// Author: fruit.com.cn

import 'dart:async';

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

import '../../core/data/models/reward.dart';
import '../../core/data/services/auth_controller.dart';
import '../../core/data/services/reward_controller.dart';
import '../../core/theme/app_colors.dart';
import '../../core/theme/app_dimens.dart';
import '../../core/widgets/auth_gate.dart';
import '../../core/widgets/app_glow_panel.dart';
import '../../l10n/app_localizations.dart';
import 'reward_tasks_view.dart';

const double _activityHeight = 128;
const double _headerHeight = 52;
const double _headerIconSize = 16;
const double _headerTouchTargetSize = 44;
const double _headerTitleFont = 21;
const double _tabHeight = 56;
const double _tabFont = 18;
const double _tabIndicatorWidth = 24;
const double _tabIndicatorHeight = 3;
const double _helpButtonSize = 24;
const double _helpBorderWidth = 1;
const double _helpFont = 14;
const double _helpDialogMaxWidth = 320;
const double _helpDialogRadius = 20;
const double _helpDialogIconSize = 48;
const double _helpDialogIconFont = 24;
const double _helpDialogTitleFont = 18;
const double _helpDialogBodyFont = 14;
const double _helpDialogButtonHeight = 44;
const int _loadDelayMilliseconds = 1;
const String _loadKeySeparator = '|';
const Color _helpBorder = Color(0xFFE9E9EA);
const Color _tabInactive = Color(0xFF9B9B9F);

/// 奖励中心根页面，展示余额、签到、任务与活动。
class RewardPage extends StatefulWidget {
  const RewardPage({
    super.key,
    required this.active,
    this.onBack,
    this.onHelp,
    this.onTaskAction,
    this.onOpenWallet,
  });

  final bool active;
  final VoidCallback? onBack;
  final VoidCallback? onHelp;
  final ValueChanged<RewardTask>? onTaskAction;
  final VoidCallback? onOpenWallet;

  @override
  State<RewardPage> createState() => _RewardPageState();
}

class _RewardPageState extends State<RewardPage> {
  bool _showActivities = false;
  bool _loadScheduled = false;
  String? _autoLoadKey;

  @override
  void didChangeDependencies() {
    super.didChangeDependencies();
    _scheduleLoad();
  }

  @override
  void didUpdateWidget(covariant RewardPage oldWidget) {
    super.didUpdateWidget(oldWidget);
    if (widget.active && !oldWidget.active) _scheduleLoad(force: true);
  }

  void _scheduleLoad({bool force = false}) {
    if (!widget.active || _loadScheduled) return;
    final rewards = context.read<RewardController>();
    final auth = context.read<AuthController>();
    final locale = Localizations.localeOf(context).languageCode;
    final loadKey = '$locale$_loadKeySeparator${auth.isSignedIn}';
    if (!force && _autoLoadKey == loadKey) return;
    _autoLoadKey = loadKey;
    _loadScheduled = true;
    Future<void>.delayed(
      const Duration(milliseconds: _loadDelayMilliseconds),
      () async {
        if (!mounted) return;
        _loadScheduled = false;
        if (!widget.active) return;
        await rewards.load(locale);
      },
    );
  }

  @override
  Widget build(BuildContext context) {
    final rewards = context.watch<RewardController>();
    context.watch<AuthController>();
    final l10n = AppLocalizations.of(context)!;
    return DecoratedBox(
      decoration: const BoxDecoration(
        gradient: LinearGradient(
          begin: Alignment.topCenter,
          end: Alignment.bottomCenter,
          colors: [AppColors.followingGlow, AppColors.ink, AppColors.ink],
          stops: [0, 0.3, 1],
        ),
      ),
      child: SafeArea(
        bottom: false,
        child: Column(
          children: [
            _header(l10n),
            Expanded(child: _body(l10n, rewards)),
          ],
        ),
      ),
    );
  }

  Widget _header(AppLocalizations l10n) {
    return Column(
      children: [
        SizedBox(
          width: double.infinity,
          height: _headerHeight,
          child: Stack(
            alignment: Alignment.center,
            children: [
              Positioned(left: 4, child: _backButton()),
              Text(
                l10n.rewardCenterTitle,
                style: const TextStyle(
                  color: AppColors.textPrimary,
                  fontSize: _headerTitleFont,
                  fontWeight: FontWeight.w800,
                ),
              ),
              Positioned(right: 8, child: _helpButton()),
            ],
          ),
        ),
        Row(
          children: [
            Expanded(
              child: _tab(
                key: const Key('reward-tab-tasks'),
                indicatorKey: const Key('reward-tab-indicator-tasks'),
                label: l10n.rewardTasksTab,
                selected: !_showActivities,
                showActivities: false,
              ),
            ),
            Expanded(
              child: _tab(
                key: const Key('reward-tab-activities'),
                indicatorKey: const Key('reward-tab-indicator-activities'),
                label: l10n.rewardActivitiesTab,
                selected: _showActivities,
                showActivities: true,
              ),
            ),
          ],
        ),
      ],
    );
  }

