package org.simantics.district.imports.ui;

import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.Collection;
import java.util.HashMap;
import java.util.Map;

import org.eclipse.jface.layout.GridDataFactory;
import org.eclipse.jface.layout.GridLayoutFactory;
import org.eclipse.jface.wizard.WizardPage;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.events.SelectionListener;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Combo;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Group;
import org.simantics.Simantics;
import org.simantics.db.ReadGraph;
import org.simantics.db.Resource;
import org.simantics.db.common.request.ReadRequest;
import org.simantics.db.exception.DatabaseException;
import org.simantics.district.imports.CSVImportModel;
import org.simantics.district.network.ui.function.Functions;
import org.simantics.modeling.ModelingResources;
import org.simantics.utils.ui.widgets.FileOrDirectorySelectionWidget;
import org.simantics.utils.ui.widgets.FileSelectionListener;
import org.simantics.utils.ui.widgets.FileSelectionWidget;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class CSVImportWizardFirstPage extends WizardPage implements FileSelectionListener {

    private static final Logger LOGGER = LoggerFactory.getLogger(CSVImportWizardFirstPage.class);

    private final CSVImportModel model;
    
    private Map<String, Resource> diagrams = new HashMap<>();
    
    private Combo diagramCombo;
    private FileSelectionWidget csvSelection;

    public CSVImportWizardFirstPage(CSVImportModel model) {
        super("Select source for CSV data");
        this.model = model;
        setMessage("Select target network diagram and source for CSV-data");
    }
    
    @Override
    public void createControl(Composite parent) {
        Composite composite = new Composite(parent, SWT.NONE);
        composite.setLayout(new GridLayout(1,false));
        GridDataFactory.fillDefaults().grab(true, true).align(SWT.FILL, SWT.FILL).applyTo(composite);
        
        Group parentConfigurationGroup = new Group(composite, SWT.NONE);
        parentConfigurationGroup.setText("Select target network diagram");
        GridDataFactory.fillDefaults().grab(true, false).span(2, 1).applyTo(parentConfigurationGroup);
        
        diagramCombo = new Combo(parentConfigurationGroup, SWT.DROP_DOWN | SWT.READ_ONLY);
        diagramCombo.addSelectionListener(new SelectionListener() {
            
            @Override
            public void widgetSelected(SelectionEvent e) {
                widgetDefaultSelected(e);
            }
            
            @Override
            public void widgetDefaultSelected(SelectionEvent e) {
                String selection = diagramCombo.getItem(diagramCombo.getSelectionIndex());
                model.setParentDiagram(diagrams.get(selection));
                validateComplete();
            }
        });
        
        GridLayoutFactory.fillDefaults().numColumns(1).equalWidth(false).extendedMargins(12, 12, 12, 12).spacing(5, 4).applyTo(parentConfigurationGroup);
        
        csvSelection = new FileSelectionWidget(composite, "CSV file", SWT.OPEN);
        csvSelection.addListener(this);
        
        updateAvailableParents();
        
        validateComplete();
        
        setControl(composite);
    }

    private void updateAvailableParents() {
        try {
            Simantics.getSession().syncRequest(new ReadRequest() {
                
                @Override
                public void run(ReadGraph graph) throws DatabaseException {
                    Collection<Resource> diagrams = Functions.getDistrictDiagrams(graph);
                    ModelingResources MOD = ModelingResources.getInstance(graph);
                    Resource projectResource = Simantics.getProjectResource();
                    String projectURI = graph.getURI(projectResource);
                    for (Resource diagram : diagrams) {
                        Resource composite = graph.getSingleObject(diagram, MOD.DiagramToComposite);
                        String compositeURI = graph.getURI(composite);
                        String path = compositeURI.replace(projectURI, "");
                        CSVImportWizardFirstPage.this.diagrams.put(path, diagram);
                    }
                }
            });
            diagramCombo.setItems(diagrams.keySet().toArray(new String[diagrams.size()]));
            if (diagrams.size() > 0) {
                diagramCombo.select(0);
                model.setParentDiagram(diagrams.get(diagramCombo.getItem(0)));
                diagramCombo.getDisplay().asyncExec(() -> validateComplete());
            }
        } catch (DatabaseException e) {
            LOGGER.error("Could not update available parents", e);
        }
    }

    @Override
    public void fileSelected(FileOrDirectorySelectionWidget source, String[] filename) {
        String[] selection = csvSelection.getFilename();
        if (selection != null && selection.length > 0) {
            Path csvFile = Paths.get(selection[0]);
            if (!Files.exists(csvFile)) {
                setErrorMessage("File " + csvFile.toAbsolutePath() + " does not exist");
            } else {
                model.setSource(csvFile);
                validateComplete();
            }
        }
    }
    
    private void validateComplete() {
        setPageComplete(model.getSource() != null && model.getParentDiagram() != null);
    }
}