import 'dart:async';

import 'package:flutter/material.dart';

import '../../core/theme/app_colors.dart';
import '../../core/widgets/app_icon.dart';
import '../../data/models/jellyfin_library.dart';
import '../../data/models/jellyfin_models.dart';
import '../../data/services/jellyfin_library_service.dart';

Future<List<JellyfinGenreSelection>?> showJellyfinGenreDialog(
  BuildContext context, {
  required JellyfinLibraryService library,
  required List<JellyfinGenreSelection> selected,
}) {
  return showDialog<List<JellyfinGenreSelection>>(
    context: context,
    builder: (_) => JellyfinGenreDialog(library: library, selected: selected),
  );
}

/// Grouped multi-select for the Random row. At most five families; the server
/// genre list is fetched each time so new tags appear after a library scan.
class JellyfinGenreDialog extends StatefulWidget {
  const JellyfinGenreDialog({
    super.key,
    required this.library,
    required this.selected,
  });

  final JellyfinLibraryService library;
  final List<JellyfinGenreSelection> selected;

  @override
  State<JellyfinGenreDialog> createState() => _JellyfinGenreDialogState();
}

class _JellyfinGenreDialogState extends State<JellyfinGenreDialog> {
  static const _maxSelections = 5;

  final TextEditingController _search = TextEditingController();
  List<JellyfinGenreFamily>? _families;
  final Set<String> _selectedIds = {};
  bool _loading = true;
  String? _error;
  String _query = '';

  @override
  void initState() {
    super.initState();
    _selectedIds.addAll(widget.selected.map((selection) => selection.id));
    unawaited(_load());
  }

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

  Future<void> _load() async {
    setState(() {
      _loading = true;
      _error = null;
    });
    try {
      final families = await widget.library.genreFamilies(force: true);
      if (!mounted) return;
      final ids = families.map((family) => family.id).toSet();
      setState(() {
        _families = families;
        _selectedIds.removeWhere((id) => !ids.contains(id));
        _loading = false;
      });
    } on JellyfinException catch (exception) {
      if (!mounted) return;
      setState(() {
        _loading = false;
        _error = exception.message;
      });
    } catch (_) {
      if (!mounted) return;
      setState(() {
        _loading = false;
        _error = 'Could not load the music library.';
      });
    }
  }

  void _toggle(JellyfinGenreFamily family) {
    final selected = _selectedIds.contains(family.id);
    if (!selected && _selectedIds.length >= _maxSelections) return;
    setState(() {
      if (selected) {
        _selectedIds.remove(family.id);
      } else {
        _selectedIds.add(family.id);
      }
    });
  }

  void _save() {
    final families = _families;
    if (families == null) return;
    final selections = families
        .where((family) => _selectedIds.contains(family.id))
        .map(
          (family) =>
              JellyfinGenreSelection(id: family.id, label: family.label),
        )
        .toList(growable: false);
    Navigator.of(context).pop(selections);
  }

  @override
  Widget build(BuildContext context) {
    final colors = context.colors;
    final theme = Theme.of(context);
    final screen = MediaQuery.sizeOf(context);
    final width = (screen.width - 120).clamp(420.0, 680.0);
    final height = (screen.height - 160).clamp(320.0, 500.0);

    return AlertDialog(
      title: Row(
        children: [
          Text('Random genres', style: theme.textTheme.titleLarge),
          const Spacer(),
          Text(
            '${_selectedIds.length} / $_maxSelections',
            style: theme.textTheme.labelLarge?.copyWith(
              color: _selectedIds.length >= _maxSelections
                  ? colors.accent
                  : colors.inkMuted,
            ),
          ),
        ],
      ),
      content: SizedBox(
        width: width,
        height: height,
        child: _buildContent(context),
      ),
      actions: [
        TextButton(
          onPressed: () => Navigator.of(context).pop(),
          child: const Text('Cancel'),
        ),
        FilledButton(
          onPressed: _loading || _error != null ? null : _save,
          child: const Text('Save'),
        ),
      ],
    );
  }

