/*
 * Copyright 2015 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */

package com.google.cloud.tools.eclipse.dataflow.ui.page;

import com.google.cloud.tools.eclipse.dataflow.core.project.DataflowMavenCoordinates;
import com.google.cloud.tools.eclipse.dataflow.core.project.DataflowProjectArchetype;
import com.google.cloud.tools.eclipse.dataflow.core.project.DataflowProjectCreator;
import com.google.cloud.tools.eclipse.dataflow.core.project.DataflowProjectValidationStatus;
import com.google.cloud.tools.eclipse.dataflow.core.project.MajorVersion;
import com.google.cloud.tools.eclipse.dataflow.ui.Messages;
import com.google.cloud.tools.eclipse.dataflow.ui.util.ButtonFactory;
import com.google.cloud.tools.eclipse.util.ArtifactRetriever;
import com.google.common.base.Strings;
import java.io.File;
import java.net.URI;
import java.util.Collection;
import org.apache.maven.artifact.versioning.ArtifactVersion;
import org.eclipse.core.resources.ResourcesPlugin;
import org.eclipse.jface.resource.ImageDescriptor;
import org.eclipse.jface.wizard.WizardPage;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.FocusEvent;
import org.eclipse.swt.events.FocusListener;
import org.eclipse.swt.events.ModifyEvent;
import org.eclipse.swt.events.ModifyListener;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.events.SelectionListener;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Combo;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.DirectoryDialog;
import org.eclipse.swt.widgets.Group;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Text;
import org.eclipse.ui.PlatformUI;
import org.eclipse.ui.plugin.AbstractUIPlugin;

/**
 * The landing page for the New Cloud Dataflow Project wizard.
 */
public class NewDataflowProjectWizardLandingPage extends WizardPage  {

  private final DataflowProjectCreator targetCreator;

  private Text groupIdInput;
  private Text artifactIdInput;
  private Text packageInput;

  private Button useDefaultLocation;
  private Text locationInput;
  private Button locationBrowse;

  private Combo templateDropdown;
  private Combo templateVersionDropdown;
  private Combo projectNameTemplate;

  public NewDataflowProjectWizardLandingPage(DataflowProjectCreator targetCreator) {
    super("newDataflowProjectWizardLandingPage"); //$NON-NLS-1$
    this.targetCreator = targetCreator;
    setTitle(Messages.getString("create.dataflow.project")); //$NON-NLS-1$
    setDescription(Messages.getString("wizard.description")); //$NON-NLS-1$
    setImageDescriptor(getDataflowIcon());
    setPageComplete(false);
  }

  private static ImageDescriptor getDataflowIcon() {
    String imageFilePath = "icons/Dataflow_64.png"; //$NON-NLS-1$
    return AbstractUIPlugin.imageDescriptorFromPlugin(
        "com.google.cloud.tools.eclipse.dataflow.ui", imageFilePath); //$NON-NLS-1$
  }

  private static void addLabel(Composite formComposite, String labelText) {
    Label label = new Label(formComposite, SWT.NULL);
    label.setText(labelText);
  }

  private static Text addLabeledText(Composite formComposite, String labelText) {
    addLabel(formComposite, labelText);

    Text widget = new Text(formComposite, SWT.SINGLE | SWT.BORDER);
    widget.setLayoutData(gridSpan(GridData.FILL_HORIZONTAL, 2));
    return widget;
  }

  private static Button addCheckbox(Composite formComposite, String labelText,
      boolean initialValue) {
    Button checkbox = new Button(formComposite, SWT.CHECK);
    checkbox.setText(labelText);
    checkbox.setLayoutData(gridSpan(SWT.NULL, 3));

    checkbox.setSelection(initialValue);
    return checkbox;
  }

  private static Combo addCombo(Composite formComposite, String labelText, boolean readOnly) {
    addLabel(formComposite, labelText);

