fix：第一轮跑

lib/features/ads/presentation/home_ad_banner.dart

@@ -0,0 +1,134 @@
+import 'dart:async';
+
+import 'package:flutter/material.dart';
+import 'package:go_router/go_router.dart';
+import 'package:hooks_riverpod/hooks_riverpod.dart';
+import 'package:url_launcher/url_launcher.dart';
+
+import '../../../common/router/app_router.dart';
+import '../data/ads_api_client.dart';
+import 'ad_media.dart';
+
+class HomeAdBanner extends ConsumerStatefulWidget {
+  const HomeAdBanner({super.key});
+  @override
+  ConsumerState<HomeAdBanner> createState() => _HomeAdBannerState();
+}
+
+class _HomeAdBannerState extends ConsumerState<HomeAdBanner> {
+  final pages = PageController();
+  final impressed = <String>{};
+  Timer? timer;
+  int index = 0;
+  int _length = 0;
+  @override
+  void dispose() {
+    timer?.cancel();
+    pages.dispose();
+    super.dispose();
+  }
+
+  void _sync(List<AdCreative> ads) {
+    if (_length == ads.length) return;
+    _length = ads.length;
+    timer?.cancel();
+    if (ads.length > 1) {
+      timer = Timer.periodic(const Duration(seconds: 4), (_) {
+        if (pages.hasClients) {
+          pages.nextPage(
+            duration: const Duration(milliseconds: 320),
+            curve: Curves.easeOut,
+          );
+        }
+      });
+    }
+  }
+
+  void _impression(AdCreative ad, String? id) {
+    if (!impressed.add(ad.adId)) return;
+    unawaited(
+      ref
+          .read(adsApiClientProvider)
+          .report(ad, 'ad_impression', trackingId: id),
+    );
+  }
+
+  Future<void> _open(AdCreative ad, String? tracking) async {
+    final client = ref.read(adsApiClientProvider);
+    final id = client.newClickId();
+    final uri = ad.clickUri(id);
+    if (uri == null) return;
+    unawaited(client.report(ad, 'ad_click', clickId: id, trackingId: tracking));
+    if (!mounted) return;
+    if (ad.openMode == AdOpenMode.inApp) {
+      context.push(
+        '${AppRoutes.web}?url=${Uri.encodeComponent(uri.toString())}',
+      );
+    } else {
+      await launchUrl(uri, mode: LaunchMode.externalApplication);
+    }
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final async = ref.watch(featuredAdsProvider(homeBannerAdPlacement));
+    return async.maybeWhen(
+      data: (value) {
+        if (!value.hasAds) return const SizedBox.shrink();
+        final ads = value.ads;
+        _sync(ads);
+        WidgetsBinding.instance.addPostFrameCallback((_) {
+          if (mounted) {
+            _impression(ads[index.clamp(0, ads.length - 1)], value.trackingId);
+          }
+        });
+        return Column(
+          children: [
+            AspectRatio(
+              aspectRatio: 750 / 200,
+              child: ClipRRect(
+                borderRadius: BorderRadius.circular(12),
+                child: PageView.builder(
+                  controller: pages,
+                  onPageChanged: (page) {
+                    setState(() => index = page % ads.length);
+                    _impression(ads[index], value.trackingId);
+                  },
+                  itemBuilder: (_, page) {
+                    final ad = ads[page % ads.length];
+                    return GestureDetector(
+                      onTap: () => _open(ad, value.trackingId),
+                      child: AdMedia(ad: ad),
+                    );
+                  },
+                ),
+              ),
+            ),
+            if (ads.length > 1)
+              Padding(
+                padding: const EdgeInsets.only(top: 8),
+                child: Row(
+                  mainAxisAlignment: MainAxisAlignment.center,
+                  children: List.generate(
+                    ads.length,
+                    (i) => Container(
+                      width: i == index ? 14 : 6,
+                      height: 6,
+                      margin: const EdgeInsets.symmetric(horizontal: 3),
+                      decoration: BoxDecoration(
+                        color: i == index
+                            ? Theme.of(context).colorScheme.primary
+                            : Theme.of(context).dividerColor,
+                        borderRadius: BorderRadius.circular(3),
+                      ),
+                    ),
+                  ),
+                ),
+              ),
+          ],
+        );
+      },
+      orElse: () => const SizedBox.shrink(),
+    );
+  }
+}