import 'dart:async';
import 'dart:io';
import 'dart:math' show max;

import 'package:cached_network_image/cached_network_image.dart';
import 'package:client_proxy_framework/client_proxy_framework.dart';
import 'package:flutter/material.dart';
import 'package:google_fonts/google_fonts.dart';
import 'package:image_picker/image_picker.dart';
import 'package:video_player/video_player.dart';

import '../../core/app_env.dart';
import '../../core/user/user_state.dart';
import '../../design/pencil_theme.dart';
import '../../widgets/pencil_chrome.dart';
import 'generate_progress_screen.dart';

/// `EYsUi` 生成图片页 — 左 112×108 槽位 +「=」+ 右侧效果图；分辨率在「开始生成」上方横排。
/// [ExtConfigItem.imgNeed] == 2 时需两张图并上传；其余（含视频类模板）只传一张，请在配置里将视频项 `img_need` 设为 1。
/// [template] 来自首页选中的 [ExtConfigItem]。
class GenerateScreen extends StatefulWidget {
  const GenerateScreen({super.key, this.template});

  final ExtConfigItem? template;

  @override
  State<GenerateScreen> createState() => _GenerateScreenState();
}

class _GenerateScreenState extends State<GenerateScreen> {
  final _picker = ImagePicker();
  File? _picked;
  File? _picked2;
  /// 对应 create-task 逻辑字段 `size`（换皮 `seminar`），如 480p / 720p。
  String _outputSize = '720p';
  bool _busy = false;

  VideoPlayerController? _previewVideo;
  bool _previewVideoFailed = false;

  static const double _slotW = 112;
  static const double _slotH = 108;
  static const double _previewH = 359;
  static const double _previewOuterR = 20;
  static const double _previewBorderW = 1.5;

  File? get _primaryFile => _picked ?? _picked2;

  /// 双图：仅当扩展配置 `img_need == 2`（与 [ExtConfigItem.imgNeed] 一致）。
  bool get _needTwoImages => widget.template?.imgNeed == 2;

  /// 与 [app_client] `ImageApi.createTask` 的 `congregation` 一致：值为 [ExtConfigItem.templateName]，
  /// 缺省（纯本地 extConfig）时用 [ExtConfigItem.title]；`BananaTask` 不传。
  String? get _templateNameForCreateTask {
    final tpl = widget.template;
    if (tpl == null) return null;
    final tn = tpl.templateName?.trim();
    final raw = (tn != null && tn.isNotEmpty ? tn : tpl.title.trim());
    if (raw.isEmpty || raw == 'BananaTask') return null;
    return raw;
  }

  /// 任务类型：FunyMee 文档/换皮为逻辑 `taskType`（V2 `liaison`）；优先 [ExtConfigItem.taskType]，再 [params]/[detail]。
  String? get _taskTypeForCreateTask {
    final tt = widget.template?.taskType?.trim();
    if (tt != null && tt.isNotEmpty) return tt;
    final p = widget.template?.params?.trim();
    if (p != null && p.isNotEmpty) return p;
    final d = widget.template?.detail?.trim();
    return (d != null && d.isNotEmpty) ? d : null;
  }

  /// 对应 `ext`（profile）：仅当 params 与 detail 同时存在时传 detail，避免与 taskType 重复。
  String? get _extForCreateTask {
    final p = widget.template?.params?.trim();
    final d = widget.template?.detail?.trim();
    if (p != null && p.isNotEmpty && d != null && d.isNotEmpty) return d;
    return null;
  }

  Future<void> _pickSlot(int slot) async {
    if (!mounted) return;
    final source = await _showPickImageSourceSheet(context);
    if (source == null || !mounted) return;
    final x = await _picker.pickImage(
      source: source,
      imageQuality: 92,
    );
    if (x == null || !mounted) return;
    setState(() {
      if (slot == 0) {
        _picked = File(x.path);
      } else {
        _picked2 = File(x.path);
      }
    });
  }