    Combo combo = new Combo(formComposite,
        SWT.DROP_DOWN | (readOnly ? SWT.READ_ONLY : SWT.NULL));
    combo.setLayoutData(gridSpan(GridData.FILL_HORIZONTAL, 2));
    return combo;
  }

  private static GridData gridSpan(int style, int span) {
    GridData gridData = new GridData(style);
    gridData.horizontalSpan = span;
    return gridData;
  }

  @Override
  public void createControl(Composite parent) {
    Composite formComposite = new Composite(parent, SWT.NULL);
    formComposite.setLayout(new GridLayout(3, false));
    setControl(formComposite);
    setHelp(formComposite);
    
    groupIdInput = addLabeledText(formComposite, Messages.getString("group.id")); //$NON-NLS-1$
    groupIdInput.setMessage(Messages.getString("example.group.id"));//$NON-NLS-1$
    groupIdInput.setToolTipText(Messages.getString("GROUP_ID_TOOLTIP")); //$NON-NLS-1$
    artifactIdInput = addLabeledText(formComposite, Messages.getString("artifact.id")); //$NON-NLS-1$
    artifactIdInput.setToolTipText(Messages.getString("ARTIFACT_ID_TOOLTIP")); //$NON-NLS-1$

    templateDropdown = addCombo(formComposite,
        Messages.getString("project.template"), true); //$NON-NLS-1$
    for (DataflowProjectArchetype template : DataflowProjectArchetype.values()) {
      templateDropdown.add(template.getLabel());
    }
    templateVersionDropdown = addCombo(formComposite,
        Messages.getString("dataflow.version"), false); //$NON-NLS-1$

    templateDropdown.select(0);
    updateAvailableVersions();

    packageInput = addLabeledText(formComposite, Messages.getString("package")); //$NON-NLS-1$
    packageInput.setToolTipText(Messages.getString("package.tooltip")); //$NON-NLS-1$
    packageInput.setMessage(Messages.getString("example.group.id"));//$NON-NLS-1$

    // Add a labeled text and button for the default location.
    Group locationGroup = new Group(formComposite, SWT.NULL);
    locationGroup.setLayoutData(gridSpan(GridData.FILL_HORIZONTAL, 3));
    locationGroup.setLayout(new GridLayout(3, false));

    useDefaultLocation = addCheckbox(locationGroup,
        Messages.getString("use.default.workspace.location"), true); //$NON-NLS-1$

    addLabel(locationGroup, Messages.getString("location")); //$NON-NLS-1$

    String defaultLocation = ResourcesPlugin.getWorkspace().getRoot().getLocation().toString();
    locationInput = new Text(locationGroup, SWT.SINGLE | SWT.BORDER);
    locationInput.setText(defaultLocation);
    locationInput.setEnabled(false);
    locationInput.setLayoutData(new GridData(GridData.FILL_HORIZONTAL));
    locationInput.setToolTipText(Messages.getString("location.tooltip")); //$NON-NLS-1$

    locationBrowse = ButtonFactory.newPushButton(locationGroup, Messages.getString("browse")); //$NON-NLS-1$
    locationBrowse.setEnabled(false);

    projectNameTemplate = addCombo(formComposite, Messages.getString("name.template"), false); //$NON-NLS-1$
    projectNameTemplate.setToolTipText(
        Messages.getString("name.template.tooltip")); //$NON-NLS-1$
    projectNameTemplate.add("[artifactId]"); //$NON-NLS-1$
    projectNameTemplate.add("[groupId]-[artifactId]"); //$NON-NLS-1$
    projectNameTemplate.setLayoutData(gridSpan(GridData.FILL_HORIZONTAL, 1));

