package com.onaro.util.jfc.tables;

import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.Transferable;
import java.awt.datatransfer.UnsupportedFlavorException;
import java.io.IOException;
import java.io.StringReader;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;

import javax.swing.JComponent;
import javax.swing.JTable;
import javax.swing.TransferHandler;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

import com.onaro.sanscreen.client.view.selection.SelectedObject;
import com.onaro.util.jfc.NonModalDialog;

/**
 * Extends {@link JTable}'s default transfer-handler (cut&paste and drun&drop) to support the transfer of
 * {@link SelectedObject} arrays.
 */
public abstract class TableTransferHandler extends TransferHandler {

	private static final long serialVersionUID = 1L;

    static final Logger logger = LogManager.getLogger(NonModalDialog.class);
	
    /**
     * The flavor for SelectedObject arrays.
     */
    private static final DataFlavor selectedObjectFlavor;

    /**
     * Maps flavors to getters which in turn create the {@link Transferable} data.
     */
    static final Map<DataFlavor,TransferGetter> dataFlavorsToTrasnferGetter;

    /**
     * The flavors are ordered according to preference of usage.
     */
    static final DataFlavor dataFlavors[];

    static {
        dataFlavorsToTrasnferGetter = new HashMap<DataFlavor,TransferGetter>();
        List<DataFlavor> flavorList = new LinkedList<DataFlavor>();
        DataFlavor tmpSelectedObjectFlavor = null;
        try {
            DataFlavor flavor = new DataFlavor("text/html;class=java.lang.String"); //$NON-NLS-1$
            TransferGetter transferGetter = new TransferGetter() {
                            public Object getData(TableTransferable transfer) {
                                return transfer.htmlData;
                            }
                        };
            flavorList.add(flavor); dataFlavorsToTrasnferGetter.put(flavor, transferGetter);

            flavor = new DataFlavor("text/html;class=java.io.Reader"); //$NON-NLS-1$
            transferGetter = new TransferGetter() {
                            public Object getData(TableTransferable transfer) {
                                return new StringReader(transfer.htmlData);
                            }
                        };
            flavorList.add(flavor); dataFlavorsToTrasnferGetter.put(flavor, transferGetter);

            flavor = new DataFlavor("text/plain;class=java.lang.String"); //$NON-NLS-1$
            transferGetter = new TransferGetter() {
                            public Object getData(TableTransferable transfer) {
                                return transfer.plainData;
                            }
                        };
            flavorList.add(flavor); dataFlavorsToTrasnferGetter.put(flavor, transferGetter);

            flavor = new DataFlavor("text/plain;class=java.io.Reader"); //$NON-NLS-1$
            transferGetter = new TransferGetter() {
                            public Object getData(TableTransferable transfer) {
                                return new StringReader(transfer.plainData);
                            }
                        };
            flavorList.add(flavor); dataFlavorsToTrasnferGetter.put(flavor, transferGetter);

            tmpSelectedObjectFlavor = flavor = new DataFlavor(new SelectedObject[0].getClass(), DataFlavor.javaJVMLocalObjectMimeType + ";class=" + (new SelectedObject[0]).getClass().getName()); //$NON-NLS-1$
            transferGetter = new TransferGetter() {
                            public Object getData(TableTransferable transfer) {
                                return transfer.selectedObjects;
                            }
                        };
            flavorList.add(flavor); dataFlavorsToTrasnferGetter.put(flavor, transferGetter);

        } catch (ClassNotFoundException e) {
        	logger.warn("Failed initializing the list of transfarable  - " + e.getMessage(), e); //$NON-NLS-1$
        }
        dataFlavors = flavorList.toArray(new DataFlavor[flavorList.size()]);
        selectedObjectFlavor = tmpSelectedObjectFlavor;
    }

    /**
     * This handler supports copying data from the table, not dragging.
     * @param c the table
     * @return {@link TransferHandler#COPY}
     */
    @Override
	public int getSourceActions(JComponent c) {
        return COPY;
    }

