import 'dart:async';
import 'dart:html' as html;
import 'dart:typed_data';

import 'package:file_picker/file_picker.dart';
import 'package:flutter/material.dart';
import 'package:manager_app/Components/fetch_resource_icon.dart';
import 'package:manager_app/Screens/Resources/resource_formatting.dart';
import 'package:manager_app/constants.dart';
import 'package:manager_app/l10n/app_localizations.dart';
import 'package:manager_api_new/api.dart';

const List<String> kAcceptedExtensions = [
  'jpg', 'jpeg', 'png', 'gif', 'mp3', 'mp4', 'webm', 'pdf', 'json',
];

/// Une entrée en attente d'envoi : soit un fichier local, soit une URL.
///
/// Les deux vivent dans la même liste parce que c'est ainsi que l'utilisateur les
/// voit — l'ancien dialogue les séparait en deux onglets, ce qui imposait un choix
/// technique (où vivent les octets) avant même d'avoir choisi quoi que ce soit.
class PickedResource {
  final PlatformFile? file;
  final String? url;
  final ResourceType? type;

  const PickedResource.file(this.file, this.type) : url = null;
  const PickedResource.url(this.url, this.type) : file = null;

  bool get isUrl => url != null;
  String get name => isUrl ? url! : file!.name;
  int get sizeBytes => isUrl ? 0 : file!.size;
}

class ResourcePicker extends StatefulWidget {
  final List<PickedResource> picked;
  final VoidCallback onChanged;

  const ResourcePicker({
    Key? key,
    required this.picked,
    required this.onChanged,
  }) : super(key: key);

  @override
  State<ResourcePicker> createState() => _ResourcePickerState();
}

class _ResourcePickerState extends State<ResourcePicker> {
  bool _hot = false;
  bool _urlOpen = false;
  String? _error;
  final TextEditingController _urlController = TextEditingController();

  StreamSubscription<html.MouseEvent>? _overSub;
  StreamSubscription<html.MouseEvent>? _leaveSub;
  StreamSubscription<html.MouseEvent>? _dropSub;

  @override
  void initState() {
    super.initState();
    _listenToBrowserDrops();
  }

  @override
  void dispose() {
    _urlController.dispose();
    _overSub?.cancel();
    _leaveSub?.cancel();
    _dropSub?.cancel();
    super.dispose();
  }

  /// Flutter web ne reçoit pas les fichiers glissés depuis le bureau : c'est le
  /// document HTML qui les reçoit. On écoute donc `document`, et on annule son
  /// comportement par défaut — sans quoi le navigateur quitte l'application pour
  /// afficher le fichier lâché.
  void _listenToBrowserDrops() {
    _overSub = html.document.onDragOver.listen((event) {
      event.preventDefault();
      if (!_hot) setState(() => _hot = true);
    });
    _leaveSub = html.document.onDragLeave.listen((event) {
      event.preventDefault();
      if (_hot) setState(() => _hot = false);
    });
    _dropSub = html.document.onDrop.listen((event) async {
      event.preventDefault();
      setState(() => _hot = false);
      final files = event.dataTransfer.files;
      if (files == null) return;
      for (final file in files) {
        final bytes = await _readBytes(file);
        if (bytes != null) _add(file.name, bytes);
      }
    });
  }

  Future<Uint8List?> _readBytes(html.File file) {
    final completer = Completer<Uint8List?>();
    final reader = html.FileReader();
    reader.onLoadEnd.listen((_) {
      final result = reader.result;
      completer.complete(result is Uint8List ? result : null);
    });
    reader.onError.listen((_) => completer.complete(null));
    reader.readAsArrayBuffer(file);
    return completer.future;
  }

  String? _extensionOf(String name) {
    final dot = name.lastIndexOf('.');
    return dot == -1 ? null : name.substring(dot + 1).toLowerCase();
  }

  void _add(String name, Uint8List bytes) {
    final l = AppLocalizations.of(context)!;
    final extension = _extensionOf(name);

    if (!kAcceptedExtensions.contains(extension)) {
      setState(() => _error = '${l.mediaUnsupportedFormat} : $name');
      return;
    }
    if (widget.picked.any((p) => !p.isUrl && p.name == name)) {
      setState(() => _error = l.mediaFileAlreadyAdded);
      return;
    }

    setState(() {
      _error = null;
      widget.picked.add(PickedResource.file(
        PlatformFile(name: name, size: bytes.length, bytes: bytes),
        resourceTypeForExtension(extension),
      ));
    });
    widget.onChanged();
  }

