import 'dart:async';

import 'package:flutter/material.dart';

import '../../../../core/auth/session_store.dart';
import '../../../divination/presentation/screens/divination_screen.dart';
import '../../../divination/presentation/screens/divination_result_screen.dart';
import '../../../divination/data/apis/divination_api.dart';
import '../../../divination/data/models/divination_params.dart';
import '../../../divination/data/models/divination_result.dart';
import '../../../settings/data/models/profile_settings.dart';
import '../../../settings/presentation/screens/settings_screen.dart';
import '../../../../l10n/app_localizations.dart';
import '../../../../shared/theme/app_color_palette.dart';
import '../../../../shared/theme/design_tokens.dart';
import '../../../../shared/widgets/bottom_nav_bar.dart';
import '../../../../shared/widgets/divination/divination_summary_card.dart';
import '../../../../shared/widgets/toast/toast.dart';
import '../../../../shared/widgets/toast/toast_type.dart';

class HomeScreen extends StatefulWidget {
  const HomeScreen({
    super.key,
    required this.account,
    required this.sessionStore,
    required this.currentLocale,
    required this.profileSettings,
    required this.historyRecords,
    required this.coinBalance,
    required this.divinationApi,
    required this.onLocaleChanged,
    required this.onProfileSettingsChanged,
    required this.onSaveProfile,
    required this.onUploadAvatar,
    required this.onDivinationCompleted,
    required this.onDeleteHistorySession,
    required this.onLogout,
  });

  final String account;
  final SessionStore sessionStore;
  final Locale currentLocale;
  final ProfileSettingsV1 profileSettings;
  final List<DivinationResultData> historyRecords;
  final int coinBalance;
  final DivinationApi divinationApi;
  final Future<void> Function(String languageTag) onLocaleChanged;
  final Future<void> Function(ProfileSettingsV1 settings)
  onProfileSettingsChanged;
  final Future<ProfileSettingsV1> Function(ProfileSettingsV1 updated)
  onSaveProfile;
  final Future<ProfileSettingsV1> Function(String filePath) onUploadAvatar;
  final Future<void> Function(DivinationResultData result)
  onDivinationCompleted;
  final Future<void> Function(String threadId) onDeleteHistorySession;
  final Future<void> Function() onLogout;

  @override
  State<HomeScreen> createState() => _HomeScreenState();
}

class _HomeScreenState extends State<HomeScreen> {
  MainTab _currentTab = MainTab.home;

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addPostFrameCallback((_) {
      _tryShowWelcomeDialog();
    });
  }

  Future<void> _tryShowWelcomeDialog() async {
    final hasRead = await widget.sessionStore.hasReadWelcome();
    if (hasRead || !mounted) {
      return;
    }
    await showDialog<void>(
      context: context,
      barrierDismissible: false,
      builder: (context) {
        return _WelcomeDialog(
          onDone: () async {
            await widget.sessionStore.setWelcomeRead(true);
          },
        );
      },
    );
  }

  @override
  Widget build(BuildContext context) {
    final colors = Theme.of(context).colorScheme;
    final historyItems = widget.historyRecords;

    return Scaffold(
      backgroundColor: colors.surfaceContainerLow,
      body: IndexedStack(
        index: _currentTab == MainTab.home ? 0 : 1,
        children: [
          _HomeTab(
            historyItems: historyItems,
            sessionStore: widget.sessionStore,
            userId: widget.account,
            divinationApi: widget.divinationApi,
            onDivinationCompleted: widget.onDivinationCompleted,
            onDeleteHistorySession: widget.onDeleteHistorySession,
            allowVibration: widget.profileSettings.notification.allowVibration,
          ),
          _ProfileTab(
            account: widget.account,
            settings: widget.profileSettings,
            coinBalance: widget.coinBalance,
            onLocaleChanged: widget.onLocaleChanged,
            onSettingsChanged: widget.onProfileSettingsChanged,
            onSaveProfile: widget.onSaveProfile,
            onUploadAvatar: widget.onUploadAvatar,
            onLogout: widget.onLogout,
          ),
        ],
      ),
      bottomNavigationBar: BottomNavBar(
        currentTab: _currentTab,
        onTabChange: (tab) {
          setState(() => _currentTab = tab);
        },
        onLogoTap: _onStartDivination,
      ),
    );
  }

