import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:intl/intl.dart';

import '../../../../core/network/api_problem.dart';
import '../../../../core/network/api_problem_mapper.dart';
import '../../../../l10n/app_localizations.dart';
import '../../../../shared/theme/design_tokens.dart';
import '../../../../shared/widgets/divination/divination_shared_widgets.dart';
import '../../../../shared/widgets/divination/divination_terms.dart';
import '../../../../shared/widgets/divination/yao_legend.dart';
import '../../../../shared/widgets/divination/yao_line_row.dart';
import '../../../../shared/widgets/toast/toast.dart';
import '../../../../shared/widgets/toast/toast_type.dart';
import '../../../../shared/widgets/date_time_picker/date_time_picker_bottom_sheet.dart';
import '../../data/models/divination_params.dart';
import '../../data/services/divination_run_service.dart';
import 'divination_result_screen.dart';

class ManualDivinationScreen extends StatefulWidget {
  const ManualDivinationScreen({
    super.key,
    required this.params,
    required this.runService,
  });

  final DivinationParams params;
  final DivinationRunService runService;

  @override
  State<ManualDivinationScreen> createState() => _ManualDivinationScreenState();
}

class _ManualDivinationScreenState extends State<ManualDivinationScreen>
    with TickerProviderStateMixin {
  late DateTime _selectedTime;
  final List<YaoType?> _selectedYaos = List<YaoType?>.filled(6, null);
  late final AnimationController _blinkController;
  bool _submitting = false;

  @override
  void initState() {
    super.initState();
    _selectedTime = widget.params.divinationTime;
    _blinkController = AnimationController(
      vsync: this,
      duration: const Duration(milliseconds: 500),
    )..repeat(reverse: true);
  }

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

  bool get _allSelected => _selectedYaos.every((v) => v != null);

  @override
  Widget build(BuildContext context) {
    final colors = Theme.of(context).colorScheme;
    final l10n = AppLocalizations.of(context)!;
    return Scaffold(
      backgroundColor: colors.surface,
      appBar: AppBar(
        title: Text(l10n.manualScreenTitle),
        centerTitle: true,
        backgroundColor: colors.surface,
        surfaceTintColor: colors.surface,
      ),
      body: SingleChildScrollView(
        padding: const EdgeInsets.all(AppSpacing.xl),
        child: Column(
          children: [
            _buildInstruction(),
            const SizedBox(height: AppSpacing.lg),
            _TimeCard(selectedTime: _selectedTime, onPickTime: _pickTime),
            const SizedBox(height: AppSpacing.lg),
            _YaoSelectionCard(
              selectedYaos: _selectedYaos,
              blinkAnimation: _blinkController,
              onSelect: _onSelectYao,
              onNeedTip: _showOrderTip,
            ),
            const SizedBox(height: AppSpacing.xl),
            AnimatedBuilder(
              animation: _blinkController,
              builder: (context, _) {
                final base = colors.primary;
                return SizedBox(
                  width: double.infinity,
                  height: 50,
                  child: FilledButton(
                    onPressed: _allSelected && !_submitting ? _submitRun : null,
                    style: FilledButton.styleFrom(
                      backgroundColor: _allSelected
                          ? base.withValues(
                              alpha: 0.6 + _blinkController.value * 0.4,
                            )
                          : base,
                    ),
                    child: _submitting
                        ? const SizedBox(
                            width: 18,
                            height: 18,
                            child: CircularProgressIndicator(strokeWidth: 2),
                          )
                        : Text(l10n.manualStartResolve),
                  ),
                );
              },
            ),
          ],
        ),
      ),
    );
  }

  Widget _buildInstruction() {
    final l10n = AppLocalizations.of(context)!;
    return DivinationInstructionCard(
      text: l10n.manualYaoInstruction,
      onTap: () {
        showDialog<void>(
          context: context,
          builder: (_) {
            return DivinationGuideDialog(
              title: l10n.manualSelectYaoTitle,
              guideImages: const [
                'assets/images/qigua/lc2.jpg',
                'assets/images/qigua/lc3.jpg',
                'assets/images/qigua/lc4.jpg',
                'assets/images/qigua/lc5.jpg',
              ],
              instructionText: l10n.manualYaoTipContent,
            );
          },
        );
      },
    );
  }