  Widget _buildContent(BuildContext context) {
    final colors = context.colors;
    final theme = Theme.of(context);
    if (_loading) {
      return const Center(child: CircularProgressIndicator());
    }
    final error = _error;
    if (error != null) {
      return Center(
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            Text(
              error,
              textAlign: TextAlign.center,
              style: theme.textTheme.bodyMedium?.copyWith(
                color: colors.inkMuted,
              ),
            ),
            const SizedBox(height: 10),
            TextButton(
              onPressed: _load,
              style: TextButton.styleFrom(foregroundColor: colors.accent),
              child: const Text('Retry'),
            ),
          ],
        ),
      );
    }

    final families = _families ?? const <JellyfinGenreFamily>[];
    if (families.isEmpty) {
      return Center(
        child: Text(
          'No genres found in the music library.',
          style: theme.textTheme.bodyMedium?.copyWith(color: colors.inkMuted),
        ),
      );
    }

    final query = _query.trim().toLowerCase();
    final visible = query.isEmpty
        ? families
        : families
              .where(
                (family) =>
                    family.label.toLowerCase().contains(query) ||
                    family.rawGenres.any(
                      (raw) => raw.toLowerCase().contains(query),
                    ),
              )
              .toList(growable: false);
    final atLimit = _selectedIds.length >= _maxSelections;

    return Column(
      crossAxisAlignment: CrossAxisAlignment.stretch,
      children: [
        if (families.length > 12)
          Padding(
            padding: const EdgeInsets.only(bottom: 8),
            child: TextField(
              controller: _search,
              onChanged: (value) => setState(() => _query = value),
              style: theme.textTheme.bodyMedium,
              decoration: InputDecoration(
                hintText: 'Search genres',
                isDense: true,
                prefixIcon: Padding(
                  padding: const EdgeInsets.only(left: 2),
                  child: SizedBox(
                    width: 18,
                    height: 18,
                    child: Center(
                      child: AppIcon(
                        'assets/icons/search.svg',
                        size: 15,
                        color: colors.inkFaint,
                      ),
                    ),
                  ),
                ),
                prefixIconConstraints: const BoxConstraints(
                  minWidth: 34,
                  minHeight: 34,
                ),
              ),
            ),
          ),
        if (atLimit)
          Padding(
            padding: const EdgeInsets.only(bottom: 4),
            child: Text(
              'Deselect one to choose another.',
              style: theme.textTheme.bodySmall?.copyWith(
                color: colors.inkMuted,
              ),
            ),
          ),
        Expanded(
          child: visible.isEmpty
              ? Center(
                  child: Text(
                    'No genres match that search.',
                    style: theme.textTheme.bodySmall?.copyWith(
                      color: colors.inkMuted,
                    ),
                  ),
                )
              : ListView.builder(
                  itemCount: visible.length,
                  itemBuilder: (context, index) {
                    final family = visible[index];
                    final selected = _selectedIds.contains(family.id);
                    final enabled = selected || !atLimit;
                    return _GenreFamilyRow(
                      family: family,
                      selected: selected,
                      enabled: enabled,
                      onTap: enabled ? () => _toggle(family) : null,
                    );
                  },
                ),
        ),
      ],
    );
  }
}

class _GenreFamilyRow extends StatelessWidget {
  const _GenreFamilyRow({
    required this.family,
    required this.selected,
    required this.enabled,
    required this.onTap,
  });

  final JellyfinGenreFamily family;
  final bool selected;
  final bool enabled;
  final VoidCallback? onTap;

  @override
  Widget build(BuildContext context) {
    final colors = context.colors;
    final theme = Theme.of(context);
    final count = family.rawCount;
    return InkWell(
      borderRadius: BorderRadius.circular(12),
      onTap: onTap,
      child: Padding(
        padding: const EdgeInsets.symmetric(vertical: 4, horizontal: 2),
        child: Row(
          children: [
            Checkbox(
              value: selected,
              onChanged: enabled ? (_) => onTap?.call() : null,
              activeColor: colors.accent,
              checkColor: colors.accentInk,
              side: BorderSide(color: colors.border),
            ),
            const SizedBox(width: 4),
            Expanded(
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  Text(
                    family.label,
                    style: theme.textTheme.bodyLarge?.copyWith(
                      color: enabled ? colors.ink : colors.inkFaint,
                    ),
                  ),
                  Text(
                    '$count ${count == 1 ? 'genre' : 'genres'}',
                    style: theme.textTheme.bodySmall?.copyWith(
                      color: colors.inkMuted,
                    ),
                  ),
                ],
              ),
            ),
          ],
        ),
      ),
    );
  }
}