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

import '../../../../core/logging/logger.dart';
import '../../../../l10n/app_localizations.dart';
import '../../../../shared/theme/app_color_palette.dart';
import '../../../../shared/theme/design_tokens.dart';
import '../../../../shared/widgets/toast/toast.dart';
import '../../../../shared/widgets/toast/toast_type.dart';
import '../../data/repositories/invite_repository.dart';

class InviteScreen extends StatefulWidget {
  const InviteScreen({super.key, required this.inviteRepository});

  final InviteRepository inviteRepository;

  @override
  State<InviteScreen> createState() => _InviteScreenState();
}

class _InviteScreenState extends State<InviteScreen> {
  final Logger _logger = getLogger('features.settings.invite_screen');
  final _bindCodeController = TextEditingController();
  final _formKey = GlobalKey<FormState>();

  bool _isBinding = false;
  bool _isGenerating = false;
  bool _isLoading = true;
  bool _hasError = false;

  String? _myInviteCode;
  int _invitedCount = 0;
  final bool _hasInviter = false;

  @override
  void initState() {
    super.initState();
    _loadInviteCode();
  }

  Future<void> _loadInviteCode() async {
    setState(() {
      _isLoading = true;
      _hasError = false;
    });
    try {
      final result = await widget.inviteRepository.getMyInviteCode();
      if (!mounted) return;
      setState(() {
        _myInviteCode = result.code;
        _invitedCount = result.usedCount;
        _isLoading = false;
      });
    } catch (error, stackTrace) {
      _logger.error(
        message: 'Failed to load invite code',
        error: error,
        stackTrace: stackTrace,
      );
      if (!mounted) return;
      setState(() {
        _hasError = true;
        _isLoading = false;
      });
    }
  }

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

  bool get _hasMyInviteCode =>
      _myInviteCode != null && _myInviteCode!.isNotEmpty;

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

    if (_isLoading) {
      return Scaffold(
        backgroundColor: colors.surfaceContainerLow,
        appBar: AppBar(
          title: Text(l10n.settingsInviteTitle),
          centerTitle: true,
          backgroundColor: colors.surfaceContainerLow,
          surfaceTintColor: colors.surfaceContainerLow,
        ),
        body: const Center(child: CircularProgressIndicator()),
      );
    }

    if (_hasError) {
      return Scaffold(
        backgroundColor: colors.surfaceContainerLow,
        appBar: AppBar(
          title: Text(l10n.settingsInviteTitle),
          centerTitle: true,
          backgroundColor: colors.surfaceContainerLow,
          surfaceTintColor: colors.surfaceContainerLow,
        ),
        body: Center(
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: [
              Text(
                l10n.settingsInviteEmptyTitle,
                style: Theme.of(context).textTheme.bodyLarge,
              ),
              const SizedBox(height: AppSpacing.md),
              FilledButton(
                onPressed: _loadInviteCode,
                child: const Text('Retry'),
              ),
            ],
          ),
        ),
      );
    }

    return Scaffold(
      backgroundColor: colors.surfaceContainerLow,
      appBar: AppBar(
        title: Text(l10n.settingsInviteTitle),
        centerTitle: true,
        backgroundColor: colors.surfaceContainerLow,
        surfaceTintColor: colors.surfaceContainerLow,
      ),
      body: ListView(
        padding: const EdgeInsets.all(AppSpacing.lg),
        children: [
          if (_hasMyInviteCode) ...[
            _InviteCodeCard(
              inviteCode: _myInviteCode!,
              onCopy: _copyInviteCode,
            ),
            const SizedBox(height: AppSpacing.lg),
            _InviteStatsCard(count: _invitedCount),
            const SizedBox(height: AppSpacing.xl),
            _BindCodeSection(
              controller: _bindCodeController,
              formKey: _formKey,
              isBinding: _isBinding,
              onBind: _bindInviteCode,
            ),
          ] else ...[
            _EmptyStateCard(
              controller: _bindCodeController,
              formKey: _formKey,
              isBinding: _isBinding,
              isGenerating: _isGenerating,
              hasInviter: _hasInviter,
              onBind: _bindInviteCode,
              onGenerate: _generateInviteCode,
            ),
          ],
        ],
      ),
    );
  }

