✨ Add publishAt to video update (#238)

* Add publishAt support to video update

video insert already scheduled uploads. update did not, so MCP and CLI
could not set a publish time on an existing video.

* Do not force public videos private when scheduling

publishAt on update now errors unless the video is already private or
privacy private is set explicitly, so a live video cannot go offline
by accident.

pkg/video/video.go

@@ -21,13 +21,16 @@ import (
 )
 
 var (
-	errGetVideo    = errors.New("failed to get video")
-	errInsertVideo = errors.New("failed to insert video")
-	errUpdateVideo = errors.New("failed to update video")
-	errRating      = errors.New("failed to rate video")
-	errGetRating   = errors.New("failed to get rating")
-	errDeleteVideo = errors.New("failed to delete video")
-	errReportAbuse = errors.New("failed to report abuse")
+	errGetVideo           = errors.New("failed to get video")
+	errInsertVideo        = errors.New("failed to insert video")
+	errUpdateVideo        = errors.New("failed to update video")
+	errRating             = errors.New("failed to rate video")
+	errGetRating          = errors.New("failed to get rating")
+	errDeleteVideo        = errors.New("failed to delete video")
+	errReportAbuse        = errors.New("failed to report abuse")
+	errScheduleNonPrivate = errors.New(
+		"publishAt requires privacy private; a public or unlisted video would go offline until the scheduled time",
+	)
 )
 
 type Video struct {
@@ -331,6 +334,14 @@ func (v *Video) Update(writer io.Writer) error {
 	if v.Privacy != "" {
 		video.Status.PrivacyStatus = v.Privacy
 	}
+	if v.PublishAt != "" {
+		// YouTube only accepts a schedule on private videos. Do not coerce
+		// public/unlisted to private here: that would take a live video offline.
+		if video.Status.PrivacyStatus != "private" {
+			return errors.Join(errUpdateVideo, errScheduleNonPrivate)
+		}
+		video.Status.PublishAt = v.PublishAt
+	}
 	if v.Embeddable != nil {
 		video.Status.Embeddable = *v.Embeddable
 	}

pkg/video/video_test.go

@@ -792,11 +792,11 @@ func TestVideo_Update(t *testing.T) {
 	containsSyntheticMediaTrue := true
 
 	tests := []struct {
-		name         string
-		opts         []Option
-		getResponse  string
-		verify       func(*http.Request)
-		wantErr      bool
+		name        string
+		opts        []Option
+		getResponse string
+		verify      func(*http.Request)
+		wantErr     bool
 	}{
 		{
 			name: "update video",
@@ -901,6 +901,85 @@ func TestVideo_Update(t *testing.T) {
 			},
 			wantErr: false,
 		},
+		{
+			name: "update video with publishAt on private video",
+			opts: []Option{
+				WithIds([]string{"video-id"}),
+				WithPublishAt("2026-08-18T15:00:00Z"),
+				WithMaxResults(1),
+			},
+			getResponse: `{"items": [{"id": "video-id", "snippet": {"title": "Old Title"}, "status": {"privacyStatus": "private"}}]}`,
+			verify: func(r *http.Request) {
+				if r.Method == "PUT" {
+					var body youtube.Video
+					if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
+						t.Fatalf("failed to decode update body: %v", err)
+					}
+					if body.Status.PublishAt != "2026-08-18T15:00:00Z" {
+						t.Errorf("expected publishAt=2026-08-18T15:00:00Z, got %s", body.Status.PublishAt)
+					}
+					if body.Status.PrivacyStatus != "private" {
+						t.Errorf("expected privacyStatus=private when scheduling, got %s", body.Status.PrivacyStatus)
+					}
+				}
+			},
+			wantErr: false,
+		},
+		{
+			name: "update video with publishAt and explicit private on public video",
+			opts: []Option{
+				WithIds([]string{"video-id"}),
+				WithPrivacy("private"),
+				WithPublishAt("2026-08-18T15:00:00Z"),
+				WithMaxResults(1),
+			},
+			getResponse: `{"items": [{"id": "video-id", "snippet": {"title": "Old Title"}, "status": {"privacyStatus": "public"}}]}`,
+			verify: func(r *http.Request) {
+				if r.Method == "PUT" {
+					var body youtube.Video
+					if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
+						t.Fatalf("failed to decode update body: %v", err)
+					}
+					if body.Status.PublishAt != "2026-08-18T15:00:00Z" {
+						t.Errorf("expected publishAt=2026-08-18T15:00:00Z, got %s", body.Status.PublishAt)
+					}
+					if body.Status.PrivacyStatus != "private" {
+						t.Errorf("expected privacyStatus=private when scheduling, got %s", body.Status.PrivacyStatus)
+					}
+				}
+			},
+			wantErr: false,
+		},
+		{
+			name: "update video with publishAt rejects public without explicit private",
+			opts: []Option{
+				WithIds([]string{"video-id"}),
+				WithPublishAt("2026-08-18T15:00:00Z"),
+				WithMaxResults(1),
+			},
+			getResponse: `{"items": [{"id": "video-id", "snippet": {"title": "Old Title"}, "status": {"privacyStatus": "public"}}]}`,
+			verify: func(r *http.Request) {
+				if r.Method == "PUT" {
+					t.Error("expected no update request when scheduling a public video")
+				}
+			},
+			wantErr: true,
+		},
+		{
+			name: "update video with publishAt rejects unlisted without explicit private",
+			opts: []Option{
+				WithIds([]string{"video-id"}),
+				WithPublishAt("2026-08-18T15:00:00Z"),
+				WithMaxResults(1),
+			},
+			getResponse: `{"items": [{"id": "video-id", "snippet": {"title": "Old Title"}, "status": {"privacyStatus": "unlisted"}}]}`,
+			verify: func(r *http.Request) {
+				if r.Method == "PUT" {
+					t.Error("expected no update request when scheduling an unlisted video")
+				}
+			},
+			wantErr: true,
+		},
 		{
 			name: "update video with embeddable, containsSyntheticMedia, recordingDate",
 			opts: []Option{