  Future<ImageSource?> _showPickImageSourceSheet(BuildContext context) {
    return showModalBottomSheet<ImageSource>(
      context: context,
      backgroundColor: Colors.transparent,
      builder: (ctx) {
        return Container(
          decoration: const BoxDecoration(
            color: Colors.white,
            borderRadius: BorderRadius.vertical(top: Radius.circular(16)),
            boxShadow: [
              BoxShadow(
                color: Color(0x20000000),
                blurRadius: 16,
                offset: Offset(0, -4),
              ),
            ],
          ),
          child: SafeArea(
            child: Column(
              mainAxisSize: MainAxisSize.min,
              children: [
                const SizedBox(height: 12),
                Container(
                  width: 40,
                  height: 4,
                  decoration: BoxDecoration(
                    color: PencilTheme.genNavBackStroke,
                    borderRadius: BorderRadius.circular(2),
                  ),
                ),
                const SizedBox(height: 8),
                ListTile(
                  leading: Icon(
                    Icons.camera_alt_outlined,
                    color: PencilTheme.profileAvatarIcon,
                  ),
                  title: Text(
                    'Camera',
                    style: GoogleFonts.inter(
                      fontSize: 16,
                      fontWeight: FontWeight.w600,
                      color: PencilTheme.stone900,
                    ),
                  ),
                  onTap: () => Navigator.pop(ctx, ImageSource.camera),
                ),
                ListTile(
                  leading: Icon(
                    Icons.photo_library_outlined,
                    color: PencilTheme.profileAvatarIcon,
                  ),
                  title: Text(
                    'Photo library',
                    style: GoogleFonts.inter(
                      fontSize: 16,
                      fontWeight: FontWeight.w600,
                      color: PencilTheme.stone900,
                    ),
                  ),
                  onTap: () => Navigator.pop(ctx, ImageSource.gallery),
                ),
                const Divider(height: 1),
                ListTile(
                  title: Text(
                    'Cancel',
                    textAlign: TextAlign.center,
                    style: GoogleFonts.inter(
                      fontWeight: FontWeight.w600,
                      color: PencilTheme.stone600,
                    ),
                  ),
                  onTap: () => Navigator.pop(ctx),
                ),
              ],
            ),
          ),
        );
      },
    );
  }

  Future<void> _start() async {
    final uid = UserState.userId.value;
    if (uid == null || uid.isEmpty) {
      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(content: Text('Please sign in first.')),
      );
      return;
    }
    if (_needTwoImages) {
      if (_picked == null || _picked2 == null) {
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(content: Text('Please select two images first.')),
        );
        return;
      }
    } else {
      final file = _primaryFile;
      if (file == null) {
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(content: Text('Please select an image first.')),
        );
        return;
      }
    }

    setState(() => _busy = true);
    try {
      final ImagePresignedUploadCreateTaskResult result;
      if (_needTwoImages) {
        result = await ImagePresignedUploadCreateTaskFlow.runTwoSourceFiles(
          sourceFile1: _picked!,
          sourceFile2: _picked2!,
          userId: uid,
          size: _outputSize,
          taskType: _taskTypeForCreateTask,
          templateName: _templateNameForCreateTask,
          ext: _extForCreateTask,
          compressFirst: true,
          compressOptions: const CompressImageForUploadOptions(
            maxSide: 1024,
            jpegQuality: 75,
          ),
          saveLocalUploadCover: true,
        );
      } else {
        result = await ImagePresignedUploadCreateTaskFlow.run(
          sourceFile: _primaryFile!,
          userId: uid,
          size: _outputSize,
          taskType: _taskTypeForCreateTask,
          templateName: _templateNameForCreateTask,
          ext: _extForCreateTask,
          compressFirst: true,
          compressOptions: const CompressImageForUploadOptions(
            maxSide: 1024,
            jpegQuality: 75,
          ),
          saveLocalUploadCover: true,
        );
      }

      final taskId = result.createResponse.taskId;
      if (taskId == null || taskId.isEmpty) {
        throw StateError('No task id');
      }

      await UserAccountRefresh.fetchAndNotify(
        app: currentBackendAppType(),
        userId: uid,
        onAccount: (a) {
          if (a.credits != null) UserState.setCredits(a.credits!);
        },
      );

      if (!mounted) return;
      Navigator.of(context).pushReplacement(
        MaterialPageRoute<void>(
          builder: (_) => GenerateProgressScreen(
            taskId: taskId,
            localPreviewPath: result.fileUsedForUpload.path,
          ),
        ),
      );
    } catch (e) {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text('$e')),
        );
      }
    } finally {
      if (mounted) setState(() => _busy = false);
    }
  }

