package com.sencha.gxt.explorer.client.binding;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Set;

import javax.validation.ConstraintViolation;

import com.google.gwt.core.client.Callback;
import com.google.gwt.core.client.EntryPoint;
import com.google.gwt.core.client.GWT;
import com.google.gwt.editor.client.Editor;
import com.google.gwt.event.logical.shared.SelectionEvent;
import com.google.gwt.event.logical.shared.SelectionHandler;
import com.google.gwt.event.shared.SimpleEventBus;
import com.google.gwt.user.client.ui.HorizontalPanel;
import com.google.gwt.user.client.ui.IsWidget;
import com.google.gwt.user.client.ui.RootPanel;
import com.google.gwt.user.client.ui.Widget;
import com.google.web.bindery.requestfactory.gwt.client.RequestFactoryEditorDriver;
import com.google.web.bindery.requestfactory.shared.EntityProxy;
import com.google.web.bindery.requestfactory.shared.Receiver;
import com.google.web.bindery.requestfactory.shared.RequestContext;
import com.sencha.gxt.core.client.ValueProvider;
import com.sencha.gxt.data.shared.ModelKeyProvider;
import com.sencha.gxt.data.shared.TreeStore;
import com.sencha.gxt.data.shared.loader.ChildTreeStoreBinding;
import com.sencha.gxt.data.shared.loader.DataProxy;
import com.sencha.gxt.data.shared.loader.TreeLoader;
import com.sencha.gxt.examples.resources.client.images.ExampleImages;
import com.sencha.gxt.examples.resources.shared.ExampleRequestFactory;
import com.sencha.gxt.examples.resources.shared.FolderProxy;
import com.sencha.gxt.examples.resources.shared.FolderRequest;
import com.sencha.gxt.examples.resources.shared.MusicProxy;
import com.sencha.gxt.examples.resources.shared.MusicRequest;
import com.sencha.gxt.examples.resources.shared.NamedProxy;
import com.sencha.gxt.explorer.client.model.Example.Detail;
import com.sencha.gxt.widget.core.client.button.TextButton;
import com.sencha.gxt.widget.core.client.container.FlowLayoutContainer;
import com.sencha.gxt.widget.core.client.event.SelectEvent;
import com.sencha.gxt.widget.core.client.event.SelectEvent.SelectHandler;
import com.sencha.gxt.widget.core.client.form.FieldLabel;
import com.sencha.gxt.widget.core.client.form.TextField;
import com.sencha.gxt.widget.core.client.tree.Tree;

public class RequestFactoryBindingExample implements Editor<MusicProxy>, IsWidget, EntryPoint {
  private final ExampleRequestFactory rf = GWT.create(ExampleRequestFactory.class);

// This is a custom data proxy, designed to serve as the interface between the
  // client's needs and the server's capabilities. If the server and client were
  // in complete agreement, it would be possible to write this as a
  // RequestFactoryProxy impl
  private final DataProxy<NamedProxy, List<NamedProxy>> proxy = new DataProxy<NamedProxy, List<NamedProxy>>() {
    @Override
    public void load(final NamedProxy loadConfig, final Callback<List<NamedProxy>, Throwable> callback) {
      Receiver<List<? extends NamedProxy>> receiver = new Receiver<List<? extends NamedProxy>>() {
        @Override
        public void onSuccess(List<? extends NamedProxy> response) {
          if (response.size() == 0) {
            // assuming that only folders OR music will be returned.
            return;
          }
          callback.onSuccess(new ArrayList<NamedProxy>(response));
        }
      };
      if (loadConfig == null) {
        rf.folder().getRootFolder().fire(new Receiver<FolderProxy>() {
          @Override
          public void onSuccess(FolderProxy response) {
            callback.onSuccess(Arrays.<NamedProxy> asList(response));
          }
        });
      } else {
        FolderRequest req = rf.folder();
        req.getChildren().using((FolderProxy) loadConfig).to(receiver);
        req.getSubFolders().using((FolderProxy) loadConfig).to(receiver);
        req.fire();
      }
    }
  };