  void _onStartDivination() {
    Navigator.of(context).push(
      MaterialPageRoute<void>(
        builder: (_) => DivinationScreen(
          sessionStore: widget.sessionStore,
          userId: widget.account,
          onCompleted: widget.onDivinationCompleted,
          allowVibration: widget.profileSettings.notification.allowVibration,
        ),
      ),
    );
  }
}

class _HomeTab extends StatelessWidget {
  const _HomeTab({
    required this.historyItems,
    required this.sessionStore,
    required this.userId,
    required this.divinationApi,
    required this.onDivinationCompleted,
    required this.onDeleteHistorySession,
    required this.allowVibration,
  });

  final List<DivinationResultData> historyItems;
  final SessionStore sessionStore;
  final String userId;
  final DivinationApi divinationApi;
  final Future<void> Function(DivinationResultData result)
  onDivinationCompleted;
  final Future<void> Function(String threadId) onDeleteHistorySession;
  final bool allowVibration;

  @override
  Widget build(BuildContext context) {
    final l10n = AppLocalizations.of(context)!;
    final colors = Theme.of(context).colorScheme;
    final palette = Theme.of(context).extension<AppColorPalette>()!;

    return SafeArea(
      child: SingleChildScrollView(
        padding: const EdgeInsets.only(
          top: AppSpacing.lg,
          bottom: AppSpacing.lg,
        ),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Padding(
              padding: const EdgeInsets.symmetric(horizontal: AppSpacing.lg),
              child: Row(
                mainAxisAlignment: MainAxisAlignment.spaceBetween,
                children: [
                  Text(
                    l10n.historyTitle,
                    style: Theme.of(
                      context,
                    ).textTheme.titleLarge?.copyWith(color: colors.primary),
                  ),
                  IconButton(
                    onPressed: () {
                      Toast.show(
                        context,
                        l10n.featurePending,
                        type: ToastType.info,
                      );
                    },
                    icon: Icon(
                      Icons.notifications,
                      color: colors.primary,
                      size: 28,
                    ),
                    tooltip: l10n.notify,
                  ),
                ],
              ),
            ),
            const SizedBox(height: AppSpacing.xl),
            Padding(
              padding: const EdgeInsets.symmetric(horizontal: AppSpacing.lg),
              child: Container(
                width: double.infinity,
                padding: const EdgeInsets.all(AppSpacing.xl),
                decoration: BoxDecoration(
                  borderRadius: BorderRadius.circular(AppRadius.lg),
                  gradient: LinearGradient(
                    colors: [colors.primary, palette.accentPurple],
                  ),
                ),
                child: Column(
                  children: [
                    Icon(Icons.auto_awesome, color: colors.onPrimary, size: 48),
                    const SizedBox(height: AppSpacing.lg),
                    Text(
                      l10n.startJourney,
                      style: Theme.of(context).textTheme.titleMedium?.copyWith(
                        color: colors.onPrimary,
                        fontWeight: FontWeight.w700,
                      ),
                    ),
                    const SizedBox(height: AppSpacing.sm),
                    Text(
                      l10n.journeySubtitle,
                      style: Theme.of(
                        context,
                      ).textTheme.bodyMedium?.copyWith(color: colors.onPrimary),
                    ),
                    const SizedBox(height: AppSpacing.lg),
                    FilledButton(
                      style: FilledButton.styleFrom(
                        backgroundColor: colors.surface,
                        foregroundColor: colors.primary,
                        shape: RoundedRectangleBorder(
                          borderRadius: BorderRadius.circular(AppRadius.sm),
                        ),
                      ),
                      onPressed: () {
                        Navigator.of(context).push(
                          MaterialPageRoute<void>(
                            builder: (_) => DivinationScreen(
                              sessionStore: sessionStore,
                              userId: userId,
                              onCompleted: onDivinationCompleted,
                              allowVibration: allowVibration,
                            ),
                          ),
                        );
                      },
                      child: Text(l10n.startNow),
                    ),
                  ],
                ),
              ),
            ),
            const SizedBox(height: AppSpacing.xl),
            Padding(
              padding: const EdgeInsets.symmetric(horizontal: AppSpacing.lg),
              child: Row(
