import 'package:flutter/material.dart';

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

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

  final ProgramUseCases programUseCases;
  final ExerciseUseCases exerciseUseCases;

  @override
  State<ProgramListScreen> createState() => _ProgramListScreenState();
}

final class _ProgramListScreenState extends State<ProgramListScreen> {
  late Future<List<Program>> _programs;

  @override
  void initState() {
    super.initState();
    _programs = widget.programUseCases.listActive();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('Programmes')),
      floatingActionButton: FloatingActionButton.extended(
        onPressed: () => _openForm(),
        icon: const Icon(Icons.add),
        label: const Text('Créer'),
      ),
      body: FutureBuilder<List<Program>>(
        future: _programs,
        builder: (context, snapshot) {
          if (snapshot.connectionState != ConnectionState.done) {
            return const Center(child: CircularProgressIndicator());
          }
          if (snapshot.hasError) {
            return _CenteredMessage(
              title: 'Impossible de charger les programmes',
              actionLabel: 'Réessayer',
              onAction: _reload,
            );
          }
          final programs = snapshot.data ?? const <Program>[];
          if (programs.isEmpty) {
            return _CenteredMessage(
              title: 'Aucun programme pour le moment',
              message:
                  'Crée un programme pour organiser tes exercices en séries.',
              actionLabel: 'Créer un programme',
              onAction: () => _openForm(),
            );
          }
          return ListView.separated(
            itemCount: programs.length,
            separatorBuilder: (context, index) => const Divider(height: 1),
            itemBuilder: (context, index) {
              final program = programs[index];
              return ListTile(
                title: Text(program.name),
                subtitle: Text(_programSummary(program)),
                trailing: const Icon(Icons.chevron_right),
                onTap: () => _openForm(program: program),
              );
            },
          );
        },
      ),
    );
  }

  void _reload() {
    setState(() {
      _programs = widget.programUseCases.listActive();
    });
  }

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

final class ProgramFormScreen extends StatefulWidget {
  const ProgramFormScreen({
    required this.programUseCases,
    required this.exerciseUseCases,
    this.program,
    super.key,
  });

  final ProgramUseCases programUseCases;
  final ExerciseUseCases exerciseUseCases;
  final Program? program;

  @override
  State<ProgramFormScreen> createState() => _ProgramFormScreenState();
}

final class _ProgramFormScreenState extends State<ProgramFormScreen> {
  final _formKey = GlobalKey<FormState>();
  late final TextEditingController _nameController;
  late final TextEditingController _defaultRestController;
  late final List<_ProgramExerciseDraft> _exercises;
  var _saving = false;

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

  int get _defaultRestSeconds {
    return int.tryParse(_defaultRestController.text.trim()) ?? 0;
  }

  @override
  void initState() {
    super.initState();
    final program = widget.program;
    _nameController = TextEditingController(text: program?.name);
    _defaultRestController = TextEditingController(
      text: '${program?.defaultRestSeconds ?? 60}',
    );
    _exercises = [
      for (final exercise in program?.exercises ?? const <ProgramExercise>[])
        _ProgramExerciseDraft.fromProgramExercise(exercise),
    ];
  }