  Future<void> _browse() async {
    final result = await FilePicker.platform.pickFiles(
      type: FileType.custom,
      allowMultiple: true,
      withData: true,
      allowedExtensions: kAcceptedExtensions,
    );
    if (result == null) return;
    for (final file in result.files) {
      if (file.bytes != null) _add(file.name, file.bytes!);
    }
  }

  void _addUrl() {
    final l = AppLocalizations.of(context)!;
    final url = _urlController.text.trim();

    if (url.isEmpty) return;
    if (!Uri.parse(url).isAbsolute) {
      setState(() => _error = l.mediaUrlInvalid);
      return;
    }
    if (widget.picked.any((p) => p.isUrl && p.url == url)) {
      setState(() => _error = l.mediaUrlAlreadyAdded);
      return;
    }

    setState(() {
      _error = null;
      _urlController.clear();
      widget.picked.add(PickedResource.url(url, _typeForUrl(url)));
    });
    widget.onChanged();
  }

  /// Même règle qu'avant, mais lisible : une URL YouTube est une vidéo, un `.json`
  /// ou un `.php` un flux JSON, tout le reste une image.
  ResourceType _typeForUrl(String url) {
    final youtube = RegExp(
        r'^https?://(?:www\.)?(?:youtube\.com/(?:[^/]+/[^/]+/|(?:v|e(?:mbed)?)\/|.*[?&]v=)|youtu\.be/)([^"&?/=%]{11})');
    if (youtube.hasMatch(url)) return ResourceType.VideoUrl;
    if (url.endsWith('json') || url.contains('.php')) return ResourceType.JsonUrl;
    return ResourceType.ImageUrl;
  }

  void _remove(PickedResource entry) {
    setState(() {
      _error = null;
      widget.picked.remove(entry);
    });
    widget.onChanged();
  }

  @override
  Widget build(BuildContext context) {
    final l = AppLocalizations.of(context)!;

    return Column(
      crossAxisAlignment: CrossAxisAlignment.stretch,
      mainAxisSize: MainAxisSize.min,
      children: [
        _dropZone(l),
        const SizedBox(height: kSpace4),
        _urlToggle(l),
        if (_urlOpen) ...[
          const SizedBox(height: kSpace3),
          _urlRow(l),
        ],
        if (_error != null) ...[
          const SizedBox(height: kSpace3),
          Text(_error!, style: const TextStyle(fontSize: 12.5, color: kError)),
        ],
        if (widget.picked.isNotEmpty) ...[
          const SizedBox(height: kSpace4),
          _list(l),
        ],
      ],
    );
  }

  Widget _dropZone(AppLocalizations l) {
    return InkWell(
      onTap: _browse,
      borderRadius: BorderRadius.circular(kRadiusCard),
      child: DottedBorderBox(
        active: _hot,
        child: Padding(
          padding: const EdgeInsets.symmetric(vertical: kSpace7, horizontal: kSpace5),
          child: Column(
            mainAxisSize: MainAxisSize.min,
            children: [
              Icon(Icons.file_upload_outlined,
                  size: 26, color: _hot ? kPrimaryColor : kInk3),
              const SizedBox(height: kSpace3),
              Text(
                l.mediaDropZone,
                textAlign: TextAlign.center,
                style: const TextStyle(
                    fontSize: 13.5, fontWeight: FontWeight.w600, color: kInk),
              ),
              const SizedBox(height: kSpace1),
              Text(l.mediaDropFormats, style: kTextHint),
            ],
          ),
        ),
      ),
    );
  }

  Widget _urlToggle(AppLocalizations l) {
    return Row(
      children: [
        const Expanded(child: Divider(height: 1, color: kLineSoft)),
        TextButton.icon(
          onPressed: () => setState(() => _urlOpen = !_urlOpen),
          icon: const Icon(Icons.link, size: 14, color: kInk2),
          label: Text(l.mediaOrPasteUrl,
              style: const TextStyle(fontSize: 12.5, color: kInk2)),
          style: TextButton.styleFrom(
            visualDensity: VisualDensity.compact,
            padding: const EdgeInsets.symmetric(horizontal: kSpace3),
          ),
        ),
        const Expanded(child: Divider(height: 1, color: kLineSoft)),
      ],
    );
  }

