import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import 'package:uuid/uuid.dart';
import 'package:dialer/services/cryptography/asymmetric_crypto_service.dart';

class ManageKeysPage extends StatefulWidget {
  @override
  _ManageKeysPageState createState() => _ManageKeysPageState();
}

class _ManageKeysPageState extends State<ManageKeysPage> {
  List<Map<String, dynamic>> _keys = [];
  bool _isLoading = true;

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

  Future<void> _fetchKeys() async {
    final AsymmetricCryptoService cryptoService = Provider.of<AsymmetricCryptoService>(context, listen: false);
    try {
      final keys = await cryptoService.getAllKeys();
      setState(() {
        _keys = keys;
        _isLoading = false;
      });
    } catch (e) {
      // Handle error, e.g., show a snackbar
      setState(() {
        _isLoading = false;
      });
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text('Error fetching keys: $e')),
      );
    }
  }

  Future<void> _createKey() async {
    final AsymmetricCryptoService cryptoService = Provider.of<AsymmetricCryptoService>(context, listen: false);
    String? label = await _showCreateKeyDialog();
    if (label == null) return; // User cancelled

    try {
      await cryptoService.generateKeyPair(label: label);
      await _fetchKeys();
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text('Key "$label" created successfully.')),
      );
    } catch (e) {
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text('Error creating key: $e')),
      );
    }
  }

  Future<String?> _showCreateKeyDialog() async {
    String label = '';
    return showDialog<String>(
      context: context,
      builder: (context) {
        return AlertDialog(
          title: Text('Create New Key'),
          content: TextField(
            onChanged: (value) {
              label = value;
            },
            decoration: InputDecoration(hintText: "Enter key label"),
          ),
          actions: [
            TextButton(
              onPressed: () => Navigator.of(context).pop(null),
              child: Text('Cancel'),
            ),
            ElevatedButton(
              onPressed: () => Navigator.of(context).pop(label.trim().isEmpty ? 'Key ${Uuid().v4()}' : label.trim()),
              child: Text('Create'),
            ),
          ],
        );
      },
    );
  }

  Future<void> _deleteKey(String alias, String label) async {
    final AsymmetricCryptoService cryptoService = Provider.of<AsymmetricCryptoService>(context, listen: false);

    bool confirm = await _showDeleteConfirmationDialog(label);
    if (!confirm) return;

    try {
      await cryptoService.deleteKeyPair(alias);
      await _fetchKeys();
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text('Key "$label" deleted successfully.')),
      );
    } catch (e) {
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text('Error deleting key: $e')),
      );
    }
  }

  Future<bool> _showDeleteConfirmationDialog(String label) async {
    return await showDialog<bool>(
      context: context,
      builder: (context) => AlertDialog(
        title: Text('Delete Key'),
        content: Text('Are you sure you want to delete the key "$label"? This action cannot be undone.'),
        actions: [
          TextButton(
            onPressed: () => Navigator.of(context).pop(false),
            child: Text('Cancel'),
          ),
          ElevatedButton(
            onPressed: () => Navigator.of(context).pop(true),
            style: ElevatedButton.styleFrom(foregroundColor: Colors.red),
            child: Text('Delete'),
          ),
        ],
      ),
    ) ??
        false;
  }

  Future<void> _viewPublicKey(String alias, String label) async {
    final AsymmetricCryptoService cryptoService = Provider.of<AsymmetricCryptoService>(context, listen: false);
    try {
      final String publicKey = await cryptoService.getPublicKey(alias);
      await showDialog(
        context: context,
        builder: (context) => AlertDialog(
          title: Text('Public Key for "$label"'),
          content: SelectableText(publicKey),
          actions: [
            TextButton(
              onPressed: () => Navigator.of(context).pop(),
              child: Text('Close'),
            ),
            // Optionally, add a button to copy the key to clipboard
          ],
        ),
      );
    } catch (e) {
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text('Error retrieving public key: $e')),
      );
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(
          title: Text('Manage Keys'),
          actions: [
            IconButton(
              icon: Icon(Icons.add),
              onPressed: _createKey,
              tooltip: 'Create New Key',
            ),
          ],
        ),
        body: _isLoading
            ? Center(child: CircularProgressIndicator())
            : _keys.isEmpty
            ? Center(child: Text('No keys found.'))
            : ListView.builder(
          itemCount: _keys.length,
          itemBuilder: (context, index) {
            final key = _keys[index];
            return ListTile(
              title: Text(key['label']),
              subtitle: Text('Created at: ${key['created_at']}'),
              trailing: Row(
                mainAxisSize: MainAxisSize.min,
                children: [
                  IconButton(
                    icon: Icon(Icons.edit),
                    onPressed: () => _editKeyLabel(key['alias'], key['label']),
                    tooltip: 'Edit Label',
                  ),
                  IconButton(
                    icon: Icon(Icons.visibility),
                    onPressed: () => _viewPublicKey(key['alias'], key['label']),
                    tooltip: 'View Public Key',
                  ),
                  IconButton(
                    icon: Icon(Icons.delete, color: Colors.red),
                    onPressed: () => _deleteKey(key['alias'], key['label']),
                    tooltip: 'Delete Key',
                  ),
                ],
              ),
            );
          },
        ));
  }

  /// Updates the label of a key.
  Future<void> _editKeyLabel(String alias, String currentLabel) async {
    final AsymmetricCryptoService cryptoService = Provider.of<AsymmetricCryptoService>(context, listen: false);
    String? newLabel = await _showEditLabelDialog(currentLabel);
    if (newLabel == null) return; // User cancelled

    try {
      await cryptoService.updateKeyLabel(alias, newLabel);
      await _fetchKeys();
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text('Key label updated to "$newLabel".')),
      );
    } catch (e) {
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text('Error updating key label: $e')),
      );
    }
  }

  Future<String?> _showEditLabelDialog(String currentLabel) async {
    String label = currentLabel;
    return showDialog<String>(
      context: context,
      builder: (context) {
        return AlertDialog(
          title: Text('Edit Key Label'),
          content: TextField(
            onChanged: (value) {
              label = value;
            },
            decoration: InputDecoration(hintText: "Enter new key label"),
            controller: TextEditingController(text: currentLabel),
          ),
          actions: [
            TextButton(
              onPressed: () => Navigator.of(context).pop(null),
              child: Text('Cancel'),
            ),
            ElevatedButton(
              onPressed: () => Navigator.of(context).pop(label.trim().isEmpty ? currentLabel : label.trim()),
              child: Text('Save'),
            ),
          ],
        );
      },
    );
  }

}