Show the queued show and its start time in the index.php sidebar

- Shows get a description and an icon upload; broadcasts get a scheduled_at
  start time. schema.sql adds the columns to existing databases and seeds
  the descriptions from the old hand-written sidebar.
- The dashboard and cli/set_show.php take an optional date and Eastern start
  time when queuing; index.php shows it with the UTC conversion.
- liveBroadcast() and currentShow() ignore broadcasts unseen for longer than
  the grace period, so a stopped poller can't leave a show stuck as live.

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

includes/broadcasts.php

@@ -12,11 +12,17 @@ require_once __DIR__ . '/icecast.php';
 const BROADCAST_GRACE_MINUTES = 5;
 // Tracks are cleared this long after their broadcast ends
 const TRACK_RETENTION_MINUTES = 10;
+// Show times are entered and displayed in the station's time zone; the database stores UTC
+const STATION_TIMEZONE = 'America/New_York';
+const STATION_TIMEZONE_LABEL = 'Eastern';
 
+// A broadcast unseen for longer than the grace period is treated as over even before the poller marks it
+// ended, so a stopped poller or a long status API outage can't leave a show showing as live.
 function liveBroadcast(PDO $db): ?array {
     $row = $db->query(
         'SELECT * FROM broadcasts
          WHERE started_at IS NOT NULL AND ended_at IS NULL
+           AND last_seen_at >= NOW() - INTERVAL ' . BROADCAST_GRACE_MINUTES . ' MINUTE
          ORDER BY started_at DESC LIMIT 1'
     )->fetch();
     return $row ?: null;
@@ -31,28 +37,42 @@ function pendingBroadcast(PDO $db): ?array {
     return $row ?: null;
 }
 
-// The show for the live broadcast, or the queued one if nothing is live yet
+// The show for the live broadcast, or the queued one if nothing is live yet,
+// with the broadcast's scheduled_at and started_at. Stale broadcasts are skipped as in liveBroadcast().
 function currentShow(PDO $db): ?array {
     $row = $db->query(
-        'SELECT s.* FROM broadcasts b
+        'SELECT s.*, b.scheduled_at, b.started_at FROM broadcasts b
          JOIN shows s ON s.id = b.show_id
          WHERE b.ended_at IS NULL
+           AND (b.started_at IS NULL OR b.last_seen_at >= NOW() - INTERVAL ' . BROADCAST_GRACE_MINUTES . ' MINUTE)
          ORDER BY b.started_at IS NULL, b.started_at DESC, b.created_at DESC
          LIMIT 1'
     )->fetch();
     return $row ?: null;
 }
 
+// Converts a 'YYYY-MM-DD HH:MM' station time to a UTC DATETIME string, or null if it isn't a valid time
+function stationTimeToUtc(string $local): ?string {
+    $dt = DateTimeImmutable::createFromFormat('!Y-m-d H:i', $local, new DateTimeZone(STATION_TIMEZONE));
+    // Reformatting catches overflowing dates (Feb 30) and times skipped by the DST change
+    if ($dt === false || $dt->format('Y-m-d H:i') !== $local) return null;
+    return $dt->setTimezone(new DateTimeZone('UTC'))->format('Y-m-d H:i:s');
+}
+
+function utcToStationTime(string $utc): DateTimeImmutable {
+    return (new DateTimeImmutable($utc, new DateTimeZone('UTC')))->setTimezone(new DateTimeZone(STATION_TIMEZONE));
+}
+
 // Assigns a show to the live broadcast, or queues it for the next one if nothing is live.
-// Returns 'live' or 'queued'.
-function setBroadcastShow(PDO $db, int $showId): string {
+// $scheduledAt (UTC) is the advertised start time of a queued show. Returns 'live' or 'queued'.
+function setBroadcastShow(PDO $db, int $showId, ?string $scheduledAt = null): string {
     $live = liveBroadcast($db);
     if ($live !== null) {
         $db->prepare('UPDATE broadcasts SET show_id = ? WHERE id = ?')->execute([$showId, $live['id']]);
         return 'live';
     }
     clearQueuedShow($db);
-    $db->prepare('INSERT INTO broadcasts (show_id) VALUES (?)')->execute([$showId]);
+    $db->prepare('INSERT INTO broadcasts (show_id, scheduled_at) VALUES (?, ?)')->execute([$showId, $scheduledAt]);
     return 'queued';
 }