/// 相册分享页（UI-06 重设计：三种分享方式，用户需求 2026-09-23）。
///
/// 1. 卡片模式（默认）：系统分享面板（share_plus）——微信 / 手机上其他应用，
///    分享文本 = 相册标题 + 观众链接；
/// 2. 生成二维码：弹出**二维码海报**（顶部宣传图 → 活动标题 / 时间 / 地址 /
///    二维码），可**下载海报图**到相册（gal，RepaintBoundary 渲染 3x PNG）；
/// 3. 复制链接。
/// 相册未公开时琥珀提示明确「该链接目前无法公开浏览」；URL 文本可长按复制。
library;

import 'dart:ui' as ui;

import 'package:flutter/material.dart';
import 'package:flutter/rendering.dart';
import 'package:flutter/services.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:gal/gal.dart';
import 'package:qr_flutter/qr_flutter.dart';
import 'package:share_plus/share_plus.dart';
import 'package:url_launcher/url_launcher.dart';

import '../core/api_client.dart';
import '../core/config.dart';
import '../features/albums/album_format.dart';
import '../features/albums/models.dart';
import '../l10n/app_localizations.dart';
import '../ui/components/photo_thumbnail.dart';
import '../ui/tokens.dart';

/// 外链打开注入点（生产=url_launcher；测试 override）。
typedef UrlLauncher = Future<bool> Function(String url);

/// 观众分享链接语言参数（viewer i18n 仅认 zh-CN/en；App locale 前缀映射）。
String shareLangParam(String localeName) =>
    localeName.toLowerCase().startsWith('zh') ? 'zh-CN' : 'en';

/// 分享链接（二维码 / 复制 / 系统分享同一 URL）。
String shareAlbumUrl(Album album, String localeName) =>
    ApiConfig.viewerAlbumUrl(
      album.publicToken,
      lang: shareLangParam(localeName),
    );

/// Provider：外部浏览器打开 URL。
final urlLauncherProvider = Provider<UrlLauncher>(
  (ref) =>
      (url) => launchUrl(Uri.parse(url), mode: LaunchMode.externalApplication),
);

/// 系统分享注入点（生产=share_plus；测试 override）。
typedef ShareLauncher = Future<void> Function(String text);

final shareLauncherProvider = Provider<ShareLauncher>(
  // share_plus 11：SharePlus.instance.share（旧 Share.share 已废弃）。
  (ref) =>
      (text) async => SharePlus.instance.share(
        ShareParams(text: text, subject: text.split('\n').first),
      ),
);

/// 海报保存相册注入点（生产=gal；测试 override）。
typedef PosterSaver = Future<void> Function(ui.Image image);

final posterSaverProvider = Provider<PosterSaver>(
  (ref) => (image) async {
    final bytes = await image.toByteData(format: ui.ImageByteFormat.png);
    if (bytes == null) throw StateError('poster encode failed');
    await Gal.putImageBytes(bytes.buffer.asUint8List());
  },
);

/// 观众分享页（三方式：系统分享卡片 / 二维码海报 / 复制链接）。
class ShareQrPage extends ConsumerWidget {
  const ShareQrPage({required this.album, super.key});

  final Album album;

  Future<void> _copy(BuildContext context, String url) async {
    await Clipboard.setData(ClipboardData(text: url));
    if (!context.mounted) return;
    ScaffoldMessenger.of(context).showSnackBar(
      SnackBar(content: Text(AppLocalizations.of(context).copiedToClipboard)),
    );
  }

  Future<void> _shareToApps(
    BuildContext context,
    WidgetRef ref,
    String url,
    String title,
  ) async {
    await ref.read(shareLauncherProvider)('$title\n$url');
  }

