import 'package:flutter/material.dart';
import 'package:image_picker/image_picker.dart';

import '../application/application.dart';
import '../domain/domain.dart';

abstract interface class MediaSourcePicker {
  Future<String?> pickPath(MediaKind kind);
}

final class ImagePickerMediaSourcePicker implements MediaSourcePicker {
  const ImagePickerMediaSourcePicker();

  @override
  Future<String?> pickPath(MediaKind kind) async {
    final picker = ImagePicker();
    final file = switch (kind) {
      MediaKind.image => await picker.pickImage(source: ImageSource.gallery),
      MediaKind.video => await picker.pickVideo(source: ImageSource.gallery),
    };
    return file?.path;
  }
}

final class ExerciseLibraryScreen extends StatefulWidget {
  const ExerciseLibraryScreen({
    required this.exerciseUseCases,
    required this.mediaUseCases,
    super.key,
  });

  final ExerciseUseCases exerciseUseCases;
  final MediaUseCases mediaUseCases;

  @override
  State<ExerciseLibraryScreen> createState() => _ExerciseLibraryScreenState();
}

final class _ExerciseLibraryScreenState extends State<ExerciseLibraryScreen> {
  final _searchController = TextEditingController();
  var _selectedMeasures = <WorkoutMeasure>{};
  late Future<List<Exercise>> _exercises;

  @override
  void initState() {
    super.initState();
    _exercises = widget.exerciseUseCases.listActive();
    _searchController.addListener(() => setState(() {}));
  }

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

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('Exercices')),
      floatingActionButton: FloatingActionButton.extended(
        onPressed: () => _openForm(),
        icon: const Icon(Icons.add),
        label: const Text('Créer'),
      ),
      body: FutureBuilder<List<Exercise>>(
        future: _exercises,
        builder: (context, snapshot) {
          if (snapshot.connectionState != ConnectionState.done) {
            return const Center(child: CircularProgressIndicator());
          }
          if (snapshot.hasError) {
            return _CenteredMessage(
              title: 'Impossible de charger les exercices',
              actionLabel: 'Réessayer',
              onAction: _reload,
            );
          }

          final exercises = snapshot.data ?? const <Exercise>[];
          final filtered = _filter(exercises);
          return RefreshIndicator(
            onRefresh: () {
              _reload();
              return Future<void>.value();
            },
            child: CustomScrollView(
              slivers: [
                SliverToBoxAdapter(
                  child: Padding(
                    padding: const EdgeInsets.fromLTRB(16, 12, 16, 8),
                    child: Column(
                      crossAxisAlignment: CrossAxisAlignment.start,
                      children: [
                        TextField(
                          controller: _searchController,
                          decoration: const InputDecoration(
                            labelText: 'Rechercher',
                            prefixIcon: Icon(Icons.search),
                          ),
                        ),
                        const SizedBox(height: 12),
                        Wrap(
                          spacing: 8,
                          runSpacing: 8,
                          children: WorkoutMeasure.values.map((measure) {
                            return FilterChip(
                              label: Text(measure.label),
                              selected: _selectedMeasures.contains(measure),
                              onSelected: (selected) {
                                setState(() {
                                  if (selected) {
                                    _selectedMeasures = {
                                      ..._selectedMeasures,
                                      measure,
                                    };
                                  } else {
                                    _selectedMeasures = {..._selectedMeasures}
                                      ..remove(measure);
                                  }
                                });
                              },
                            );
                          }).toList(),
                        ),
                      ],
                    ),
                  ),
                ),
                if (exercises.isEmpty)
                  SliverFillRemaining(
                    hasScrollBody: false,
                    child: _CenteredMessage(
                      title: 'Aucun exercice pour le moment',
                      message:
                          'Crée ton premier exercice pour composer tes programmes.',
                      actionLabel: 'Créer un exercice',
                      onAction: () => _openForm(),
                    ),
                  )
                else if (filtered.isEmpty)
                  const SliverFillRemaining(
                    hasScrollBody: false,
                    child: _CenteredMessage(
                      title: 'Aucun exercice ne correspond',
                      message:
                          'Modifie la recherche ou les filtres de mesures.',
                    ),
                  )
                else
                  SliverList(
                    delegate: SliverChildBuilderDelegate((context, index) {
                      if (index.isOdd) {
                        return const Divider(height: 1, indent: 72);
                      }
                      final exercise = filtered[index ~/ 2];
                      return ExerciseListTile(
                        exercise: exercise,
                        onTap: () => _openForm(exercise: exercise),
                      );
                    }, childCount: filtered.length * 2 - 1),
                  ),
              ],
            ),
          );
        },
      ),
    );
  }

