import 'package:background_downloader/background_downloader.dart';
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';

import '../controllers/upload_controller.dart';
import '../core/app_theme.dart';

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

  @override
  State<UploadHistoryScreen> createState() => _UploadHistoryScreenState();
}

class _UploadHistoryScreenState extends State<UploadHistoryScreen> {
  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addPostFrameCallback((_) {
      if (mounted) context.read<UploadController>().refreshHistory();
    });
  }

  @override
  Widget build(BuildContext context) => Scaffold(
    appBar: AppBar(
      title: const Text(
        'Upload history',
        style: TextStyle(fontWeight: FontWeight.w800),
      ),
      actions: [
        Consumer<UploadController>(
          builder: (context, controller, _) =>
              controller.uploads.any((item) => item.isFinished)
              ? TextButton(
                  onPressed: () => _clearFinished(controller),
                  child: const Text('Clear finished'),
                )
              : const SizedBox.shrink(),
        ),
        const SizedBox(width: 6),
      ],
    ),
    body: Consumer<UploadController>(
      builder: (context, controller, _) {
        final uploads = controller.uploads;
        if (uploads.isEmpty) {
          return const _HistoryEmptyState();
        }
        final active = uploads.where((item) => !item.isFinished).length;
        final complete = uploads
            .where((item) => item.status == TaskStatus.complete)
            .length;
        final failed = uploads
            .where(
              (item) =>
                  item.status == TaskStatus.failed ||
                  item.status == TaskStatus.notFound,
            )
            .length;
        return RefreshIndicator(
          onRefresh: controller.refreshHistory,
          child: ListView(
            padding: const EdgeInsets.fromLTRB(16, 14, 16, 28),
            children: [
              _Summary(active: active, complete: complete, failed: failed),
              const SizedBox(height: 18),
              for (final item in uploads) ...[
                _UploadCard(
                  item: item,
                  onOpen: () => Navigator.of(context).push(
                    MaterialPageRoute(
                      builder: (_) => UploadDetailScreen(taskId: item.taskId),
                    ),
                  ),
                  onCancel: () => controller.cancel(item.taskId),
                  onRetry: () => _retry(controller, item.taskId),
                  onRemove: () => controller.removeHistory(item.taskId),
                ),
                const SizedBox(height: 10),
              ],
            ],
          ),
        );
      },
    ),
  );

  Future<void> _retry(UploadController controller, String taskId) async {
    try {
      await controller.retry(taskId);
    } catch (error) {
      if (mounted) {
        ScaffoldMessenger.of(
          context,
        ).showSnackBar(SnackBar(content: Text(_cleanError(error))));
      }
    }
  }

  Future<void> _clearFinished(UploadController controller) async {
    final confirmed = await showDialog<bool>(
      context: context,
      builder: (context) => AlertDialog(
        title: const Text('Clear finished uploads?'),
        content: const Text(
          'This removes completed, failed, and canceled entries from local history. Files already in Google Drive are not deleted.',
        ),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(context, false),
            child: const Text('Keep'),
          ),
          FilledButton(
            onPressed: () => Navigator.pop(context, true),
            child: const Text('Clear'),
          ),
        ],
      ),
    );
    if (confirmed == true) await controller.clearFinished();
  }
}

class UploadDetailScreen extends StatelessWidget {
  const UploadDetailScreen({super.key, required this.taskId});

  final String taskId;