  /// 与当前 [_outputSize] 一致；优先 [ExtConfigItem.cost480p] / [ExtConfigItem.cost720p]，
  /// 否则用 [ExtConfigItem.cost] 作 720p，480p 按半档估算。
  /// 与 [HomeScreen] `_HomeItemVideoBackground`：优先 [ExtConfigItem.videoUrl]，否则用 `image`。
  String? _previewPlayUrl(ExtConfigItem? t) {
    if (t == null) return null;
    final v = t.videoUrl?.trim();
    if (v != null && v.isNotEmpty) return v;
    final u = t.image.trim();
    return u.isEmpty ? null : u;
  }

  bool get _previewIsVideo {
    final u = _previewPlayUrl(widget.template);
    return u != null && _urlLooksLikeVideo(u);
  }

  Future<void> _pauseThenDispose(VideoPlayerController c) async {
    try {
      await c.pause();
    } catch (_) {}
    try {
      await c.dispose();
    } catch (_) {}
  }

  void _disposePreviewVideo() {
    final c = _previewVideo;
    _previewVideo = null;
    _previewVideoFailed = false;
    if (c != null) {
      unawaited(_pauseThenDispose(c));
    }
  }

  Future<void> _tryInitPreviewVideo() async {
    final playUrl = _previewPlayUrl(widget.template);
    if (playUrl == null || !_urlLooksLikeVideo(playUrl)) return;
    final uri = Uri.tryParse(playUrl);
    if (uri == null) {
      if (mounted) setState(() => _previewVideoFailed = true);
      return;
    }
    final c = VideoPlayerController.networkUrl(uri)
      ..setLooping(true)
      ..setVolume(1);
    try {
      await c.initialize();
      await c.play();
      if (!mounted) {
        await c.dispose();
        return;
      }
      setState(() => _previewVideo = c);
    } catch (_) {
      await c.dispose();
      if (mounted) setState(() => _previewVideoFailed = true);
    }
  }

  @override
  void initState() {
    super.initState();
    unawaited(_tryInitPreviewVideo());
  }

  @override
  void didUpdateWidget(covariant GenerateScreen oldWidget) {
    super.didUpdateWidget(oldWidget);
    if (oldWidget.template?.videoUrl != widget.template?.videoUrl ||
        oldWidget.template?.image != widget.template?.image) {
      _disposePreviewVideo();
      unawaited(_tryInitPreviewVideo());
    }
  }

  @override
  void dispose() {
    _disposePreviewVideo();
    super.dispose();
  }

  int get _estimatedCost {
    const fallback = 20;
    final t = widget.template;
    if (t == null) return fallback;

    int effective720() {
      if (t.cost720p != null && t.cost720p! > 0) return t.cost720p!;
      if (t.cost > 0) return t.cost;
      return fallback;
    }

    if (_outputSize == '480p') {
      if (t.cost480p != null && t.cost480p! > 0) return t.cost480p!;
      final h = effective720();
      return max(1, (h / 2).round());
    }
    final c = effective720();
    return c > 0 ? c : fallback;
  }

