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

import '../utils/app_update_util.dart';
import '../viewmodels/update_progress_view_model.dart';

class UpdateProgressView extends StatefulWidget {
  final UpdateInfo update;
  final bool simulate;
  final bool simulateError;

  const UpdateProgressView({
    super.key,
    required this.update,
    this.simulate = false,
    this.simulateError = false,
  });

  @override
  State<UpdateProgressView> createState() => _UpdateProgressViewState();
}

class _UpdateProgressViewState extends State<UpdateProgressView> {
  late final UpdateProgressViewModel _vm;

  @override
  void initState() {
    super.initState();
    _vm = UpdateProgressViewModel(
      update: widget.update,
      simulate: widget.simulate,
      simulateError: widget.simulateError,
    );
    _vm.addListener(_onVmChange);
    _vm.start();
  }

  void _onVmChange() {
    if (!mounted) return;

    if (_vm.phase == OtaPhase.done) {
      _showRestartDialog();
    } else if (_vm.phase == OtaPhase.error) {
      _showErrorSnackBar();
    }
  }

  void _showRestartDialog() {
    showDialog(
      context: context,
      barrierDismissible: false,
      builder: (context) => AlertDialog(
        title: const Text('Update ready'),
        content: const Text(
          'The update has been downloaded and installed. '
          'Restart the app now to apply the changes.',
        ),
        actions: [
          TextButton(
            onPressed: () {
              Navigator.pop(context);
              this.context.go('/bar');
            },
            child: const Text('Later'),
          ),
          FilledButton(
            onPressed: () {
              Navigator.pop(context);
            },
            child: const Text('Restart app'),
          ),
        ],
      ),
    );
  }

  void _showErrorSnackBar() {
    ScaffoldMessenger.of(context).showSnackBar(
      SnackBar(
        content: Text(_vm.errorMessage ?? 'Update failed'),
        backgroundColor: Theme.of(context).colorScheme.error,
        action: SnackBarAction(
          label: 'Retry',
          onPressed: () {
            _vm.cancel();
            _vm.start();
          },
        ),
      ),
    );
  }

  @override
  void dispose() {
    _vm.removeListener(_onVmChange);
    _vm.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        leading: IconButton(
          icon: const Icon(Icons.close),
          onPressed: () => _showCancelDialog(),
        ),
        title: const Text('Updating'),
        centerTitle: true,
        automaticallyImplyLeading: false,
      ),
      body: ListenableBuilder(
        listenable: _vm,
        builder: (context, child) {
          return Center(
            child: ConstrainedBox(
              constraints: const BoxConstraints(maxWidth: 480),
              child: Padding(
                padding: const EdgeInsets.all(32),
                child: Column(
                  mainAxisSize: MainAxisSize.min,
                  children: [
                    _buildHeader(),
                    const SizedBox(height: 40),
                    _buildProgress(_vm),
                    const SizedBox(height: 24),
                    _buildStatus(_vm),
                    const Spacer(),
                    _buildVersionInfo(_vm),
                  ],
                ),
              ),
            ),
          );
        },
      ),
    );
  }

  Widget _buildHeader() {
    return Column(
      children: [
        Container(
          padding: const EdgeInsets.all(24),
          decoration: BoxDecoration(
            color: Theme.of(context).colorScheme.primary.withValues(alpha: 0.1),
            shape: BoxShape.circle,
          ),
          child: Icon(
            Icons.system_update_alt_rounded,
            size: 56,
            color: Theme.of(context).colorScheme.primary,
          ),
        ),
        const SizedBox(height: 24),
        Text(
          'KoolTab',
          style: Theme.of(context).textTheme.headlineMedium,
        ),
        const SizedBox(height: 8),
        Text(
          'Version ${widget.update.version}',
          style: Theme.of(context).textTheme.titleMedium?.copyWith(
            color: Theme.of(context).colorScheme.primary,
          ),
        ),
      ],
    );
  }

  Widget _buildProgress(UpdateProgressViewModel vm) {
    final scheme = Theme.of(context).colorScheme;

    return Column(
      children: [
        SizedBox(
          width: 200,
          height: 200,
          child: Stack(
            alignment: Alignment.center,
            children: [
              SizedBox.expand(
                child: CircularProgressIndicator(
                  value: vm.phase == OtaPhase.installing ? null : vm.progress,
                  strokeWidth: 10,
                  backgroundColor: scheme.primary.withValues(alpha: 0.12),
                  color: vm.phase == OtaPhase.error
                      ? scheme.error
                      : scheme.primary,
                ),
              ),
              Column(
                mainAxisSize: MainAxisSize.min,
                children: [
                  if (vm.phase == OtaPhase.error)
                    Icon(
                      Icons.error_outline_rounded,
                      size: 48,
                      color: scheme.error,
                    )
                  else if (vm.phase == OtaPhase.installing)
                    Icon(
                      Icons.settings_rounded,
                      size: 48,
                      color: scheme.primary,
                    )
                  else
                    Text(
                      '${(vm.progress * 100).toStringAsFixed(0)}%',
                      style: Theme.of(context).textTheme.headlineLarge,
                    ),
                  const SizedBox(height: 4),
                  Text(
                    vm.phase == OtaPhase.installing ? 'Installing' : '',
                    style: Theme.of(context).textTheme.bodyMedium?.copyWith(
                      color: scheme.onSurface.withValues(alpha: 0.6),
                    ),
                  ),
                ],
              ),
            ],
          ),
        ),
        const SizedBox(height: 24),
        if (vm.phase == OtaPhase.downloading)
          LinearProgressIndicator(
            value: vm.progress,
            minHeight: 6,
            borderRadius: BorderRadius.circular(999),
          ),
      ],
    );
  }

  Widget _buildStatus(UpdateProgressViewModel vm) {
    final scheme = Theme.of(context).colorScheme;

    final color = switch (vm.phase) {
      OtaPhase.error => scheme.error,
      OtaPhase.done => Colors.green,
      _ => scheme.onSurface,
    };

    return Text(
      vm.statusText,
      style: Theme.of(context).textTheme.titleMedium?.copyWith(color: color),
      textAlign: TextAlign.center,
    );
  }

  Widget _buildVersionInfo(UpdateProgressViewModel vm) {
    return Row(
      mainAxisAlignment: MainAxisAlignment.center,
      children: [
        Icon(
          Icons.info_outline_rounded,
          size: 14,
          color: Theme.of(context).colorScheme.onSurface.withValues(alpha: 0.4),
        ),
        const SizedBox(width: 6),
        Text(
          'Do not close the app during the update',
          style: Theme.of(context).textTheme.bodySmall?.copyWith(
            color: Theme.of(context).colorScheme.onSurface.withValues(alpha: 0.4),
          ),
        ),
      ],
    );
  }

  void _showCancelDialog() {
    showDialog(
      context: context,
      builder: (context) => AlertDialog(
        title: const Text('Cancel update?'),
        content: const Text(
          'The update is in progress. If you leave now, '
          'the app may become unstable.',
        ),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(context),
            child: const Text('Continue update'),
          ),
          FilledButton(
            style: FilledButton.styleFrom(
              backgroundColor: Theme.of(context).colorScheme.error,
            ),
            onPressed: () {
              Navigator.pop(context);
              _vm.cancel();
              this.context.go('/bar');
            },
            child: const Text('Cancel update'),
          ),
        ],
      ),
    );
  }
}