package org.simantics.fileimport.ui;

import java.nio.file.Paths;
import java.util.Map;
import java.util.Optional;
import java.util.function.Consumer;

import javax.inject.Named;

import org.eclipse.core.runtime.IAdaptable;
import org.eclipse.e4.core.di.annotations.CanExecute;
import org.eclipse.e4.core.di.annotations.Execute;
import org.eclipse.e4.ui.services.IServiceConstants;
import org.eclipse.jface.viewers.ISelection;
import org.eclipse.jface.viewers.StructuredSelection;
import org.eclipse.swt.SWT;
import org.eclipse.swt.widgets.FileDialog;
import org.eclipse.swt.widgets.Shell;
import org.simantics.db.Resource;
import org.simantics.fileimport.FileImportService;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class ImportFileHandler {

    private static final Logger LOGGER = LoggerFactory.getLogger(ImportFileHandler.class);
    
    @CanExecute
    public boolean canExecute() {
        return !FileImportService.supportedExtensionsWithFilters().isEmpty();
    }

    @Execute
    public void execute(@Named(IServiceConstants.ACTIVE_SELECTION) ISelection selection,
    		@Named(IServiceConstants.ACTIVE_SHELL) Shell shell) {
        Map<String, String> extensions = FileImportService.supportedExtensionsWithFilters();
        String[] filterExtensions = (String[]) extensions.keySet().toArray(new String[extensions.keySet().size()]);
        String[] filterNames = (String[]) extensions.values().toArray(new String[extensions.values().size()]);
        
        // Sanity check
        for (int i = 0; i < filterExtensions.length; i++) {
            String extension = filterExtensions[i];
            if (!extension.startsWith("*.")) { //$NON-NLS-1$
                System.err.println("Invalid extension filter provied: " + extension); //$NON-NLS-1$
            }
        }

        FileDialog dialog = new FileDialog(shell, SWT.OPEN);
        dialog.setText(Messages.ImportFileHandler_ChooseFile);
        dialog.setFilterExtensions(filterExtensions);
        dialog.setFilterNames(filterNames);
        final String fileName = dialog.open();
        if (fileName == null)
            return;
        
        Resource selectedResource = null;
        try {
	        if(selection instanceof StructuredSelection) {
	    		StructuredSelection structuredSelection = (StructuredSelection)selection;
		        Object elem = structuredSelection.getFirstElement();
		        IAdaptable a = (IAdaptable)elem;
		        selectedResource = a.getAdapter(Resource.class);
	        }
        } catch(NullPointerException | ClassCastException npe) {
        	LOGGER.warn("Failed to find selection, passing null to file importer", npe); //$NON-NLS-1$
        }
        
        FileImportService.performFileImport(Paths.get(fileName), Optional.of(selectedResource), Optional.of((Consumer<Throwable>) t -> {
            LOGGER.error("Could not import file " + fileName, t); //$NON-NLS-1$
        }));
    }
}