  @override
  Widget build(BuildContext context) {
    final credits = UserState.credits.value;
    return Container(
      decoration: const BoxDecoration(
        gradient: PencilTheme.yellowWhitePageGradient,
      ),
      child: Scaffold(
        backgroundColor: Colors.transparent,
        body: SafeArea(
          bottom: false,
          child: Column(
            children: [
              Padding(
                padding: const EdgeInsets.fromLTRB(2, 0, 14, 10),
                child: SizedBox(
                  height: 56,
                  child: Row(
                    children: [
                      PencilRoundBackButton(
                        onPressed: () => Navigator.of(context).pop(),
                      ),
                      Expanded(
                        child: Center(
                          child: Text(
                            'Generate',
                            style: GoogleFonts.inter(
                              fontSize: 19,
                              fontWeight: FontWeight.w700,
                              fontStyle: FontStyle.italic,
                              color: PencilTheme.stone900,
                            ),
                          ),
                        ),
                      ),
                      const SizedBox(width: 44),
                    ],
                  ),
                ),
              ),
              Padding(
                padding: const EdgeInsets.symmetric(horizontal: 16),
                child: _hintBox(),
              ),
              const SizedBox(height: 8),
              Expanded(
                child: Padding(
                  padding: const EdgeInsets.fromLTRB(16, 6, 16, 4),
                  child: Row(
                    crossAxisAlignment: CrossAxisAlignment.center,
                    children: [
                      _needTwoImages ? _leftTwoSlotsColumn() : _leftSingleSlotColumn(),
                      const SizedBox(width: 14),
                      _equalsColumn(),
                      const SizedBox(width: 14),
                      Expanded(child: _effectPreviewPanel()),
                    ],
                  ),
                ),
              ),
              Padding(
                padding: const EdgeInsets.fromLTRB(20, 0, 20, 28),
                child: Column(
                  children: [
                    Row(
                      mainAxisAlignment: MainAxisAlignment.center,
                      children: [
                        _resoChip(
                          '480p',
                          _outputSize == '480p',
                          () => setState(() => _outputSize = '480p'),
                        ),
                        const SizedBox(width: 12),
                        _resoChip(
                          '720p',
                          _outputSize == '720p',
                          () => setState(() => _outputSize = '720p'),
                        ),
                      ],
                    ),
                    const SizedBox(height: 12),
                    FilledButton(
                      style: FilledButton.styleFrom(
                        backgroundColor: PencilTheme.underlineGold,
                        foregroundColor: Colors.white,
                        minimumSize: const Size.fromHeight(54),
                        padding: const EdgeInsets.symmetric(vertical: 16),
                        shape: RoundedRectangleBorder(
                          borderRadius: BorderRadius.circular(14),
                        ),
                      ),
                      onPressed: _busy ? null : _start,
                      child: _busy
                          ? const SizedBox(
                              height: 22,
                              width: 22,
                              child: CircularProgressIndicator(
                                strokeWidth: 2,
                                color: Colors.white,
                              ),
                            )
                          : Text(
                              'Start',
                              style: GoogleFonts.inter(
                                fontSize: 16,
                                fontWeight: FontWeight.w700,
                              ),
                            ),
                    ),
                    const SizedBox(height: 12),
                    Text(
                      'Est. cost · $_estimatedCost credits',
                      textAlign: TextAlign.center,
                      style: GoogleFonts.inter(
                        fontSize: 13,
                        fontWeight: FontWeight.w600,
                        color: PencilTheme.stone600,
                      ),
                    ),
                    const SizedBox(height: 8),
                    Text(
                      'Balance · ${credits.toStringAsFixed(2)}',
                      style: GoogleFonts.inter(
                        fontSize: 12,
                        color: PencilTheme.inkSoft,
                      ),
                    ),
                  ],
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }

  /// 设计稿 Lcol：114 宽，双槽 112×108，中间 32 高加号。
  Widget _leftTwoSlotsColumn() {
    return SizedBox(
      width: 114,
      child: Column(
        mainAxisSize: MainAxisSize.min,
        mainAxisAlignment: MainAxisAlignment.center,
        children: [
          _imageSlot(slotIndex: 0, label: 'Image 1'),
          const SizedBox(height: 10),
          SizedBox(
            height: 32,
            child: Center(
              child: Icon(
                Icons.add,
                size: 24,
                color: PencilTheme.profileCredits,
              ),
            ),
          ),
          const SizedBox(height: 10),
          _imageSlot(slotIndex: 1, label: 'Image 2'),
        ],
      ),
    );
  }

  /// 单图：仅 `img_need != 2` 或视频菜单开启时；槽位尺寸与设计一致。
  Widget _leftSingleSlotColumn() {
    return SizedBox(
      width: 114,
      child: Column(
        mainAxisSize: MainAxisSize.min,
        mainAxisAlignment: MainAxisAlignment.center,
        children: [
          _imageSlot(slotIndex: 0, label: 'Image 1'),
        ],
      ),
    );
  }

  Widget _equalsColumn() {
    return SizedBox(
      width: 32,
      child: Center(
        child: Text(
          '=',
          style: GoogleFonts.inter(
            fontSize: 26,
            fontWeight: FontWeight.w800,
            color: PencilTheme.profileCredits,
          ),
        ),
      ),
    );
  }

