/*
    * scriptable-dataset (https://github.com/hazendaz/scriptable-dataset)
    *
    * Copyright 2011-2025 Hazendaz.
    *
    * All rights reserved. This program and the accompanying materials
    * are made available under the terms of The Apache Software License,
    * Version 2.0 which accompanies this distribution, and is available at
    * https://www.apache.org/licenses/LICENSE-2.0.txt
   *
   * Contributors:
   *     Gunnar Morling
   *     Hazendaz (Jeremy Landis).
   */
  package de.gmorling.scriptabledataset;
  
  import de.gmorling.scriptabledataset.handlers.ScriptInvocationHandler;
  import de.gmorling.scriptabledataset.handlers.StandardHandlerConfig;
  
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  import java.util.Map.Entry;
  
  import javax.script.ScriptEngine;
  import javax.script.ScriptEngineManager;
  import javax.script.ScriptException;
  
  import org.dbunit.dataset.DataSetException;
  import org.dbunit.dataset.ITable;
  import org.dbunit.dataset.ITableMetaData;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * ITable implementation, that allows the usage of script statements as field values.
   */
  public class ScriptableTable implements ITable {
  
      /** The logger. */
      private final Logger logger = LoggerFactory.getLogger(ScriptableTable.class);
  
      /** The wrapped. */
      private ITable wrapped;
  
      /** The engines by prefix. */
      private Map<String, ScriptEngine> enginesByPrefix = new HashMap<>();
  
      /** The handlers by prefix. */
      private Map<String, List<ScriptInvocationHandler>> handlersByPrefix = new HashMap<>();
  
      /**
       * Creates a new ScriptableTable.
       *
       * @param wrapped
       *            The ITable to be wrapped by this scriptable table. May not be null.
       * @param configurations
       *            An list with configurations
       */
      public ScriptableTable(ITable wrapped, List<ScriptableDataSetConfig> configurations) {
  
          this.wrapped = wrapped;
  
          ScriptEngineManager manager = new ScriptEngineManager();
  
          // load the engines
          for (ScriptableDataSetConfig oneConfig : configurations) {
  
              ScriptEngine engine = manager.getEngineByName(oneConfig.getLanguageName());
  
              if (engine == null) {
                  throw new RuntimeException(
                          "No scripting engine found for language \"" + oneConfig.getLanguageName() + "\".");
              }
              enginesByPrefix.put(oneConfig.getPrefix(), engine);
  
              List<ScriptInvocationHandler> handlers = getAllHandlers(oneConfig);
  
              for (ScriptInvocationHandler oneHandler : handlers) {
                  oneHandler.setScriptEngine(engine);
              }
  
              handlersByPrefix.put(oneConfig.getPrefix(), handlers);
  
              logger.info("Registered scripting engine {} for language {}.", engine, oneConfig.getLanguageName());
          }
      }
  
      @Override
      public int getRowCount() {
          return wrapped.getRowCount();
      }
  
      @Override
      public ITableMetaData getTableMetaData() {
          return wrapped.getTableMetaData();
      }
 
     @Override
     public Object getValue(int row, String column) throws DataSetException {
 
         Object theValue = wrapped.getValue(row, column);
 
         // only strings can be processed
         if (theValue instanceof String script) {
 
             for (Entry<String, ScriptEngine> oneEntry : enginesByPrefix.entrySet()) {
 
                 String prefix = oneEntry.getKey();
 
                 // found engine for prefix
                 if (script.startsWith(prefix)) {
 
                     ScriptEngine engine = oneEntry.getValue();
                     script = script.substring(prefix.length());
 
                     List<ScriptInvocationHandler> handlers = handlersByPrefix.get(oneEntry.getKey());
 
                     // preInvoke
                     for (ScriptInvocationHandler handler : handlers) {
                         script = handler.preInvoke(script);
                     }
 
                     logger.debug("Executing script: {}", script);
 
                     // the actual script evaluation
                     try {
                         theValue = engine.eval(script);
                     } catch (ScriptException e) {
                         throw new RuntimeException(e);
                     }
 
                     // call postInvoke in reversed order
                     Collections.reverse(handlers);
                     for (ScriptInvocationHandler handler : handlers) {
                         theValue = handler.postInvoke(theValue);
                     }
                 }
             }
         }
 
         return theValue;
     }
 
     /**
      * Returns a list with all standard handlers registered for the language of the config and all handlers declared in
      * the config itself.
      *
      * @param config
      *            A config object.
      *
      * @return A list with handlers. Never null.
      */
     private List<ScriptInvocationHandler> getAllHandlers(ScriptableDataSetConfig config) {
 
         List<ScriptInvocationHandler> theValue = new ArrayList<>(
                 StandardHandlerConfig.getStandardHandlersByLanguage(config.getLanguageName()));
 
         // custom handlers
         theValue.addAll(config.getHandlers());
 
         return theValue;
     }
 }