  List<Exercise> _filter(List<Exercise> exercises) {
    final query = _searchController.text.trim().toLowerCase();
    return exercises.where((exercise) {
      final matchesQuery =
          query.isEmpty ||
          exercise.name.toLowerCase().contains(query) ||
          (exercise.description?.toLowerCase().contains(query) ?? false);
      final matchesMeasures =
          _selectedMeasures.isEmpty ||
          _selectedMeasures.every(exercise.availableMeasures.contains);
      return matchesQuery && matchesMeasures;
    }).toList();
  }

  void _reload() {
    setState(() {
      _exercises = widget.exerciseUseCases.listActive();
    });
  }

  Future<void> _openForm({Exercise? exercise}) async {
    final changed = await Navigator.of(context).push<bool>(
      MaterialPageRoute(
        builder: (context) => ExerciseFormScreen(
          exerciseUseCases: widget.exerciseUseCases,
          mediaUseCases: widget.mediaUseCases,
          exercise: exercise,
        ),
      ),
    );
    if (changed == true) {
      if (!mounted) return;
      _reload();
    }
  }
}

final class ExerciseListTile extends StatelessWidget {
  const ExerciseListTile({required this.exercise, this.onTap, super.key});

  final Exercise exercise;
  final VoidCallback? onTap;

  @override
  Widget build(BuildContext context) {
    final description = exercise.description?.trim();
    final hasMedia =
        exercise.imageMediaId != null || exercise.videoMediaId != null;
    return ListTile(
      onTap: onTap,
      leading: CircleAvatar(
        child: Icon(
          hasMedia ? Icons.perm_media_outlined : Icons.fitness_center,
        ),
      ),
      title: Text(exercise.name),
      subtitle: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          if (description != null && description.isNotEmpty)
            Padding(
              padding: const EdgeInsets.only(top: 2, bottom: 6),
              child: Text(
                description,
                maxLines: 2,
                overflow: TextOverflow.ellipsis,
              ),
            )
          else
            const SizedBox(height: 6),
          Wrap(
            spacing: 6,
            runSpacing: 6,
            children: [
              ...exercise.availableMeasures.map(
                (measure) => MeasureBadge(
                  measure: measure,
                  scoreUnit: exercise.scoreUnit,
                  scoreInputMode: exercise.scoreInputMode,
                ),
              ),
              if (hasMedia)
                const Tooltip(
                  message: 'Média associé',
                  child: Icon(Icons.image_outlined, size: 18),
                ),
            ],
          ),
        ],
      ),
      trailing: const Icon(Icons.chevron_right),
    );
  }
}

final class ExerciseFormScreen extends StatefulWidget {
  const ExerciseFormScreen({
    required this.exerciseUseCases,
    required this.mediaUseCases,
    this.mediaPicker = const ImagePickerMediaSourcePicker(),
    this.exercise,
    super.key,
  });

  final ExerciseUseCases exerciseUseCases;
  final MediaUseCases mediaUseCases;
  final MediaSourcePicker mediaPicker;
  final Exercise? exercise;

  @override
  State<ExerciseFormScreen> createState() => _ExerciseFormScreenState();
}

final class _ExerciseFormScreenState extends State<ExerciseFormScreen> {
  final _formKey = GlobalKey<FormState>();
  late final TextEditingController _nameController;
  late final TextEditingController _descriptionController;
  late final TextEditingController _scoreLabelController;
  late final TextEditingController _scoreUnitController;
  String? _imageMediaId;
  String? _videoMediaId;
  String? _selectedImageName;
  String? _selectedVideoName;
  var _hasTime = true;
  var _hasReps = false;
  var _hasScore = false;
  var _scoreInputMode = ScoreInputMode.manual;
  var _saving = false;
  var _importingImage = false;
  var _importingVideo = false;
  String? _measureError;
  String? _warning;

  bool get _isEditing => widget.exercise != null;

  @override
  void initState() {
    super.initState();
    final exercise = widget.exercise;
    _nameController = TextEditingController(text: exercise?.name);
    _descriptionController = TextEditingController(text: exercise?.description);
    _scoreLabelController = TextEditingController(text: exercise?.scoreLabel);
    _scoreUnitController = TextEditingController(text: exercise?.scoreUnit);
    _imageMediaId = exercise?.imageMediaId;
    _videoMediaId = exercise?.videoMediaId;
    _hasTime = exercise?.hasTimeMeasure ?? true;
    _hasReps = exercise?.hasRepsMeasure ?? false;
    _hasScore = exercise?.hasScoreMeasure ?? false;
    _scoreInputMode = exercise?.scoreInputMode ?? ScoreInputMode.manual;
  }