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final l10n = AppLocalizations.of(context);
    final theme = Theme.of(context);
    final localeName = l10n.localeName;
    final url = shareAlbumUrl(album, localeName);
    final title = albumDisplayTitle(album, localeName);
    final venue = albumDisplayVenue(album, localeName);
    final start = formatAlbumDateTime(
      album.startAt,
      album.timezone,
      localeName,
    );
    final end = album.endAt == null
        ? null
        : formatAlbumDateTime(album.endAt!, album.timezone, localeName);
    final dateRange = end == null ? start : '$start ~ $end';
    final meta = venue == null ? dateRange : '$dateRange · $venue';
    return Scaffold(
      appBar: AppBar(title: Text(l10n.shareAlbum)),
      body: SingleChildScrollView(
        child: Center(
          child: ConstrainedBox(
            constraints: const BoxConstraints(maxWidth: 480),
            child: Card(
              margin: const EdgeInsets.all(kSpace16),
              child: Padding(
                padding: const EdgeInsets.all(kSpace16),
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.stretch,
                  children: [
                    // 相册信息（封面 + 标题 + meta）。
                    ClipRRect(
                      borderRadius: BorderRadius.circular(kRadiusInput),
                      child: PhotoThumbnail(
                        url: album.cover?.url,
                        aspectRatio: 16 / 9,
                      ),
                    ),
                    const SizedBox(height: kSpace16),
                    Text(
                      title,
                      textAlign: TextAlign.center,
                      style: theme.textTheme.titleLarge,
                    ),
                    const SizedBox(height: kSpace4),
                    Text(
                      meta,
                      textAlign: TextAlign.center,
                      style: theme.textTheme.bodySmall?.copyWith(
                        color: theme.colorScheme.onSurfaceVariant,
                      ),
                    ),
                    if (!album.publicEnabled) ...[
                      const SizedBox(height: kSpace12),
                      Container(
                        padding: const EdgeInsets.all(kSpace12),
                        decoration: BoxDecoration(
                          color: theme.brightness == Brightness.light
                              ? kColorWaiting.withValues(alpha: 0.12)
                              : kColorWaitingDark.withValues(alpha: 0.12),
                          borderRadius: BorderRadius.circular(kRadiusBadge),
                        ),
                        child: Row(
                          children: [
                            Icon(
                              Icons.warning_amber_rounded,
                              size: 18,
                              color: theme.brightness == Brightness.light
                                  ? kColorWaiting
                                  : kColorWaitingDark,
                            ),
                            const SizedBox(width: kSpace8),
                            Expanded(
                              child: Text(
                                l10n.shareNotPublic,
                                style: theme.textTheme.bodySmall?.copyWith(
                                  color: theme.brightness == Brightness.light
                                      ? kColorWaiting
                                      : kColorWaitingDark,
                                ),
                              ),
                            ),
                          ],
                        ),
                      ),
                    ],
                    const SizedBox(height: kSpace24),

                    // ── 方式 1：卡片模式（默认）——系统分享面板 ──
                    FilledButton.icon(
                      onPressed: () => _shareToApps(context, ref, url, title),
                      icon: const Icon(Icons.share_outlined, size: 18),
                      label: Text(l10n.shareCardMode),
                    ),
                    const SizedBox(height: kSpace8),

                    // ── 方式 2：生成二维码（弹出海报）──
                    OutlinedButton.icon(
                      onPressed: () => _openPoster(context),
                      icon: const Icon(Icons.qr_code_2, size: 20),
                      label: Text(l10n.sharePosterMode),
                    ),
                    const SizedBox(height: kSpace8),

                    // ── 方式 3：复制链接 ──
                    OutlinedButton.icon(
                      onPressed: () => _copy(context, url),
                      icon: const Icon(Icons.copy_outlined, size: 18),
                      label: Text(l10n.copyLink),
                    ),
                    const SizedBox(height: kSpace8),

                    // 链接文本（长按选中复制；浏览器打开为次级入口）。
                    SelectableText(
                      url,
                      textAlign: TextAlign.center,
                      style: theme.textTheme.labelSmall?.copyWith(
                        color: theme.colorScheme.onSurfaceVariant,
                      ),
                    ),
                    TextButton(
                      onPressed: () async {
                        final launched = await ref.read(urlLauncherProvider)(
                          url,
                        );
                        if (launched && context.mounted) {
                          Navigator.of(context).pop();
                        }
                      },
                      child: Text(l10n.openInBrowser),
                    ),
                  ],
                ),
              ),
            ),
          ),
        ),
      ),
    );
  }