    // Register all the listeners
    addListeners(defaultLocation);

    formComposite.layout();
    parent.layout();
  }
  

  private void setHelp(Composite container) {
    PlatformUI.getWorkbench().getHelpSystem().setHelp(container,
        "com.google.cloud.tools.eclipse.dataflow.ui.NewDataflowProjectContext"); //$NON-NLS-1$
  }

  private void validateAndSetError() {
    Collection<DataflowProjectValidationStatus> validations = targetCreator.validate();
    for (DataflowProjectValidationStatus status : validations) {
      if (status.isError()) {
        setErrorMessage(status.getMessage());
        setPageComplete(false);
        return;
      }
    }
    for (DataflowProjectValidationStatus status : validations) {
      if (status.isMissing()) {
        setErrorMessage(null);
        setMessage(status.getMessage());
        setPageComplete(false);
        return;
      }
    }
    setMessage(null);
    setErrorMessage(null);
    setPageComplete(true);
  }

  private void addListeners(String defaultProjectLocation) {
    // When default location is selected, overwrite the input with the defaultProjectLocation
    useDefaultLocation.addSelectionListener(
        showDefaultOrCustomValueListener(defaultProjectLocation));

    // When the Browse button is pressed, open a directory selection dialogue
    locationBrowse.addSelectionListener(folderSelectionListener(getShell()));

    // Updating the group ID updates the the default package name
    ModifyListener propagateGroupIdToPackageListener = propagateGroupIdToPackageListener();
    groupIdInput.addModifyListener(propagateGroupIdToPackageListener);
    packageInput.addFocusListener(
        changeGroupIdPropogationListener(propagateGroupIdToPackageListener));

    // When the project inputs are modified, validate them and update the error message
    locationInput.addModifyListener(validateAndSetProjectLocationListener());
    groupIdInput.addModifyListener(validateAndSetMavenGroupIdListener());
    artifactIdInput.addModifyListener(validateAndSetMavenArtifactIdListener());
    packageInput.addModifyListener(validateAndSetPackageListener());
    projectNameTemplate.addModifyListener(setProjectNameTemplate());

    templateDropdown.addSelectionListener(templateListener());
    templateVersionDropdown.addModifyListener(customTemplateVersionListener());
    templateVersionDropdown.addSelectionListener(templateVersionListener());
  }

  private ModifyListener setProjectNameTemplate() {
    return new ModifyListener() {
      @Override
      public void modifyText(ModifyEvent event) {
        targetCreator.setProjectNameTemplate(projectNameTemplate.getText());
      }
    };
  }

  private ModifyListener propagateGroupIdToPackageListener() {
    return new ModifyListener() {
      @Override
      public void modifyText(ModifyEvent event) {
        packageInput.setText(groupIdInput.getText());
      }
    };
  }

  private FocusListener changeGroupIdPropogationListener(final ModifyListener propogationListener) {
    return new FocusListener() {
      @Override
      public void focusLost(FocusEvent event) {
        if (Strings.isNullOrEmpty(packageInput.getText())
            || packageInput.getText().equals(groupIdInput.getText())) {
          packageInput.setText(groupIdInput.getText());
          groupIdInput.addModifyListener(propogationListener);
        }
      }

      @Override
      public void focusGained(FocusEvent event) {
        groupIdInput.removeModifyListener(propogationListener);
      }
    };
  }

  private SelectionListener templateListener() {
    return new SelectionAdapter() {
      @Override
      public void widgetSelected(SelectionEvent event) {
        targetCreator.setTemplate(DataflowProjectArchetype.values()[templateDropdown.getSelectionIndex()]);
        updateAvailableVersions();
      }
    };
  }

  /**
   * Update the dropdown of available template (archetype) versions to versions that are available
   * for the currently selected template. If the available versions for the currently selected
   * template do not include the currently selected version, select the latest stable version.
   */
  private void updateAvailableVersions() {
    String selected = templateVersionDropdown.getText();
    templateVersionDropdown.removeAll();

