/*
    * Themis: Java Project Framework
    * Copyright 2026. Tony Washer
    *
    * 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 io.github.tonywasher.joceanus.themis.gui.source;
  
  import io.github.tonywasher.joceanus.oceanus.event.OceanusEventManager;
  import io.github.tonywasher.joceanus.oceanus.event.OceanusEventRegistrar;
  import io.github.tonywasher.joceanus.oceanus.event.OceanusEventRegistrar.OceanusEventProvider;
  import io.github.tonywasher.joceanus.tethys.api.base.TethysUIComponent;
  import io.github.tonywasher.joceanus.tethys.api.base.TethysUIEvent;
  import io.github.tonywasher.joceanus.tethys.api.button.TethysUIScrollButtonManager;
  import io.github.tonywasher.joceanus.tethys.api.control.TethysUIControlFactory;
  import io.github.tonywasher.joceanus.tethys.api.control.TethysUILabel;
  import io.github.tonywasher.joceanus.tethys.api.factory.TethysUIFactory;
  import io.github.tonywasher.joceanus.tethys.api.menu.TethysUIScrollItem;
  import io.github.tonywasher.joceanus.tethys.api.menu.TethysUIScrollMenu;
  import io.github.tonywasher.joceanus.tethys.api.pane.TethysUIBoxPaneManager;
  import io.github.tonywasher.joceanus.tethys.api.pane.TethysUIPaneFactory;
  import io.github.tonywasher.joceanus.themis.gui.base.ThemisUIResource;
  import io.github.tonywasher.joceanus.themis.parser.base.ThemisChar;
  import io.github.tonywasher.joceanus.themis.parser.proj.ThemisModule;
  import io.github.tonywasher.joceanus.themis.parser.proj.ThemisPackage;
  
  /**
   * Button to select package from module.
   */
  public class ThemisUISourcePackageSelect
          implements OceanusEventProvider<TethysUIEvent>, TethysUIComponent {
      /**
       * The Event Manager.
       */
      private final OceanusEventManager<TethysUIEvent> theEventManager;
  
      /**
       * The scroll button.
       */
      private final TethysUIScrollButtonManager<ThemisPackage> theButton;
  
      /**
       * The package menu.
       */
      private final TethysUIScrollMenu<ThemisPackage> thePackageMenu;
  
      /**
       * The package select.
       */
      private final ThemisUISourceFileSelect theFileSelect;
  
      /**
       * The prefixLabel.
       */
      private final TethysUILabel thePrefixLabel;
  
      /**
       * The panel.
       */
      private final TethysUIBoxPaneManager thePanel;
  
      /**
       * The current module.
       */
      private ThemisModule theModule;
  
      /**
       * The current package.
       */
      private ThemisPackage thePackage;
  
      /**
       * The current prefix.
       */
      private String thePrefix;
  
      /**
       * Constructor.
       *
       * @param pFactory    the factory
       * @param pFileSelect the fileSelectButton
       */
      ThemisUISourcePackageSelect(final TethysUIFactory<?> pFactory,
                                  final ThemisUISourceFileSelect pFileSelect) {
          /* Store the file select */
          theFileSelect = pFileSelect;
  
          /* Create Event Manager */
         theEventManager = new OceanusEventManager<>();
 
         /* Create the labels */
         final TethysUIControlFactory myControls = pFactory.controlFactory();
         thePrefixLabel = myControls.newLabel();
         final TethysUILabel myPromptLabel = myControls.newLabel(ThemisUIResource.PROMPT_PACKAGE.getValue());
 
         /* Create the button */
         theButton = pFactory.buttonFactory().newScrollButton(ThemisPackage.class);
         thePackageMenu = theButton.getMenu();
 
         /* Create the panel */
         final TethysUIPaneFactory myPanes = pFactory.paneFactory();
         thePanel = myPanes.newHBoxPane();
         thePanel.addNode(myPromptLabel);
         thePanel.addNode(thePrefixLabel);
         thePanel.addNode(theButton);
 
         /* Set listeners */
         final OceanusEventRegistrar<TethysUIEvent> myRegistrar = theButton.getEventRegistrar();
         myRegistrar.addEventListener(TethysUIEvent.NEWVALUE, e -> handleNewPackage());
         theButton.setMenuConfigurator(e -> buildPackageMenu());
     }
 
     @Override
     public OceanusEventRegistrar<TethysUIEvent> getEventRegistrar() {
         return theEventManager.getEventRegistrar();
     }
 
     @Override
     public TethysUIComponent getUnderlying() {
         return thePanel;
     }
 
     /**
      * Obtain the current package.
      *
      * @return the current package
      */
     ThemisPackage getCurrentPackage() {
         return thePackage;
     }
 
     /**
      * Set the current module.
      *
      * @param pModule the current module
      */
     void setCurrentModule(final ThemisModule pModule) {
         /* Store the module */
         theModule = pModule;
 
