feat: the admin Overview shows who is listening, downloads, the library and its disk, and the server's version, uptime and recent errors; a download waiting on you, a client not answering or a full disk count in its verdict (M504 #5627 #5628 #5629 #5630)

The version moves to internal/buildinfo, so /rest/ping reports the build
instead of "dev".

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/api/admin_status_test.go

@@ -0,0 +1,89 @@
+package api
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/jackc/pgx/v5/pgtype"
+
+	"git.fabledsword.com/bvandeusen/minstrel/internal/buildinfo"
+	"git.fabledsword.com/bvandeusen/minstrel/internal/logging"
+)
+
+// openPlay records a play by user of track that started ago and has not
+// ended.
+func openPlay(t *testing.T, h *handlers, user, track pgtype.UUID, ago string) {
+	t.Helper()
+	ctx := context.Background()
+	var session pgtype.UUID
+	if err := h.pool.QueryRow(ctx,
+		`INSERT INTO play_sessions (user_id, started_at, last_event_at) VALUES ($1, now(), now()) RETURNING id`,
+		user).Scan(&session); err != nil {
+		t.Fatalf("session: %v", err)
+	}
+	if _, err := h.pool.Exec(ctx,
+		`INSERT INTO play_events (user_id, track_id, session_id, started_at, client_id)
+		 VALUES ($1, $2, $3, now() - $4::interval, 'web')`, user, track, session, ago); err != nil {
+		t.Fatalf("play: %v", err)
+	}
+}
+
+// The Overview's status (M504): a play still inside its track's length is
+// listening now; one long past it, never closed by its client, is not.
+func TestAdminStatus_ListeningAndServer(t *testing.T) {
+	h, pool := testHandlers(t)
+	truncateLibrary(t, pool)
+	admin := seedUser(t, pool, "admin", "pw", true)
+
+	fresh, _ := seedTrackOnDisk(t, h, "statusfresh") // 30 s long
+	stale, _ := seedTrackOnDisk(t, h, "statusstale")
+	openPlay(t, h, admin.ID, fresh.ID, "10 seconds")
+	openPlay(t, h, admin.ID, stale.ID, "1 hour")
+
+	req := withUser(httptest.NewRequest(http.MethodGet, "/api/admin/status", nil), admin)
+	w := httptest.NewRecorder()
+	h.handleGetAdminStatus(w, req)
+	if w.Code != http.StatusOK {
+		t.Fatalf("status %d: %s", w.Code, w.Body.String())
+	}
+	var got adminStatusView
+	if err := json.Unmarshal(w.Body.Bytes(), &got); err != nil {
+		t.Fatalf("decode: %v", err)
+	}
+
+	var sawFresh, sawStale bool
+	for _, p := range got.Listening.Now {
+		switch p.TrackID {
+		case uuidToString(fresh.ID):
+			sawFresh = true
+			if p.Username != admin.Username || p.Client != "web" || p.Title != "AdmQ Track statusfresh" {
+				t.Errorf("listening row = %+v", p)
+			}
+		case uuidToString(stale.ID):
+			sawStale = true
+		}
+	}
+	if !sawFresh || sawStale {
+		t.Errorf("listening now: fresh %v (want true), stale %v (want false)", sawFresh, sawStale)
+	}
+	if got.Listening.PlaysDay < 2 || got.Listening.LastPlayAt == nil {
+		t.Errorf("last day: plays %d, last %v", got.Listening.PlaysDay, got.Listening.LastPlayAt)
+	}
+
+	if got.Library.Tracks != 2 || got.Library.Albums != 2 || got.Library.Bytes != 10 {
+		t.Errorf("library = %+v, want 2 tracks, 2 albums, 10 bytes", got.Library)
+	}
+	if got.Downloads.Live == nil || got.Downloads.ClientsDown == nil || got.Library.Disks == nil {
+		t.Error("lists must be [], never null")
+	}
+
+	if got.Server.Version != buildinfo.Version || got.Server.StartedAt == "" || got.Server.Migration < 92 {
+		t.Errorf("server = %+v", got.Server)
+	}
+	if _, total := logging.Errors.Snapshot(); got.Server.ErrorCount != total {
+		t.Errorf("error count = %d, ring says %d", got.Server.ErrorCount, total)
+	}
+}