  @override
  void dispose() {
    _nameController.dispose();
    _descriptionController.dispose();
    _scoreLabelController.dispose();
    _scoreUnitController.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(_isEditing ? 'Modifier l’exercice' : 'Créer un exercice'),
      ),
      body: Form(
        key: _formKey,
        child: ListView(
          padding: const EdgeInsets.all(16),
          children: [
            TextFormField(
              controller: _nameController,
              decoration: const InputDecoration(labelText: 'Nom'),
              textInputAction: TextInputAction.next,
              validator: (value) => value == null || value.trim().isEmpty
                  ? 'Le nom est obligatoire.'
                  : null,
            ),
            const SizedBox(height: 12),
            TextFormField(
              controller: _descriptionController,
              decoration: const InputDecoration(labelText: 'Description'),
              minLines: 2,
              maxLines: 4,
            ),
            const SizedBox(height: 24),
            Text(
              'Média optionnel',
              style: Theme.of(context).textTheme.titleMedium,
            ),
            const SizedBox(height: 8),
            _MediaImportField(
              label: 'Image',
              selectedFileName: _selectedImageName,
              imported: _imageMediaId != null,
              importing: _importingImage,
              actionLabel: 'Choisir une image',
              onPick: () => _importMedia(MediaKind.image),
            ),
            const SizedBox(height: 8),
            _MediaImportField(
              label: 'Vidéo',
              selectedFileName: _selectedVideoName,
              imported: _videoMediaId != null,
              importing: _importingVideo,
              actionLabel: 'Choisir une vidéo',
              onPick: () => _importMedia(MediaKind.video),
            ),
            const SizedBox(height: 24),
            Text(
              'Mesures disponibles',
              style: Theme.of(context).textTheme.titleMedium,
            ),
            const SizedBox(height: 8),
            _MeasureSwitch(
              title: 'Temps',
              subtitle: 'Chronométrer la durée d’une série.',
              value: _hasTime,
              onChanged: (value) => _setMeasure(() => _hasTime = value),
            ),
            _MeasureSwitch(
              title: 'Répétitions',
              subtitle: 'Compter le nombre de mouvements réalisés.',
              value: _hasReps,
              onChanged: (value) => _setMeasure(() => _hasReps = value),
            ),
            _MeasureSwitch(
              title: 'Score',
              subtitle: 'Saisir une valeur libre avec son unité.',
              value: _hasScore,
              onChanged: (value) => _setMeasure(() => _hasScore = value),
            ),
            if (_measureError != null)
              Padding(
                padding: const EdgeInsets.only(top: 8),
                child: Text(
                  _measureError!,
                  style: TextStyle(color: Theme.of(context).colorScheme.error),
                ),
              ),
            if (_hasScore) ...[
              const SizedBox(height: 12),
              Text(
                'Mode de saisie',
                style: Theme.of(context).textTheme.titleSmall,
              ),
              RadioListTile<ScoreInputMode>(
                contentPadding: EdgeInsets.zero,
                title: const Text('Saisie libre'),
                value: ScoreInputMode.manual,
                groupValue: _scoreInputMode,
                onChanged: (value) {
                  if (value == null) return;
                  setState(() => _scoreInputMode = value);
                },
              ),
              RadioListTile<ScoreInputMode>(
                contentPadding: EdgeInsets.zero,
                title: const Text('Chrono intégré'),
                subtitle: const Text('Temps réalisé'),
                value: ScoreInputMode.stopwatch,
                groupValue: _scoreInputMode,
                onChanged: (value) {
                  if (value == null) return;
                  setState(() => _scoreInputMode = value);
                },
              ),
              if (_scoreInputMode == ScoreInputMode.manual) ...[
                const SizedBox(height: 12),
                TextFormField(
                  controller: _scoreLabelController,
                  decoration: const InputDecoration(
                    labelText: 'Score à saisir',
                  ),
                  validator: (value) {
                    if (!_hasScore ||
                        _scoreInputMode != ScoreInputMode.manual) {
                      return null;
                    }
                    return value == null || value.trim().isEmpty
                        ? 'Le libellé du score est obligatoire.'
                        : null;
                  },
                ),
                const SizedBox(height: 12),
                TextFormField(
                  controller: _scoreUnitController,
                  decoration: const InputDecoration(labelText: 'Unité'),
                  validator: (value) {
                    if (!_hasScore ||
                        _scoreInputMode != ScoreInputMode.manual) {
                      return null;
                    }
                    return value == null || value.trim().isEmpty
                        ? 'L’unité du score est obligatoire.'
                        : null;
                  },
                ),
              ],
            ],
            if (_warning != null) ...[
              const SizedBox(height: 16),
              MaterialBanner(
                content: Text(_warning!),
                leading: const Icon(Icons.info_outline),
                actions: [
                  TextButton(
                    onPressed: () => setState(() => _warning = null),
                    child: const Text('OK'),
                  ),
                ],
              ),
            ],
            const SizedBox(height: 24),
            FilledButton.icon(
              onPressed: _saving ? null : _save,
              icon: _saving
                  ? const SizedBox.square(
                      dimension: 18,
                      child: CircularProgressIndicator(strokeWidth: 2),
                    )
                  : const Icon(Icons.check),
              label: const Text('Enregistrer'),
            ),
          ],
        ),
      ),
    );
  }