  void _copyInviteCode() {
    final l10n = AppLocalizations.of(context)!;
    Clipboard.setData(ClipboardData(text: _myInviteCode!));
    Toast.show(
      context,
      l10n.settingsInviteCopySuccess,
      type: ToastType.success,
    );
  }

  Future<void> _bindInviteCode() async {
    if (!_formKey.currentState!.validate()) return;

    setState(() => _isBinding = true);

    // Simulate API call
    await Future.delayed(const Duration(seconds: 1));

    if (!mounted) return;

    final l10n = AppLocalizations.of(context)!;
    Toast.show(
      context,
      l10n.settingsInviteBindSuccess,
      type: ToastType.success,
    );

    setState(() => _isBinding = false);
  }

  Future<void> _generateInviteCode() async {
    setState(() => _isGenerating = true);

    // Simulate API call
    await Future.delayed(const Duration(seconds: 1));

    if (!mounted) return;

    final l10n = AppLocalizations.of(context)!;
    Toast.show(
      context,
      l10n.settingsInviteGenerateSuccess,
      type: ToastType.success,
    );

    setState(() => _isGenerating = false);
  }
}

class _InviteCodeCard extends StatelessWidget {
  const _InviteCodeCard({required this.inviteCode, required this.onCopy});

  final String inviteCode;
  final VoidCallback onCopy;

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

    return Stack(
      children: [
        Container(
          width: double.infinity,
          padding: const EdgeInsets.all(AppSpacing.xl),
          decoration: BoxDecoration(
            borderRadius: BorderRadius.circular(AppRadius.xl),
            gradient: LinearGradient(
              colors: [colors.primary, palette.accentPurple],
            ),
          ),
          child: Column(
            children: [
              Icon(
                Icons.card_giftcard_rounded,
                color: colors.onPrimary,
                size: 40,
              ),
              const SizedBox(height: AppSpacing.md),
              Text(
                l10n.settingsInviteMyCode,
                style: Theme.of(context).textTheme.bodyMedium?.copyWith(
                  color: colors.onPrimary.withValues(alpha: 0.88),
                ),
              ),
              const SizedBox(height: AppSpacing.md),
              Text(
                inviteCode,
                style: Theme.of(context).textTheme.headlineLarge?.copyWith(
                  color: colors.onPrimary,
                  fontWeight: FontWeight.w700,
                  letterSpacing: 6,
                ),
              ),
            ],
          ),
        ),
        Positioned(
          top: AppSpacing.sm,
          right: AppSpacing.sm,
          child: Material(
            color: colors.onPrimary.withValues(alpha: 0.18),
            borderRadius: BorderRadius.circular(AppRadius.full),
            child: InkWell(
              onTap: onCopy,
              borderRadius: BorderRadius.circular(AppRadius.full),
              child: Container(
                padding: const EdgeInsets.all(AppSpacing.sm),
                child: Icon(
                  Icons.copy_rounded,
                  color: colors.onPrimary,
                  size: 20,
                ),
              ),
            ),
          ),
        ),
      ],
    );
  }
}

class _InviteStatsCard extends StatelessWidget {
  const _InviteStatsCard({required this.count});

  final int count;

