/*
    * Licensed to the Apache Software Foundation (ASF) under one or more
    * contributor license agreements.  See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The ASF licenses this file to You 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 org.apache.commons.jexl2; 
  
  import java.lang.reflect.Constructor;
  import java.lang.reflect.Method;
  import java.util.Iterator;
  import java.util.Map;
  import java.util.List;
  import java.util.ArrayList;
  
  import org.apache.commons.jexl2.parser.JexlNode;
  import org.apache.commons.jexl2.parser.ASTJexlScript;
  
  import junit.framework.TestCase;
  
  /**
   * Implements runTest methods to dynamically instantiate and invoke a test,
   * wrapping the call with setUp(), tearDown() calls.
   * Eases the implementation of main methods to debug.
   */
  public class JexlTestCase extends TestCase {
      /** No parameters signature for test run. */
      private static final Class<?>[] noParms = {};
      /** String parameter signature for test run. */
      private static final Class<?>[] stringParm = {String.class};
  
      /** A default Jexl engine instance. */
      protected final JexlEngine JEXL;
  
      public JexlTestCase(String name) {
          this(name, new JexlEngine());
      }
      protected JexlTestCase(String name, JexlEngine jexl) {
          super(name);
          JEXL = jexl;
          JEXL.setCache(512);
      }
      public JexlTestCase() {
          this(new JexlEngine());
      }
      protected JexlTestCase(JexlEngine jexl) {
          super();
          JEXL = jexl;
          JEXL.setCache(512);
      }
  
      @Override
      protected void tearDown() throws Exception {
          debuggerCheck(JEXL);
      }
  
      public static JexlEngine createEngine(boolean lenient) {
          return new JexlEngine(null, new JexlArithmetic(lenient), null, null);
      }
  
      public static JexlEngine createThreadedArithmeticEngine(boolean lenient) {
          return new JexlEngine(null, new JexlThreadedArithmetic(lenient), null, null);
      }
      
      /**
       * Will force testing the debugger for each derived test class by
       * recreating each expression from the JexlNode in the JexlEngine cache &
       * testing them for equality with the origin.
       * @throws Exception
       */
      public static void debuggerCheck(JexlEngine jexl) throws Exception {
          // without a cache, nothing to check
          if (jexl.cache == null) {
              return;
          }
          JexlEngine jdbg = new JexlEngine();
          jdbg.parser.ALLOW_REGISTERS = true;
          Debugger dbg = new Debugger();
          // iterate over all expression in cache
          Iterator<Map.Entry<String,ASTJexlScript>> inodes = jexl.cache.entrySet().iterator();
          while (inodes.hasNext()) {
              Map.Entry<String,ASTJexlScript> entry = inodes.next();
              JexlNode node = entry.getValue();
              // recreate expr string from AST
              dbg.debug(node);
              String expressiondbg = dbg.data();
              // recreate expr from string
              Script exprdbg = jdbg.createScript(expressiondbg);
             // make arg cause become the root cause
             JexlNode root = ((ExpressionImpl) exprdbg).script;
             while (root.jjtGetParent() != null) {
                 root = root.jjtGetParent();
             }
             // test equality
             String reason = JexlTestCase.checkEquals(root, node);
             if (reason != null) {
                 throw new RuntimeException("debugger equal failed: "
                                            + expressiondbg
                                            +" /**** "  +reason+" **** */ "
                                            + entry.getKey());
             }
         }
     }
 
     /**
      * Creates a list of all descendants of a script including itself.
      * @param script the script to flatten
      * @return the descendants-and-self list
      */
     protected static ArrayList<JexlNode> flatten(JexlNode node) {
         ArrayList<JexlNode> list = new ArrayList<JexlNode>();
         flatten(list, node);
         return list;
     }
 
     /**
      * Recursively adds all children of a script to the list of descendants.
      * @param list the list of descendants to add to
      * @param script the script & descendants to add
      */
     private static void flatten(List<JexlNode> list, JexlNode node) {
         int nc = node.jjtGetNumChildren();
         list.add(node);
         for(int c = 0; c < nc; ++c) {
             flatten(list, node.jjtGetChild(c));
         }
     }
 
