import 'dart:io';
import 'package:flutter/material.dart';
import 'package:file_picker/file_picker.dart';
import 'package:google_fonts/google_fonts.dart';
import 'package:open_filex/open_filex.dart';
import 'package:path/path.dart' as path;
import 'package:permission_handler/permission_handler.dart';
import 'package:path_provider/path_provider.dart';
import 'package:shared_preferences/shared_preferences.dart';
import 'note_editor.dart';

class NoteListScreen extends StatefulWidget {
  final void Function(bool) toggleTheme;
  final VoidCallback toggleTags;
  final bool isDarkMode;
  final bool showTags;

  NoteListScreen({
    required this.toggleTheme,
    required this.toggleTags,
    required this.isDarkMode,
    required this.showTags,
  });

  @override
  _NoteListScreenState createState() => _NoteListScreenState();
}

class _NoteListScreenState extends State<NoteListScreen> {
  TextEditingController searchController = TextEditingController();
  List<File> notes = [];
  List<File> filteredNotes = [];
  String? notesDirectoryPath;
  String? defaultDir;
  bool _useExternalEditor = false;

  @override
  void initState() {
    super.initState();
    _initializeApp(); // Call an async method to handle initialization
    searchController.addListener(() {
      final text = searchController.text.trim();
      if (text.startsWith(':')) {
        _handleCommand(text);
      } else {
        _filterNotes();
      }
    });
  }

  Future<void> _toggleExternalEditor(bool value) async {
    setState(() {
      _useExternalEditor = value;
    });
    SharedPreferences.getInstance().then((prefs) {
      prefs.setBool('use_external_editor', value);
    });
  }

  Future<void> _requestStoragePermission() async {
    if (Platform.isAndroid) {
      if (await Permission.storage.request().isGranted) {
        print("✅ Basic storage permission granted.");
        return;
      }

      if (await Permission.manageExternalStorage.request().isGranted) {
        print("✅ Full file access granted.");
        return;
      }

      print("❌ Storage permission denied. Opening settings...");
      await openAppSettings(); // Open settings if denied
    }
  }

  Future<void> _initializeApp() async {
    final prefs = await SharedPreferences.getInstance();
    final dir = await getApplicationDocumentsDirectory();

    setState(() {
      defaultDir = dir.path;
      _useExternalEditor = prefs.getBool('use_external_editor') ?? false;
    });

    await _loadNotes();
  }

  void _showDirectoryChoiceDialog(String defaultPath) {
    showDialog(
      context: context,
      barrierDismissible: false, // Force user to make a choice
      builder: (BuildContext context) {
        return AlertDialog(
          title: Text("Choose Notes Directory"),
          content: Text(
              "Your notes will be saved in:\n\n📂 $defaultPath\n\nWould you like to use a different folder?"),
          actions: [
            TextButton(
              onPressed: () async {
                // Reset to default directory
                final prefs = await SharedPreferences.getInstance();
                await prefs.remove(
                    'notes_directory'); // Remove custom directory from preferences
                setState(() {
                  notesDirectoryPath = defaultDir; // Reset to default directory
                });
                Navigator.pop(context); // Close dialog
                _loadNotes(); // Reload notes from the default directory
              },
              child: Text("Use Default"),
            ),
            TextButton(
              onPressed: () async {
                await _requestStoragePermission();
                Navigator.pop(context); // Close the current dialog
                await _selectNotesDirectory(); // Allow user to pick a folder
              },
              child: Text("Choose Folder"),
            ),
          ],
        );
      },
    );
  }

  Future<void> _selectNotesDirectory() async {
    String? selectedDirectory = await FilePicker.platform.getDirectoryPath();
    if (selectedDirectory != null) {
      final prefs = await SharedPreferences.getInstance();
      await prefs.setString(
          'notes_directory', selectedDirectory); // Save custom directory
      setState(() {
        notesDirectoryPath = selectedDirectory; // Update state
      });
      _loadNotes(); // Reload notes from the new directory
    }
  }