  Future<void> _pickTime() async {
    final result = await showDateTimePickerBottomSheet(
      context: context,
      initialDateTime: _selectedTime,
      minDateTime: DateTime(2000),
      maxDateTime: DateTime(2100),
    );
    if (result == null || !mounted) return;
    setState(() {
      _selectedTime = result;
    });
  }

  void _onSelectYao(int index, YaoType type) {
    setState(() {
      _selectedYaos[index] = type;
    });
    HapticFeedback.selectionClick();
  }

  Future<void> _showOrderTip() async {
    final l10n = AppLocalizations.of(context)!;
    await showDialog<void>(
      context: context,
      builder: (context) {
        return AlertDialog(
          title: Text(l10n.manualYaoTipTitle),
          content: Text(l10n.manualYaoTipContent),
          actions: [
            TextButton(
              onPressed: () => Navigator.of(context).pop(),
              child: Text(l10n.divinationIAcknowledge),
            ),
          ],
        );
      },
    );
  }

  Future<void> _submitRun() async {
    final l10n = AppLocalizations.of(context)!;
    setState(() {
      _submitting = true;
    });
    try {
      final aggregate = await widget.runService.run(
        params: widget.params.copyWith(divinationTime: _selectedTime),
        yaoStates: _selectedYaos.cast<YaoType>(),
      );
      if (!mounted) {
        return;
      }
      Navigator.of(context).push(
        MaterialPageRoute<void>(
          builder: (_) => DivinationResultScreen(
            data: aggregate.toViewData(
              widget.params.copyWith(divinationTime: _selectedTime),
            ),
          ),
        ),
      );
    } catch (error) {
      if (!mounted) {
        return;
      }
      final message = error is ApiProblem
          ? mapApiProblemToMessage(error, l10n)
          : l10n.errorRequestGeneric;
      Toast.show(context, message, type: ToastType.error);
    } finally {
      if (!mounted) {
        return;
      }
      setState(() {
        _submitting = false;
      });
    }
  }
}

class _TimeCard extends StatelessWidget {
  const _TimeCard({required this.selectedTime, required this.onPickTime});

  final DateTime selectedTime;
  final VoidCallback onPickTime;

  @override
  Widget build(BuildContext context) {
    final colors = Theme.of(context).colorScheme;
    final l10n = AppLocalizations.of(context)!;
    return Card(
      margin: EdgeInsets.zero,
      color: colors.surface,
      elevation: 2,
      shape: RoundedRectangleBorder(
        borderRadius: BorderRadius.circular(AppRadius.md),
      ),
      child: Padding(
        padding: const EdgeInsets.all(AppSpacing.lg),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Text(
              l10n.manualSelectTime,
              style: Theme.of(context).textTheme.titleMedium?.copyWith(
                color: colors.primary,
                fontWeight: FontWeight.w700,
              ),
            ),
            const SizedBox(height: AppSpacing.md),
            Row(
              children: [
                Expanded(
                  child: Text(
                    DateFormat.yMd(
                      Localizations.localeOf(context).toString(),
                    ).add_Hm().format(selectedTime),
                    style: Theme.of(context).textTheme.titleMedium,
                  ),
                ),
                OutlinedButton(
                  onPressed: onPickTime,
                  child: Text(l10n.divinationModify),
                ),
              ],
            ),
          ],
        ),
      ),
    );
  }
}

class _YaoSelectionCard extends StatelessWidget {
  const _YaoSelectionCard({
    required this.selectedYaos,
    required this.blinkAnimation,
    required this.onSelect,
    required this.onNeedTip,
  });

  final List<YaoType?> selectedYaos;
  final Animation<double> blinkAnimation;
  final void Function(int, YaoType) onSelect;
  final Future<void> Function() onNeedTip;