  @override
  void dispose() {
    _nameController.dispose();
    _defaultRestController.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(
          _isEditing ? 'Modifier le programme' : 'Créer un programme',
        ),
      ),
      bottomNavigationBar: SafeArea(
        minimum: const EdgeInsets.all(16),
        child: 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'),
        ),
      ),
      body: Column(
        children: [
          Padding(
            padding: const EdgeInsets.all(16),
            child: Form(
              key: _formKey,
              child: Column(
                children: [
                  TextFormField(
                    controller: _nameController,
                    decoration: const InputDecoration(labelText: 'Nom'),
                    validator: (value) => value == null || value.trim().isEmpty
                        ? 'Le nom est obligatoire.'
                        : null,
                  ),
                  const SizedBox(height: 12),
                  TextFormField(
                    controller: _defaultRestController,
                    decoration: const InputDecoration(
                      labelText: 'Repos par défaut (s)',
                    ),
                    keyboardType: TextInputType.number,
                    validator: _nonNegativeIntValidator,
                    onChanged: (_) => setState(() {}),
                  ),
                  const SizedBox(height: 12),
                  SizedBox(
                    width: double.infinity,
                    child: OutlinedButton.icon(
                      onPressed: _addExercise,
                      icon: const Icon(Icons.add),
                      label: const Text('Ajouter un exercice'),
                    ),
                  ),
                ],
              ),
            ),
          ),
          Expanded(
            child: _exercises.isEmpty
                ? const _CenteredMessage(
                    title: 'Aucun exercice ajouté',
                    message: 'Ajoute un exercice depuis la bibliothèque.',
                  )
                : ReorderableListView.builder(
                    buildDefaultDragHandles: false,
                    padding: const EdgeInsets.fromLTRB(16, 0, 16, 16),
                    itemCount: _exercises.length,
                    onReorder: _reorderExercise,
                    itemBuilder: (context, index) {
                      final exercise = _exercises[index];
                      return _ProgramExerciseCard(
                        key: ValueKey(exercise.key),
                        draft: exercise,
                        defaultRestSeconds: _defaultRestSeconds,
                        onChanged: () => setState(() {}),
                        index: index,
                      );
                    },
                  ),
          ),
        ],
      ),
    );
  }

  Future<void> _addExercise() async {
    final exercise = await Navigator.of(context).push<Exercise>(
      MaterialPageRoute(
        builder: (context) =>
            ExerciseSelectionScreen(exerciseUseCases: widget.exerciseUseCases),
      ),
    );
    if (exercise == null) return;
    if (!mounted) return;
    setState(() {
      _exercises.add(_ProgramExerciseDraft.fromExercise(exercise));
    });
  }

  void _reorderExercise(int oldIndex, int newIndex) {
    setState(() {
      if (newIndex > oldIndex) {
        newIndex -= 1;
      }
      final item = _exercises.removeAt(oldIndex);
      _exercises.insert(newIndex, item);
    });
  }

  Future<void> _save() async {
    if (!_formKey.currentState!.validate()) {
      return;
    }
    setState(() => _saving = true);
    try {
      await widget.programUseCases.saveConfigured(
        id: widget.program?.metadata.id,
        name: _nameController.text.trim(),
        defaultRestSeconds: _defaultRestSeconds,
        exercises: _exercises.map((exercise) => exercise.toConfig()).toList(),
      );
      if (mounted) {
        Navigator.of(context).pop(true);
      }
    } on Exception catch (error) {
      _showSnackBar(error.toString());
    } finally {
      if (mounted) {
        setState(() => _saving = false);
      }
    }
  }

  String? _nonNegativeIntValidator(String? value) {
    final number = int.tryParse(value?.trim() ?? '');
    if (number == null || number < 0) {
      return 'Saisis un nombre positif.';
    }
    return null;
  }

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

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

  final ExerciseUseCases exerciseUseCases;

  @override
  State<ExerciseSelectionScreen> createState() =>
      _ExerciseSelectionScreenState();
}

final class _ExerciseSelectionScreenState
    extends State<ExerciseSelectionScreen> {
  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('Ajouter un exercice')),
      body: FutureBuilder<List<Exercise>>(
        future: _exercises,
        builder: (context, snapshot) {
          if (snapshot.connectionState != ConnectionState.done) {
            return const Center(child: CircularProgressIndicator());
          }
          final exercises = _filter(snapshot.data ?? const <Exercise>[]);
          return ListView(
            children: [
              Padding(
                padding: const EdgeInsets.all(16),
                child: Column(
                  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(_measureLabel(measure)),
                          selected: _selectedMeasures.contains(measure),
                          onSelected: (selected) {
                            setState(() {
                              if (selected) {
                                _selectedMeasures = {
                                  ..._selectedMeasures,
                                  measure,
                                };
                              } else {
                                _selectedMeasures = {..._selectedMeasures}
                                  ..remove(measure);
                              }
                            });
                          },
                        );
                      }).toList(),
                    ),
                  ],
                ),
              ),
              if (exercises.isEmpty)
                const _CenteredMessage(
                  title: 'Aucun exercice disponible',
                  message: 'Crée un exercice dans la bibliothèque.',
                )
              else
                for (final exercise in exercises)
                  ExerciseListTile(
                    exercise: exercise,
                    onTap: () => Navigator.of(context).pop(exercise),
                  ),
            ],
          );
        },
      ),
    );
  }