    /**
     * Tests if any of the given flavours could be imported to the specified component.
     * @param comp target component
     * @param transferFlavors the flavours to test if any of them is supported by the component
     * @return true if the component will allow to import data of the given flavors
     */
    @Override
	public boolean canImport(JComponent comp, DataFlavor[] transferFlavors) {
        for (int i = 0; i < transferFlavors.length; i++) {
            DataFlavor flavor = transferFlavors[i];
            if (flavor != null && selectedObjectFlavor.equals(flavor)) return true;
        }
        return false;
    }

    /**
     * Tests if the given transferable can be imported by forwarding the question to {@link TableTransferHandler#canImport(com.onaro.sanscreen.client.view.selection.SelectedObject[]).
     * @param transfarable the data to test if could be imported
     * @return true if this handler will accept the given data
     */
    public boolean canImport(Transferable transfarable) {
        if (transfarable.isDataFlavorSupported(selectedObjectFlavor)) {
            try {
                return canImport(getSelectedObjects(transfarable));
            } catch (UnsupportedFlavorException e) {
                return false;
            } catch (IOException e) {
                return false;
            }
        }

        return false;
    }

    /**
     * If the imported data support the {@link SelectedObject}s array, then the array is delegated to the
     * {@link TableTransferHandler#importData(com.onaro.sanscreen.client.view.selection.SelectedObject[])} method
     * so it could actually import it to the table.
     * @param comp the table
     * @param transfarable the imported data
     * @return true if the data was imported
     */
    @Override
	public boolean importData(JComponent comp, Transferable transfarable) {
        if (transfarable.isDataFlavorSupported(selectedObjectFlavor)) {
            try {
                return importData(getSelectedObjects(transfarable));
            } catch (UnsupportedFlavorException e) {
            	logger.warn("Failed importing data into '" + comp.getName() + "', transfarable is :" + transfarable+ " - " + e.getMessage(), e); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
            } catch (IOException e) {
            	logger.warn("Failed importing data into '" + comp.getName() + "', transfarable is :" + transfarable+ " - " + e.getMessage(), e); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
            }
        }

        return super.importData(comp, transfarable);
    }

    /**
     * Delegate the actual importing of {@link SelectedObject} to the implementing sub-class.
     * @param selectedObjects the data to be imported
     * @return true if the import was completed successfully
     */
    public abstract boolean importData(SelectedObject selectedObjects[]);

    /**
     * Ask the implementing sub-class if the {@link SelectedObject} can be imported.
     * @param selectedObjects the data that may be imported
     * @return true if the data could be imported
     */
    public abstract boolean canImport(SelectedObject[] selectedObjects);

    /**
     * Asks implementing sub-class for the {@link SelectedObject}s representing selected rows.
     */
    public abstract SelectedObject[] getSelectedObjects();

    private SelectedObject[] getSelectedObjects(Transferable transfarable) throws UnsupportedFlavorException, IOException {
        return (SelectedObject[]) transfarable.getTransferData(selectedObjectFlavor);
    }

    public static class TableTransferable implements Transferable {

        protected String plainData;
        protected String htmlData;
        protected SelectedObject[] selectedObjects;

        public TableTransferable(SelectedObject[] selectedObjects, String plainData, String htmlData) {
            this.plainData = plainData;
            this.htmlData = htmlData;
            this.selectedObjects = selectedObjects;
        }

        public DataFlavor[] getTransferDataFlavors() {
            return dataFlavors;
        }

        public boolean isDataFlavorSupported(DataFlavor flavor) {
            return dataFlavorsToTrasnferGetter.containsKey(flavor);
        }

        public Object getTransferData(DataFlavor flavor) throws UnsupportedFlavorException, IOException {
            TransferGetter transferGetter = dataFlavorsToTrasnferGetter.get(flavor);
            if (transferGetter != null) return transferGetter.getData(this);
            throw new UnsupportedFlavorException(flavor);
        }

    }

    interface TransferGetter {
        public Object getData(TableTransferable transfer);
    }

}