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

    return Card(
      margin: EdgeInsets.zero,
      elevation: 0,
      color: colors.surface,
      shape: RoundedRectangleBorder(
        borderRadius: BorderRadius.circular(AppRadius.xl),
      ),
      child: Padding(
        padding: const EdgeInsets.all(AppSpacing.lg),
        child: Row(
          children: [
            Container(
              width: 48,
              height: 48,
              decoration: BoxDecoration(
                color: colors.primary.withValues(alpha: 0.1),
                borderRadius: BorderRadius.circular(AppRadius.md),
              ),
              child: Icon(Icons.people_outline_rounded, color: colors.primary),
            ),
            const SizedBox(width: AppSpacing.md),
            Expanded(
              child: Text(
                l10n.settingsInviteStats(count),
                style: Theme.of(context).textTheme.titleMedium,
              ),
            ),
          ],
        ),
      ),
    );
  }
}

class _BindCodeSection extends StatelessWidget {
  const _BindCodeSection({
    required this.controller,
    required this.formKey,
    required this.isBinding,
    required this.onBind,
  });

  final TextEditingController controller;
  final GlobalKey<FormState> formKey;
  final bool isBinding;
  final Future<void> Function() onBind;

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

    return Card(
      margin: EdgeInsets.zero,
      elevation: 0,
      color: colors.surface,
      shape: RoundedRectangleBorder(
        borderRadius: BorderRadius.circular(AppRadius.xl),
      ),
      child: Padding(
        padding: const EdgeInsets.all(AppSpacing.lg),
        child: Form(
          key: formKey,
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Row(
                children: [
                  Icon(Icons.link_rounded, color: colors.primary, size: 20),
                  const SizedBox(width: AppSpacing.sm),
                  Text(
                    l10n.settingsInviteBindCode,
                    style: Theme.of(context).textTheme.titleMedium,
                  ),
                ],
              ),
              const SizedBox(height: AppSpacing.md),
              TextFormField(
                controller: controller,
                textCapitalization: TextCapitalization.characters,
                decoration: InputDecoration(
                  hintText: l10n.settingsInviteBindPlaceholder,
                  filled: true,
                  fillColor: colors.surfaceContainerHighest,
                  border: OutlineInputBorder(
                    borderRadius: BorderRadius.circular(AppRadius.md),
                    borderSide: BorderSide.none,
                  ),
                  contentPadding: const EdgeInsets.symmetric(
                    horizontal: AppSpacing.md,
                    vertical: AppSpacing.md,
                  ),
                ),
                inputFormatters: [
                  FilteringTextInputFormatter.allow(RegExp(r'[A-Za-z0-9]')),
                  LengthLimitingTextInputFormatter(6),
                ],
                validator: (value) {
                  if (value == null || value.isEmpty) {
                    return null; // Optional field
                  }
                  if (value.length != 6) {
                    return l10n.settingsInviteInvalidCode;
                  }
                  return null;
                },
              ),
              const SizedBox(height: AppSpacing.md),
              SizedBox(
                width: double.infinity,
                child: FilledButton(
                  onPressed: null,
                  style: FilledButton.styleFrom(
                    elevation: 0,
                    padding: const EdgeInsets.symmetric(
                      vertical: AppSpacing.md,
                    ),
                    shape: RoundedRectangleBorder(
                      borderRadius: BorderRadius.circular(AppRadius.full),
                    ),
                  ),
                  child: Text(l10n.settingsComingSoon),
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }
}

class _EmptyStateCard extends StatelessWidget {
  const _EmptyStateCard({
    required this.controller,
    required this.formKey,
    required this.isBinding,
    required this.isGenerating,
    required this.hasInviter,
    required this.onBind,
    required this.onGenerate,
  });

  final TextEditingController controller;
  final GlobalKey<FormState> formKey;
  final bool isBinding;
  final bool isGenerating;
  final bool hasInviter;
  final Future<void> Function() onBind;
  final Future<void> Function() onGenerate;