  @override
  Widget build(BuildContext context) => Consumer<UploadController>(
    builder: (context, controller, _) {
      final matches = controller.uploads.where((item) => item.taskId == taskId);
      if (matches.isEmpty) {
        return Scaffold(
          appBar: AppBar(title: const Text('Upload details')),
          body: const Center(child: Text('This history entry was removed.')),
        );
      }
      final item = matches.first;
      final visual = _statusVisual(item.status);
      return Scaffold(
        appBar: AppBar(
          title: const Text(
            'Upload details',
            style: TextStyle(fontWeight: FontWeight.w800),
          ),
        ),
        body: ListView(
          padding: const EdgeInsets.all(20),
          children: [
            Card(
              child: Padding(
                padding: const EdgeInsets.all(22),
                child: Column(
                  children: [
                    CircleAvatar(
                      radius: 31,
                      backgroundColor: visual.color.withValues(alpha: .12),
                      child: Icon(visual.icon, color: visual.color, size: 32),
                    ),
                    const SizedBox(height: 14),
                    Text(
                      item.name,
                      textAlign: TextAlign.center,
                      style: const TextStyle(
                        fontSize: 19,
                        fontWeight: FontWeight.w800,
                      ),
                    ),
                    const SizedBox(height: 5),
                    Text(
                      visual.label,
                      style: TextStyle(
                        color: visual.color,
                        fontWeight: FontWeight.w700,
                      ),
                    ),
                    const SizedBox(height: 18),
                    LinearProgressIndicator(
                      value: item.progress.clamp(0, 1),
                      minHeight: 8,
                      borderRadius: BorderRadius.circular(8),
                      color: visual.color,
                      backgroundColor: visual.color.withValues(alpha: .12),
                    ),
                    const SizedBox(height: 8),
                    Text('${(item.progress.clamp(0, 1) * 100).round()}%'),
                  ],
                ),
              ),
            ),
            const SizedBox(height: 14),
            Card(
              child: Padding(
                padding: const EdgeInsets.all(18),
                child: Column(
                  children: [
                    _DetailRow(
                      label: 'Started',
                      value: _dateTime(item.createdAt),
                    ),
                    _DetailRow(
                      label: 'File size',
                      value: _size(item.sizeBytes),
                    ),
                    _DetailRow(label: 'Status', value: visual.label),
                    _DetailRow(label: 'Task ID', value: item.taskId),
                    if (item.errorMessage != null)
                      _DetailRow(label: 'Error', value: item.errorMessage!),
                  ],
                ),
              ),
            ),
            const SizedBox(height: 18),
            if (!item.isFinished)
              OutlinedButton.icon(
                onPressed: () => controller.cancel(item.taskId),
                icon: const Icon(Icons.close_rounded),
                label: const Text('Cancel upload'),
              ),
            if (item.canRetry)
              FilledButton.icon(
                onPressed: () async {
                  try {
                    await controller.retry(item.taskId);
                  } catch (error) {
                    if (context.mounted) {
                      ScaffoldMessenger.of(context).showSnackBar(
                        SnackBar(content: Text(_cleanError(error))),
                      );
                    }
                  }
                },
                icon: const Icon(Icons.refresh_rounded),
                label: const Text('Retry upload'),
              ),
          ],
        ),
      );
    },
  );
}

class _Summary extends StatelessWidget {
  const _Summary({
    required this.active,
    required this.complete,
    required this.failed,
  });

  final int active;
  final int complete;
  final int failed;

  @override
  Widget build(BuildContext context) => Row(
    children: [
      Expanded(
        child: _SummaryItem(
          value: active,
          label: 'Active',
          color: AppTheme.blue,
        ),
      ),
      const SizedBox(width: 8),
      Expanded(
        child: _SummaryItem(
          value: complete,
          label: 'Done',
          color: const Color(0xFF15805A),
        ),
      ),
      const SizedBox(width: 8),
      Expanded(
        child: _SummaryItem(
          value: failed,
          label: 'Failed',
          color: const Color(0xFFC43B3B),
        ),
      ),
    ],
  );
}

class _SummaryItem extends StatelessWidget {
  const _SummaryItem({
    required this.value,
    required this.label,
    required this.color,
  });
  final int value;
  final String label;
  final Color color;

  @override
  Widget build(BuildContext context) => Card(
    child: Padding(
      padding: const EdgeInsets.symmetric(vertical: 15),
      child: Column(
        children: [
          Text(
            '$value',
            style: TextStyle(
              fontSize: 22,
              fontWeight: FontWeight.w800,
              color: color,
            ),
          ),
          Text(
            label,
            style: const TextStyle(fontSize: 12, color: Colors.black54),
          ),
        ],
      ),
    ),
  );
}

class _UploadCard extends StatelessWidget {
  const _UploadCard({
    required this.item,
    required this.onOpen,
    required this.onCancel,
    required this.onRetry,
    required this.onRemove,
  });

  final UploadRecord item;
  final VoidCallback onOpen;
  final VoidCallback onCancel;
  final VoidCallback onRetry;
  final VoidCallback onRemove;