  void _setMeasure(VoidCallback update) {
    setState(() {
      update();
      _measureError = null;
      _warning = null;
    });
  }

  Future<void> _importMedia(MediaKind kind) async {
    final sourcePath = await widget.mediaPicker.pickPath(kind);
    if (sourcePath == null) {
      return;
    }
    final fileName = _fileNameFromPath(sourcePath);
    setState(() {
      if (kind == MediaKind.image) {
        _importingImage = true;
        _selectedImageName = fileName;
      } else {
        _importingVideo = true;
        _selectedVideoName = fileName;
      }
    });
    try {
      final asset = await widget.mediaUseCases.importMedia(
        sourcePath: sourcePath,
        kind: kind,
      );
      if (!mounted) return;
      setState(() {
        if (kind == MediaKind.image) {
          _imageMediaId = asset.metadata.id;
        } else {
          _videoMediaId = asset.metadata.id;
        }
      });
      _showSnackBar(
        kind == MediaKind.image ? 'Image importée.' : 'Vidéo importée.',
      );
    } on Exception catch (error) {
      _showSnackBar(error.toString());
    } finally {
      if (mounted) {
        setState(() {
          _importingImage = false;
          _importingVideo = false;
        });
      }
    }
  }

  Future<void> _save() async {
    final hasMeasure = _hasTime || _hasReps || _hasScore;
    setState(() {
      _measureError = hasMeasure
          ? null
          : 'Active au moins une mesure pour enregistrer.';
    });
    if (!_formKey.currentState!.validate() || !hasMeasure) {
      return;
    }

    final exercise = widget.exercise;
    if (exercise != null &&
        _measuresChanged(exercise) &&
        _warning == null &&
        await widget.exerciseUseCases.isUsedInPrograms(exercise.metadata.id)) {
      if (!mounted) return;
      setState(() {
        _warning =
            'Cet exercice est déjà utilisé dans un programme. '
            'Les programmes existants restent inchangés.';
      });
      return;
    }

    setState(() => _saving = true);
    final scoreInputMode = _hasScore ? _scoreInputMode : ScoreInputMode.manual;
    final scoreLabel = _hasScore
        ? switch (scoreInputMode) {
            ScoreInputMode.manual => _scoreLabelController.text.trim(),
            ScoreInputMode.stopwatch => 'Temps réalisé',
          }
        : null;
    final scoreUnit = _hasScore && scoreInputMode == ScoreInputMode.manual
        ? _scoreUnitController.text.trim()
        : null;
    try {
      if (exercise == null) {
        await widget.exerciseUseCases.create(
          name: _nameController.text.trim(),
          description: _optionalText(_descriptionController),
          imageMediaId: _imageMediaId,
          videoMediaId: _videoMediaId,
          hasTimeMeasure: _hasTime,
          hasRepsMeasure: _hasReps,
          hasScoreMeasure: _hasScore,
          scoreInputMode: scoreInputMode,
          scoreLabel: scoreLabel,
          scoreUnit: scoreUnit,
        );
      } else {
        await widget.exerciseUseCases.update(
          id: exercise.metadata.id,
          name: _nameController.text.trim(),
          description: _optionalText(_descriptionController),
          imageMediaId: _imageMediaId,
          videoMediaId: _videoMediaId,
          hasTimeMeasure: _hasTime,
          hasRepsMeasure: _hasReps,
          hasScoreMeasure: _hasScore,
          scoreInputMode: scoreInputMode,
          scoreLabel: scoreLabel,
          scoreUnit: scoreUnit,
        );
      }
      if (mounted) {
        final navigator = Navigator.of(context);
        if (navigator.canPop()) {
          navigator.pop(true);
        }
      }
    } on Exception catch (error) {
      _showSnackBar(error.toString());
    } finally {
      if (mounted) {
        setState(() => _saving = false);
      }
    }
  }

  bool _measuresChanged(Exercise exercise) {
    return exercise.hasTimeMeasure != _hasTime ||
        exercise.hasRepsMeasure != _hasReps ||
        exercise.hasScoreMeasure != _hasScore ||
        exercise.scoreInputMode != _scoreInputMode;
  }

