import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import 'package:uuid/uuid.dart';

import '../../localization/app_localizations.dart';
import '../amount.dart';
import '../models/recipe.dart';
import '../photo_store.dart';
import '../recipe_draft.dart';
import '../recipe_list_provider.dart';
import '../recipe_repository.dart';
import 'widgets/ingredient_editor.dart';
import 'widgets/photo_editor.dart';
import 'widgets/step_editor.dart';

/// Create a Recipe (no [recipeId]) or edit an existing one.
class RecipeEditView extends StatefulWidget {
  const RecipeEditView({super.key, this.recipeId});

  static const routeName = '/recipe/edit';

  final String? recipeId;

  @override
  State<RecipeEditView> createState() => _RecipeEditViewState();
}

class _RecipeEditViewState extends State<RecipeEditView> {
  final _form = GlobalKey<FormState>();
  Recipe? _original;
  bool _loading = true;
  bool _dirty = false;
  bool _saved = false;

  final _name = TextEditingController();
  final _servings = TextEditingController();
  final _prep = TextEditingController();
  final _cook = TextEditingController();
  final _kcal = TextEditingController();
  final _tags = TextEditingController();
  final _notes = TextEditingController();
  final _sources = TextEditingController();
  String? _courseId;
  CaloriesBasis _basis = CaloriesBasis.perServing;
  List<String> _photos = [];
  final _addedPhotos = <String>[];
  List<IngredientEntry> _ingredients = [];
  List<StepEntry> _steps = [];

  late final PhotoStore _photoStore;

  @override
  void initState() {
    super.initState();
    _photoStore = context.read<PhotoStore>();
    _load();
  }

  Future<void> _load() async {
    final id = widget.recipeId;
    final recipe = id == null ? null : await context.read<RecipeRepository>().getRecipe(id);
    if (!mounted) return;
    setState(() {
      _original = recipe;
      _name.text = recipe?.name ?? '';
      _servings.text = recipe?.servings == null ? '' : formatNumber(recipe!.servings!);
      _prep.text = recipe?.prepMinutes?.toString() ?? '';
      _cook.text = recipe?.cookMinutes?.toString() ?? '';
      _kcal.text = recipe?.calories?.kcal.toString() ?? '';
      _basis = recipe?.calories?.basis ?? CaloriesBasis.perServing;
      _tags.text = recipe?.tags.join(', ') ?? '';
      _notes.text = recipe?.notes ?? '';
      _sources.text = recipe?.sources.join('\n') ?? '';
      _courseId = recipe?.courseId;
      _photos = [...?recipe?.photos];
      _ingredients = recipe == null ? [LineEntry()] : ingredientEntriesFrom(recipe.ingredientGroups);
      _steps = recipe == null ? [StepTextEntry()] : stepEntriesFrom(recipe.stepSections);
      _loading = false;
    });
  }

  void _changed() => setState(() => _dirty = true);

  Future<void> _save() async {
    if (!_form.currentState!.validate()) return;
    final repository = context.read<RecipeRepository>();
    final now = DateTime.now();
    final original = _original;
    final kcal = int.tryParse(_kcal.text.trim());
    final recipe = Recipe(
      id: original?.id ?? const Uuid().v4(),
      name: _name.text.trim(),
      courseId: _courseId,
      tags: tagsFrom(_tags.text),
      servings: parseAmount(_servings.text)?.amount,
      prepMinutes: int.tryParse(_prep.text.trim()),
      cookMinutes: int.tryParse(_cook.text.trim()),
      calories: kcal == null ? null : Calories(kcal, _basis),
      ingredientGroups: ingredientGroupsFrom(_ingredients),
      stepSections: stepSectionsFrom(_steps),
      photos: _photos,
      sources: linesFrom(_sources.text),
      notes: _notes.text.trim().isEmpty ? null : _notes.text.trim(),
      favourite: original?.favourite ?? false,
      reviewReasons: original?.reviewReasons ?? const [],
      createdAt: original?.createdAt ?? now,
      updatedAt: now,
    );
    await repository.saveRecipe(recipe);
    final removed = original?.photos.where((p) => !_photos.contains(p)) ?? const <String>[];
    await _photoStore.delete(removed);
    _saved = true;
    if (mounted) Navigator.pop(context, recipe.id);
  }

  Future<void> _confirmDiscard() async {
    final l10n = AppLocalizations.of(context);
    final discard = await showDialog<bool>(
      context: context,
      builder: (context) => AlertDialog(
        title: Text(l10n.discardTitle),
        content: Text(l10n.discardBody),
        actions: [
          TextButton(onPressed: () => Navigator.pop(context, false), child: Text(l10n.keepEditing)),
          FilledButton(onPressed: () => Navigator.pop(context, true), child: Text(l10n.discard)),
        ],
      ),
    );
    if (discard == true && mounted) {
      setState(() => _dirty = false);
      // PopScope only allows the pop once it has rebuilt with canPop: true.
      WidgetsBinding.instance.addPostFrameCallback((_) {
        if (mounted) Navigator.pop(context);
      });
    }
  }

  @override
  void dispose() {
    if (!_saved && _addedPhotos.isNotEmpty) {
      _photoStore.delete(_addedPhotos);
    }
    for (final c in [_name, _servings, _prep, _cook, _kcal, _tags, _notes, _sources]) {
      c.dispose();
    }
    for (final e in _ingredients) {
      e.dispose();
    }
    for (final e in _steps) {
      e.dispose();
    }
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    final l10n = AppLocalizations.of(context);
    final theme = Theme.of(context);
    final courses = context.watch<RecipeListProvider>().courses;
    final courseIds = {for (final c in courses) c.id};