    DataflowProjectArchetype template = DataflowProjectArchetype.values()[templateDropdown.getSelectionIndex()];
    for (MajorVersion majorVersion : template.getSdkVersions().descendingSet()) {
      ArtifactVersion latestArtifact = ArtifactRetriever.DEFAULT.getLatestReleaseVersion(
          DataflowMavenCoordinates.GROUP_ID, template.getArtifactId(),
          majorVersion.getVersionRange());

      if (latestArtifact != null) {
        templateVersionDropdown.add(latestArtifact.toString());
        if (latestArtifact.toString().equals(selected)) {
          templateVersionDropdown.select(templateVersionDropdown.getItemCount() - 1);
        }
      }
    }

    if (templateVersionDropdown.getSelectionIndex() == -1) {
      templateVersionDropdown.select(0);
    }
    updateArchetypeVersion();
  }

  private ModifyListener customTemplateVersionListener() {
    return new ModifyListener() {
      @Override
      public void modifyText(ModifyEvent modifyEvent) {
        updateArchetypeVersion();
      }
    };
  }

  private SelectionListener templateVersionListener() {
    return new SelectionAdapter() {
      @Override
      public void widgetSelected(SelectionEvent event) {
        updateArchetypeVersion();
      }
    };
  }

  private void updateArchetypeVersion() {
    targetCreator.setArchetypeVersion(templateVersionDropdown.getText());
    validateAndSetError();
  }

  private SelectionListener showDefaultOrCustomValueListener(final String defaultValue) {
    return new SelectionAdapter() {
      private String customValue = ""; //$NON-NLS-1$

      @Override
      public void widgetSelected(SelectionEvent event) {
        boolean customLocation = !useDefaultLocation.getSelection();

        // Update the targetCreator
        targetCreator.setCustomLocation(customLocation);

        // Enable/disable the location inputs as appropriate
        locationBrowse.setEnabled(customLocation);
        locationInput.setEnabled(customLocation);

        // Capture the current customValue if we're disabling custom values.
        if (!customLocation) {
          customValue = locationInput.getText();
        }

        // Update the locationInput box
        locationInput.setText(customLocation ? customValue : defaultValue);
      }
    };
  }

  private ModifyListener validateAndSetMavenArtifactIdListener() {
    return new ModifyListener() {
      @Override
      public void modifyText(ModifyEvent event) {
        targetCreator.setMavenArtifactId(artifactIdInput.getText());
        validateAndSetError();
      }
    };
  }
  private ModifyListener validateAndSetMavenGroupIdListener() {
    return new ModifyListener() {
      @Override
      public void modifyText(ModifyEvent event) {
        targetCreator.setMavenGroupId(groupIdInput.getText());
        validateAndSetError();
      }
    };
  }

  private ModifyListener validateAndSetProjectLocationListener() {
    return new ModifyListener() {
      @Override
      public void modifyText(ModifyEvent event) {
        String locationInputString = locationInput.getText();
        if (Strings.isNullOrEmpty(locationInputString)) {
          targetCreator.setProjectLocation(null);
          validateAndSetError();
        } else {
          File file = new File(locationInputString);
          URI location = file.toURI();
          targetCreator.setProjectLocation(location);
          validateAndSetError();
        }
      }
    };
  }

  private ModifyListener validateAndSetPackageListener() {
    return new ModifyListener() {
      @Override
      public void modifyText(ModifyEvent event) {
        String packageInputString = packageInput.getText();
        targetCreator.setPackage(packageInputString);
        validateAndSetError();
      }
    };
  }

  /**
   * A listener that opens a folder selection dialog when the button is pressed and sets the text
   * when the dialog was closed if a selection was made.
   */
  private SelectionListener folderSelectionListener(final Shell shell) {
    return new SelectionAdapter() {
      @Override
      public void widgetSelected(SelectionEvent event) {
        DirectoryDialog dialog = new DirectoryDialog(shell);
        dialog.setMessage(Messages.getString("select.project.location")); //$NON-NLS-1$
        String result = dialog.open();
        if (!Strings.isNullOrEmpty(result)) {
          locationInput.setText(result);
        }
      }
    };
  }

  public boolean isDefaultLocation() {
    return useDefaultLocation.getSelection();
  }

  public URI getProjectLocation() {
    if (isDefaultLocation()) {
      return null;
    }
    return URI.create(locationInput.getText());
  }

  public String getGroupId() {
    return groupIdInput.getText();
  }

  public String getArtifactId() {
    return artifactIdInput.getText();
  }
}