private final TreeLoader<NamedProxy> loader = new TreeLoader<NamedProxy>(proxy) {
    public boolean hasChildren(NamedProxy parent) {
      return parent instanceof FolderProxy;
    }
  };

private final TreeStore<NamedProxy> treeStore = new TreeStore<NamedProxy>(new ModelKeyProvider<NamedProxy>() {
    @Override
    public String getKey(NamedProxy item) {
      assert item instanceof EntityProxy;
      return rf.getHistoryToken(((EntityProxy) item).stableId());
    }
  });

interface Driver extends RequestFactoryEditorDriver<MusicProxy, RequestFactoryBindingExample> {
  }

private Driver driver = GWT.create(Driver.class);

/*
   * Fields (i.e. sub-editors) that the editor driver will bind to. If using UI
   * binder, these will be created and configured in xml instead of in code.
   */
  TextField name;
  TextField author;
  TextField genre;

private TextButton save;

public RequestFactoryBindingExample() {
    // Using a simple, very local, event bus, just for this simple example.
    // Typically this would be an application-wide event bus, so other parts of
    // the app can monitor changes made on the server
    rf.initialize(new SimpleEventBus());

loader.addLoadHandler(new ChildTreeStoreBinding<NamedProxy>(treeStore));
  }

@Override
  public Widget asWidget() {
    HorizontalPanel hp = new HorizontalPanel();
    hp.setSpacing(10);

final Tree<NamedProxy, String> tree = new Tree<NamedProxy, String>(treeStore,
        new ValueProvider<NamedProxy, String>() {

@Override
          public String getValue(NamedProxy object) {
            return object.getName();
          }

@Override
          public void setValue(NamedProxy object, String value) {
          }

@Override
          public String getPath() {
            return "name";
          }
        });
    tree.setLoader(loader);
    tree.getStyle().setLeafIcon(ExampleImages.INSTANCE.music());
    tree.getSelectionModel().addSelectionHandler(new SelectionHandler<NamedProxy>() {
      @Override
      public void onSelection(SelectionEvent<NamedProxy> event) {
        if (event.getSelectedItem() instanceof MusicProxy) {
          // When a Music object is selected, edit it
          // TODO disallow editing in cases where the last has not been saved?

MusicProxy music = (MusicProxy) event.getSelectedItem();
          // dealing with a bug in Tree, where update doesn't work
          music = (MusicProxy) treeStore.findModel(music);

MusicRequest req = rf.music();
          req.persist().using(music).to(new Receiver<MusicProxy>() {
            @Override
            public void onSuccess(MusicProxy response) {
              treeStore.update(response);
            }

@Override
            public void onConstraintViolation(Set<ConstraintViolation<?>> violations) {
              if (driver.setConstraintViolations(violations)) {
                super.onConstraintViolation(violations);
              }
            }
          });
          driver.edit(music, req);
          save.setEnabled(true);
        } else {
          name.setValue("");
          author.setValue("");
          genre.setValue("");
          save.setEnabled(false);
        }
      }
    });

hp.add(tree);
    hp.setCellWidth(tree, "260px");

FlowLayoutContainer lc = new FlowLayoutContainer();
    lc.setWidth(200);

// Create the fields
    name = new TextField();
    lc.add(new FieldLabel(name, "Name"));

author = new TextField();
    lc.add(new FieldLabel(author, "Author"));

genre = new TextField();
    lc.add(new FieldLabel(genre, "Genre"));

// Clicking this save button will check for errors and save the request
    save = new TextButton("Save");
    save.setEnabled(false);
    save.addSelectHandler(new SelectHandler() {

@Override
      public void onSelect(SelectEvent event) {
        RequestContext req = driver.flush();
        if (req.isChanged() && !driver.hasErrors()) {
          req.fire();
        }
      }
    });

lc.add(save);

hp.add(lc);

// Now that all of the sub-editors exist, bind the driver to them
    driver.initialize(rf, this);
    return hp;
  }

@Override
  public void onModuleLoad() {
    RootPanel.get().add(this);
  }
}