import 'package:flutter/material.dart';
import '../../data/nostr/nostr_service.dart';
import '../../data/nostr/models/nostr_keypair.dart';
import '../../data/nostr/models/nostr_event.dart';
import '../../data/nostr/models/nostr_relay.dart';
import '../../data/sync/sync_engine.dart';

/// Screen for displaying and testing Nostr events.
class NostrEventsScreen extends StatefulWidget {
  final NostrService? nostrService;
  final SyncEngine? syncEngine;

  const NostrEventsScreen({
    super.key,
    this.nostrService,
    this.syncEngine,
  });

  @override
  State<NostrEventsScreen> createState() => _NostrEventsScreenState();
}

class _NostrEventsScreenState extends State<NostrEventsScreen> {
  NostrKeyPair? _keyPair;
  List<NostrRelay> _relays = [];
  Map<String, bool> _connectionStatus = {};
  List<String> _events = [];
  bool _isLoading = false;
  final TextEditingController _nsecController = TextEditingController();
  final TextEditingController _npubController = TextEditingController();
  final TextEditingController _hexPrivateKeyController = TextEditingController();
  bool _showImportFields = false;

  @override
  void initState() {
    super.initState();
    _loadRelays();
    _generateKeyPair();
  }

  @override
  void dispose() {
    _nsecController.dispose();
    _npubController.dispose();
    _hexPrivateKeyController.dispose();
    super.dispose();
  }

  void _loadRelays() {
    if (widget.nostrService == null) return;
    
    setState(() {
      _relays = widget.nostrService!.getRelays();
      _connectionStatus = {
        for (var relay in _relays) relay.url: relay.isConnected
      };
    });
  }

  void _generateKeyPair() {
    if (widget.nostrService == null) return;
    
    setState(() {
      _keyPair = widget.nostrService!.generateKeyPair();
      _nsecController.clear();
      _npubController.clear();
      _hexPrivateKeyController.clear();
      _showImportFields = false;
    });
  }

  void _importFromNsec() {
    final nsec = _nsecController.text.trim();
    if (nsec.isEmpty) {
      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(
          content: Text('Please enter an nsec key'),
          backgroundColor: Colors.orange,
        ),
      );
      return;
    }

    try {
      setState(() {
        _keyPair = NostrKeyPair.fromNsec(nsec);
        _showImportFields = false;
      });

      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(
          content: Text('Keypair imported from nsec'),
          backgroundColor: Colors.green,
        ),
      );
    } catch (e) {
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(
          content: Text('Failed to import nsec: ${e.toString()}'),
          backgroundColor: Colors.red,
        ),
      );
    }
  }

  void _importFromNpub() {
    final npub = _npubController.text.trim();
    if (npub.isEmpty) {
      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(
          content: Text('Please enter an npub key'),
          backgroundColor: Colors.orange,
        ),
      );
      return;
    }

    try {
      setState(() {
        _keyPair = NostrKeyPair.fromNpub(npub);
        _showImportFields = false;
      });

      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(
          content: Text('Public key imported from npub (note: cannot sign events without private key)'),
          backgroundColor: Colors.orange,
        ),
      );
    } catch (e) {
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(
          content: Text('Failed to import npub: ${e.toString()}'),
          backgroundColor: Colors.red,
        ),
      );
    }
  }

  void _importFromHexPrivateKey() {
    final hexKey = _hexPrivateKeyController.text.trim();
    if (hexKey.isEmpty) {
      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(
          content: Text('Please enter a hex private key'),
          backgroundColor: Colors.orange,
        ),
      );
      return;
    }

    try {
      setState(() {
        _keyPair = NostrKeyPair.fromHexPrivateKey(hexKey);
        _showImportFields = false;
      });

      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(
          content: Text('Keypair imported from hex private key'),
          backgroundColor: Colors.green,
        ),
      );
    } catch (e) {
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(
          content: Text('Failed to import hex key: ${e.toString()}'),
          backgroundColor: Colors.red,
        ),
      );
    }
  }

  Future<void> _connectToRelay(String relayUrl) async {
    if (widget.nostrService == null) return;

    setState(() {
      _isLoading = true;
    });

    try {
      await widget.nostrService!.connectRelay(relayUrl).timeout(
        const Duration(seconds: 5),
        onTimeout: () {
          throw Exception('Connection timeout');
        },
      );
      
      setState(() {
        _connectionStatus[relayUrl] = true;
        _isLoading = false;
      });

      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(
            content: Text('Connected to $relayUrl'),
            backgroundColor: Colors.green,
          ),
        );
      }
      
      _loadRelays();
    } catch (e) {
      setState(() {
        _connectionStatus[relayUrl] = false;
        _isLoading = false;
      });

      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(
            content: Text('Failed to connect: ${e.toString()}'),
            backgroundColor: Colors.red,
          ),
        );
      }
    }
  }