  @override
  Widget build(BuildContext context) {
    final visual = _statusVisual(item.status);
    return Card(
      clipBehavior: Clip.antiAlias,
      child: InkWell(
        onTap: onOpen,
        child: Padding(
          padding: const EdgeInsets.fromLTRB(14, 14, 8, 14),
          child: Row(
            children: [
              CircleAvatar(
                backgroundColor: visual.color.withValues(alpha: .12),
                child: Icon(visual.icon, color: visual.color),
              ),
              const SizedBox(width: 12),
              Expanded(
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    Text(
                      item.name,
                      maxLines: 1,
                      overflow: TextOverflow.ellipsis,
                      style: const TextStyle(fontWeight: FontWeight.w700),
                    ),
                    const SizedBox(height: 3),
                    Text(
                      '${visual.label} • ${_dateTime(item.createdAt)}',
                      style: TextStyle(fontSize: 11, color: visual.color),
                    ),
                    const SizedBox(height: 8),
                    LinearProgressIndicator(
                      value: item.progress.clamp(0, 1),
                      minHeight: 5,
                      borderRadius: BorderRadius.circular(5),
                      color: visual.color,
                      backgroundColor: visual.color.withValues(alpha: .12),
                    ),
                  ],
                ),
              ),
              PopupMenuButton<String>(
                onSelected: (value) {
                  if (value == 'cancel') onCancel();
                  if (value == 'retry') onRetry();
                  if (value == 'remove') onRemove();
                },
                itemBuilder: (_) => [
                  if (!item.isFinished)
                    const PopupMenuItem(value: 'cancel', child: Text('Cancel')),
                  if (item.canRetry)
                    const PopupMenuItem(value: 'retry', child: Text('Retry')),
                  if (item.isFinished)
                    const PopupMenuItem(
                      value: 'remove',
                      child: Text('Remove history'),
                    ),
                ],
              ),
            ],
          ),
        ),
      ),
    );
  }
}

class _DetailRow extends StatelessWidget {
  const _DetailRow({required this.label, required this.value});
  final String label;
  final String value;

  @override
  Widget build(BuildContext context) => Padding(
    padding: const EdgeInsets.symmetric(vertical: 8),
    child: Row(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        SizedBox(
          width: 82,
          child: Text(label, style: const TextStyle(color: Colors.black54)),
        ),
        Expanded(
          child: SelectableText(
            value,
            style: const TextStyle(fontWeight: FontWeight.w600),
          ),
        ),
      ],
    ),
  );
}

class _HistoryEmptyState extends StatelessWidget {
  const _HistoryEmptyState();

  @override
  Widget build(BuildContext context) => const Center(
    child: Padding(
      padding: EdgeInsets.all(36),
      child: Column(
        mainAxisSize: MainAxisSize.min,
        children: [
          Icon(Icons.history_rounded, size: 64, color: AppTheme.blue),
          SizedBox(height: 16),
          Text(
            'No uploads yet',
            style: TextStyle(fontSize: 20, fontWeight: FontWeight.w800),
          ),
          SizedBox(height: 6),
          Text(
            'Uploads and their progress will appear here.',
            textAlign: TextAlign.center,
            style: TextStyle(color: Colors.black54),
          ),
        ],
      ),
    ),
  );
}

({String label, IconData icon, Color color}) _statusVisual(TaskStatus status) =>
    switch (status) {
      TaskStatus.enqueued => (
        label: 'Queued',
        icon: Icons.schedule_rounded,
        color: AppTheme.blue,
      ),
      TaskStatus.running => (
        label: 'Uploading',
        icon: Icons.cloud_upload_rounded,
        color: AppTheme.blue,
      ),
      TaskStatus.complete => (
        label: 'Uploaded',
        icon: Icons.check_circle_rounded,
        color: const Color(0xFF15805A),
      ),
      TaskStatus.failed => (
        label: 'Failed',
        icon: Icons.error_rounded,
        color: const Color(0xFFC43B3B),
      ),
      TaskStatus.notFound => (
        label: 'Not found',
        icon: Icons.error_rounded,
        color: const Color(0xFFC43B3B),
      ),
      TaskStatus.canceled => (
        label: 'Canceled',
        icon: Icons.cancel_rounded,
        color: Colors.blueGrey,
      ),
      TaskStatus.waitingToRetry => (
        label: 'Waiting to retry',
        icon: Icons.refresh_rounded,
        color: const Color(0xFFB36B00),
      ),
      TaskStatus.paused => (
        label: 'Paused',
        icon: Icons.pause_circle_rounded,
        color: const Color(0xFFB36B00),
      ),
    };

String _dateTime(DateTime value) {
  final local = value.toLocal();
  String two(int number) => number.toString().padLeft(2, '0');
  return '${two(local.day)}/${two(local.month)}/${local.year} ${two(local.hour)}:${two(local.minute)}';
}

String _size(int bytes) {
  if (bytes < 0) return 'Calculating';
  if (bytes < 1024) return '$bytes B';
  if (bytes < 1024 * 1024) return '${(bytes / 1024).toStringAsFixed(1)} KB';
  if (bytes < 1024 * 1024 * 1024) {
    return '${(bytes / 1024 / 1024).toStringAsFixed(1)} MB';
  }
  return '${(bytes / 1024 / 1024 / 1024).toStringAsFixed(2)} GB';
}

String _cleanError(Object error) => error
    .toString()
    .replaceFirst('Bad state: ', '')
    .replaceFirst('Exception: ', '');