  /// 设计稿 prevBx：高 359，圆角 20，描边 #FBBF24。
  /// 描边叠在图片之上（否则子组件会先盖住 decoration 内缘的线）。
  Widget _effectPreviewPanel() {
    final t = widget.template;
    final url = t?.image.trim() ?? '';
    final fix = t?.imageFix?.trim();

    final innerR = _previewOuterR - _previewBorderW;

    return SizedBox(
      height: _previewH,
      child: Container(
        decoration: BoxDecoration(
          borderRadius: BorderRadius.circular(_previewOuterR),
          boxShadow: [
            BoxShadow(
              color: Colors.black.withValues(alpha: 0.08),
              blurRadius: 24,
              offset: const Offset(0, 8),
            ),
          ],
        ),
        clipBehavior: Clip.none,
        child: Stack(
          fit: StackFit.expand,
          children: [
            ClipRRect(
              borderRadius: BorderRadius.circular(innerR),
              child: _buildPreviewMediaLayer(url, fix),
            ),
            Positioned.fill(
              child: IgnorePointer(
                child: DecoratedBox(
                  decoration: BoxDecoration(
                    borderRadius: BorderRadius.circular(_previewOuterR),
                    border: Border.all(
                      color: PencilTheme.profileAvatarRing,
                      width: _previewBorderW,
                    ),
                  ),
                ),
              ),
            ),
          ],
        ),
      ),
    );
  }

  /// 视频预览：与 [GenerateResultScreen] / 首页背景一致，循环播放；失败则回退静态图。
  Widget _buildPreviewMediaLayer(String url, String? fix) {
    if (_previewIsVideo) {
      if (_previewVideoFailed) {
        return _buildPreviewStaticImageLayer(url, fix);
      }
      final c = _previewVideo;
      if (c == null || !c.value.isInitialized) {
        return _previewPlaceholder(loading: true);
      }
      return LayoutBuilder(
        builder: (context, constraints) {
          final cw = constraints.maxWidth;
          final ch = constraints.maxHeight;
          final w = c.value.size.width;
          final h = c.value.size.height;
          if (w <= 0 ||
              h <= 0 ||
              !cw.isFinite ||
              !ch.isFinite ||
              cw <= 0 ||
              ch <= 0) {
            return _previewPlaceholder(loading: true);
          }
          return Stack(
            fit: StackFit.expand,
            children: [
              Positioned.fill(
                child: ClipRect(
                  child: SizedBox(
                    width: cw,
                    height: ch,
                    child: FittedBox(
                      fit: BoxFit.cover,
                      alignment: Alignment.center,
                      clipBehavior: Clip.none,
                      child: SizedBox(
                        width: w,
                        height: h,
                        child: VideoPlayer(c),
                      ),
                    ),
                  ),
                ),
              ),
            ],
          );
        },
      );
    }
    return _buildPreviewStaticImageLayer(url, fix);
  }

  Widget _buildPreviewStaticImageLayer(String url, String? fix) {
    if (url.isNotEmpty) {
      return CachedNetworkImage(
        imageUrl: url,
        fit: BoxFit.cover,
        width: double.infinity,
        height: _previewH,
        placeholder: (_, _) => _previewPlaceholder(loading: true),
        errorWidget: (_, _, _) {
          if (fix != null && fix.isNotEmpty) {
            return CachedNetworkImage(
              imageUrl: fix,
              fit: BoxFit.cover,
              width: double.infinity,
              height: _previewH,
              errorWidget: (_, _, _) => _previewPlaceholder(),
            );
          }
          return _previewPlaceholder();
        },
      );
    }
    if (fix != null && fix.isNotEmpty) {
      return CachedNetworkImage(
        imageUrl: fix,
        fit: BoxFit.cover,
        width: double.infinity,
        height: _previewH,
        errorWidget: (_, _, _) => _previewPlaceholder(),
      );
    }
    return _previewPlaceholder();
  }

