTable{}
+	music := catalog.New(netease, porttest.NewSource(track.QQ), bilibili, bilibili, tracks, noHistory{}, store, roomQuota{})
+	q := &accountQuota{}
+	return fixture{svc: New(store, store, tracks, music, q), store: store, tracks: tracks, quota: q}
+}
+
+func (f fixture) member(t *testing.T, username string) member.Member {
+	t.Helper()
+	hash := sha256.Sum256([]byte(username))
+	m, err := f.store.CreateMember(t.Context(), hash[:], "游客-"+username)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if username != "" {
+		if err := f.store.Register(t.Context(), m.ID, username, "hash"); err != nil {
+			t.Fatal(err)
+		}
+	}
+	return m
+}
+
+func (f fixture) favorites(t *testing.T, memberID string) string {
+	t.Helper()
+	lists, err := f.svc.List(t.Context(), memberID)
+	if err != nil || len(lists) == 0 || !lists[0].Favorites {
+		t.Fatalf("歌单 = %#v, %v", lists, err)
+	}
+	return lists[0].ID
+}
+
+func TestGuestCannotUsePlaylists(t *testing.T) {
+	f := newFixture(t)
+	guest := f.member(t, "")
+	if _, err := f.svc.List(t.Context(), guest.ID); !errors.Is(err, ErrNotRegistered) {
+		t.Errorf("游客读取歌单 = %v，期望 ErrNotRegistered", err)
+	}
+	if _, err := f.svc.Create(t.Context(), guest.ID, "通勤"); !errors.Is(err, ErrNotRegistered) {
+		t.Errorf("游客新建歌单 = %v，期望 ErrNotRegistered", err)
+	}
+	if _, err := f.svc.Add(t.Context(), guest.ID, "any", sunny); !errors.Is(err, ErrNotRegistered) {
+		t.Errorf("游客收藏 = %v，期望 ErrNotRegistered", err)
+	}
+	if len(f.quota.keys) != 0 {
+		t.Errorf("游客不应消耗额度：%v", f.quota.keys)
+	}
+}
+
+func TestCreateValidatesName(t *testing.T) {
+	f := newFixture(t)
+	alice := f.member(t, "alice")
+	p, err := f.svc.Create(t.Context(), alice.ID, "  通勤  ")
+	if err != nil || p.Name != "通勤" {
+		t.Fatalf("Create = %#v, %v，期望去掉首尾空白", p, err)
+	}
+	for _, name := range []string{"", "   ", strings.Repeat("歌", 51), "通\n勤", "\u200b"} {
+		if _, err := f.svc.Create(t.Context(), alice.ID, name); !errors.Is(err, ErrInvalidName) {
+			t.Errorf("Create(%q) = %v，期望 ErrInvalidName", name, err)
+		}
+		if err := f.svc.Rename(t.Context(), alice.ID, p.ID, name); !errors.Is(err, ErrInvalidName) {
+			t.Errorf("Rename(%q) = %v，期望 ErrInvalidName", name, err)
+		}
+	}
+	if _, err := f.svc.Create(t.Context(), alice.ID, strings.Repeat("歌", 50)); err != nil {
+		t.Errorf("50 个字的歌单名 = %v，期望可以", err)
+	}
+}
+
+func TestCreateStopsAtFiftyPlaylists(t *testing.T) {
+	f := newFixture(t)
+	alice := f.member(t, "alice")
+	for i := range 49 {
+		if _, err := f.svc.Create(t.Context(), alice.ID, "歌单"+strconv.Itoa(i)); err != nil {
+			t.Fatal(err)
+		}
+	}
+	if _, err := f.svc.Create(t.Context(), alice.ID, "第 51 个"); !errors.Is(err, ErrTooManyPlaylists) {
+		t.Errorf("第 51 个歌单 = %v，期望 ErrTooManyPlaylists", err)
+	}
+}
+
+func TestAddTakesMetaFromTheServer(t *testing.T) {
+	f := newFixture(t)
+	alice := f.member(t, "alice")
