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

import '../../../../backend/transfer/model.dart';

class TransferItem extends StatelessWidget {
  const TransferItem({
    super.key,
    required this.transfer,
    this.onAccept,
    this.onReject,
    this.onCancel,
    this.onDelete,
  });

  final Transfer transfer;
  final VoidCallback? onAccept;
  final VoidCallback? onReject;
  final VoidCallback? onCancel;
  final VoidCallback? onDelete;

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);

    return Card(
      child: Padding(
        padding: const EdgeInsets.all(14),
        child: Column(
          children: [
            Row(
              children: [
                CircleAvatar(
                  backgroundColor: theme.colorScheme.secondaryContainer,
                  child: Icon(
                    _iconForContentType(transfer.contentType),
                    color: theme.colorScheme.onSecondaryContainer,
                  ),
                ),
                const SizedBox(width: 10),
                Expanded(
                  child: Column(
                    crossAxisAlignment: CrossAxisAlignment.start,
                    children: [
                      Text(
                        transfer.fileName.isNotEmpty
                            ? transfer.fileName
                            : '文本消息',
                        maxLines: 1,
                        overflow: TextOverflow.ellipsis,
                        style: theme.textTheme.titleMedium,
                      ),
                      Text(
                        '${transfer.sender.name} · ${transfer.type.name}',
                        style: theme.textTheme.bodySmall?.copyWith(
                          color: theme.colorScheme.onSurfaceVariant,
                        ),
                      ),
                    ],
                  ),
                ),
                _StatusChip(status: transfer.status),
              ],
            ),
            const SizedBox(height: 12),
            LinearProgressIndicator(
              value: _progressOrNull(transfer),
              color: _progressColor(theme, transfer.status),
            ),
            const SizedBox(height: 10),
            Row(
              children: [
                Expanded(
                  child: Text(
                    '进度 ${_progressPercent(transfer).toStringAsFixed(0)}%   大小 ${_formatSize(transfer.fileSize)}   速度 ${_formatSpeed(transfer.speed)}',
                    style: theme.textTheme.bodySmall,
                  ),
                ),
                Wrap(spacing: 8, children: _buildActions(context)),
              ],
            ),
          ],
        ),
      ),
    );
  }

  List<Widget> _buildActions(BuildContext context) {
    final actions = <Widget>[];

    if (transfer.status is TransferStatus_Pending) {
      if (onReject != null) {
        actions.add(
          OutlinedButton.icon(
            onPressed: onReject,
            icon: const Icon(Icons.close_rounded),
            label: const Text('拒绝'),
          ),
        );
      }
      if (onAccept != null) {
        actions.add(
          FilledButton.icon(
            onPressed: onAccept,
            icon: const Icon(Icons.check_rounded),
            label: const Text('接收'),
          ),
        );
      }
      return actions;
    }

    if ((transfer.status is TransferStatus_Active ||
            transfer.status is TransferStatus_Accepted) &&
        onCancel != null) {
      actions.add(
        OutlinedButton.icon(
          onPressed: onCancel,
          icon: const Icon(Icons.stop_circle_outlined),
          label: const Text('取消'),
        ),
      );
    }

    final canPreviewText =
        transfer.type == TransferType.receive &&
        transfer.contentType == ContentType.text &&
        transfer.status is TransferStatus_Completed;

    if (canPreviewText) {
      actions.add(
        IconButton(
          tooltip: '复制文本',
          onPressed: () async {
            final messenger = ScaffoldMessenger.of(context);
            await Clipboard.setData(ClipboardData(text: transfer.text));
            messenger.showSnackBar(const SnackBar(content: Text('文本已复制')));
          },
          icon: const Icon(Icons.copy_rounded),
        ),
      );

      actions.add(
        IconButton(
          tooltip: '查看文本',
          onPressed: () {
            showDialog<void>(
              context: context,
              builder: (_) => AlertDialog(
                title: const Text('接收文本内容'),
                content: SizedBox(
                  width: 560,
                  child: SingleChildScrollView(
                    child: SelectableText(transfer.text),
                  ),
                ),
                actions: [
                  TextButton(
                    onPressed: () => Navigator.of(context).pop(),
                    child: const Text('关闭'),
                  ),
                ],
              ),
            );
          },
          icon: const Icon(Icons.visibility_rounded),
        ),
      );
    }

    if ((transfer.status is TransferStatus_Completed ||
            transfer.status is TransferStatus_Error ||
            transfer.status is TransferStatus_Canceled) &&
        onDelete != null) {
      actions.add(
        IconButton(
          tooltip: '删除记录',
          onPressed: onDelete,
          icon: const Icon(Icons.delete_outline_rounded),
        ),
      );
    }

    return actions;
  }

  IconData _iconForContentType(ContentType contentType) {
    return switch (contentType) {
      ContentType.file => Icons.insert_drive_file_rounded,
      ContentType.folder => Icons.folder_zip_rounded,
      ContentType.text => Icons.text_snippet_rounded,
    };
  }

  double? _progressOrNull(Transfer transfer) {
    if (transfer.status is TransferStatus_Pending) {
      return null;
    }
    return _progressFraction(transfer);
  }

  Color _progressColor(ThemeData theme, TransferStatus status) {
    return switch (status) {
      TransferStatus_Completed() => theme.colorScheme.primary,
      TransferStatus_Active() ||
      TransferStatus_Accepted() => theme.colorScheme.tertiary,
      TransferStatus_Rejected() ||
      TransferStatus_Error() => theme.colorScheme.error,
      TransferStatus_Canceled() => theme.colorScheme.outline,
      TransferStatus_Pending() => theme.colorScheme.secondary,
    };
  }

  String _formatSpeed(double? bytesPerSec) {
    if (bytesPerSec == null || bytesPerSec <= 0) {
      return '--';
    }
    return '${_formatSize(bytesPerSec)}/s';
  }

  String _formatSize(double bytes) {
    if (bytes <= 0) {
      return '0 B';
    }

    const units = ['B', 'KB', 'MB', 'GB', 'TB'];
    var size = bytes;
    var i = 0;
    while (size >= 1024 && i < units.length - 1) {
      size /= 1024;
      i++;
    }

    final fixed = size >= 100 ? 0 : (size >= 10 ? 1 : 2);
    return '${size.toStringAsFixed(fixed)} ${units[i]}';
  }

  double _progressedBytes(Transfer transfer) {
    final current = transfer.progress;
    if (current <= 0) {
      return 0;
    }
    if (transfer.fileSize <= 0) {
      return current;
    }
    return current.clamp(0, transfer.fileSize).toDouble();
  }

  double _progressFraction(Transfer transfer) {
    if (transfer.fileSize <= 0) {
      return 0;
    }
    return (_progressedBytes(transfer) / transfer.fileSize)
        .clamp(0, 1)
        .toDouble();
  }

  double _progressPercent(Transfer transfer) {
    return _progressFraction(transfer) * 100;
  }
}

class _StatusChip extends StatelessWidget {
  const _StatusChip({required this.status});

  final TransferStatus status;

  @override
  Widget build(BuildContext context) {
    final label = switch (status) {
      TransferStatus_Pending() => 'Pending',
      TransferStatus_Accepted() => 'Accepted',
      TransferStatus_Rejected() => 'Rejected',
      TransferStatus_Completed() => 'Completed',
      TransferStatus_Error() => 'Error',
      TransferStatus_Canceled() => 'Canceled',
      TransferStatus_Active() => 'Active',
    };

    return Chip(label: Text(label));
  }
}