                mainAxisAlignment: MainAxisAlignment.spaceBetween,
                children: [
                  Text(
                    l10n.historyTitle,
                    style: Theme.of(context).textTheme.titleMedium,
                  ),
                  if (historyItems.length > 4)
                    TextButton(
                      onPressed: () {
                        Navigator.of(context).push(
                          MaterialPageRoute<void>(
                            builder: (_) => DivinationHistoryScreen(
                              initialItems: historyItems,
                              divinationApi: divinationApi,
                              onDeleteHistorySession: onDeleteHistorySession,
                            ),
                          ),
                        );
                      },
                      child: Text(l10n.more),
                    ),
                ],
              ),
            ),
            const SizedBox(height: AppSpacing.md),
            if (historyItems.isEmpty)
              SizedBox(
                width: double.infinity,
                height: 200,
                child: Column(
                  mainAxisAlignment: MainAxisAlignment.center,
                  children: [
                    Text(
                      l10n.noRecords,
                      style: Theme.of(context).textTheme.titleMedium,
                    ),
                    const SizedBox(height: AppSpacing.sm),
                    Text(l10n.noRecordsSubtitle),
                  ],
                ),
              )
            else
              Column(
                crossAxisAlignment: CrossAxisAlignment.stretch,
                children: historyItems.take(4).map((item) {
                  final threadId = item.threadId;
                  return Padding(
                    padding: const EdgeInsets.only(
                      left: AppSpacing.md,
                      right: AppSpacing.md,
                      bottom: AppSpacing.md,
                    ),
                    child: threadId == null
                        ? _HistoryCard(
                            item: item,
                            onTap: () {
                              Navigator.of(context).push(
                                MaterialPageRoute<void>(
                                  builder: (_) => DivinationResultScreen(
                                    data: item,
                                    divinationApi: null,
                                    enableIntroTransition: false,
                                  ),
                                ),
                              );
                            },
                          )
                        : Dismissible(
                            key: ValueKey<String>('home-history-$threadId'),
                            direction: DismissDirection.endToStart,
                            background: Container(
                              alignment: Alignment.centerRight,
                              padding: const EdgeInsets.symmetric(
                                horizontal: AppSpacing.lg,
                              ),
                              decoration: BoxDecoration(
                                color: colors.errorContainer,
                                borderRadius: BorderRadius.circular(
                                  AppRadius.md,
                                ),
                              ),
                              child: Icon(
                                Icons.delete_outline,
                                color: colors.onErrorContainer,
                              ),
                            ),
                            confirmDismiss: (_) async => true,
                            onDismissed: (_) {
                              unawaited(onDeleteHistorySession(threadId));
                            },
                            child: _HistoryCard(
                              item: item,
                              onTap: () {
                                Navigator.of(context).push(
                                  MaterialPageRoute<void>(
                                    builder: (_) => DivinationResultScreen(
                                      data: item,
                                      divinationApi: divinationApi,
                                      enableIntroTransition: false,
                                    ),
                                  ),
                                );
                              },
                            ),
                          ),
                  );
                }).toList(),
              ),
          ],
        ),
      ),
    );
  }
}

class DivinationHistoryScreen extends StatefulWidget {
  const DivinationHistoryScreen({
    super.key,
    required this.initialItems,
    required this.divinationApi,
    required this.onDeleteHistorySession,
  });

  final List<DivinationResultData> initialItems;
  final DivinationApi divinationApi;
  final Future<void> Function(String threadId) onDeleteHistorySession;