  Widget _previewPlaceholder({bool loading = false}) {
    return Container(
      color: PencilTheme.cardThumbBg,
      alignment: Alignment.center,
      child: loading
          ? SizedBox(
              width: 28,
              height: 28,
              child: CircularProgressIndicator(
                strokeWidth: 2,
                color: PencilTheme.profileAvatarIcon.withValues(alpha: 0.8),
              ),
            )
          : Column(
              mainAxisSize: MainAxisSize.min,
              children: [
                Icon(
                  Icons.auto_awesome_outlined,
                  size: 40,
                  color: PencilTheme.stone600.withValues(alpha: 0.5),
                ),
                const SizedBox(height: 8),
                Text(
                  'Preview',
                  style: GoogleFonts.inter(
                    fontSize: 13,
                    fontWeight: FontWeight.w600,
                    color: PencilTheme.stone600.withValues(alpha: 0.75),
                  ),
                ),
              ],
            ),
    );
  }

  Widget _imageSlot({required int slotIndex, required String label}) {
    final file = slotIndex == 0 ? _picked : _picked2;

    return SizedBox(
      width: _slotW,
      height: _slotH,
      child: Material(
        color: Colors.white,
        shape: RoundedRectangleBorder(
          borderRadius: BorderRadius.circular(16),
          side: const BorderSide(
            color: PencilTheme.genSlotBorder,
            width: 1.5,
          ),
        ),
        child: InkWell(
          onTap: () => _pickSlot(slotIndex),
          borderRadius: BorderRadius.circular(16),
          child: file == null
              ? Column(
                  mainAxisAlignment: MainAxisAlignment.center,
                  children: [
                    Icon(
                      Icons.add_photo_alternate_outlined,
                      color: PencilTheme.profileAvatarIcon,
                      size: 26,
                    ),
                    const SizedBox(height: 6),
                    Text(
                      label,
                      style: GoogleFonts.inter(
                        fontSize: 11,
                        fontWeight: FontWeight.w700,
                        color: PencilTheme.stone600,
                      ),
                    ),
                  ],
                )
              : ClipRRect(
                  borderRadius: BorderRadius.circular(14),
                  child: Image.file(file, fit: BoxFit.cover),
                ),
        ),
      ),
    );
  }

  Widget _hintBox() {
    return Container(
      padding: const EdgeInsets.fromLTRB(18, 14, 18, 12),
      decoration: BoxDecoration(
        color: Colors.white,
        borderRadius: BorderRadius.circular(10),
        border: Border.all(color: PencilTheme.genHintBorder),
        boxShadow: [
          BoxShadow(
            color: const Color(0x30CA8A04),
            blurRadius: 20,
            offset: const Offset(0, 6),
          ),
        ],
      ),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Row(
            children: [
              Icon(Icons.auto_awesome,
                  size: 18, color: PencilTheme.profileAvatarIcon),
              const SizedBox(width: 8),
              Text(
                'Upload tips',
                style: GoogleFonts.inter(
                  fontSize: 13,
                  fontWeight: FontWeight.w700,
                  color: PencilTheme.genHintTitle,
                ),
              ),
            ],
          ),
          const SizedBox(height: 8),
          Text(
            'Upload JPG or PNG (≤ 5 MB each, up to 2). You can use the camera or photo library. Use clear, front-facing photos when possible.',
            style: GoogleFonts.inter(
              fontSize: 13,
              fontWeight: FontWeight.w500,
              height: 1.45,
              color: PencilTheme.stone600,
            ),
          ),
        ],
      ),
    );
  }

  Widget _resoChip(String t, bool on, VoidCallback fn) {
    return Material(
      color: on ? PencilTheme.underlineGold.withValues(alpha: 0.2) : Colors.white,
      shape: RoundedRectangleBorder(
        borderRadius: BorderRadius.circular(12),
        side: BorderSide(
          color: on ? PencilTheme.underlineGold : PencilTheme.genNavBackStroke,
        ),
      ),
      child: InkWell(
        onTap: fn,
        borderRadius: BorderRadius.circular(12),
        child: Padding(
          padding: const EdgeInsets.symmetric(horizontal: 20, vertical: 10),
          child: Text(
            t,
            style: GoogleFonts.inter(
              fontWeight: FontWeight.w600,
              color: PencilTheme.stone900,
            ),
          ),
        ),
      ),
    );
  }
}

bool _urlLooksLikeVideo(String url) {
  if (url.isEmpty) return false;
  final lower = url.toLowerCase();
  const hints = ['.mp4', '.m3u8', '.webm', '.mov', '.mkv', '.avi'];
  return hints.any((h) => lower.contains(h));
}