import os
import shutil
from PyQt5.QtWidgets import QFileDialog, QMessageBox

class FileService:
    def __init__(self, main_window, upload_dir):
        self.main_window = main_window
        self.upload_dir = upload_dir
        self.destination = None
        
    def upload_file(self):
        """Handle file upload process"""
        try:
            print("Calling QFileDialog.getOpenFileName")
            options = QFileDialog.Options()
            file_path, _ = QFileDialog.getOpenFileName(
                self.main_window, 
                "Upload File", 
                "", 
                "All Files (*)", 
                options=options
            )
            print("File path obtained:", file_path)
            
            if file_path:
                print("Checking if upload directory exists")
                if not os.path.exists(self.upload_dir):
                    os.makedirs(self.upload_dir)
                    print(f"Created UPLOAD_DIR: {self.upload_dir}")
                    
                print("Checking if original file exists:", file_path)
                if not os.path.exists(file_path):
                    self.show_message(QMessageBox.Critical, "Error", "Selected file not found")
                    return None
                    
                file_name = os.path.basename(file_path)
                self.destination = os.path.join(self.upload_dir, file_name)
                print("Target path:", self.destination)
                
                # Check if target path is writable
                try:
                    print("Testing file write permission")
                    with open(self.destination, 'wb') as test_file:
                        pass
                    os.remove(self.destination)
                    print("Test file creation and deletion successful")
                except PermissionError:
                    self.show_message(QMessageBox.Critical, "Error", "Cannot write to target directory")
                    return None
                    
                print("Starting file copy")
                shutil.copy2(file_path, self.destination)
                print("File copy complete")
                self.show_message(QMessageBox.Information, "Success", f"File uploaded to: {self.destination}")
                
                return self.destination
            
            return None
            
        except Exception as e:
            import traceback
            print("Exception during upload process:\n", traceback.format_exc())
            self.show_message(QMessageBox.Critical, "Error", f"Upload error: {str(e)}")
            return None
            
    def show_message(self, icon, title, message):
        """Display a message box with custom styling"""
        msgBox = QMessageBox(self.main_window)
        msgBox.setIcon(icon)
        msgBox.setWindowTitle(title)
        msgBox.setText(message)
        msgBox.setStyleSheet("""
            QLabel { color: white; }
            QPushButton { color: white; }
            QMessageBox { background-color: #2b2b2b; }
        """)
        msgBox.exec_()