  @override
  State<DivinationHistoryScreen> createState() =>
      _DivinationHistoryScreenState();
}

class _DivinationHistoryScreenState extends State<DivinationHistoryScreen> {
  late List<DivinationResultData> _items;

  @override
  void initState() {
    super.initState();
    _items = List<DivinationResultData>.from(
      widget.initialItems,
      growable: true,
    );
  }

  @override
  Widget build(BuildContext context) {
    final l10n = AppLocalizations.of(context)!;
    final colors = Theme.of(context).colorScheme;

    return Scaffold(
      appBar: AppBar(title: Text(l10n.historyTitle)),
      backgroundColor: colors.surfaceContainerLow,
      body: _items.isEmpty
          ? Center(child: Text(l10n.noRecords))
          : ListView.builder(
              padding: const EdgeInsets.symmetric(vertical: AppSpacing.md),
              itemCount: _items.length,
              itemBuilder: (context, index) {
                final item = _items[index];
                final threadId = item.threadId;
                return Padding(
                  padding: const EdgeInsets.only(
                    left: AppSpacing.md,
                    right: AppSpacing.md,
                    bottom: AppSpacing.md,
                  ),
                  child: threadId == null
                      ? _HistoryCard(
                          item: item,
                          onTap: () {
                            Navigator.of(context).push(
                              MaterialPageRoute<void>(
                                builder: (_) => DivinationResultScreen(
                                  data: item,
                                  divinationApi: null,
                                  enableIntroTransition: false,
                                ),
                              ),
                            );
                          },
                        )
                      : Dismissible(
                          key: ValueKey<String>('history-$threadId'),
                          direction: DismissDirection.endToStart,
                          background: Container(
                            alignment: Alignment.centerRight,
                            padding: const EdgeInsets.symmetric(
                              horizontal: AppSpacing.lg,
                            ),
                            decoration: BoxDecoration(
                              color: colors.errorContainer,
                              borderRadius: BorderRadius.circular(AppRadius.md),
                            ),
                            child: Icon(
                              Icons.delete_outline,
                              color: colors.onErrorContainer,
                            ),
                          ),
                          confirmDismiss: (_) async => true,
                          onDismissed: (_) {
                            setState(() {
                              _items.removeAt(index);
                            });
                            unawaited(widget.onDeleteHistorySession(threadId));
                          },
                          child: _HistoryCard(
                            item: item,
                            onTap: () {
                              Navigator.of(context).push(
                                MaterialPageRoute<void>(
                                  builder: (_) => DivinationResultScreen(
                                    data: item,
                                    divinationApi: widget.divinationApi,
                                    enableIntroTransition: false,
                                  ),
                                ),
                              );
                            },
                          ),
                        ),
                );
              },
            ),
    );
  }
}

class _ProfileTab extends StatelessWidget {
  const _ProfileTab({
    required this.account,
    required this.settings,
    required this.coinBalance,
    required this.onLocaleChanged,
    required this.onSettingsChanged,
    required this.onSaveProfile,
    required this.onUploadAvatar,
    required this.onLogout,
  });

  final String account;
  final ProfileSettingsV1 settings;
  final int coinBalance;
  final Future<void> Function(String languageTag) onLocaleChanged;
  final Future<void> Function(ProfileSettingsV1 settings) onSettingsChanged;
  final Future<ProfileSettingsV1> Function(ProfileSettingsV1 updated)
  onSaveProfile;
  final Future<ProfileSettingsV1> Function(String filePath) onUploadAvatar;
  final Future<void> Function() onLogout;