  Future<void> _disconnectFromRelay(String relayUrl) async {
    if (widget.nostrService == null) return;

    widget.nostrService!.disconnectRelay(relayUrl);
    
    setState(() {
      _connectionStatus[relayUrl] = false;
    });

    if (mounted) {
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(
          content: Text('Disconnected from $relayUrl'),
        ),
      );
    }
    
    _loadRelays();
  }

  Future<void> _publishTestEvent() async {
    if (widget.nostrService == null || _keyPair == null) {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(
            content: Text('Nostr service or keypair not available'),
            backgroundColor: Colors.red,
          ),
        );
      }
      return;
    }

    if (_relays.isEmpty) {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(
            content: Text('No relays configured. Add relays in Settings.'),
            backgroundColor: Colors.orange,
          ),
        );
      }
      return;
    }

    setState(() {
      _isLoading = true;
    });

    if (_keyPair!.privateKey.isEmpty) {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(
            content: Text('Cannot publish: No private key available. Import nsec or hex private key.'),
            backgroundColor: Colors.red,
          ),
        );
      }
      setState(() {
        _isLoading = false;
      });
      return;
    }

    try {
      // Create a test event
      final event = NostrEvent.create(
        content: 'Test event from Flutter app - ${DateTime.now().toIso8601String()}',
        kind: 1, // Text note
        privateKey: _keyPair!.privateKey,
      );

      // Publish to all connected relays
      final results = await widget.nostrService!.publishEventToAllRelays(event);

      setState(() {
        _isLoading = false;
        _events.insert(0, 'Event published: ${event.id.substring(0, 8)}...');
      });

      final successCount = results.values.where((v) => v == true).length;
      final totalCount = results.length;

      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(
            content: Text('Published to $successCount/$totalCount relays'),
            backgroundColor: successCount > 0 ? Colors.green : Colors.orange,
          ),
        );
      }
    } catch (e) {
      setState(() {
        _isLoading = false;
      });

      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(
            content: Text('Failed to publish: ${e.toString()}'),
            backgroundColor: Colors.red,
          ),
        );
      }
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Nostr Events'),
        actions: [
          IconButton(
            icon: const Icon(Icons.refresh),
            onPressed: () {
              _loadRelays();
              _generateKeyPair();
            },
            tooltip: 'Refresh',
          ),
        ],
      ),
      body: _isLoading
          ? const Center(child: CircularProgressIndicator())
          : SingleChildScrollView(
              padding: const EdgeInsets.all(16),
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.stretch,
                children: [
                  _buildKeyPairSection(),
                  const SizedBox(height: 24),
                  _buildRelaysSection(),
                  const SizedBox(height: 24),
                  _buildActionsSection(),
                  if (_events.isNotEmpty) ...[
                    const SizedBox(height: 24),
                    _buildEventsSection(),
                  ],
                ],
              ),
            ),
    );
  }

  Widget _buildKeyPairSection() {
    return Card(
      child: Padding(
        padding: const EdgeInsets.all(16),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Row(
              mainAxisAlignment: MainAxisAlignment.spaceBetween,
              children: [
                const Text(
                  'Keypair',
                  style: TextStyle(
                    fontSize: 18,
                    fontWeight: FontWeight.bold,
                  ),
                ),
                TextButton.icon(
                  onPressed: () {
                    setState(() {
                      _showImportFields = !_showImportFields;
                    });
                  },
                  icon: Icon(_showImportFields ? Icons.visibility_off : Icons.import_export),
                  label: Text(_showImportFields ? 'Hide Import' : 'Import Key'),
                ),
              ],
            ),
            const SizedBox(height: 12),
            if (_keyPair != null) ...[
              const Text(
                'Public Key:',
                style: TextStyle(fontSize: 12, fontWeight: FontWeight.bold),
              ),
              SelectableText(
                _keyPair!.publicKey,
                style: const TextStyle(fontSize: 11, fontFamily: 'monospace'),
              ),
              const SizedBox(height: 8),
              if (_keyPair!.privateKey.isNotEmpty) ...[
                const Text(
                  'Private Key:',
                  style: TextStyle(fontSize: 12, fontWeight: FontWeight.bold),
                ),
                SelectableText(
                  _keyPair!.privateKey,
                  style: const TextStyle(fontSize: 11, fontFamily: 'monospace'),
                ),
              ] else ...[
                const Text(
                  'Private Key: (not available - imported from npub only)',
                  style: TextStyle(fontSize: 12, color: Colors.orange),
                ),
              ],
            ] else ...[
              const Text('No keypair generated'),
            ],
            const SizedBox(height: 12),
            if (_showImportFields) ...[
              const Divider(),
              const SizedBox(height: 8),
              const Text(
                'Import Key',
                style: TextStyle(fontSize: 14, fontWeight: FontWeight.bold),
              ),
              const SizedBox(height: 8),
              TextField(
                controller: _nsecController,
                decoration: const InputDecoration(
                  labelText: 'nsec (private key)',
                  hintText: 'nsec1...',
                  border: OutlineInputBorder(),
                  helperText: 'Enter your nsec private key',
                ),
              ),
              const SizedBox(height: 8),
              ElevatedButton(
                onPressed: _importFromNsec,
                child: const Text('Import from nsec'),
              ),
              const SizedBox(height: 16),
              TextField(
                controller: _npubController,
                decoration: const InputDecoration(
                  labelText: 'npub (public key)',
                  hintText: 'npub1...',
                  border: OutlineInputBorder(),
                  helperText: 'Enter npub to view only (cannot sign events)',
                ),
              ),
              const SizedBox(height: 8),
              ElevatedButton(
                onPressed: _importFromNpub,
                child: const Text('Import from npub'),
              ),
              const SizedBox(height: 16),
              TextField(
                controller: _hexPrivateKeyController,
                decoration: const InputDecoration(
                  labelText: 'Hex Private Key',
                  hintText: '64 hex characters',
                  border: OutlineInputBorder(),
                  helperText: 'Enter private key in hex format (64 characters)',
                ),
              ),
              const SizedBox(height: 8),
              ElevatedButton(
                onPressed: _importFromHexPrivateKey,
                child: const Text('Import from Hex'),
              ),
              const Divider(),
              const SizedBox(height: 8),
            ],
            ElevatedButton.icon(
              onPressed: _generateKeyPair,
              icon: const Icon(Icons.refresh),
              label: const Text('Generate New Keypair'),
            ),
          ],
        ),
      ),
    );
  }

