import 'dart:io';
import 'package:flutter/material.dart';
import 'package:path_provider/path_provider.dart';
import 'package:permission_handler/permission_handler.dart';
import 'package:open_filex/open_filex.dart';

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

  @override
  State<PdfListScreen> createState() => _PdfListScreenState();
}

class _PdfListScreenState extends State<PdfListScreen> {
  List<FileSystemEntity> _pdfFiles = [];
  bool _loading = true;

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

  Future<void> _fetchPdfFiles() async {
    // Request storage permission
    final status = await Permission.storage.request();
    if (!status.isGranted) {
      setState(() {
        _loading = false;
      });
      return;
    }

    // Prefer to look in the Downloads folder if available
    Directory? downloadsDir;
    if (Platform.isAndroid) {
      downloadsDir = await getExternalStorageDirectory();
      // The Downloads folder may be a subdirectory; adjust as needed
      if (downloadsDir != null) {
        downloadsDir = Directory('${downloadsDir.path}/Download');
      }
    } else if (Platform.isIOS) {
      downloadsDir = await getApplicationDocumentsDirectory();
    } else {
      downloadsDir = await getApplicationDocumentsDirectory();
    }

    if (downloadsDir == null || !await downloadsDir.exists()) {
      setState(() {
        _loading = false;
      });
      return;
    }

    final files = downloadsDir
        .listSync()
        .where((f) => f.path.toLowerCase().endsWith('.pdf'))
        .toList();

    setState(() {
      _pdfFiles = files;
      _loading = false;
    });
  }

  void _openFile(FileSystemEntity file) async {
    final result = await OpenFilex.open(file.path);
    if (result.type != ResultType.success) {
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text('Could not open ${file.path}')),
      );
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('PDF ファイル一覧'),
      ),
      body: _loading
          ? const Center(child: CircularProgressIndicator())
          : _pdfFiles.isEmpty
              ? const Center(child: Text('PDF ファイルが見つかりません。'))
              : ListView.builder(
                  itemCount: _pdfFiles.length,
                  itemBuilder: (context, index) {
                    final file = _pdfFiles[index];
                    final fileName = file.path.split(Platform.pathSeparator).last;
                    return ListTile(
                      leading: const Icon(Icons.picture_as_pdf),
                      title: Text(fileName),
                      onTap: () => _openFile(file),
                    );
                  },
                ),
    );
  }
}