  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();
  }
}

final class _ProgramExerciseCard extends StatelessWidget {
  const _ProgramExerciseCard({
    required this.draft,
    required this.defaultRestSeconds,
    required this.onChanged,
    required this.index,
    super.key,
  });

  final _ProgramExerciseDraft draft;
  final int defaultRestSeconds;
  final VoidCallback onChanged;
  final int index;

  @override
  Widget build(BuildContext context) {
    final scoreUnit = draft.scoreUnitSnapshot;
    return Card(
      margin: const EdgeInsets.only(bottom: 12),
      child: Padding(
        padding: const EdgeInsets.all(12),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Row(
              children: [
                ReorderableDragStartListener(
                  index: index,
                  child: const Padding(
                    padding: EdgeInsets.only(right: 8),
                    child: Icon(Icons.drag_handle),
                  ),
                ),
                Expanded(
                  child: Text(
                    draft.exerciseNameSnapshot,
                    style: Theme.of(context).textTheme.titleMedium,
                  ),
                ),
                if (draft.exerciseArchivedSnapshot)
                  const Chip(label: Text('Exercice archivé')),
              ],
            ),
            const SizedBox(height: 4),
            Text(_exerciseSummary(draft, defaultRestSeconds)),
            const SizedBox(height: 12),
            TextFormField(
              initialValue: '${draft.setsCount}',
              decoration: const InputDecoration(labelText: 'Nombre de séries'),
              keyboardType: TextInputType.number,
              onChanged: (value) {
                draft.setsCount = int.tryParse(value) ?? draft.setsCount;
                onChanged();
              },
            ),
            const SizedBox(height: 12),
            Text(
              'Mesures à suivre',
              style: Theme.of(context).textTheme.titleSmall,
            ),
            if (draft.availableTimeSnapshot)
              CheckboxListTile(
                contentPadding: EdgeInsets.zero,
                title: const Text('Temps'),
                value: draft.enabledMeasures.contains(WorkoutMeasure.time),
                onChanged: (value) => _toggle(WorkoutMeasure.time, value),
              ),
            if (draft.availableRepsSnapshot)
              CheckboxListTile(
                contentPadding: EdgeInsets.zero,
                title: const Text('Répétitions'),
                value: draft.enabledMeasures.contains(WorkoutMeasure.reps),
                onChanged: (value) => _toggle(WorkoutMeasure.reps, value),
              ),
            if (draft.availableScoreSnapshot)
              CheckboxListTile(
                contentPadding: EdgeInsets.zero,
                title: Text(scoreUnit == null ? 'Score' : 'Score ($scoreUnit)'),
                value: draft.enabledMeasures.contains(WorkoutMeasure.score),
                onChanged: (value) => _toggle(WorkoutMeasure.score, value),
              ),
            if (draft.enabledMeasures.contains(WorkoutMeasure.time))
              _NumberField(
                label: 'Cible temps (s)',
                initialValue: draft.targetTimeSeconds,
                onChanged: (value) => draft.targetTimeSeconds = value?.round(),
              ),
            if (draft.enabledMeasures.contains(WorkoutMeasure.reps))
              _NumberField(
                label: 'Cible répétitions',
                initialValue: draft.targetReps,
                onChanged: (value) => draft.targetReps = value?.round(),
              ),
            if (draft.enabledMeasures.contains(WorkoutMeasure.score))
              _NumberField(
                label: scoreUnit == null
                    ? 'Cible score'
                    : 'Cible score ($scoreUnit)',
                initialValue: draft.targetScore,
                onChanged: (value) => draft.targetScore = value,
              ),
            const SizedBox(height: 12),
            TextFormField(
              initialValue:
                  '${draft.restSecondsOverride ?? defaultRestSeconds}',
              decoration: const InputDecoration(
                labelText: 'Repos après chaque série (s)',
                helperText: 'Pas de repos après la toute dernière série.',
              ),
              keyboardType: TextInputType.number,
              onChanged: (value) {
                draft.restSecondsOverride = int.tryParse(value);
                onChanged();
              },
            ),
          ],
        ),
      ),
    );
  }