  Future<void> _loadNotes() async {
    final prefs = await SharedPreferences.getInstance();
    notesDirectoryPath = prefs.getString('notes_directory') ?? defaultDir;

    final notesDir = Directory(notesDirectoryPath!);
    if (!notesDir.existsSync()) {
      notesDir.createSync(recursive: true);
    }

    List<File> allNotes = [];
    Map<String, DateTime> folderTimestamps = {}; // Store latest edit time per folder

    void fetchNotes(Directory dir, String relativePath) {
      final entries = dir.listSync(recursive: false);

      for (var entry in entries) {
        if (entry is File && entry.path.endsWith('.md')) {
          allNotes.add(entry);

          // Store latest edit time per folder
          final folder = path.dirname(entry.path);
          if (!folderTimestamps.containsKey(folder) ||
              entry.lastModifiedSync().isAfter(folderTimestamps[folder]!)) {
            folderTimestamps[folder] = entry.lastModifiedSync();
          }
        } else if (entry is Directory && path.basename(entry.path) != 'trash') {
          fetchNotes(entry, path.join(relativePath, path.basename(entry.path)));
        }
      }
    }

    fetchNotes(notesDir, '');

    // Sorting logic:
    allNotes.sort((a, b) {
      String folderA = path.dirname(a.path);
      String folderB = path.dirname(b.path);

      bool isRootA = folderA == notesDirectoryPath; // Root folder check
      bool isRootB = folderB == notesDirectoryPath;

      if (isRootA && !isRootB) return -1; // Root files first
      if (!isRootA && isRootB) return 1;  // Subfolder files later

      // If both are in the root OR both are in subfolders, sort by latest edit time
      DateTime timeA = folderTimestamps[folderA] ?? DateTime(0);
      DateTime timeB = folderTimestamps[folderB] ?? DateTime(0);
      return timeB.compareTo(timeA);
    });

    setState(() {
      notes = allNotes;
      filteredNotes = allNotes;
    });
  }

  void _filterNotes() {
    final query = searchController.text.trim().toLowerCase();

    setState(() {
      if (query.startsWith('/')) {
        // Extract subfolder path and search term
        final parts = query.split('/');
        final subfolderPath = parts.sublist(1, parts.length - 1).join('/');
        final searchTerm = parts.last;

        filteredNotes = notes.where((note) {
          final relativePath = path.relative(note.path, from: notesDirectoryPath!);
          return relativePath.startsWith(subfolderPath) &&
              (relativePath.contains(searchTerm) || note.readAsStringSync().toLowerCase().contains(searchTerm));
        }).toList();
      } else {
        // Default search across all notes
        filteredNotes = notes.where((note) {
          final content = note.readAsStringSync().toLowerCase();
          return note.uri.pathSegments.last.toLowerCase().contains(query) || content.contains(query);
        }).toList();
      }
    });
  }

  List<InlineSpan> _formatTags(String content) {
    final tagPattern = RegExp(r'([#@+][a-zA-Z0-9_]+)');
    final List<InlineSpan> spans = [];
    for (final match in tagPattern.allMatches(content)) {
      final tag = match.group(0)!;
      Color tagColor = Colors.white;
      if (tag.startsWith('#')) tagColor = Colors.pinkAccent;
      if (tag.startsWith('+')) tagColor = Colors.cyan;
      if (tag.startsWith('@')) tagColor = Colors.orange;

      spans.add(TextSpan(
          text: tag + ' ',
          style: TextStyle(color: tagColor, fontWeight: FontWeight.bold)));
    }
    return spans;
  }

  void _createNewNote(String title) async {
    try {
      String notePath = title.trim();
      String? subfolder;
      String safeTitle;

      if (notePath.startsWith('/')) {
        final parts = notePath.split('/');
        parts.removeWhere((element) => element.isEmpty);
        if (parts.length > 1) {
          subfolder = parts.sublist(0, parts.length - 1).join('/');
        }
        safeTitle = _sanitizeFilename(parts.last);
      } else {
        safeTitle = _sanitizeFilename(title);
      }