  @override
  Widget build(BuildContext context) {
    return SettingsScreen(
      account: account,
      settings: settings,
      coinBalance: coinBalance,
      onInterfaceLanguageChanged: onLocaleChanged,
      onSettingsChanged: onSettingsChanged,
      onSaveProfile: onSaveProfile,
      onUploadAvatar: onUploadAvatar,
      onLogout: onLogout,
    );
  }
}

class _HistoryCard extends StatelessWidget {
  const _HistoryCard({required this.item, required this.onTap});

  final DivinationResultData item;
  final VoidCallback onTap;

  @override
  Widget build(BuildContext context) {
    final l10n = AppLocalizations.of(context)!;
    final colors = Theme.of(context).colorScheme;
    final palette = Theme.of(context).extension<AppColorPalette>()!;

    final categoryLabel = switch (item.params.questionType) {
      QuestionType.career => l10n.questionTypeCareer,
      QuestionType.love => l10n.questionTypeLove,
      QuestionType.wealth => l10n.questionTypeWealth,
      QuestionType.fortune => l10n.questionTypeFortune,
      QuestionType.dream => l10n.questionTypeDream,
      QuestionType.health => l10n.questionTypeHealth,
      QuestionType.study => l10n.questionTypeStudy,
      QuestionType.search => l10n.questionTypeSearch,
      QuestionType.other => l10n.questionTypeOther,
    };

    final categoryStyle = switch (item.params.questionType) {
      QuestionType.career || QuestionType.study => (
        palette.categoryCareerBg,
        palette.categoryCareerText,
      ),
      QuestionType.love => (palette.categoryLoveBg, palette.categoryLoveText),
      _ => (palette.categoryMoneyBg, palette.categoryMoneyText),
    };

    final normalizedSignType = item.signType.trim();
    final isBestSign = normalizedSignType.contains('上上');
    final isGoodSign = !isBestSign && normalizedSignType.contains('中上');
    final isWorstSign = normalizedSignType.contains('下下');

    final signLabel = isBestSign
        ? l10n.signTypeShangShang
        : isGoodSign
        ? l10n.signTypeZhongShang
        : isWorstSign
        ? l10n.signTypeXiaXia
        : l10n.signTypeZhongXia;

    final signStyle = isBestSign
        ? (palette.historyGoldBg, palette.historyGoldText)
        : isGoodSign
        ? (colors.surfaceContainerHighest, colors.primary)
        : isWorstSign
        ? (colors.errorContainer, colors.onErrorContainer)
        : (palette.historyGrayBg, palette.historyGrayText);

    return SizedBox(
      width: double.infinity,
      child: DivinationSummaryCard(
        question: item.params.question,
        onTap: onTap,
        leading: Icon(
          Icons.auto_awesome,
          color: palette.historyBlueText,
          size: 22,
        ),
        leadingBackgroundColor: palette.historyBlueBg,
        tags: [
          DivinationSummaryTagData(
            label: categoryLabel,
            background: categoryStyle.$1,
            foreground: categoryStyle.$2,
          ),
          DivinationSummaryTagData(
            label: item.guaName,
            background: palette.historyBlueBg,
            foreground: palette.historyBlueText,
          ),
          DivinationSummaryTagData(
            label: signLabel,
            background: signStyle.$1,
            foreground: signStyle.$2,
          ),
        ],
      ),
    );
  }
}

class _WelcomeDialog extends StatefulWidget {
  const _WelcomeDialog({required this.onDone});

  final Future<void> Function() onDone;

  @override
  State<_WelcomeDialog> createState() => _WelcomeDialogState();
}

class _WelcomeDialogState extends State<_WelcomeDialog> {
  final ScrollController _scrollController = ScrollController();
  bool _hasScrolledToBottom = false;

  @override
  void initState() {
    super.initState();
    _scrollController.addListener(_handleScroll);
    WidgetsBinding.instance.addPostFrameCallback((_) {
      _syncScrollState();
    });
  }