+	favorites := f.favorites(t, alice.ID)
+	item, err := f.svc.Add(t.Context(), alice.ID, favorites, sunny)
+	if want := (port.PlaylistItem{Track: sunny, Meta: sunnyMeta}); err != nil || item != want {
+		t.Fatalf("Add = %#v, %v，期望 %#v", item, err, want)
+	}
+	if items, err := f.svc.Items(t.Context(), alice.ID, favorites); err != nil || !slices.Equal(items, []port.PlaylistItem{item}) {
+		t.Errorf("Items = %#v, %v", items, err)
+	}
+	if want := []string{"playlist:member:" + alice.ID}; !slices.Equal(f.quota.keys, want) {
+		t.Errorf("取的额度 = %v，期望 %v", f.quota.keys, want)
+	}
+	if err := f.svc.Remove(t.Context(), alice.ID, favorites, sunny); err != nil {
+		t.Fatal(err)
+	}
+	if items, _ := f.svc.Items(t.Context(), alice.ID, favorites); len(items) != 0 {
+		t.Errorf("移除之后 = %#v，期望为空", items)
+	}
+}
+
+func TestAddLinkNeedsPreparedTrack(t *testing.T) {
+	f := newFixture(t)
+	alice := f.member(t, "alice")
+	favorites := f.favorites(t, alice.ID)
+	if _, err := f.svc.Add(t.Context(), alice.ID, favorites, clip); !errors.Is(err, ErrTrackNotReady) {
+		t.Errorf("没准备过的链接 = %v，期望 ErrTrackNotReady", err)
+	}
+	meta := track.Meta{Title: "a.mp3", CoverKey: "covers/abc", PageURL: clip.ID, Duration: time.Minute}
+	f.tracks[clip] = port.PreparedTrack{Meta: meta}
+	if item, err := f.svc.Add(t.Context(), alice.ID, favorites, clip); err != nil || item.Meta != meta {
+		t.Errorf("准备过的链接 = %#v, %v，期望用曲目表里的元数据", item, err)
+	}
+}
+
+func TestAddIsRateLimited(t *testing.T) {
+	f := newFixture(t)
+	alice := f.member(t, "alice")
+	favorites := f.favorites(t, alice.ID)
+	f.quota.exhausted = true
+	if _, err := f.svc.Add(t.Context(), alice.ID, favorites, sunny); !errors.Is(err, ErrTooFast) {
+		t.Errorf("额度用完时 = %v，期望 ErrTooFast", err)
+	}
+	if items, _ := f.svc.Items(t.Context(), alice.ID, favorites); len(items) != 0 {
+		t.Errorf("额度用完时不应加入：%#v", items)
+	}
+}
+
+type fullPlaylists struct{ *porttest.Store }
+
+func (fullPlaylists) AddPlaylistItem(context.Context, string, string, port.PlaylistItem, int) error {
+	return port.ErrPlaylistLimit
+}
+
+func TestAddReportsFullPlaylist(t *testing.T) {
+	f := newFixture(t)
+	alice := f.member(t, "alice")
+	favorites := f.favorites(t, alice.ID)
+	f.svc.playlists = fullPlaylists{f.store}
+	if _, err := f.svc.Add(t.Context(), alice.ID, favorites, sunny); !errors.Is(err, ErrPlaylistFull) {
+		t.Errorf("歌单满了时 = %v，期望 ErrPlaylistFull", err)
+	}
+}
+
+func TestFavoritesStayFixed(t *testing.T) {
+	f := newFixture(t)
+	alice := f.member(t, "alice")
+	favorites := f.favorites(t, alice.ID)
+	if err := f.svc.Rename(t.Context(), alice.ID, favorites, "别的"); !errors.Is(err, port.ErrFavoritesFixed) {
+		t.Errorf("“我喜欢”改名 = %v，期望 ErrFavoritesFixed", err)
+	}
+	if err := f.svc.Delete(t.Context(), alice.ID, favorites); !errors.Is(err, port.ErrFavoritesFixed) {
+		t.Errorf("删除“我喜欢” = %v，期望 ErrFavoritesFixed", err)
+	}
+}