  Widget _backButton() {
    return IconButton(
      key: const Key('reward-back-button'),
      tooltip: MaterialLocalizations.of(context).backButtonTooltip,
      onPressed: widget.onBack ?? () {},
      icon: const Icon(
        Icons.arrow_back_ios_new_rounded,
        color: AppColors.textPrimary,
        size: _headerIconSize,
      ),
    );
  }

  Widget _helpButton() {
    return IconButton(
      key: const Key('reward-help-button'),
      tooltip: AppLocalizations.of(context)!.rewardHelpTitle,
      onPressed: widget.onHelp ?? _showHelp,
      padding: EdgeInsets.zero,
      constraints: const BoxConstraints.tightFor(
        width: _headerTouchTargetSize,
        height: _headerTouchTargetSize,
      ),
      icon: Container(
        key: const Key('reward-help-icon'),
        width: _helpButtonSize,
        height: _helpButtonSize,
        alignment: Alignment.center,
        decoration: BoxDecoration(
          shape: BoxShape.circle,
          border: Border.all(color: _helpBorder, width: _helpBorderWidth),
        ),
        child: const Text(
          '?',
          style: TextStyle(
            color: AppColors.textPrimary,
            fontSize: _helpFont,
            fontWeight: FontWeight.w500,
          ),
        ),
      ),
    );
  }

  Widget _tab({
    required Key key,
    required Key indicatorKey,
    required String label,
    required bool selected,
    required bool showActivities,
  }) {
    return InkWell(
      key: key,
      onTap: () => setState(() => _showActivities = showActivities),
      child: SizedBox(
        height: _tabHeight,
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            Text(
              label,
              style: TextStyle(
                color: selected ? AppColors.textPrimary : _tabInactive,
                fontSize: _tabFont,
                fontWeight: selected ? FontWeight.w800 : FontWeight.w500,
              ),
            ),
            const SizedBox(height: AppDimens.spaceSm),
            AnimatedContainer(
              key: indicatorKey,
              duration: AppDimens.homePrimaryTabAnimationDuration,
              width: selected ? _tabIndicatorWidth : 0,
              height: _tabIndicatorHeight,
              decoration: BoxDecoration(
                color: AppColors.brandRed,
                borderRadius: BorderRadius.circular(AppDimens.pillRadius),
              ),
            ),
          ],
        ),
      ),
    );
  }

  Widget _body(AppLocalizations l10n, RewardController rewards) {
    if (rewards.loading && rewards.overview == null) {
      return const Center(
        child: CircularProgressIndicator(color: AppColors.brandRed),
      );
    }
    if (rewards.error != null && rewards.overview == null) {
      return _errorState(l10n, rewards);
    }
    final overview = rewards.overview;
    if (overview == null) return const SizedBox.shrink();
    return _showActivities
        ? _activities(l10n, overview)
        : RewardTasksView(
            l10n: l10n,
            rewards: rewards,
            overview: overview,
            onRefresh: () =>
                rewards.load(Localizations.localeOf(context).languageCode),
            onCheckIn: () => _checkIn(l10n, rewards),
            onTaskAction: (task) => _handleTask(l10n, rewards, task),
            onOpenWallet: widget.onOpenWallet,
            onBoostCheckIn: () => _showResult(l10n.rewardComingSoon),
          );
  }

  Widget _activities(AppLocalizations l10n, RewardOverview overview) {
    return ListView(
      physics: const AlwaysScrollableScrollPhysics(),
      padding: const EdgeInsets.all(AppDimens.pageHorizontal),
      children: overview.activities.isEmpty
          ? [_empty(l10n.rewardEmptyActivities)]
          : [for (final activity in overview.activities) _activity(activity)],
    );
  }

  Widget _activity(RewardActivity activity) {
    return Container(
      height: _activityHeight,
      margin: const EdgeInsets.only(bottom: AppDimens.spaceLg),
      padding: const EdgeInsets.all(AppDimens.cardPadding),
      decoration: BoxDecoration(
        gradient: const LinearGradient(
          colors: [AppColors.vipCardStart, AppColors.contentCard],
        ),
        borderRadius: BorderRadius.circular(AppDimens.cardRadius),
        border: Border.all(color: AppColors.vipCardBorder),
      ),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        mainAxisAlignment: MainAxisAlignment.center,
        children: [
          Text(
            activity.title,
            style: const TextStyle(
              color: AppColors.textPrimary,
              fontSize: AppDimens.pageTitle,
              fontWeight: FontWeight.w800,
            ),
          ),
          const SizedBox(height: AppDimens.spaceSm),
          Text(
            activity.summary,
            style: const TextStyle(color: AppColors.textSecondary),
          ),
        ],
      ),
    );
  }

  Widget _errorState(AppLocalizations l10n, RewardController rewards) {
    return Center(
      child: FilledButton(
        onPressed: () =>
            rewards.load(Localizations.localeOf(context).languageCode),
        child: Text(l10n.rewardRetry),
      ),
    );
  }