      // Construct the final file path
      String fullPath = subfolder != null
          ? path.join(notesDirectoryPath!, subfolder, '$safeTitle.md')
          : path.join(notesDirectoryPath!, '$safeTitle.md');

      final newNote = File(fullPath);

      // Prevent duplicate note creation
      if (notes.any((note) => note.path == newNote.path)) {
        print("❌ Note already exists at: $fullPath");
        return;
      }

      // Ensure subfolder exists
      final parentDir = newNote.parent;
      if (!parentDir.existsSync()) {
        parentDir.createSync(recursive: true);
      }

      if (!newNote.existsSync()) {
        newNote.writeAsStringSync('# $safeTitle\n\n');
        setState(() {
          notes.add(newNote);
          filteredNotes.add(newNote);
        });

        Navigator.push(
          context,
          MaterialPageRoute(
            builder: (context) => NoteEditorScreen(
              note: newNote,
              isDarkMode: widget.isDarkMode,
              notesDirectoryPath: notesDirectoryPath,
            ),
          ),
        );
      }
    } catch (e) {
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(
          content: Text('Failed to create note: $e'),
        ),
      );
    }
  }

  bool _isNewNote(String title) {
    String notePath = title.trim();
    String? subfolder;
    String safeTitle;

    if (notePath.startsWith('/')) {
      final parts = notePath.split('/');
      parts.removeWhere((element) => element.isEmpty); // Remove empty elements
      if (parts.length > 1) {
        subfolder = parts.sublist(0, parts.length - 1).join('/');
      }
      safeTitle = _sanitizeFilename(parts.last);
    } else {
      safeTitle = _sanitizeFilename(title);
    }

    // Construct the expected file path
    String fullPath = subfolder != null
        ? path.join(notesDirectoryPath!, subfolder, '$safeTitle.md')
        : path.join(notesDirectoryPath!, '$safeTitle.md');

    return !notes.any((note) => note.path == fullPath);
  }

  String _sanitizeFilename(String title) {
    return title
        .replaceAll(RegExp(r'[<>:"/\\|?*]'), '') // Remove invalid characters
        .trim();
  }

  void _deleteNote(File note) {
    final rootTrashDir = Directory(path.join(notesDirectoryPath!, 'trash'));

    if (!rootTrashDir.existsSync()) {
      rootTrashDir.createSync(recursive: true);
    }

    // Define the base trashed file path
    String trashedPath = path.join(rootTrashDir.path, note.uri.pathSegments.last);
    File trashedNote = File(trashedPath);

    // If the file already exists in trash, append a timestamp to avoid conflicts
    if (trashedNote.existsSync()) {
      final timestamp = DateTime.now().millisecondsSinceEpoch;
      final newFileName = '${path.basenameWithoutExtension(note.path)}_$timestamp.md';
      trashedNote = File(path.join(rootTrashDir.path, newFileName));
    }

    // Move the file to trash
    note.renameSync(trashedNote.path);

    // Check if the original directory is now empty and delete it if needed
    _deleteEmptyParentFolders(note.parent);

    setState(() {
      notes.remove(note);
      filteredNotes.remove(note);
    });

    ScaffoldMessenger.of(context).showSnackBar(
      SnackBar(
        content: Text('Note moved to trash'),
        action: SnackBarAction(
          label: 'Undo',
          onPressed: () {
            trashedNote.renameSync(note.path);
            setState(() {
              notes.add(note);
              filteredNotes.add(note);
            });
          },
        ),
      ),
    );
  }

// ✅ Recursively deletes empty parent folders up to the notes directory
  void _deleteEmptyParentFolders(Directory folder) {
    if (folder.path == notesDirectoryPath) return; // Don't delete the root folder

    try {
      if (folder.existsSync() && folder.listSync().isEmpty) {
        folder.deleteSync();
        _deleteEmptyParentFolders(folder.parent); // Recursively check parent
      }
    } catch (e) {
      print("❌ Error deleting empty folder: $e");
    }
  }