  void _toggle(WorkoutMeasure measure, bool? value) {
    if (value == true) {
      draft.enabledMeasures = {...draft.enabledMeasures, measure};
    } else if (draft.enabledMeasures.length > 1) {
      draft.enabledMeasures = {...draft.enabledMeasures}..remove(measure);
    }
    onChanged();
  }
}

final class _NumberField extends StatelessWidget {
  const _NumberField({
    required this.label,
    required this.initialValue,
    required this.onChanged,
  });

  final String label;
  final num? initialValue;
  final ValueChanged<double?> onChanged;

  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: const EdgeInsets.only(top: 8),
      child: TextFormField(
        initialValue: initialValue?.toString(),
        decoration: InputDecoration(labelText: label),
        keyboardType: TextInputType.number,
        onChanged: (value) => onChanged(double.tryParse(value)),
      ),
    );
  }
}

final class _ProgramExerciseDraft {
  _ProgramExerciseDraft({
    required this.key,
    this.existingMetadata,
    this.sourceExerciseId,
    required this.exerciseNameSnapshot,
    this.exerciseDescriptionSnapshot,
    this.exerciseImageMediaIdSnapshot,
    this.exerciseVideoMediaIdSnapshot,
    this.exerciseArchivedSnapshot = false,
    required this.availableTimeSnapshot,
    required this.availableRepsSnapshot,
    required this.availableScoreSnapshot,
    this.scoreLabelSnapshot,
    this.scoreUnitSnapshot,
    required this.setsCount,
    required this.enabledMeasures,
    this.targetTimeSeconds,
    this.targetReps,
    this.targetScore,
    this.restSecondsOverride,
  });

  factory _ProgramExerciseDraft.fromExercise(Exercise exercise) {
    return _ProgramExerciseDraft(
      key: UniqueKey().toString(),
      sourceExerciseId: exercise.metadata.id,
      exerciseNameSnapshot: exercise.name,
      exerciseDescriptionSnapshot: exercise.description,
      exerciseImageMediaIdSnapshot: exercise.imageMediaId,
      exerciseVideoMediaIdSnapshot: exercise.videoMediaId,
      exerciseArchivedSnapshot: exercise.archivedAt != null,
      availableTimeSnapshot: exercise.hasTimeMeasure,
      availableRepsSnapshot: exercise.hasRepsMeasure,
      availableScoreSnapshot: exercise.hasScoreMeasure,
      scoreLabelSnapshot: exercise.scoreLabel,
      scoreUnitSnapshot: exercise.scoreUnit,
      setsCount: 3,
      enabledMeasures: exercise.availableMeasures,
    );
  }