  String? _optionalText(TextEditingController controller) {
    final text = controller.text.trim();
    return text.isEmpty ? null : text;
  }

  String _fileNameFromPath(String path) {
    final parts = path.split(RegExp(r'[/\\]'));
    return parts.isEmpty ? path : parts.last;
  }

  void _showSnackBar(String message) {
    if (!mounted) return;
    ScaffoldMessenger.of(
      context,
    ).showSnackBar(SnackBar(content: Text(message)));
  }
}

final class MeasureBadge extends StatelessWidget {
  const MeasureBadge({
    required this.measure,
    this.scoreInputMode = ScoreInputMode.manual,
    this.scoreUnit,
    super.key,
  });

  final WorkoutMeasure measure;
  final ScoreInputMode scoreInputMode;
  final String? scoreUnit;

  @override
  Widget build(BuildContext context) {
    final unit = scoreUnit?.trim();
    var label = measure.label;
    if (measure == WorkoutMeasure.score &&
        scoreInputMode == ScoreInputMode.stopwatch) {
      label = 'Score chrono';
    } else if (measure == WorkoutMeasure.score &&
        unit != null &&
        unit.isNotEmpty) {
      label = '${measure.label} ($unit)';
    }
    return Semantics(
      label: label,
      excludeSemantics: true,
      child: Chip(visualDensity: VisualDensity.compact, label: Text(label)),
    );
  }
}

final class _MeasureSwitch extends StatelessWidget {
  const _MeasureSwitch({
    required this.title,
    required this.subtitle,
    required this.value,
    required this.onChanged,
  });

  final String title;
  final String subtitle;
  final bool value;
  final ValueChanged<bool> onChanged;

  @override
  Widget build(BuildContext context) {
    return SwitchListTile(
      contentPadding: EdgeInsets.zero,
      title: Text(title),
      subtitle: Text(subtitle),
      value: value,
      onChanged: onChanged,
    );
  }
}

final class _MediaImportField extends StatelessWidget {
  const _MediaImportField({
    required this.label,
    required this.selectedFileName,
    required this.imported,
    required this.importing,
    required this.actionLabel,
    required this.onPick,
  });

  final String label;
  final String? selectedFileName;
  final bool imported;
  final bool importing;
  final String actionLabel;
  final VoidCallback onPick;

  @override
  Widget build(BuildContext context) {
    final fileName = selectedFileName;
    final status = fileName == null
        ? imported
              ? 'Média déjà importé'
              : 'Aucun fichier sélectionné'
        : fileName;
    return InputDecorator(
      decoration: InputDecoration(labelText: label),
      child: Row(
        children: [
          Icon(imported ? Icons.check_circle_outline : Icons.perm_media),
          const SizedBox(width: 12),
          Expanded(
            child: Text(status, maxLines: 1, overflow: TextOverflow.ellipsis),
          ),
          const SizedBox(width: 12),
          OutlinedButton.icon(
            onPressed: importing ? null : onPick,
            icon: importing
                ? const SizedBox.square(
                    dimension: 16,
                    child: CircularProgressIndicator(strokeWidth: 2),
                  )
                : const Icon(Icons.upload_file),
            label: Text(actionLabel),
          ),
        ],
      ),
    );
  }
}

final class _CenteredMessage extends StatelessWidget {
  const _CenteredMessage({
    required this.title,
    this.message,
    this.actionLabel,
    this.onAction,
  });

  final String title;
  final String? message;
  final String? actionLabel;
  final VoidCallback? onAction;

  @override
  Widget build(BuildContext context) {
    return Center(
      child: Padding(
        padding: const EdgeInsets.all(24),
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            Text(
              title,
              textAlign: TextAlign.center,
              style: Theme.of(context).textTheme.titleMedium,
            ),
            if (message != null) ...[
              const SizedBox(height: 8),
              Text(message!, textAlign: TextAlign.center),
            ],
            if (actionLabel != null && onAction != null) ...[
              const SizedBox(height: 16),
              FilledButton(onPressed: onAction, child: Text(actionLabel!)),
            ],
          ],
        ),
      ),
    );
  }
}

extension on WorkoutMeasure {
  String get label {
    return switch (this) {
      WorkoutMeasure.time => 'Temps',
      WorkoutMeasure.reps => 'Répétitions',
      WorkoutMeasure.score => 'Score',
    };
  }
}