  Future<void> _emptyTrash() async {
    final prefs = await SharedPreferences.getInstance();
    final notesPath = prefs.getString('notes_directory') ??
        (await getApplicationDocumentsDirectory()).path;
    final trashDir = Directory('$notesPath/trash');
    if (trashDir.existsSync()) {
      trashDir.deleteSync(recursive: true);
      trashDir.createSync();
    }
  }

  void _confirmEmptyTrash() {
    showDialog(
      context: context,
      builder: (context) {
        return AlertDialog(
          title: Text("Empty Trash"),
          content: Text(
              "Are you sure you want to permanently delete all trashed notes?"),
          actions: [
            TextButton(
              onPressed: () => Navigator.pop(context),
              child: Text("Cancel"),
            ),
            TextButton(
              onPressed: () {
                _emptyTrash();
                Navigator.pop(context);
              },
              child: Text("Empty Trash"),
            ),
          ],
        );
      },
    );
  }

  void _handleCommand(String text) {
    switch (text) {
      case ':tags':
        widget.toggleTags();
        break;
      case ':notags':
        widget.toggleTags();
        break;
      case ':day':
        widget.toggleTheme(false);
        break;
      case ':night':
        widget.toggleTheme(true);
        break;
      case ':extern':
        _toggleExternalEditor(true);
        break;
      case ':intern':
        _toggleExternalEditor(false);
        break;
      case ':emptytrash':
        _confirmEmptyTrash();
        break;
      default:
        return; // Do nothing for unrecognized commands
    }
    searchController.clear();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Padding(
          padding: EdgeInsets.symmetric(horizontal: 15),
          child: TextField(
            enableInteractiveSelection: true,
            autocorrect: false,
            textInputAction: TextInputAction.done,
            controller: searchController,
            decoration: InputDecoration(
              hintText: 'Search or enter a command...',
              border: InputBorder.none,
            ),
            style: GoogleFonts.ibmPlexMono(color: Colors.grey[300]),
            onSubmitted: (text) {
              final trimmedText = text.trim();
              if (trimmedText.isNotEmpty && _isNewNote(trimmedText)) {
                _createNewNote(trimmedText);
                searchController
                    .clear(); // Clears the search field after creation
              }
            },
          ),
        ),
        actions: [
          Padding(
            padding: EdgeInsets.symmetric(horizontal: 15),
            child: PopupMenuButton<String>(
              icon: Icon(Icons.radio_button_checked,
                  color: Colors.orange), // Menu button (⋮)
              onSelected: (String value) {
                switch (value) {
                  case 'Toggle Tags':
                    widget.toggleTags();
                    break;
                  case 'Toggle Theme':
                    setState(() {
                      widget.toggleTheme(!widget.isDarkMode);
                    });
                    break;
                  case 'External Editor':
                    _toggleExternalEditor(!_useExternalEditor);
                    break;
                  case 'Select Folder':
                    _showDirectoryChoiceDialog(
                        notesDirectoryPath ?? ''); // Re-trigger popup
                    break;
                  case 'Empty Trash':
                    _confirmEmptyTrash();
                    break;
                }
              },
              itemBuilder: (BuildContext context) => [
                PopupMenuItem<String>(
                  value: 'Toggle Tags',
                  child: ListTile(
                    leading:
                        Icon(widget.showTags ? Icons.label_off : Icons.label),
                    title: Text(widget.showTags ? 'Hide Tags' : 'Show Tags'),
                  ),
                ),
                PopupMenuItem<String>(
                  value: 'Toggle Theme',
                  child: ListTile(
                    leading: Icon(
                      Theme.of(context).brightness == Brightness.dark
                          ? Icons.light_mode
                          : Icons.dark_mode,
                    ),
                    title: Text(
                      Theme.of(context).brightness == Brightness.dark
                          ? 'Switch to Light Mode'
                          : 'Switch to Dark Mode',
                    ),
                  ),
                ),
                PopupMenuItem<String>(
                  value: 'External Editor',
                  child: ListTile(
                    leading: Icon(
                      _useExternalEditor
                          ? Icons.open_in_new_off
                          : Icons.open_in_new,
                    ),
                    title: Text(
                      !_useExternalEditor
                          ? 'Use External Editor'
                          : 'Use Internal Editor',
                    ),
                  ),
                ),
                PopupMenuItem<String>(
                  value: 'Select Folder',
                  child: ListTile(
                    leading: Icon(Icons.folder),
                    title: Text('Set Notes Directory'),
                  ),
                ),
                PopupMenuItem<String>(
                  value: 'Empty Trash',
                  child: ListTile(
                    leading: Icon(Icons.delete, color: Colors.redAccent),
                    title: Text('Empty Trash',
                        style: TextStyle(color: Colors.redAccent)),
                  ),
                ),
              ],
            ),
          ),
        ],
      ),
      body: Padding(
        padding: EdgeInsets.symmetric(horizontal: 15),
        child: ListView.builder(
          itemCount: filteredNotes.length,
          itemBuilder: (context, index) {
            final noteFile = filteredNotes[index];
            final noteContent = noteFile.readAsStringSync();
            final tagSpans = _formatTags(noteContent).isNotEmpty
                ? _formatTags(noteContent)
                : [TextSpan(text: '')];