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

    return Column(
      children: [
        Container(
          padding: const EdgeInsets.all(AppSpacing.xxl),
          decoration: BoxDecoration(
            color: colors.surface,
            borderRadius: BorderRadius.circular(AppRadius.xl),
          ),
          child: Column(
            children: [
              Container(
                width: 80,
                height: 80,
                decoration: BoxDecoration(
                  gradient: LinearGradient(
                    colors: [
                      colors.primary.withValues(alpha: 0.1),
                      palette.accentPurple.withValues(alpha: 0.1),
                    ],
                  ),
                  borderRadius: BorderRadius.circular(AppRadius.xl),
                ),
                child: Icon(
                  Icons.celebration_rounded,
                  color: colors.primary,
                  size: 40,
                ),
              ),
              const SizedBox(height: AppSpacing.lg),
              Text(
                l10n.settingsInviteEmptyTitle,
                style: Theme.of(
                  context,
                ).textTheme.titleLarge?.copyWith(fontWeight: FontWeight.w700),
                textAlign: TextAlign.center,
              ),
              const SizedBox(height: AppSpacing.sm),
              Text(
                l10n.settingsInviteEmptyDescription,
                style: Theme.of(context).textTheme.bodyMedium?.copyWith(
                  color: colors.onSurfaceVariant,
                ),
                textAlign: TextAlign.center,
              ),
            ],
          ),
        ),
        const SizedBox(height: AppSpacing.lg),
        if (!hasInviter) ...[
          Card(
            margin: EdgeInsets.zero,
            elevation: 0,
            color: colors.surface,
            shape: RoundedRectangleBorder(
              borderRadius: BorderRadius.circular(AppRadius.xl),
            ),
            child: Padding(
              padding: const EdgeInsets.all(AppSpacing.lg),
              child: Form(
                key: formKey,
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    Text(
                      l10n.settingsInviteInputLabel,
                      style: Theme.of(context).textTheme.titleSmall?.copyWith(
                        color: colors.onSurfaceVariant,
                      ),
                    ),
                    const SizedBox(height: AppSpacing.sm),
                    TextFormField(
                      controller: controller,
                      textCapitalization: TextCapitalization.characters,
                      decoration: InputDecoration(
                        hintText: l10n.settingsInviteInputHint,
                        filled: true,
                        fillColor: colors.surfaceContainerHighest,
                        border: OutlineInputBorder(
                          borderRadius: BorderRadius.circular(AppRadius.md),
                          borderSide: BorderSide.none,
                        ),
                        contentPadding: const EdgeInsets.symmetric(
                          horizontal: AppSpacing.md,
                          vertical: AppSpacing.md,
                        ),
                      ),
                      inputFormatters: [
                        FilteringTextInputFormatter.allow(
                          RegExp(r'[A-Za-z0-9]'),
                        ),
                        LengthLimitingTextInputFormatter(6),
                      ],
                      validator: (value) {
                        if (value == null || value.isEmpty) {
                          return null;
                        }
                        if (value.length != 6) {
                          return l10n.settingsInviteInvalidCode;
                        }
                        return null;
                      },
                    ),
                  ],
                ),
              ),
            ),
          ),
          const SizedBox(height: AppSpacing.md),
        ],
        SizedBox(
          width: double.infinity,
          child: FilledButton(
            onPressed: isGenerating ? null : onGenerate,
            style: FilledButton.styleFrom(
              elevation: 0,
              padding: const EdgeInsets.symmetric(vertical: AppSpacing.md),
              shape: RoundedRectangleBorder(
                borderRadius: BorderRadius.circular(AppRadius.full),
              ),
            ),
            child: isGenerating
                ? const SizedBox(
                    width: 20,
                    height: 20,
                    child: CircularProgressIndicator(
                      strokeWidth: 2,
                      color: Colors.white,
                    ),
                  )
                : Row(
                    mainAxisAlignment: MainAxisAlignment.center,
                    children: [
                      const Icon(Icons.add_rounded, size: 20),
                      const SizedBox(width: AppSpacing.sm),
                      Text(l10n.settingsInviteGenerateButton),
                    ],
                  ),
          ),
        ),
      ],
    );
  }
}