import 'dart:async';

import 'package:flutter/material.dart';
import 'package:get/get.dart';
import 'package:connectivity_plus/connectivity_plus.dart';

import 'package:miler/helpers/app_bootstrap.dart';
import 'package:miler/views/helpers/constants/Colorconstants.dart';
import 'package:miler/views/helpers/constants/design_constants.dart';
import 'package:miler/views/helpers/constants/miler_type.dart';
import 'package:miler/views/helpers/widgets/app_widgets.dart';

class OfflinePage extends StatefulWidget {
  const OfflinePage({super.key});

  @override
  State<OfflinePage> createState() => _OfflinePageState();
}

class _OfflinePageState extends State<OfflinePage>
    with SingleTickerProviderStateMixin {
  late final AnimationController _pulse;

  bool _checking = false;
  Timer? _autoRetry;

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

    _pulse = AnimationController(
      vsync: this,
      duration: const Duration(milliseconds: 1800),
    )..repeat(reverse: true);

    // Automatically retry every 5 seconds.
    _autoRetry = Timer.periodic(const Duration(seconds: 5), (_) {
      if (mounted && !_checking) {
        _handleRetry();
      }
    });
  }

  @override
  void dispose() {
    _pulse.dispose();
    _autoRetry?.cancel();
    super.dispose();
  }

  Future<void> _handleRetry() async {
    if (_checking) return;

    setState(() => _checking = true);

    try {
      final results = await Connectivity().checkConnectivity();

      final isOnline =
          results.isNotEmpty &&
          results.any((r) => r != ConnectivityResult.none);

      if (isOnline) {
        Get.offAll(() => const AppBootstrap());
        return;
      }

      if (mounted) {
        AppFeedback.info(context, "Still offline. We'll keep checking.");
      }
    } finally {
      if (mounted) {
        setState(() => _checking = false);
      }
    }
  }

  @override
  Widget build(BuildContext context) {
    final size = MediaQuery.of(context).size;

    return Scaffold(
      backgroundColor: const Color(0xffF7F8FC),
      body: SafeArea(
        child: Stack(
          children: [
            Positioned(
              bottom: -size.height * .10,
              left: -40,
              right: -40,
              child: Container(
                height: size.height * .25,
                decoration: const BoxDecoration(
                  color: ColorConstants.neutralLight,
                  borderRadius: BorderRadius.only(
                    topLeft: Radius.circular(250),
                    topRight: Radius.circular(250),
                  ),
                ),
              ),
            ),

            Center(
              child: Padding(
                padding: const EdgeInsets.symmetric(horizontal: 24),
                child: TweenAnimationBuilder<double>(
                  duration: const Duration(milliseconds: 700),
                  tween: Tween(begin: 0, end: 1),
                  curve: Curves.easeOut,
                  builder: (context, value, child) {
                    return Opacity(
                      opacity: value,
                      child: Transform.translate(
                        offset: Offset(0, (1 - value) * 30),
                        child: child,
                      ),
                    );
                  },
                  child: Container(
                    padding: const EdgeInsets.all(28),
                    decoration: BoxDecoration(
                      color: ColorConstants.pureSurface,
                      borderRadius: BorderRadius.circular(DesignConstants.radiusXl),
                      boxShadow: [
                        BoxShadow(
                          color: ColorConstants.slateText.withValues(alpha: .05),
                          blurRadius: 25,
                          offset: const Offset(0, 12),
                        ),
                      ],
                    ),
                    child: Column(
                      mainAxisSize: MainAxisSize.min,
                      children: [
                        AnimatedBuilder(
                          animation: _pulse,
                          builder: (_, child) {
                            final t = Curves.easeInOut.transform(_pulse.value);

                            return Container(
                              width: 130,
                              height: 130,
                              decoration: BoxDecoration(
                                shape: BoxShape.circle,
                                color: ColorConstants.primary.withValues(alpha: .08),
                                boxShadow: [
                                  BoxShadow(
                                    color: ColorConstants.primary.withValues(alpha: 
                                      .10 + (.15 * t),
                                    ),
                                    blurRadius: 25 + (18 * t),
                                    spreadRadius: 2 + (8 * t),
                                  ),
                                ],
                              ),
                              child: child,
                            );
                          },
                          child: Icon(
                            Icons.wifi_off_rounded,
                            color: ColorConstants.primary,
                            size: 68,
                          ),
                        ),

                        const SizedBox(height: 28),

                        Text("You're offline", style: MilerType.hero),

                        const SizedBox(height: 12),

                        Text(
                          "We can't reach Miler right now. Your shift will "
                          "load as soon as you're back online.",
                          textAlign: TextAlign.center,
                          style: MilerType.caption,
                        ),

                        const SizedBox(height: 28),

                        SizedBox(
                          width: double.infinity,
                          height: ButtonSizes.primary,
                          child: ElevatedButton(
                            onPressed: _checking ? null : _handleRetry,
                            style: ElevatedButton.styleFrom(
                              elevation: 0,
                              backgroundColor: ColorConstants.primary,
                              foregroundColor: Colors.white,
                              padding: const EdgeInsets.symmetric(
                                horizontal: 16,
                              ),
                              minimumSize: Size.zero,
                              tapTargetSize: MaterialTapTargetSize.shrinkWrap,
                              shape: RoundedRectangleBorder(
                                borderRadius: BorderRadius.circular(
                                  ButtonSizes.radius,
                                ),
                              ),
                            ),
                            child: AnimatedSwitcher(
                              duration: const Duration(milliseconds: 250),
                              child: _checking
                                  ? const SizedBox(
                                      key: ValueKey("loading"),
                                      width: 22,
                                      height: 22,
                                      child: CircularProgressIndicator(
                                        strokeWidth: 2.5,
                                        color: Colors.white,
                                      ),
                                    )
                                  : Text(
                                      "Try again",
                                      key: const ValueKey("retry"),
                                      style: MilerType.buttonLabel(
                                        ButtonSizes.primary,
                                      ),
                                    ),
                            ),
                          ),
                        ),

                        const SizedBox(height: 16),

                        Text(
                          "Checking every few seconds",
                          style: MilerType.label,
                        ),
                      ],
                    ),
                  ),
                ),
              ),
            ),
          ],
        ),
      ),
    );
  }
}