  Future<void> _openPoster(BuildContext context) async {
    await showModalBottomSheet<void>(
      context: context,
      showDragHandle: true,
      isScrollControlled: true,
      builder: (_) => _PosterSheet(album: album),
    );
  }
}

/// 二维码海报弹层：宣传图（banner→cover 兜底）+ 标题 + 时间 + 地址 + 二维码；
/// 「保存海报图」= RepaintBoundary 3x 渲染 PNG → 相册（gal）。
class _PosterSheet extends ConsumerStatefulWidget {
  const _PosterSheet({required this.album});

  final Album album;

  @override
  ConsumerState<_PosterSheet> createState() => _PosterSheetState();
}

class _PosterSheetState extends ConsumerState<_PosterSheet> {
  final GlobalKey _posterKey = GlobalKey();
  String? _bannerUrl;
  bool _saving = false;

  @override
  void initState() {
    super.initState();
    // 宣传图（banner 全局行；失败静默回退 cover / 占位）。
    Future<void>.microtask(() async {
      try {
        final url = await ref
            .read(apiClientProvider)
            .fetchAlbumAssetUrl(widget.album.id, 'banner');
        if (mounted) setState(() => _bannerUrl = url);
      } on Object {
        // 拉不到 banner 时海报用封面兜底
      }
    });
  }

  Future<void> _save() async {
    setState(() => _saving = true);
    final messenger = ScaffoldMessenger.of(context);
    final l10n = AppLocalizations.of(context);
    try {
      final boundary =
          _posterKey.currentContext!.findRenderObject()
              as RenderRepaintBoundary;
      final image = await boundary.toImage(pixelRatio: 3);
      await ref.read(posterSaverProvider)(image);
      messenger.showSnackBar(SnackBar(content: Text(l10n.posterSaved)));
    } on Object {
      messenger.showSnackBar(SnackBar(content: Text(l10n.posterSaveFailed)));
    } finally {
      if (mounted) setState(() => _saving = false);
    }
  }

  @override
  Widget build(BuildContext context) {
    final l10n = AppLocalizations.of(context);
    final theme = Theme.of(context);
    final localeName = l10n.localeName;
    final url = shareAlbumUrl(widget.album, localeName);
    final title = albumDisplayTitle(widget.album, localeName);
    final start = formatAlbumDateTime(
      widget.album.startAt,
      widget.album.timezone,
      localeName,
    );
    final end = widget.album.endAt == null
        ? null
        : formatAlbumDateTime(
            widget.album.endAt!,
            widget.album.timezone,
            localeName,
          );
    final dateRange = end == null ? start : '$start ~ $end';
    final venue = albumDisplayVenue(widget.album, localeName);
    String? addressForPoster(AlbumSummary album) {
      for (final t in albumDisplayTranslations(album, localeName)) {
        final a = t.address?.trim();
        if (a != null && a.isNotEmpty) return a;
      }
      return null;
    }

    final address = addressForPoster(widget.album);