  Widget _urlRow(AppLocalizations l) {
    return Row(
      children: [
        Expanded(
          child: TextField(
            controller: _urlController,
            autofocus: true,
            style: const TextStyle(fontSize: 13, color: kInk),
            onSubmitted: (_) => _addUrl(),
            decoration: InputDecoration(
              isDense: true,
              filled: true,
              fillColor: kSurface2,
              hintText: l.mediaUrlHint,
              hintStyle: kTextHint,
              contentPadding: const EdgeInsets.symmetric(
                  horizontal: kSpace4, vertical: kSpace3),
              border: OutlineInputBorder(
                borderRadius: BorderRadius.circular(kRadiusInput),
                borderSide: const BorderSide(color: kLine),
              ),
              enabledBorder: OutlineInputBorder(
                borderRadius: BorderRadius.circular(kRadiusInput),
                borderSide: const BorderSide(color: kLine),
              ),
            ),
          ),
        ),
        const SizedBox(width: kSpace2),
        FilledButton(
          onPressed: _addUrl,
          style: FilledButton.styleFrom(
            backgroundColor: kPrimaryColor,
            shape: RoundedRectangleBorder(
                borderRadius: BorderRadius.circular(kRadiusPill)),
          ),
          child: Text(l.add, style: const TextStyle(fontSize: 13)),
        ),
      ],
    );
  }

  Widget _list(AppLocalizations l) {
    return Column(
      crossAxisAlignment: CrossAxisAlignment.stretch,
      children: [
        for (final entry in widget.picked)
          Container(
            decoration: const BoxDecoration(
              border: Border(bottom: BorderSide(color: kLineSoft)),
            ),
            padding: const EdgeInsets.symmetric(vertical: kSpace3),
            child: Row(
              children: [
                Icon(getResourceIcon(entry.type), size: 17, color: kInk3),
                const SizedBox(width: kSpace4),
                Expanded(
                  child: Column(
                    crossAxisAlignment: CrossAxisAlignment.start,
                    children: [
                      Text(entry.name,
                          maxLines: 1,
                          overflow: TextOverflow.ellipsis,
                          style: const TextStyle(fontSize: 13, color: kInk)),
                      if (!entry.isUrl)
                        Text(formatBytes(context, entry.sizeBytes),
                            style: kTextHint),
                    ],
                  ),
                ),
                const SizedBox(width: kSpace3),
                Container(
                  padding: const EdgeInsets.symmetric(
                      horizontal: kSpace2, vertical: 2),
                  decoration: BoxDecoration(
                    color: kSurface3,
                    borderRadius: BorderRadius.circular(kRadiusInput),
                  ),
                  child: Text(resourceTypeLabel(l, entry.type),
                      style: const TextStyle(fontSize: 10.5, color: kInk2)),
                ),
                const SizedBox(width: kSpace2),
                IconButton(
                  icon: const Icon(Icons.close, size: 15),
                  color: kInk3,
                  splashRadius: 15,
                  visualDensity: VisualDensity.compact,
                  tooltip: l.mediaRemoveFile(entry.name),
                  onPressed: () => _remove(entry),
                ),
              ],
            ),
          ),
      ],
    );
  }
}

/// Bordure en pointillés dessinée à la main : Flutter n'en fournit pas, et la seule
/// alternative était une image de bordure ou un paquet de plus.
class DottedBorderBox extends StatelessWidget {
  final Widget child;
  final bool active;
  const DottedBorderBox({Key? key, required this.child, this.active = false})
      : super(key: key);

  @override
  Widget build(BuildContext context) {
    return CustomPaint(
      painter: _DashedBorderPainter(
          color: active ? kPrimaryColor : kLine, radius: kRadiusCard),
      child: Container(
        decoration: BoxDecoration(
          color: active ? kSurface3 : kSurface2,
          borderRadius: BorderRadius.circular(kRadiusCard),
        ),
        child: child,
      ),
    );
  }
}

class _DashedBorderPainter extends CustomPainter {
  final Color color;
  final double radius;
  const _DashedBorderPainter({required this.color, required this.radius});

  @override
  void paint(Canvas canvas, Size size) {
    final paint = Paint()
      ..color = color
      ..style = PaintingStyle.stroke
      ..strokeWidth = 1.5;

    final path = Path()
      ..addRRect(RRect.fromRectAndRadius(
          Offset.zero & size, Radius.circular(radius)));

    for (final metric in path.computeMetrics()) {
      var distance = 0.0;
      while (distance < metric.length) {
        final end = (distance + 5).clamp(0.0, metric.length);
        canvas.drawPath(metric.extractPath(distance, end), paint);
        distance = end + 4;
      }
    }
  }

  @override
  bool shouldRepaint(_DashedBorderPainter oldDelegate) =>
      oldDelegate.color != color;
}