            return Dismissible(
              key: Key(noteFile.path),
              direction: DismissDirection.endToStart,
              background: Container(
                color: Colors.redAccent,
                alignment: Alignment.centerRight,
                padding: EdgeInsets.symmetric(horizontal: 20),
                child: Icon(Icons.delete, color: Colors.white),
              ),
              onDismissed: (direction) => _deleteNote(noteFile),
              child: ListTile(
                title:
                    Text(noteFile.uri.pathSegments.last.replaceAll('.md', '')),
                subtitle: Row(
                  children: [
                    path.relative(path.dirname(noteFile.path), from: notesDirectoryPath!) != "."
                    ? Text(
                        path.relative(path.dirname(noteFile.path), from: notesDirectoryPath!),
                        style: TextStyle(color: Colors.blueGrey),
                      )
                    : Text(""),
                    widget.showTags && tagSpans.isNotEmpty
                      ? RichText(
                        text: TextSpan(
                          style: DefaultTextStyle.of(context).style,
                          children: tagSpans)
                        )
                      : Text("")
                  ],
                ),
                  onTap: () async {
                    if (_useExternalEditor) {
                      // Open with system's default editor
                      try {
                        if (Platform.isLinux) {
                          final result = await Process.run('which', ['xdg-open']);
                          if (result.stdout.toString().trim().isNotEmpty) {
                            await Process.run('xdg-open', [noteFile.path]); // ✅ Use full path
                          } else {
                            print("❌ `xdg-open` is not available.");
                          }
                        } else if (Platform.isAndroid) {
                          await _requestStoragePermission();
                          final result = await OpenFilex.open(
                            noteFile.path, // ✅ Use full path
                            type: "text/markdown",
                          );
                          print("✅ OpenFilex result: ${result.type}, message: ${result.message}");
                        }
                      } catch (e) {
                        print("❌ Failed to open external editor: $e");
                      }
                    } else {
                      // Open internally in NoteEditorScreen
                      await Navigator.push(
                        context,
                        MaterialPageRoute(
                          builder: (context) => NoteEditorScreen(
                            note: noteFile, // ✅ Pass the full file path
                            isDarkMode: widget.isDarkMode,
                            notesDirectoryPath: notesDirectoryPath,
                          ),
                        ),
                      );
                      _loadNotes(); // Reload notes after returning
                      setState(() {}); // Force UI refresh
                    }
                  }
              ),
            );
          },
        ),
      ),
    );
  }
}