  factory _ProgramExerciseDraft.fromProgramExercise(ProgramExercise exercise) {
    return _ProgramExerciseDraft(
      key: exercise.metadata.id,
      existingMetadata: exercise.metadata,
      sourceExerciseId: exercise.sourceExerciseId,
      exerciseNameSnapshot: exercise.exerciseNameSnapshot,
      exerciseDescriptionSnapshot: exercise.exerciseDescriptionSnapshot,
      exerciseImageMediaIdSnapshot: exercise.exerciseImageMediaIdSnapshot,
      exerciseVideoMediaIdSnapshot: exercise.exerciseVideoMediaIdSnapshot,
      exerciseArchivedSnapshot: exercise.exerciseArchivedSnapshot,
      availableTimeSnapshot: exercise.availableTimeSnapshot,
      availableRepsSnapshot: exercise.availableRepsSnapshot,
      availableScoreSnapshot: exercise.availableScoreSnapshot,
      scoreLabelSnapshot: exercise.scoreLabelSnapshot,
      scoreUnitSnapshot: exercise.scoreUnitSnapshot,
      setsCount: exercise.setsCount,
      enabledMeasures: {
        if (exercise.timeEnabled) WorkoutMeasure.time,
        if (exercise.repsEnabled) WorkoutMeasure.reps,
        if (exercise.scoreEnabled) WorkoutMeasure.score,
      },
      targetTimeSeconds: exercise.targetTimeSeconds,
      targetReps: exercise.targetReps,
      targetScore: exercise.targetScore,
      restSecondsOverride: exercise.restSecondsOverride,
    );
  }

  final String key;
  final EntityMetadata? existingMetadata;
  final String? sourceExerciseId;
  final String exerciseNameSnapshot;
  final String? exerciseDescriptionSnapshot;
  final String? exerciseImageMediaIdSnapshot;
  final String? exerciseVideoMediaIdSnapshot;
  final bool exerciseArchivedSnapshot;
  final bool availableTimeSnapshot;
  final bool availableRepsSnapshot;
  final bool availableScoreSnapshot;
  final String? scoreLabelSnapshot;
  final String? scoreUnitSnapshot;
  int setsCount;
  Set<WorkoutMeasure> enabledMeasures;
  int? targetTimeSeconds;
  int? targetReps;
  double? targetScore;
  int? restSecondsOverride;

  ProgramExerciseConfig toConfig() {
    return ProgramExerciseConfig(
      existingMetadata: existingMetadata,
      sourceExerciseId: sourceExerciseId,
      exerciseNameSnapshot: exerciseNameSnapshot,
      exerciseDescriptionSnapshot: exerciseDescriptionSnapshot,
      exerciseImageMediaIdSnapshot: exerciseImageMediaIdSnapshot,
      exerciseVideoMediaIdSnapshot: exerciseVideoMediaIdSnapshot,
      exerciseArchivedSnapshot: exerciseArchivedSnapshot,
      availableTimeSnapshot: availableTimeSnapshot,
      availableRepsSnapshot: availableRepsSnapshot,
      availableScoreSnapshot: availableScoreSnapshot,
      scoreLabelSnapshot: scoreLabelSnapshot,
      scoreUnitSnapshot: scoreUnitSnapshot,
      setsCount: setsCount,
      enabledMeasures: enabledMeasures,
      targetTimeSeconds: targetTimeSeconds,
      targetReps: targetReps,
      targetScore: targetScore,
      restSecondsOverride: restSecondsOverride,
    );
  }
}

String _programSummary(Program program) {
  final exerciseCount = program.exercises.length;
  final setsCount = program.exercises.fold<int>(
    0,
    (total, exercise) => total + exercise.setsCount,
  );
  return '$exerciseCount exercice${exerciseCount > 1 ? 's' : ''} · '
      '$setsCount série${setsCount > 1 ? 's' : ''}';
}

String _exerciseSummary(_ProgramExerciseDraft draft, int defaultRestSeconds) {
  final measures = draft.enabledMeasures
      .map((measure) {
        final unit = draft.scoreUnitSnapshot?.trim();
        if (measure == WorkoutMeasure.score &&
            unit != null &&
            unit.isNotEmpty) {
          return 'Score ($unit)';
        }
        return _measureLabel(measure);
      })
      .join(' + ');
  final rest = draft.restSecondsOverride ?? defaultRestSeconds;
  return '${draft.setsCount} séries · $measures · Repos $rest s';
}

String _measureLabel(WorkoutMeasure measure) {
  return switch (measure) {
    WorkoutMeasure.time => 'Temps',
    WorkoutMeasure.reps => 'Répétitions',
    WorkoutMeasure.score => 'Score',
  };
}

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!)),
            ],
          ],
        ),
      ),
    );
  }
}