import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import 'package:revoltvpn/components/online_dot.dart';
import 'package:revoltvpn/logic/app_colors.dart';
import 'package:revoltvpn/logic/session_timer.dart';
import 'package:revoltvpn/logic/vpn_connection.dart';

// The one line worth showing right now, and whether it is a problem.
class _StatusDetail {
  const _StatusDetail(this.text, {this.isProblem = false});

  final String text;
  final bool isProblem;
}

_StatusDetail? _detail(VpnConnection vpn, SessionTimer timer) {
  final error = vpn.errorMessage;
  if (error != null && error.isNotEmpty) {
    return _StatusDetail(error.replaceAll('\n', ' '), isProblem: true);
  }

  if (vpn.status == VpnStatus.connecting ||
      vpn.status == VpnStatus.disconnecting) {
    return _StatusDetail(vpn.statusMessage);
  }

  // Control plane only - the tunnel still carries traffic.
  if (vpn.status == VpnStatus.connected && timer.serverUnreachable) {
    return const _StatusDetail(
      'Can\'t reach the server — still connected',
      isProblem: true,
    );
  }

  if (vpn.status != VpnStatus.connected) {
    final ended = timer.lastEndMessage;
    if (ended != null) return _StatusDetail(ended, isProblem: true);
  }

  return null;
}

class StatusBar extends StatelessWidget {
  const StatusBar({super.key});

  @override
  Widget build(BuildContext context) {
    return Consumer2<VpnConnection, SessionTimer>(
      builder: (context, vpn, timer, _) {
        final isConnected = vpn.status == VpnStatus.connected;
        final isConnecting = vpn.status == VpnStatus.connecting;
        // Rule 60: reachability is known only from a session sync that
        // succeeded, never from a probe. While disconnected the app knows
        // nothing about the server, so it claims nothing either way.
        final serverHealthy = isConnected && timer.hasSyncedOnce;

        final statusLabel = isConnected
            ? (timer.hasSyncedOnce ? 'Online' : 'Syncing…')
            : (isConnecting ? 'Connecting…' : 'Ready');

        final detail = _detail(vpn, timer);

        return Padding(
          padding: const EdgeInsets.symmetric(horizontal: 24),
          child: Column(
            mainAxisSize: MainAxisSize.min,
            children: [
              Container(
                padding:
                    const EdgeInsets.symmetric(horizontal: 20, vertical: 12),
                decoration: BoxDecoration(
                  color: AppColors.bgCard,
                  borderRadius: BorderRadius.circular(16),
                  border: Border.all(color: AppColors.slate15),
                ),
                child: Row(
                  children: [
                    Image.asset(
                      'assets/finland_flag_256.png',
                      width: 20,
                      height: 20,
                    ),
                    const SizedBox(width: 8),
                    const Expanded(
                      child: Text(
                        'Helsinki, Finland',
                        style: TextStyle(
                          color: AppColors.accent,
                          fontWeight: FontWeight.w600,
                          fontSize: 13,
                          letterSpacing: 0.5,
                        ),
                      ),
                    ),
                  ],
                ),
              ),
              const SizedBox(height: 8),
              Container(
                padding:
                    const EdgeInsets.symmetric(horizontal: 20, vertical: 10),
                decoration: BoxDecoration(
                  color: AppColors.bgCard,
                  borderRadius: BorderRadius.circular(16),
                  border: Border.all(color: AppColors.slate15),
                ),
                child: Row(
                  children: [
                    OnlineDot(
                      isOnline: serverHealthy,
                      label: statusLabel,
                    ),
                    const Spacer(),
                    if (vpn.networkTransport != 'unknown' &&
                        vpn.networkTransport != 'none')
                      Padding(
                        padding: const EdgeInsets.only(right: 8),
                        child: Text(
                          vpn.networkTransport,
                          style: const TextStyle(
                            color: AppColors.textDim,
                            fontSize: 11,
                          ),
                        ),
                      ),
                    if (isConnected)
                      const Icon(
                        Icons.lock,
                        color: AppColors.green50,
                        size: 14,
                      ),
                  ],
                ),
              ),
              // Errors and session-end reasons used to render nowhere.
              if (detail != null)
                Padding(
                  padding: const EdgeInsets.only(top: 6),
                  child: Text(
                    detail.text,
                    textAlign: TextAlign.center,
                    style: TextStyle(
                      color: detail.isProblem
                          ? AppColors.red
                          : AppColors.textDim,
                      fontSize: 11,
                    ),
                  ),
                ),
            ],
          ),
        );
      },
    );
  }
}