add workflow to build

internal/preview/preview.go

@@ -0,0 +1,142 @@
+package preview
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/user/ytdlp-navidrome/internal/config"
+	"github.com/user/ytdlp-navidrome/internal/ytdlp"
+)
+
+// State represents the per-user dialog state.
+type State int
+
+const (
+	StateIdle State = iota
+	StateSearchResults
+	StatePreviewSent
+)
+
+// UserSession holds the current dialog state for a Matrix user.
+type UserSession struct {
+	State       State
+	Query       string
+	Results     []ytdlp.SearchResult
+	VideoID     string
+	PreviewPath string
+	Timestamp   time.Time
+}
+
+// Manager handles preview lifecycle and user sessions.
+type Manager struct {
+	mu       sync.RWMutex
+	sessions map[string]*UserSession
+	cfg      *config.Config
+}
+
+func NewManager(cfg *config.Config) *Manager {
+	return &Manager{
+		sessions: make(map[string]*UserSession),
+		cfg:      cfg,
+	}
+}
+
+// GetSession returns the current session for a user.
+func (m *Manager) GetSession(userID string) *UserSession {
+	m.mu.RLock()
+	defer m.mu.RUnlock()
+	return m.sessions[userID]
+}
+
+// SetSearchResults stores search results for a user.
+func (m *Manager) SetSearchResults(userID, query string, results []ytdlp.SearchResult) {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+	m.sessions[userID] = &UserSession{
+		State:     StateSearchResults,
+		Query:     query,
+		Results:   results,
+		Timestamp: time.Now(),
+	}
+}
+
+// SetPreviewSent records that a preview was sent for a user.
+func (m *Manager) SetPreviewSent(userID, videoID, previewPath string) {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+	m.sessions[userID] = &UserSession{
+		State:       StatePreviewSent,
+		VideoID:     videoID,
+		PreviewPath: previewPath,
+		Timestamp:   time.Now(),
+	}
+}
+
+// ResetSession clears a user session (e.g., on cancel or completion).
+func (m *Manager) ResetSession(userID string) {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+	delete(m.sessions, userID)
+}
+
+// IsExpired checks if a session has exceeded the preview TTL.
+func (s *UserSession) IsExpired(ttl time.Duration) bool {
+	return time.Since(s.Timestamp) > ttl
+}
+
+// SanitizeFilename replaces forbidden characters with underscores.
+func SanitizeFilename(name string) string {
+	forbidden := []string{"/", "\\", ":", "*", "?", "\"", "<", ">", "|"}
+	result := name
+	for _, ch := range forbidden {
+		result = strings.ReplaceAll(result, ch, "_")
+	}
+	return result
+}
+
+// BuildFinalFilename constructs the final filename: "Artist - Title.ext"
+func BuildFinalFilename(result *ytdlp.SearchResult, ext string) string {
+	artist := result.Channel
+	if artist == "" {
+		artist = "unknown"
+	}
+	title := result.Title
+	if title == "" {
+		title = result.ID
+	}
+	return SanitizeFilename(fmt.Sprintf("%s - %s.%s", artist, title, ext))
+}
+
+// CleanupOldPreviews removes expired preview files from tmp dir.
+func (m *Manager) CleanupOldPreviews(ctx context.Context) {
+	ticker := time.NewTicker(5 * time.Minute)
+	defer ticker.Stop()
+
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case <-ticker.C:
+			m.mu.Lock()
+			for userID, session := range m.sessions {
+				if session.State == StatePreviewSent && session.IsExpired(m.cfg.PreviewTTL) {
+					if session.PreviewPath != "" {
+						os.Remove(session.PreviewPath)
+					}
+					delete(m.sessions, userID)
+				}
+			}
+			m.mu.Unlock()
+		}
+	}
+}
+
+// PreviewFilePath returns the expected preview file path for a video ID.
+func PreviewFilePath(tmpDir, videoID, ext string) string {
+	return filepath.Join(tmpDir, fmt.Sprintf("%s.%s", videoID, ext))
+}