  @override
  void dispose() {
    _scrollController.removeListener(_handleScroll);
    _scrollController.dispose();
    super.dispose();
  }

  void _handleScroll() {
    _syncScrollState();
  }

  void _syncScrollState() {
    if (!_scrollController.hasClients) {
      return;
    }
    final max = _scrollController.position.maxScrollExtent;
    final current = _scrollController.offset;
    final canReadAll = max <= AppSpacing.xs || current >= max - AppSpacing.md;
    if (_hasScrolledToBottom == canReadAll) {
      return;
    }
    setState(() {
      _hasScrolledToBottom = canReadAll;
    });
  }

  @override
  Widget build(BuildContext context) {
    final l10n = AppLocalizations.of(context)!;
    final colors = Theme.of(context).colorScheme;
    final palette = Theme.of(context).extension<AppColorPalette>()!;

    return Dialog(
      insetPadding: const EdgeInsets.symmetric(
        horizontal: AppSpacing.lg,
        vertical: AppSpacing.xl,
      ),
      child: ConstrainedBox(
        constraints: const BoxConstraints(maxHeight: 620),
        child: Padding(
          padding: const EdgeInsets.all(AppSpacing.xl),
          child: Column(
            children: [
              Text(
                l10n.welcomeDialogTitle,
                textAlign: TextAlign.center,
                style: Theme.of(context).textTheme.titleLarge?.copyWith(
                  color: colors.primary,
                  fontWeight: FontWeight.w700,
                ),
              ),
              const SizedBox(height: AppSpacing.lg),
              Expanded(
                child: SingleChildScrollView(
                  controller: _scrollController,
                  child: Column(
                    crossAxisAlignment: CrossAxisAlignment.start,
                    children: [
                      Text(
                        l10n.welcomeParagraph1,
                        style: Theme.of(context).textTheme.bodyMedium,
                      ),
                      const SizedBox(height: AppSpacing.md),
                      Text(
                        l10n.welcomeParagraph2,
                        style: Theme.of(context).textTheme.bodyMedium,
                      ),
                      const SizedBox(height: AppSpacing.md),
                      Text(
                        l10n.welcomeParagraph3,
                        style: Theme.of(context).textTheme.bodyMedium,
                      ),
                      const SizedBox(height: AppSpacing.lg),
                      Text(
                        l10n.warningTitle,
                        style: Theme.of(context).textTheme.titleMedium
                            ?.copyWith(color: palette.warning),
                      ),
                      const SizedBox(height: AppSpacing.xs),
                      Text(
                        l10n.warningBody,
                        style: Theme.of(context).textTheme.bodyMedium?.copyWith(
                          color: palette.warning,
                        ),
                      ),
                    ],
                  ),
                ),
              ),
              const SizedBox(height: AppSpacing.md),
              if (!_hasScrolledToBottom)
                Padding(
                  padding: const EdgeInsets.only(bottom: AppSpacing.sm),
                  child: Text(
                    l10n.scrollHint,
                    style: Theme.of(context).textTheme.bodySmall,
                  ),
                ),
              SizedBox(
                width: double.infinity,
                child: FilledButton(
                  onPressed: _hasScrolledToBottom
                      ? () async {
                          await widget.onDone();
                          if (!context.mounted) {
                            return;
                          }
                          Navigator.of(context).pop();
                        }
                      : null,
                  style: FilledButton.styleFrom(
                    backgroundColor: _hasScrolledToBottom
                        ? colors.primary
                        : colors.outline,
                    foregroundColor: colors.onPrimary,
                    shape: RoundedRectangleBorder(
                      borderRadius: BorderRadius.circular(AppRadius.sm),
                    ),
                  ),
                  child: Padding(
                    padding: const EdgeInsets.symmetric(
                      vertical: AppSpacing.sm,
                    ),
                    child: Text(
                      _hasScrolledToBottom
                          ? l10n.understood
                          : l10n.readAllFirst,
                    ),
                  ),
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }
}