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

import '../app/error_message.dart';
import '../app/load_state.dart';
import '../models/api_key_info.dart';
import '../providers/providers.dart';
import '../widgets/load_error_view.dart';

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

  @override
  ConsumerState<ApiKeysScreen> createState() => _ApiKeysScreenState();
}

class _ApiKeysScreenState extends ConsumerState<ApiKeysScreen> {
  final Set<String> _busyKeys = <String>{};
  String? _lastCreatedKey;

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

  Future<void> _load() async {
    await ref.read(apiKeysProvider.notifier).load();
  }

  @override
  Widget build(BuildContext context) {
    final keysState = ref.watch(apiKeysProvider);
    final keys = keysState.data;

    return Scaffold(
      appBar: AppBar(title: const Text('API-КЛЮЧИ')),
      body: Column(
        children: [
          if (_lastCreatedKey != null)
            _LastCreatedKeyBanner(
              keyValue: _lastCreatedKey!,
              onDismiss: () => setState(() => _lastCreatedKey = null),
            ),
          Expanded(child: _buildContent(keysState, keys)),
        ],
      ),
      floatingActionButton: FloatingActionButton(
        backgroundColor: Colors.deepOrange,
        onPressed: _showCreateDialog,
        child: const Icon(Icons.add),
      ),
    );
  }

  Widget _buildContent(
    LoadState<List<ApiKeyInfo>> keysState,
    List<ApiKeyInfo> keys,
  ) {
    if ((keysState.isIdle || keysState.isLoading) && keys.isEmpty) {
      return const Center(
        child: CircularProgressIndicator(color: Colors.deepOrange),
      );
    }

    if (keysState.hasError && keys.isEmpty) {
      return LoadErrorView(
        title: 'Не удалось загрузить API-ключи',
        message: keysState.errorMessage,
        icon: Icons.vpn_key,
        onRetry: _load,
      );
    }

    if (keys.isEmpty) {
      return const Center(
        child: Text(
          'Гостевых ключей пока нет',
          style: TextStyle(color: Colors.white54),
        ),
      );
    }

    final hasStatusHeader = keysState.isLoading || keysState.hasError;
    final statusHeaderCount = hasStatusHeader ? 1 : 0;

    return RefreshIndicator(
      color: Colors.deepOrange,
      onRefresh: _load,
      child: ListView.builder(
        physics: const AlwaysScrollableScrollPhysics(),
        padding: const EdgeInsets.all(12),
        itemCount: keys.length + statusHeaderCount,
        itemBuilder: (context, index) {
          if (hasStatusHeader && index == 0) {
            if (keysState.isLoading) {
              return const Padding(
                padding: EdgeInsets.only(bottom: 12),
                child: LinearProgressIndicator(color: Colors.deepOrange),
              );
            }

            return LoadErrorBanner(
              title: 'Не удалось обновить API-ключи',
              message: keysState.errorMessage,
              onRetry: _load,
            );
          }

          final keyData = keys[index - statusHeaderCount];
          final busy = _busyKeys.contains(keyData.key);
          return _ApiKeyCard(
            data: keyData,
            busy: busy,
            onRevoke: busy ? null : () => _revokeKey(keyData),
            onActivate: busy ? null : () => _activateKey(keyData),
          );
        },
      ),
    );
  }

  Future<void> _showCreateDialog() async {
    final formKey = GlobalKey<FormState>();
    final nameCtrl = TextEditingController();
    var isAdmin = false;
    var isCreating = false;