         /* Determine the prefix */
         determinePrefix();
 
         /* Set the default package */
         final ThemisPackage myPackage = getDefaultPackage();
         theButton.setValue(myPackage, getDisplayName(myPackage));
         handleNewPackage();
     }
 
     /**
      * Obtain the default package.
      *
      * @return the default package
      */
     private ThemisPackage getDefaultPackage() {
         /* If we have a non-null module */
         if (theModule != null) {
             /* Loop through the available packages */
             for (ThemisPackage myPackage : theModule.getPackages()) {
                 /* Skip package if necessary */
                 if (skipPackage(myPackage)) {
                     continue;
                 }
 
                 /* Return the valid package */
                 return myPackage;
             }
         }
 
         /* No package */
         return null;
     }
 
     /**
      * Determine the prefix.
      */
     private void determinePrefix() {
         /* Initialise the prefix */
         thePrefix = null;
         theButton.setVisible(false);
 
         /* If we have a non-null modules */
         if (theModule != null) {
             /* Loop through the available packages */
             for (ThemisPackage myPackage : theModule.getPackages()) {
                 /* Adjust the prefix */
                 adjustPrefix(myPackage);
             }
         }
 
         /* Update the prefixLabel */
         thePrefixLabel.setText(thePrefix);
         thePrefixLabel.setVisible(thePrefix != null && !thePrefix.isEmpty());
     }
 
     /**
      * Adjust prefix.
      *
      * @param pPackage the package
      */
     private void adjustPrefix(final ThemisPackage pPackage) {
         /* Ignore placeHolder */
         if (skipPackage(pPackage)) {
             return;
         }
 
         /* If we do not have a prefix */
         final String myName = pPackage.getPackage();
         if (thePrefix == null) {
             thePrefix = myName;
 
             /* else if we need to change the prefix */
         } else {
             /* We have more than one package so display selection button */
             theButton.setVisible(true);
 
             /* Determine common prefix */
             thePrefix = getCommonPrefix(myName, thePrefix);
         }
     }
 
     /**
      * Obtain common prefix.
      *
      * @param pFirst  the first name
      * @param pSecond the second name
      * @return the prefix
      */
     private String getCommonPrefix(final String pFirst,
                                    final String pSecond) {
         if (pFirst.equals(pSecond)) {
             return pFirst;
         }
         return pFirst.length() >= pSecond.length()
                 ? getCommonPrefix(getParentName(pFirst), pSecond)
                 : getCommonPrefix(pFirst, getParentName(pSecond));
     }
 
     /**
      * Obtain Parent Name.
      *
      * @param pName the name
      * @return the parent name
      */
     private String getParentName(final String pName) {
         /* Determine the short name */
         final int iIndex = pName.lastIndexOf(ThemisChar.PERIOD);
         return iIndex == -1 ? "" : pName.substring(0, iIndex);
     }
 
     /**
      * Obtain the displayName of the package.
      *
      * @param pPackage the package
      * @return the displayName
      */
     private String getDisplayName(final ThemisPackage pPackage) {
         final int myPrefixLen = thePrefix == null ? 0 : thePrefix.length();
         return pPackage == null ? "" : pPackage.getPackage().substring(myPrefixLen);
     }
 
     /**
      * Build the package menu.
      */
     private void buildPackageMenu() {
         /* Reset the popUp menu */
         thePackageMenu.removeAllItems();
 
         /* Record active item */
         TethysUIScrollItem<ThemisPackage> myActive = null;
         final ThemisPackage myCurr = theButton.getValue();
 
         /* Loop through the available packages */
         for (ThemisPackage myPackage : theModule.getPackages()) {
             /* skip package if required */
             if (skipPackage(myPackage)) {
                 continue;
             }
 
             /* Create a new MenuItem and add it to the popUp */
             final TethysUIScrollItem<ThemisPackage> myItem = thePackageMenu.addItem(myPackage, getDisplayName(myPackage));
 
             /* If this is the active package */
             if (myPackage.equals(myCurr)) {
                 /* Record it */
                 myActive = myItem;
             }
         }
 
         /* Ensure active item is visible */
         if (myActive != null) {
             myActive.scrollToItem();
         }
     }
 
     /**
      * Should we skip the package?
      *
      * @param pPackage the package
      * @return true/false
      */
     private boolean skipPackage(final ThemisPackage pPackage) {
         /* Skip placeholders */
         return pPackage.isPlaceHolder();
     }
 
     /**
      * Handle new Package.
      */
     private void handleNewPackage() {
         /* Select the new package */
         thePackage = theButton.getValue();
         theEventManager.fireEvent(TethysUIEvent.NEWVALUE);
         theFileSelect.setCurrentPackage(thePackage);
     }
 }