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

import '../../core/constants.dart';
import '../../core/time.dart';
import '../../data/ai/model_lifecycle.dart';
import '../../data/db/daos/habit_dao.dart';
import '../../domain/ai/frame_candidate.dart';
import '../../domain/models/habit.dart';
import '../../domain/rules/active_habit_quota.dart';
import '../../state/ai_providers.dart';
import '../../state/providers.dart';
import '../widgets/frame_suggestion_dialog.dart';

class HabitCreateScreen extends ConsumerStatefulWidget {
  const HabitCreateScreen({super.key});

  @override
  ConsumerState<HabitCreateScreen> createState() => _HabitCreateScreenState();
}

class _HabitCreateScreenState extends ConsumerState<HabitCreateScreen> {
  final _formKey = GlobalKey<FormState>();
  final _titleCtrl = TextEditingController();
  final _framedCtrl = TextEditingController();
  HabitType _type = HabitType.build;
  FrameLevel _level = FrameLevel.l2;
  bool _saving = false;

  @override
  void dispose() {
    _titleCtrl.dispose();
    _framedCtrl.dispose();
    super.dispose();
  }

  Future<void> _save() async {
    if (!_formKey.currentState!.validate()) return;
    setState(() => _saving = true);
    try {
      final dao = ref.read(habitDaoProvider);
      final count = await dao.countActive(
        userId: kLocalDefaultUserId,
        type: _type,
      );
      final quota = judgeActiveHabitQuota(type: _type, currentActiveCount: count);
      if (!quota.allowed) {
        if (!mounted) return;
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text(quota.reason)),
        );
        return;
      }
      await dao.insertWithVariants(HabitDraft(
        userId: kLocalDefaultUserId,
        type: _type,
        title: _titleCtrl.text.trim(),
        // Placeholder: vertical-slice uses the first seeded protocol.
        protocolId: _type == HabitType.build ? 'morning_sunlight' : null,
        breakProtocolId: _type == HabitType.breakHabit ? 'alcohol' : null,
        frameLevel: _level,
        frameFramedText: _framedCtrl.text.trim(),
        startedAt: _ymd(nowKst()),
      ));
      if (!mounted) return;
      Navigator.of(context).pop();
    } catch (e) {
      if (!mounted) return;
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text('저장 실패: $e')),
      );
    } finally {
      if (mounted) setState(() => _saving = false);
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('새 습관')),
      body: Padding(
        padding: const EdgeInsets.all(16),
        child: Form(
          key: _formKey,
          child: ListView(
            children: [
              TextFormField(
                controller: _titleCtrl,
                decoration: const InputDecoration(labelText: '제목'),
                validator: (v) =>
                    (v == null || v.trim().isEmpty) ? '제목을 입력하세요' : null,
              ),
              const SizedBox(height: 16),
              DropdownButtonFormField<HabitType>(
                initialValue: _type,
                items: const [
                  DropdownMenuItem(value: HabitType.build, child: Text('만들기')),
                  DropdownMenuItem(value: HabitType.breakHabit, child: Text('없애기')),
                ],
                onChanged: (v) => setState(() => _type = v ?? HabitType.build),
                decoration: const InputDecoration(labelText: '타입'),
              ),
              const SizedBox(height: 16),
              DropdownButtonFormField<FrameLevel>(
                initialValue: _level,
                items: const [
                  DropdownMenuItem(value: FrameLevel.l2, child: Text('L2 · 조건부 긍정')),
                  DropdownMenuItem(value: FrameLevel.l3, child: Text('L3 · 정체성')),
                ],
                onChanged: (v) => setState(() => _level = v ?? FrameLevel.l2),
                decoration: const InputDecoration(labelText: '프레임 레벨'),
              ),
              const SizedBox(height: 16),
              TextFormField(
                controller: _framedCtrl,
                decoration: const InputDecoration(
                  labelText: '프레임 문구',
                  hintText: '예: 아침 햇빛을 10분 받는다',
                ),
                maxLines: 2,
                validator: (v) =>
                    (v == null || v.trim().isEmpty) ? '프레임 문구를 입력하세요' : null,
              ),
              const SizedBox(height: 8),
              _AiSuggestButton(
                titleCtrl: _titleCtrl,
                framedCtrl: _framedCtrl,
                habitType: _type,
                onSelectLevel: (level) => setState(() => _level = level),
              ),
              const SizedBox(height: 16),
              FilledButton(
                onPressed: _saving ? null : _save,
                child: Text(_saving ? '저장 중...' : '저장'),
              ),
            ],
          ),
        ),
      ),
    );
  }
}

String _ymd(DateTime d) =>
    '${d.year.toString().padLeft(4, '0')}-'
    '${d.month.toString().padLeft(2, '0')}-'
    '${d.day.toString().padLeft(2, '0')}';

/// "AI 제안" button — three states (AC3, AC6, AC7):
/// - opt-in OFF → hidden (discoverability gated by Settings)
/// - opt-in ON && model not ready → visible but DISABLED + tooltip
/// - opt-in ON && model ready → enabled
class _AiSuggestButton extends ConsumerWidget {
  final TextEditingController titleCtrl;
  final TextEditingController framedCtrl;
  final HabitType habitType;
  final ValueChanged<FrameLevel> onSelectLevel;
  const _AiSuggestButton({
    required this.titleCtrl,
    required this.framedCtrl,
    required this.habitType,
    required this.onSelectLevel,
  });

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final optIn = ref.watch(aiSettingsProvider).maybeWhen(
          data: (v) => v,
          orElse: () => false,
        );
    if (!optIn) return const SizedBox.shrink();

    final ready = ref.watch(modelAvailabilityProvider).maybeWhen(
          data: (a) => a == ModelAvailability.ready,
          orElse: () => false,
        );

    final button = TextButton.icon(
      icon: const Icon(Icons.auto_awesome),
      label: const Text('AI 제안'),
      onPressed: ready
          ? () async {
              final raw = titleCtrl.text.trim();
              if (raw.isEmpty) {
                ScaffoldMessenger.of(context).showSnackBar(
                  const SnackBar(content: Text('먼저 제목을 입력해주세요')),
                );
                return;
              }
              final picked = await FrameSuggestionDialog.show(
                context,
                input: SuggestFrameInput(
                  rawText: raw,
                  habitType: habitType,
                ),
              );
              if (picked != null) {
                framedCtrl.text = picked.framedText;
                // AC5: use the candidate's explicit level, not a heuristic.
                onSelectLevel(picked.level);
              }
            }
          : null,
    );

    return Align(
      alignment: Alignment.centerRight,
      child: ready
          ? button
          : Tooltip(
              message: 'AI 도움을 먼저 켜주세요',
              child: button,
            ),
    );
  }
}