    await showDialog<void>(
      context: context,
      builder: (ctx) => StatefulBuilder(
        builder: (ctx, setDialogState) => AlertDialog(
          title: const Text('Новый API-ключ'),
          content: Form(
            key: formKey,
            autovalidateMode: AutovalidateMode.onUserInteraction,
            child: Column(
              mainAxisSize: MainAxisSize.min,
              children: [
                TextFormField(
                  controller: nameCtrl,
                  decoration: const InputDecoration(
                    labelText: 'Имя ключа',
                    hintText: 'Например: Гость',
                  ),
                  autofocus: true,
                  validator: (value) {
                    final normalized = value?.trim() ?? '';
                    if (normalized.isEmpty) {
                      return 'Укажите имя ключа';
                    }
                    if (normalized.length < 2) {
                      return 'Слишком короткое имя';
                    }
                    return null;
                  },
                ),
                const SizedBox(height: 12),
                SwitchListTile(
                  title: const Text('Дать права администратора'),
                  subtitle: const Text(
                    'Используйте только для доверенных людей',
                  ),
                  value: isAdmin,
                  activeThumbColor: Colors.deepOrange,
                  onChanged: isCreating
                      ? null
                      : (value) => setDialogState(() => isAdmin = value),
                  contentPadding: EdgeInsets.zero,
                ),
              ],
            ),
          ),
          actions: [
            TextButton(
              onPressed: isCreating ? null : () => Navigator.of(ctx).pop(),
              child: const Text('Отмена'),
            ),
            ElevatedButton(
              style: ElevatedButton.styleFrom(
                backgroundColor: Colors.deepOrange,
              ),
              onPressed: isCreating
                  ? null
                  : () async {
                      if (!formKey.currentState!.validate()) {
                        return;
                      }

                      setDialogState(() => isCreating = true);
                      try {
                        final key = await ref
                            .read(apiKeysProvider.notifier)
                            .create(nameCtrl.text.trim(), isAdmin: isAdmin);
                        if (!mounted) return;
                        setState(() => _lastCreatedKey = key);
                        if (ctx.mounted) {
                          Navigator.of(ctx).pop();
                        }
                        ScaffoldMessenger.of(context).showSnackBar(
                          const SnackBar(
                            content: Text('Ключ создан'),
                            duration: Duration(seconds: 1),
                          ),
                        );
                      } catch (e) {
                        if (!ctx.mounted) return;
                        setDialogState(() => isCreating = false);
                        ScaffoldMessenger.of(context).showSnackBar(
                          SnackBar(
                            content: Text(
                              'Ошибка создания ключа: ${describeLoadError(e)}',
                            ),
                          ),
                        );
                      }
                    },
              child: isCreating
                  ? const SizedBox(
                      width: 18,
                      height: 18,
                      child: CircularProgressIndicator(
                        strokeWidth: 2,
                        color: Colors.white,
                      ),
                    )
                  : const Text('Создать'),
            ),
          ],
        ),
      ),
    );

    nameCtrl.dispose();
  }

  Future<void> _revokeKey(ApiKeyInfo data) async {
    final confirmed = await showDialog<bool>(
      context: context,
      builder: (ctx) => AlertDialog(
        title: const Text('Отозвать ключ?'),
        content: Text('Ключ "${data.name}" перестанет работать.'),
        actions: [
          TextButton(
            onPressed: () => Navigator.of(ctx).pop(false),
            child: const Text('Отмена'),
          ),
          TextButton(
            onPressed: () => Navigator.of(ctx).pop(true),
            child: const Text(
              'Отозвать',
              style: TextStyle(color: Colors.redAccent),
            ),
          ),
        ],
      ),
    );
    if (confirmed != true) {
      return;
    }

    setState(() => _busyKeys.add(data.key));
    try {
      await ref.read(apiKeysProvider.notifier).revoke(data.key);
      if (!mounted) return;
      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(
          content: Text('Ключ отозван'),
          duration: Duration(seconds: 1),
        ),
      );
    } catch (e) {
      if (!mounted) return;
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text('Ошибка отзыва ключа: ${describeLoadError(e)}')),
      );
    } finally {
      if (mounted) {
        setState(() => _busyKeys.remove(data.key));
      }
    }
  }

  Future<void> _activateKey(ApiKeyInfo data) async {
    setState(() => _busyKeys.add(data.key));
    try {
      await ref.read(apiKeysProvider.notifier).activate(data.key);
      if (!mounted) return;
      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(
          content: Text('Ключ снова активен'),
          duration: Duration(seconds: 1),
        ),
      );
    } catch (e) {
      if (!mounted) return;
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(
          content: Text('Ошибка активации ключа: ${describeLoadError(e)}'),
        ),
      );
    } finally {
      if (mounted) {
        setState(() => _busyKeys.remove(data.key));
      }
    }
  }
}

class _LastCreatedKeyBanner extends StatelessWidget {
  final String keyValue;
  final VoidCallback onDismiss;

  const _LastCreatedKeyBanner({
    required this.keyValue,
    required this.onDismiss,
  });