    String? number(String? value, {bool decimal = false}) {
      final text = value?.trim() ?? '';
      if (text.isEmpty) return null;
      if (!decimal) return int.tryParse(text) == null ? l10n.invalidNumber : null;
      final amount = parseAmount(text);
      return amount == null || amount.amountMax != null ? l10n.invalidNumber : null;
    }

    Widget section(String title) => Padding(
      padding: const EdgeInsets.only(top: 28, bottom: 10),
      child: Text(title, style: theme.textTheme.titleLarge),
    );

    return PopScope(
      canPop: !_dirty,
      onPopInvokedWithResult: (didPop, _) {
        if (!didPop) _confirmDiscard();
      },
      child: Scaffold(
        appBar: AppBar(
          title: Text(widget.recipeId == null ? l10n.newRecipe : l10n.editRecipe),
          actions: [
            Padding(
              padding: const EdgeInsets.only(right: 8),
              child: FilledButton(onPressed: _loading ? null : _save, child: Text(l10n.save)),
            ),
          ],
        ),
        body: _loading
            ? const Center(child: CircularProgressIndicator())
            : Form(
                key: _form,
                onChanged: () {
                  if (!_dirty) _changed();
                },
                child: ListView(
                  padding: const EdgeInsets.fromLTRB(16, 8, 16, 48),
                  children: [
                    PhotoEditor(photos: _photos, onAdded: _addedPhotos.addAll, onChanged: _changed),
                    const SizedBox(height: 20),
                    TextFormField(
                      controller: _name,
                      style: theme.textTheme.titleLarge,
                      textCapitalization: TextCapitalization.sentences,
                      decoration: InputDecoration(labelText: l10n.fieldName),
                      validator: (v) => (v ?? '').trim().isEmpty ? l10n.fieldNameRequired : null,
                    ),
                    const SizedBox(height: 12),
                    DropdownButtonFormField<String?>(
                      value: courseIds.contains(_courseId) ? _courseId : null,
                      isExpanded: true,
                      decoration: InputDecoration(labelText: l10n.fieldCourse),
                      items: [
                        DropdownMenuItem(value: null, child: Text(l10n.noCourse)),
                        for (final c in courses) DropdownMenuItem(value: c.id, child: Text(c.label)),
                      ],
                      onChanged: (id) {
                        _courseId = id;
                        _changed();
                      },
                    ),
                    const SizedBox(height: 12),
                    Row(
                      crossAxisAlignment: CrossAxisAlignment.start,
                      children: [
                        Expanded(
                          child: TextFormField(
                            controller: _servings,
                            keyboardType: const TextInputType.numberWithOptions(decimal: true),
                            decoration: InputDecoration(labelText: l10n.fieldServings),
                            validator: (v) => number(v, decimal: true),
                          ),
                        ),
                        const SizedBox(width: 8),
                        Expanded(
                          child: TextFormField(
                            controller: _prep,
                            keyboardType: TextInputType.number,
                            decoration: InputDecoration(labelText: l10n.fieldPrep, suffixText: l10n.minutesSuffix),
                            validator: number,
                          ),
                        ),
                        const SizedBox(width: 8),
                        Expanded(
                          child: TextFormField(
                            controller: _cook,
                            keyboardType: TextInputType.number,
                            decoration: InputDecoration(labelText: l10n.fieldCook, suffixText: l10n.minutesSuffix),
                            validator: number,
                          ),
                        ),
                      ],
                    ),
                    const SizedBox(height: 12),
                    Row(
                      crossAxisAlignment: CrossAxisAlignment.start,
                      children: [
                        Expanded(
                          child: TextFormField(
                            controller: _kcal,
                            keyboardType: TextInputType.number,
                            decoration: InputDecoration(labelText: l10n.fieldKcal),
                            validator: number,
                          ),
                        ),
                        const SizedBox(width: 8),
                        SegmentedButton<CaloriesBasis>(
                          showSelectedIcon: false,
                          segments: [
                            ButtonSegment(value: CaloriesBasis.perServing, label: Text(l10n.basisPerServing)),
                            ButtonSegment(value: CaloriesBasis.wholeRecipe, label: Text(l10n.basisWholeRecipe)),
                          ],
                          selected: {_basis},
                          onSelectionChanged: (s) {
                            _basis = s.first;
                            _changed();
                          },
                        ),
                      ],
                    ),
                    const SizedBox(height: 12),
                    TextFormField(
                      controller: _tags,
                      decoration: InputDecoration(labelText: l10n.fieldTags, hintText: l10n.fieldTagsHint),
                    ),
                    section(l10n.ingredients),
                    IngredientEditor(entries: _ingredients, onChanged: _changed),
                    section(l10n.steps),
                    StepEditor(entries: _steps, onChanged: _changed),
                    section(l10n.notes),
                    TextFormField(
                      controller: _notes,
                      minLines: 3,
                      maxLines: null,
                      textCapitalization: TextCapitalization.sentences,
                      decoration: InputDecoration(hintText: l10n.fieldNotes),
                    ),
                    const SizedBox(height: 12),
                    TextFormField(
                      controller: _sources,
                      minLines: 1,
                      maxLines: null,
                      keyboardType: TextInputType.url,
                      decoration: InputDecoration(labelText: l10n.fieldSources, hintText: l10n.fieldSourcesHint),
                    ),
                  ],
                ),
              ),
      ),
    );
  }
}