  Widget _empty(String label) {
    return Padding(
      padding: const EdgeInsets.symmetric(vertical: AppDimens.spaceXl),
      child: Center(
        child: Text(
          label,
          style: const TextStyle(color: AppColors.textTertiary),
        ),
      ),
    );
  }

  Future<void> _checkIn(AppLocalizations l10n, RewardController rewards) async {
    if (!await ensureSignedIn(context) || !mounted) return;
    final result = await rewards.checkIn();
    if (!mounted) return;
    _showResult(
      result == null
          ? _message(l10n, rewards.actionError)
          : l10n.rewardCheckInSuccess(result.rewardCoin),
    );
  }

  Future<void> _handleTask(
    AppLocalizations l10n,
    RewardController rewards,
    RewardTask task,
  ) async {
    if (!task.claimable) {
      widget.onTaskAction?.call(task);
      return;
    }
    if (!await ensureSignedIn(context) || !mounted) return;
    final result = await rewards.claim(task.id);
    if (!mounted) return;
    _showResult(
      result == null
          ? _message(l10n, rewards.actionError)
          : l10n.rewardClaimSuccess(result.rewardCoin),
    );
  }

  String? _message(AppLocalizations l10n, String? message) {
    return switch (message) {
      'rewardActionFailed' => l10n.rewardActionFailed,
      _ => message,
    };
  }

  void _showResult(String? message) {
    if (message == null || message.isEmpty) return;
    ScaffoldMessenger.of(
      context,
    ).showSnackBar(SnackBar(content: Text(message)));
  }

  void _showHelp() {
    final l10n = AppLocalizations.of(context)!;
    showDialog<void>(
      context: context,
      builder: (dialogContext) => RepaintBoundary(
        key: const Key('reward-help-dialog'),
        child: _RewardHelpDialog(
          title: l10n.rewardHelpTitle,
          body: l10n.rewardHelpBody,
          confirmLabel: MaterialLocalizations.of(dialogContext).okButtonLabel,
        ),
      ),
    );
  }
}

class _RewardHelpDialog extends StatelessWidget {
  const _RewardHelpDialog({
    required this.title,
    required this.body,
    required this.confirmLabel,
  });

  final String title;
  final String body;
  final String confirmLabel;

  @override
  Widget build(BuildContext context) {
    return Dialog(
      backgroundColor: AppColors.transparent,
      insetPadding: const EdgeInsets.symmetric(horizontal: AppDimens.spaceXl),
      child: ConstrainedBox(
        constraints: const BoxConstraints(maxWidth: _helpDialogMaxWidth),
        child: AppGlowPanel(
          borderRadius: BorderRadius.circular(_helpDialogRadius),
          child: Padding(
            padding: const EdgeInsets.fromLTRB(
              AppDimens.spaceXl,
              AppDimens.spaceXl,
              AppDimens.spaceXl,
              AppDimens.spaceLg,
            ),
            child: Column(
              mainAxisSize: MainAxisSize.min,
              children: [
                const _HelpDialogIcon(),
                const SizedBox(height: AppDimens.spaceMd),
                Text(
                  title,
                  textAlign: TextAlign.center,
                  style: const TextStyle(
                    color: AppColors.textPrimary,
                    fontSize: _helpDialogTitleFont,
                    fontWeight: FontWeight.w800,
                  ),
                ),
                const SizedBox(height: AppDimens.spaceSm),
                Text(
                  body,
                  textAlign: TextAlign.center,
                  style: const TextStyle(
                    color: AppColors.textSecondary,
                    fontSize: _helpDialogBodyFont,
                    height: 1.45,
                  ),
                ),
                const SizedBox(height: AppDimens.spaceXl),
                SizedBox(
                  width: double.infinity,
                  height: _helpDialogButtonHeight,
                  child: FilledButton(
                    key: const Key('reward-help-close'),
                    onPressed: () => Navigator.of(context).pop(),
                    style: FilledButton.styleFrom(
                      backgroundColor: AppColors.brandRed,
                      foregroundColor: AppColors.onPrimary,
                      shape: RoundedRectangleBorder(
                        borderRadius: BorderRadius.circular(
                          AppDimens.buttonRadius,
                        ),
                      ),
                    ),
                    child: Text(
                      confirmLabel,
                      style: const TextStyle(
                        fontSize: AppDimens.body,
                        fontWeight: FontWeight.w700,
                      ),
                    ),
                  ),
                ),
              ],
            ),
          ),
        ),
      ),
    );
  }
}

class _HelpDialogIcon extends StatelessWidget {
  const _HelpDialogIcon();

  @override
  Widget build(BuildContext context) {
    return Container(
      width: _helpDialogIconSize,
      height: _helpDialogIconSize,
      alignment: Alignment.center,
      decoration: BoxDecoration(
        color: AppColors.filterChipSelected,
        shape: BoxShape.circle,
        border: Border.all(color: AppColors.brandRed, width: 1),
      ),
      child: const Text(
        '?',
        style: TextStyle(
          color: AppColors.brandRed,
          fontSize: _helpDialogIconFont,
          fontWeight: FontWeight.w800,
        ),
      ),
    );
  }
}