package org.metricshub.jawk.ext;
   
   /*-
    * ╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲
    * Jawk
    * ჻჻჻჻჻჻
    * Copyright (C) 2006 - 2025 MetricsHub
    * ჻჻჻჻჻჻
    * This program is free software: you can redistribute it and/or modify
   * it under the terms of the GNU Lesser General Public License as
   * published by the Free Software Foundation, either version 3 of the
   * License, or (at your option) any later version.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Lesser Public License for more details.
   *
   * You should have received a copy of the GNU General Lesser Public
   * License along with this program.  If not, see
   * <http://www.gnu.org/licenses/lgpl-3.0.html>.
   * ╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱
   */
  
  import java.lang.reflect.Method;
  import java.util.Collections;
  import java.util.LinkedHashMap;
  import java.util.Map;
  import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
  import org.metricshub.jawk.ext.annotations.JawkFunction;
  import org.metricshub.jawk.jrt.IllegalAwkArgumentException;
  import org.metricshub.jawk.jrt.JRT;
  import org.metricshub.jawk.jrt.VariableManager;
  import org.metricshub.jawk.util.AwkSettings;
  
  /**
   * Base class of various extensions.
   * <p>
   * Provides functionality common to most extensions,
   * such as VM and JRT variable management, and convenience
   * methods such as checkNumArgs() and toAwkString().
   *
   * @author Danny Daglas
   */
  public abstract class AbstractExtension implements JawkExtension {
  
  	private JRT jrt;
  	private VariableManager vm;
  	private AwkSettings settings;
  	private Map<String, ExtensionFunction> annotatedFunctions;
  
  	/** {@inheritDoc} */
  	@Override
  	public String getExtensionName() {
  		return getClass().getSimpleName();
  	}
  
  	/** {@inheritDoc} */
  	@Override
  	@SuppressFBWarnings(value = "EI_EXPOSE_REP2", justification = "Extension needs direct access to runtime, VM and settings")
  	public void init(VariableManager vmParam, JRT runtime, final AwkSettings conf) {
  		this.vm = vmParam;
  		this.jrt = runtime;
  		this.settings = conf;
  	}
  
  	/**
  	 * Convert a Jawk variable to a Jawk string
  	 * based on the value of the CONVFMT variable.
  	 *
  	 * @param obj The Jawk variable to convert to a Jawk string.
  	 * @return A string representation of obj after CONVFMT
  	 *         has been applied.
  	 */
  	protected final String toAwkString(Object obj) {
  		return JRT.toAwkString(obj, getVm().getCONVFMT().toString(), settings.getLocale());
  	}
  
  	/**
  	 * Verifies that an exact number of arguments
  	 * has been passed in by checking the length
  	 * of the argument array.
  	 *
  	 * @param arr The arguments to check.
  	 * @param expectedNum The expected number of arguments.
  	 */
  	protected static void checkNumArgs(Object[] arr, int expectedNum) {
  		// some sanity checks on the arguments
  		// (made into assertions so that
  		// production code does not perform
  		// these checks)
  		assert arr != null;
  		assert expectedNum >= 0;
  
  		if (arr.length != expectedNum) {
  			throw new IllegalAwkArgumentException("Expecting " + expectedNum + " arg(s), got " + arr.length);
  		}
  	}
  
 	/**
 	 * <p>
 	 * Getter for the field <code>jrt</code>.
 	 * </p>
 	 *
 	 * @return the Runtime
 	 */
 	protected JRT getJrt() {
 		return jrt;
 	}
 
 	/**
 	 * <p>
 	 * Getter for the field <code>vm</code>.
 	 * </p>
 	 *
 	 * @return the Variable Manager
 	 */
 	protected VariableManager getVm() {
 		return vm;
 	}
 
 	/**
 	 * <p>
 	 * Getter for the field <code>settings</code>.
 	 * </p>
 	 *
 	 * @return the Settings
 	 */
 	protected AwkSettings getSettings() {
 		return settings;
 	}
 
 	private Map<String, ExtensionFunction> getAnnotatedFunctions() {
 		if (annotatedFunctions == null) {
 			annotatedFunctions = Collections.unmodifiableMap(scanAnnotatedFunctions());
 		}
 		return annotatedFunctions;
 	}
 
 	private Map<String, ExtensionFunction> scanAnnotatedFunctions() {
 		Map<String, ExtensionFunction> discovered = new LinkedHashMap<String, ExtensionFunction>();
 		Class<? extends AbstractExtension> type = getClass();
 		for (Method method : type.getMethods()) {
 			JawkFunction function = method.getAnnotation(JawkFunction.class);
 			if (function == null) {
 				continue;
 			}
 			String keyword = function.value();
 			ExtensionFunction existing = discovered.put(keyword, new ExtensionFunction(keyword, method));
 			if (existing != null) {
 				throw new IllegalStateException(
 						"Duplicate @JawkFunction mapping for keyword '" + keyword + "' in " + type.getName());
 			}
 		}
 		return discovered;
 	}
 
 	/** {@inheritDoc} */
 	@Override
 	public Map<String, ExtensionFunction> getExtensionFunctions() {
 		return getAnnotatedFunctions();
 	}
 }