  @override
  Widget build(BuildContext context) {
    final colors = Theme.of(context).colorScheme;
    final l10n = AppLocalizations.of(context)!;
    final rowNames = DivinationTerms.yaoNames.reversed.toList();
    return Card(
      margin: EdgeInsets.zero,
      color: colors.surface,
      elevation: 2,
      shape: RoundedRectangleBorder(
        borderRadius: BorderRadius.circular(AppRadius.md),
      ),
      child: Padding(
        padding: const EdgeInsets.all(AppSpacing.lg),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Text(
              l10n.manualSpecifyYaoCombo,
              style: Theme.of(context).textTheme.titleMedium?.copyWith(
                color: colors.primary,
                fontWeight: FontWeight.w700,
              ),
            ),
            const SizedBox(height: AppSpacing.md),
            ...List.generate(rowNames.length, (i) {
              final yaoIndex = 5 - i;
              final current = selectedYaos[yaoIndex];
              final enabled =
                  yaoIndex == 0 || selectedYaos[yaoIndex - 1] != null;
              final shouldBlink = enabled && current == null;
              return Padding(
                padding: const EdgeInsets.only(bottom: AppSpacing.md),
                child: AnimatedBuilder(
                  animation: blinkAnimation,
                  builder: (context, _) {
                    final borderColor = shouldBlink
                        ? colors.primary.withValues(
                            alpha: 0.3 + blinkAnimation.value * 0.7,
                          )
                        : (enabled ? colors.primary : colors.outline);
                    return OutlinedButton(
                      style: OutlinedButton.styleFrom(
                        minimumSize: const Size.fromHeight(52),
                        padding: const EdgeInsets.symmetric(
                          horizontal: AppSpacing.sm,
                        ),
                        side: BorderSide(
                          color: borderColor,
                          width: shouldBlink ? 2 : 1,
                        ),
                        shape: RoundedRectangleBorder(
                          borderRadius: BorderRadius.circular(AppRadius.sm),
                        ),
                      ),
                      onPressed: () {
                        if (!enabled) {
                          onNeedTip();
                          return;
                        }
                        _showOptionsDialog(context, yaoIndex, onSelect);
                      },
                      child: YaoLineRow(
                        name: rowNames[i],
                        type: current ?? YaoType.undetermined,
                        showChangeMark: true,
                        enabled: enabled,
                      ),
                    );
                  },
                ),
              );
            }),
            const SizedBox(height: AppSpacing.xs),
            const Align(alignment: Alignment.centerLeft, child: YaoLegend()),
          ],
        ),
      ),
    );
  }

  Future<void> _showOptionsDialog(
    BuildContext context,
    int yaoIndex,
    void Function(int, YaoType) onSelect,
  ) {
    final l10n = AppLocalizations.of(context)!;
    final options = <(String, YaoType)>[
      (
        '${DivinationTerms.yaoTypeLabels[YaoTypeLabel.youngYang]} (\u2014)\uFF1A\u82B1\u5B57\u5B57',
        YaoType.youngYang,
      ),
      (
        '${DivinationTerms.yaoTypeLabels[YaoTypeLabel.youngYin]} (--)\uFF1A\u5B57\u82B1\u82B1',
        YaoType.youngYin,
      ),
      (
        '${DivinationTerms.yaoTypeLabels[YaoTypeLabel.oldYang]} (\u2014\u25CB)\uFF1A\u82B1\u82B1\u82B1',
        YaoType.oldYang,
      ),
      (
        '${DivinationTerms.yaoTypeLabels[YaoTypeLabel.oldYin]} (--\u00D7)\uFF1A\u5B57\u5B57\u5B57',
        YaoType.oldYin,
      ),
    ];
    return showDialog<void>(
      context: context,
      builder: (context) {
        return AlertDialog(
          title: Text(l10n.manualSelectYaoTitle),
          content: SingleChildScrollView(
            child: Column(
              mainAxisSize: MainAxisSize.min,
              children: [
                for (final option in options)
                  Padding(
                    padding: const EdgeInsets.only(bottom: AppSpacing.sm),
                    child: OutlinedButton(
                      onPressed: () {
                        onSelect(yaoIndex, option.$2);
                        Navigator.of(context).pop();
                      },
                      style: OutlinedButton.styleFrom(
                        minimumSize: const Size.fromHeight(44),
                      ),
                      child: Text(option.$1),
                    ),
                  ),
                const SizedBox(height: AppSpacing.sm),
                const Align(
                  alignment: Alignment.centerLeft,
                  child: Text('字花图片说明：'),
                ),
                const SizedBox(height: AppSpacing.sm),
                Image.asset(
                  'assets/images/qigua/zihua.jpg',
                  width: double.infinity,
                  height: 180,
                  fit: BoxFit.contain,
                ),
              ],
            ),
          ),
          actions: [
            TextButton(
              onPressed: () => Navigator.of(context).pop(),
              child: Text(l10n.divinationClose),
            ),
          ],
        );
      },
    );
  }
}