  Widget _buildRelaysSection() {
    return Card(
      child: Padding(
        padding: const EdgeInsets.all(16),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            const Text(
              'Relays',
              style: TextStyle(
                fontSize: 18,
                fontWeight: FontWeight.bold,
              ),
            ),
            const SizedBox(height: 12),
            if (_relays.isEmpty)
              const Text(
                'No relays configured.\nAdd relays in Settings → Relay Management.',
                style: TextStyle(color: Colors.grey),
              )
            else
              ..._relays.map((relay) => _buildRelayItem(relay)),
          ],
        ),
      ),
    );
  }

  Widget _buildRelayItem(NostrRelay relay) {
    final isConnected = _connectionStatus[relay.url] ?? false;
    
    return Card(
      margin: const EdgeInsets.only(bottom: 8),
      color: isConnected ? Colors.green.shade50 : Colors.grey.shade50,
      child: ListTile(
        title: Text(
          relay.url,
          style: const TextStyle(fontSize: 14, fontFamily: 'monospace'),
        ),
        subtitle: Text(
          isConnected ? 'Connected' : 'Disconnected',
          style: TextStyle(
            color: isConnected ? Colors.green : Colors.grey,
          ),
        ),
        trailing: Row(
          mainAxisSize: MainAxisSize.min,
          children: [
            Icon(
              isConnected ? Icons.check_circle : Icons.cancel,
              color: isConnected ? Colors.green : Colors.grey,
            ),
            const SizedBox(width: 8),
            if (isConnected)
              IconButton(
                icon: const Icon(Icons.close, size: 20),
                onPressed: () => _disconnectFromRelay(relay.url),
                tooltip: 'Disconnect',
              )
            else
              IconButton(
                icon: const Icon(Icons.play_arrow, size: 20),
                onPressed: () => _connectToRelay(relay.url),
                tooltip: 'Connect',
              ),
          ],
        ),
      ),
    );
  }

  Widget _buildActionsSection() {
    return Card(
      child: Padding(
        padding: const EdgeInsets.all(16),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.stretch,
          children: [
            const Text(
              'Actions',
              style: TextStyle(
                fontSize: 18,
                fontWeight: FontWeight.bold,
              ),
            ),
            const SizedBox(height: 12),
            ElevatedButton.icon(
              onPressed: _publishTestEvent,
              icon: const Icon(Icons.send),
              label: const Text('Publish Test Event'),
              style: ElevatedButton.styleFrom(
                padding: const EdgeInsets.symmetric(vertical: 16),
              ),
            ),
            const SizedBox(height: 8),
            TextButton.icon(
              onPressed: () {
                // Navigate to Settings where Relay Management is accessible
                // The bottom navigation bar will handle switching to Settings tab
                ScaffoldMessenger.of(context).showSnackBar(
                  const SnackBar(
                    content: Text('Go to Settings tab to manage relays'),
                  ),
                );
              },
              icon: const Icon(Icons.settings),
              label: const Text('Manage Relays'),
            ),
          ],
        ),
      ),
    );
  }

  Widget _buildEventsSection() {
    return Card(
      child: Padding(
        padding: const EdgeInsets.all(16),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            const Text(
              'Recent Events',
              style: TextStyle(
                fontSize: 18,
                fontWeight: FontWeight.bold,
              ),
            ),
            const SizedBox(height: 12),
            ..._events.take(5).map((event) => Padding(
                  padding: const EdgeInsets.only(bottom: 8),
                  child: Text(
                    event,
                    style: const TextStyle(fontSize: 12),
                  ),
                )),
          ],
        ),
      ),
    );
  }
}