import sys
import os
from PyQt6.QtCore import *

class FileSystemItem:
    def __init__(self, path, parent=None):
        self.parentItem = parent
        self.itemPath = path
        self.children = []
        self.populated = False
    
    def row(self):
        if self.parentItem:
            return self.parentItem.children.index(self)
        return 0

class FileSystemModel(QAbstractItemModel):
    rootPathChanged = pyqtSignal()

    def __init__(self, parent=None):
        super().__init__(parent)
        self._rootPath = ''
        self.rootItem = FileSystemItem(self._rootPath)
        self.header = ['Name']

    @pyqtProperty(str, notify=rootPathChanged)
    def rootPath(self):
        return self._rootPath

    @rootPath.setter
    def rootPath(self, path):
        if self._rootPath != path:
            self._rootPath = path
            self.beginResetModel()
            self.rootItem = FileSystemItem(self._rootPath)
            self.endResetModel()
            self.rootPathChanged.emit()

    def columnCount(self, parent=QModelIndex()):
        return 1

    def rowCount(self, parent=QModelIndex()):
        if not parent.isValid():
            parentItem = self.rootItem
        else:
            parentItem = parent.internalPointer()
        
        if not parentItem.populated:
            self.populateItem(parentItem)
        return len(parentItem.children)

    def populateItem(self, item):
        try:
            if os.path.isdir(item.itemPath):
                entries = os.listdir(item.itemPath)
                for entry in entries:
                    fullPath = os.path.join(item.itemPath, entry)
                    item.children.append(FileSystemItem(fullPath, item))
                item.populated = True
            else:
                item.populated = True
        except (PermissionError, NotADirectoryError):
            pass

    def data(self, index, role=Qt.ItemDataRole.DisplayRole):
        if not index.isValid():
            return None

        item = index.internalPointer()
        if role == Qt.ItemDataRole.DisplayRole:
            return os.path.basename(item.itemPath)
        elif role == Qt.ItemDataRole.UserRole + 1:  # isDirRole
            return os.path.isdir(item.itemPath)
        elif role == Qt.ItemDataRole.UserRole + 2:  # isExpandedRole
            return False
        return None

    def index(self, row, column, parent=QModelIndex()):
        if not self.hasIndex(row, column, parent):
            return QModelIndex()

        parentItem = parent.internalPointer() if parent.isValid() else self.rootItem
        childItem = parentItem.children[row]
        return self.createIndex(row, column, childItem)

    def parent(self, index):
        if not index.isValid():
            return QModelIndex()

        childItem = index.internalPointer()
        parentItem = childItem.parentItem

        if parentItem == self.rootItem:
            return QModelIndex()

        return self.createIndex(parentItem.row(), 0, parentItem)
file_system_model = FileSystemModel()