  @override
  Widget build(BuildContext context) {
    return Container(
      margin: const EdgeInsets.all(12),
      padding: const EdgeInsets.all(12),
      decoration: BoxDecoration(
        color: Colors.deepOrange.withValues(alpha: 0.15),
        borderRadius: BorderRadius.circular(12),
        border: Border.all(color: Colors.deepOrange.withValues(alpha: 0.3)),
      ),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Row(
            children: [
              const Expanded(
                child: Text(
                  'Новый ключ создан. Скопируйте его сейчас, потом приложение уже не покажет полный токен.',
                  style: TextStyle(
                    fontSize: 13,
                    fontWeight: FontWeight.bold,
                    color: Colors.deepOrange,
                  ),
                ),
              ),
              IconButton(
                onPressed: onDismiss,
                icon: const Icon(Icons.close, size: 18),
                tooltip: 'Скрыть',
              ),
            ],
          ),
          const SizedBox(height: 8),
          Row(
            children: [
              Expanded(
                child: Text(
                  keyValue,
                  style: const TextStyle(
                    fontSize: 12,
                    fontFamily: 'monospace',
                    color: Colors.white70,
                  ),
                  maxLines: 3,
                  overflow: TextOverflow.ellipsis,
                ),
              ),
              IconButton(
                icon: const Icon(Icons.copy, size: 20),
                onPressed: () {
                  Clipboard.setData(ClipboardData(text: keyValue));
                  ScaffoldMessenger.of(context).showSnackBar(
                    const SnackBar(
                      content: Text('Ключ скопирован'),
                      duration: Duration(seconds: 1),
                    ),
                  );
                },
              ),
            ],
          ),
        ],
      ),
    );
  }
}

class _ApiKeyCard extends StatelessWidget {
  final ApiKeyInfo data;
  final bool busy;
  final VoidCallback? onRevoke;
  final VoidCallback? onActivate;

  const _ApiKeyCard({
    required this.data,
    required this.busy,
    required this.onRevoke,
    required this.onActivate,
  });

  @override
  Widget build(BuildContext context) {
    return Card(
      margin: const EdgeInsets.only(bottom: 8),
      child: ListTile(
        leading: Icon(
          Icons.vpn_key,
          color: data.isActive
              ? (data.isAdmin ? Colors.amber : Colors.deepOrange)
              : Colors.white24,
        ),
        title: Row(
          children: [
            Expanded(
              child: Text(
                data.name,
                style: TextStyle(
                  fontWeight: FontWeight.bold,
                  color: data.isActive ? Colors.white : Colors.white38,
                ),
              ),
            ),
            if (data.isAdmin) ...[
              const SizedBox(width: 8),
              Container(
                padding: const EdgeInsets.symmetric(horizontal: 6, vertical: 2),
                decoration: BoxDecoration(
                  color: Colors.amber.withValues(alpha: 0.2),
                  borderRadius: BorderRadius.circular(4),
                ),
                child: const Text(
                  'admin',
                  style: TextStyle(fontSize: 10, color: Colors.amber),
                ),
              ),
            ],
            if (!data.isActive) ...[
              const SizedBox(width: 8),
              Container(
                padding: const EdgeInsets.symmetric(horizontal: 6, vertical: 2),
                decoration: BoxDecoration(
                  color: Colors.redAccent.withValues(alpha: 0.2),
                  borderRadius: BorderRadius.circular(4),
                ),
                child: const Text(
                  'отозван',
                  style: TextStyle(fontSize: 10, color: Colors.redAccent),
                ),
              ),
            ],
          ],
        ),
        subtitle: data.formattedCreatedAt.isNotEmpty
            ? Text(
                'Создан: ${data.formattedCreatedAt}',
                style: const TextStyle(fontSize: 11, color: Colors.white30),
              )
            : null,
        trailing: busy
            ? const SizedBox(
                width: 20,
                height: 20,
                child: CircularProgressIndicator(
                  strokeWidth: 2,
                  color: Colors.deepOrange,
                ),
              )
            : IconButton(
                icon: Icon(
                  data.isActive ? Icons.block : Icons.check_circle_outline,
                  size: 20,
                  color: data.isActive ? Colors.redAccent : Colors.green,
                ),
                tooltip: data.isActive ? 'Отозвать' : 'Активировать',
                onPressed: data.isActive ? onRevoke : onActivate,
              ),
      ),
    );
  }
}