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

import '../../../models/network/network_link.dart';
import '../../../models/network/network_port.dart';
import '../../../providers/network_map/network_devices_provider.dart';

/// Opens an M3 dialog to connect [portId] to a port on another device.
///
/// Returns true if a link was successfully created.
Future<bool> showLinkEditDialog({
  required BuildContext context,
  required WidgetRef ref,
  required String portId,
  required String currentDeviceId,
}) async {
  final result = await showDialog<bool>(
    context: context,
    builder: (_) => _LinkEditDialog(
      portId: portId,
      currentDeviceId: currentDeviceId,
    ),
  );
  return result == true;
}

class _LinkEditDialog extends ConsumerStatefulWidget {
  const _LinkEditDialog({
    required this.portId,
    required this.currentDeviceId,
  });

  final String portId;
  final String currentDeviceId;

  @override
  ConsumerState<_LinkEditDialog> createState() => _LinkEditDialogState();
}

class _LinkEditDialogState extends ConsumerState<_LinkEditDialog> {
  String? _selectedDeviceId;
  String? _selectedPortId;
  NetworkLinkKind? _linkKind;
  final _cableLabelCtrl = TextEditingController();
  bool _saving = false;

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

  Future<void> _save() async {
    final portA = widget.portId;
    final portB = _selectedPortId;
    if (portB == null) return;
    setState(() => _saving = true);
    try {
      ref.invalidate(networkLinksProvider);
      final controller = ref.read(networkDevicesControllerProvider);
      await controller.createLink(
        portA: portA,
        portB: portB,
        linkKind: _linkKind,
        cableLabel: _cableLabelCtrl.text.trim().isEmpty
            ? null
            : _cableLabelCtrl.text.trim(),
      );
      if (mounted) Navigator.of(context).pop(true);
    } catch (e) {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(
            content: Text('Failed to create link: $e'),
            backgroundColor: Theme.of(context).colorScheme.error,
          ),
        );
      }
    } finally {
      if (mounted) setState(() => _saving = false);
    }
  }

  @override
  Widget build(BuildContext context) {
    final devicesAsync = ref.watch(networkDevicesProvider);
    final portsAsync = _selectedDeviceId != null
        ? ref.watch(networkPortsByDeviceProvider(_selectedDeviceId!))
        : const AsyncValue<List<NetworkPort>>.data([]);
    final allLinksAsync = ref.watch(networkLinksProvider);

    final otherDevices = (devicesAsync.valueOrNull ?? const [])
        .where((d) => d.id != widget.currentDeviceId)
        .toList()
      ..sort((a, b) => a.name.compareTo(b.name));

    final allLinks = allLinksAsync.valueOrNull ?? const [];
    final usedPortIds = <String>{
      for (final link in allLinks) ...[link.portA, link.portB],
    };

    final devicePorts = portsAsync.valueOrNull ?? const [];
    final availablePorts =
        devicePorts.where((p) => !usedPortIds.contains(p.id)).toList();

    final canSave = _selectedPortId != null && !_saving;

    return AlertDialog(
      title: const Text('Connect port'),
      content: ConstrainedBox(
        constraints: const BoxConstraints(maxWidth: 420),
        child: SingleChildScrollView(
          child: Column(
            mainAxisSize: MainAxisSize.min,
            crossAxisAlignment: CrossAxisAlignment.stretch,
            children: [
              DropdownButtonFormField<String>(
                initialValue: _selectedDeviceId,
                decoration:
                    const InputDecoration(labelText: 'Remote device *'),
                items: [
                  for (final d in otherDevices)
                    DropdownMenuItem(value: d.id, child: Text(d.name)),
                ],
                onChanged: (v) => setState(() {
                  _selectedDeviceId = v;
                  _selectedPortId = null;
                }),
              ),
              const SizedBox(height: 12),
              DropdownButtonFormField<String>(
                key: ValueKey(_selectedDeviceId),
                initialValue: _selectedPortId,
                decoration: InputDecoration(
                  labelText: 'Remote port *',
                  helperText: _selectedDeviceId == null
                      ? 'Select a device first'
                      : availablePorts.isEmpty
                          ? 'No available ports on this device'
                          : null,
                ),
                items: [
                  for (final p in availablePorts)
                    DropdownMenuItem(
                      value: p.id,
                      child: Text(p.portNumber),
                    ),
                ],
                onChanged: _selectedDeviceId == null
                    ? null
                    : (v) => setState(() => _selectedPortId = v),
              ),
              const SizedBox(height: 12),
              DropdownButtonFormField<NetworkLinkKind?>(
                initialValue: _linkKind,
                decoration: const InputDecoration(labelText: 'Link type'),
                items: [
                  const DropdownMenuItem<NetworkLinkKind?>(
                    value: null,
                    child: Text('(unknown)'),
                  ),
                  for (final k in NetworkLinkKind.values)
                    DropdownMenuItem(value: k, child: Text(k.label)),
                ],
                onChanged: (v) => setState(() => _linkKind = v),
              ),
              const SizedBox(height: 12),
              TextField(
                controller: _cableLabelCtrl,
                decoration: const InputDecoration(
                  labelText: 'Cable label',
                  helperText: 'e.g. "CAT6-01", "SMF-A3" (optional)',
                ),
              ),
            ],
          ),
        ),
      ),
      actions: [
        TextButton(
          onPressed: _saving ? null : () => Navigator.pop(context, false),
          child: const Text('Cancel'),
        ),
        FilledButton(
          onPressed: canSave ? _save : null,
          child: Text(_saving ? 'Saving…' : 'Connect'),
        ),
      ],
    );
  }
}