    return SafeArea(
      top: false,
      child: SingleChildScrollView(
        child: Padding(
          padding: const EdgeInsets.fromLTRB(kSpace16, 0, kSpace16, kSpace16),
          child: Column(
            mainAxisSize: MainAxisSize.min,
            children: [
              // ── 头行：标题 + 显式关闭（海报较长时下拉手势不明显）──
              Row(
                children: [
                  Expanded(
                    child: Text(
                      l10n.sharePosterMode,
                      style: theme.textTheme.titleMedium,
                    ),
                  ),
                  IconButton(
                    tooltip: l10n.close,
                    icon: const Icon(Icons.close),
                    onPressed: () => Navigator.of(context).pop(),
                  ),
                ],
              ),
              // ── 海报（整块 RepaintBoundary；下载即渲染此区域）──
              RepaintBoundary(
                key: _posterKey,
                child: Container(
                  width: double.infinity,
                  color: Colors.white,
                  child: Column(
                    children: [
                      // 顶部宣传图：banner → cover → 品牌占位。
                      AspectRatio(
                        aspectRatio: 16 / 9,
                        child: _bannerUrl != null
                            ? Image.network(
                                _bannerUrl!,
                                fit: BoxFit.cover,
                                errorBuilder: (_, _, _) =>
                                    _posterImageFallback(widget.album),
                              )
                            : _posterImageFallback(widget.album),
                      ),
                      Padding(
                        padding: const EdgeInsets.all(kSpace24),
                        child: Column(
                          children: [
                            // 活动标题。
                            Text(
                              title,
                              textAlign: TextAlign.center,
                              style: theme.textTheme.titleLarge?.copyWith(
                                color: const Color(0xFF172033),
                                fontWeight: FontWeight.w700,
                              ),
                            ),
                            const SizedBox(height: kSpace12),
                            // 时间。
                            Row(
                              mainAxisAlignment: MainAxisAlignment.center,
                              children: [
                                Icon(
                                  Icons.event_outlined,
                                  size: 16,
                                  color: theme.colorScheme.primary,
                                ),
                                const SizedBox(width: kSpace4),
                                Flexible(
                                  child: Text(
                                    dateRange,
                                    maxLines: 1,
                                    overflow: TextOverflow.ellipsis,
                                    style: theme.textTheme.bodySmall?.copyWith(
                                      color: const Color(0xFF69778E),
                                    ),
                                  ),
                                ),
                              ],
                            ),
                            if (venue != null) ...[
                              const SizedBox(height: kSpace4),
                              Row(
                                mainAxisAlignment: MainAxisAlignment.center,
                                children: [
                                  Icon(
                                    Icons.place_outlined,
                                    size: 16,
                                    color: theme.colorScheme.primary,
                                  ),
                                  const SizedBox(width: kSpace4),
                                  Flexible(
                                    child: Text(
                                      address == null || address.isEmpty
                                          ? venue
                                          : '$venue · $address',
                                      maxLines: 1,
                                      overflow: TextOverflow.ellipsis,
                                      style: theme.textTheme.bodySmall
                                          ?.copyWith(
                                            color: const Color(0xFF69778E),
                                          ),
                                    ),
                                  ),
                                ],
                              ),
                            ],
                            const SizedBox(height: kSpace24),
                            // 二维码（白底保持扫码对比度）。
                            QrImageView(
                              data: url,
                              version: QrVersions.auto,
                              size: 200,
                              backgroundColor: Colors.white,
                            ),
                            const SizedBox(height: kSpace12),
                            Text(
                              l10n.shareScanHint,
                              style: theme.textTheme.bodySmall?.copyWith(
                                color: const Color(0xFF69778E),
                              ),
                            ),
                          ],
                        ),
                      ),
                    ],
                  ),
                ),
              ),
              const SizedBox(height: kSpace16),
              // ── 下载海报图 ──
              FilledButton.icon(
                onPressed: _saving ? null : _save,
                icon: _saving
                    ? const SizedBox(
                        width: 16,
                        height: 16,
                        child: CircularProgressIndicator(strokeWidth: 2),
                      )
                    : const Icon(Icons.download_outlined, size: 18),
                label: Text(l10n.posterDownload),
              ),
            ],
          ),
        ),
      ),
    );
  }

  /// 宣传图缺省回退：封面 → 品牌色占位。
  Widget _posterImageFallback(Album album) {
    final cover = album.cover?.url;
    if (cover != null) {
      return Image.network(
        cover,
        fit: BoxFit.cover,
        errorBuilder: (_, _, _) => _brandPlaceholder(),
      );
    }
    return _brandPlaceholder();
  }

  Widget _brandPlaceholder() => Container(
    color: const Color(0xFF12233E),
    alignment: Alignment.center,
    child: const Text(
      'PhotoLive',
      style: TextStyle(
        color: Colors.white,
        fontSize: 24,
        fontWeight: FontWeight.w700,
        letterSpacing: -0.8,
      ),
    ),
  );
}