import 'dart:io';

import 'package:desktop_drop/desktop_drop.dart';
import 'package:file_picker/file_picker.dart';
import 'package:flutter/material.dart';

import '../../../backend/api/commands.dart' as commands;
import '../../../backend/discovery/model.dart';

class SendFilesModal extends StatefulWidget {
  const SendFilesModal({
    super.key,
    required this.peer,
    required this.targetIp,
    this.initialPaths = const [],
  });

  final Peer peer;
  final String targetIp;
  final List<String> initialPaths;

  @override
  State<SendFilesModal> createState() => _SendFilesModalState();
}

class _SendFilesModalState extends State<SendFilesModal> {
  late final List<String> _paths = [...widget.initialPaths];
  bool _dragging = false;

  Future<void> _submit() async {
    if (_paths.isEmpty) {
      return;
    }

    final pending = List<String>.from(_paths);
    if (mounted) {
      Navigator.of(context).pop();
    }

    for (final path in pending) {
      final entityType = FileSystemEntity.typeSync(path);
      if (entityType == FileSystemEntityType.directory) {
        commands.sendFolder(
          target: widget.peer,
          targetIp: widget.targetIp,
          folderPath: path,
        );
      } else {
        commands.sendFile(
          target: widget.peer,
          targetIp: widget.targetIp,
          filePath: path,
        );
      }
    }
  }

  Future<void> _pickFiles() async {
    final result = await FilePicker.platform.pickFiles(allowMultiple: true);
    if (result == null || !mounted) {
      return;
    }

    final selected = result.paths.whereType<String>().where(
      (p) => p.isNotEmpty,
    );
    setState(() {
      for (final path in selected) {
        if (!_paths.contains(path)) {
          _paths.add(path);
        }
      }
    });
  }

  Future<void> _pickFolder() async {
    final folder = await FilePicker.platform.getDirectoryPath();
    if (folder == null || folder.isEmpty || !mounted) {
      return;
    }

    setState(() {
      if (!_paths.contains(folder)) {
        _paths.add(folder);
      }
    });
  }

  bool get _enableDragDrop =>
      Platform.isLinux || Platform.isWindows || Platform.isMacOS;

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

    return AlertDialog(
      title: Text('发送文件给 ${widget.peer.name}'),
      content: SizedBox(
        width: 640,
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            if (_enableDragDrop)
              DropTarget(
                onDragEntered: (_) => setState(() => _dragging = true),
                onDragExited: (_) => setState(() => _dragging = false),
                onDragDone: (details) {
                  setState(() {
                    _dragging = false;
                    _paths.addAll(
                      details.files
                          .map((f) => f.path)
                          .where((p) => p.isNotEmpty)
                          .where((p) => !_paths.contains(p)),
                    );
                  });
                },
                child: Container(
                  width: double.infinity,
                  padding: const EdgeInsets.all(20),
                  decoration: BoxDecoration(
                    borderRadius: BorderRadius.circular(12),
                    border: Border.all(
                      color: _dragging
                          ? theme.colorScheme.primary
                          : theme.colorScheme.outlineVariant,
                      width: _dragging ? 2 : 1,
                    ),
                    color: theme.colorScheme.surfaceContainerHighest.withValues(
                      alpha: 0.35,
                    ),
                  ),
                  child: Column(
                    children: [
                      Icon(
                        _dragging
                            ? Icons.file_download_done_rounded
                            : Icons.file_upload_rounded,
                        size: 36,
                      ),
                      const SizedBox(height: 8),
                      Text(_dragging ? '松手即可添加文件' : '将文件或文件夹拖到这里'),
                    ],
                  ),
                ),
              )
            else
              Container(
                width: double.infinity,
                padding: const EdgeInsets.all(20),
                decoration: BoxDecoration(
                  borderRadius: BorderRadius.circular(12),
                  border: Border.all(color: theme.colorScheme.outlineVariant),
                  color: theme.colorScheme.surfaceContainerHighest.withValues(
                    alpha: 0.35,
                  ),
                ),
                child: const Column(
                  children: [
                    Icon(Icons.file_upload_rounded, size: 36),
                    SizedBox(height: 8),
                  ],
                ),
              ),
            const SizedBox(height: 12),
            Row(
              children: [
                Expanded(
                  child: OutlinedButton.icon(
                    onPressed: _pickFiles,
                    icon: const Icon(Icons.attach_file_rounded),
                    label: const Text('选择文件'),
                  ),
                ),
                const SizedBox(width: 8),
                Expanded(
                  child: OutlinedButton.icon(
                    onPressed: _pickFolder,
                    icon: const Icon(Icons.folder_open_rounded),
                    label: const Text('选择文件夹'),
                  ),
                ),
              ],
            ),
            const SizedBox(height: 12),
            ConstrainedBox(
              constraints: const BoxConstraints(maxHeight: 260),
              child: _paths.isEmpty
                  ? const Center(
                      child: Padding(
                        padding: EdgeInsets.symmetric(vertical: 24),
                        child: Text('暂无待发送文件'),
                      ),
                    )
                  : ListView.separated(
                      shrinkWrap: true,
                      itemCount: _paths.length,
                      separatorBuilder: (_, _) => const Divider(height: 1),
                      itemBuilder: (context, index) {
                        final path = _paths[index];
                        final isDirectory =
                            FileSystemEntity.typeSync(path) ==
                            FileSystemEntityType.directory;
                        return ListTile(
                          dense: true,
                          leading: Icon(
                            isDirectory
                                ? Icons.folder_copy_rounded
                                : Icons.insert_drive_file_rounded,
                          ),
                          title: Text(
                            path.split(Platform.pathSeparator).last,
                            maxLines: 1,
                            overflow: TextOverflow.ellipsis,
                          ),
                          subtitle: Text(
                            path,
                            maxLines: 1,
                            overflow: TextOverflow.ellipsis,
                          ),
                          trailing: IconButton(
                            icon: const Icon(Icons.delete_outline_rounded),
                            onPressed: () =>
                                setState(() => _paths.removeAt(index)),
                          ),
                        );
                      },
                    ),
            ),
          ],
        ),
      ),
      actions: [
        TextButton(
          onPressed: () => Navigator.of(context).pop(),
          child: const Text('取消'),
        ),
        FilledButton.icon(
          onPressed: _paths.isEmpty ? null : _submit,
          icon: const Icon(Icons.send_rounded),
          label: Text('发送 (${_paths.length})'),
        ),
      ],
    );
  }
}