     /**
      * Checks the equality of 2 nodes by comparing all their descendants.
      * Descendants must have the same class and same image if non null.
      * @param lhs the left script
      * @param rhs the right script
      * @return null if true, a reason otherwise
      */
     private static String checkEquals(JexlNode lhs, JexlNode rhs) {
         if (lhs != rhs) {
             ArrayList<JexlNode> lhsl = flatten(lhs);
             ArrayList<JexlNode> rhsl = flatten(rhs);
             if (lhsl.size() != rhsl.size()) {
                  return "size: " + lhsl.size() + " != " + rhsl.size();
             }
             for(int n = 0; n < lhsl.size(); ++n) {
                 lhs = lhsl.get(n);
                 rhs = rhsl.get(n);
                 if (lhs.getClass() != rhs.getClass()) {
                     return "class: " + lhs.getClass() + " != " + rhs.getClass();
                 }
                 if ((lhs.image == null && rhs.image != null)
                     || (lhs.image != null && rhs.image == null)) {
                     return "image: " + lhs.image + " != " + rhs.image;
                 }
                 if (lhs.image != null && !lhs.image.equals(rhs.image)) {
                     return "image: " + lhs.image + " != " + rhs.image;
                 }
             }
         }
         return null;
     }
     
     /**
      * A helper class to help debug AST problems.
      * @param e the script
      * @return an indented version of the AST
      */
     protected String flattenedStr(Script e) {
         return e.getText() + "\n" + flattenedStr(((ExpressionImpl) e).script);
     }
 
     static private String indent(JexlNode node) {
         StringBuilder strb = new StringBuilder();
         while (node != null) {
             strb.append("  ");
             node = node.jjtGetParent();
         }
         return strb.toString();
     }
 
 
     private String flattenedStr(JexlNode node) {
         ArrayList<JexlNode> flattened = flatten(node);
         StringBuilder strb = new StringBuilder();
         for (JexlNode flat : flattened) {
             strb.append(indent(flat));
             strb.append(flat.getClass().getSimpleName());
             if (flat.image != null) {
                 strb.append(" = ");
                 strb.append(flat.image);
             }
             strb.append("\n");
         }
         return strb.toString();
     }
     /**
      * Dynamically runs a test method.
      * @param name the test method to run
      * @throws Exception if anything goes wrong
      */
     public void runTest(String name) throws Exception {
         if ("runTest".equals(name)) {
             return;
         }
         Method method = null;
         try {
             method = this.getClass().getDeclaredMethod(name, noParms);
         }
         catch(Exception xany) {
             fail("no such test: " + name);
             return;
         }
         try {
             this.setUp();
             method.invoke(this);
         } finally {
             this.tearDown();
         }
     }
 
     /**
      * Instantiate and runs a test method; useful for debugging purpose.
      * For instance:
      * <code>
      * public static void main(String[] args) throws Exception {
      *   runTest("BitwiseOperatorTest","testAndVariableNumberCoercion");
      * }
      * </code>
      * @param tname the test class name
      * @param mname the test class method
      * @throws Exception
      */
     public static void runTest(String tname, String mname) throws Exception {
         String testClassName = "org.apache.commons.jexl2."+tname;
         Class<JexlTestCase> clazz = null;
         JexlTestCase test = null;
         // find the class
         try {
             clazz = (Class<JexlTestCase>) Class.forName(testClassName);
         }
         catch(ClassNotFoundException xclass) {
             fail("no such class: " + testClassName);
             return;
         }
         // find ctor & instantiate
         Constructor<JexlTestCase> ctor = null;
         try {
             ctor = clazz.getConstructor(stringParm);
             test = ctor.newInstance("debug");
         }
         catch(NoSuchMethodException xctor) {
             // instantiate default class ctor
             try {
                 test = clazz.newInstance();
             }
             catch(Exception xany) {
                 fail("cant instantiate test: " + xany);
                 return;
             }
         }
         catch(Exception xany) {
             fail("cant instantiate test: " + xany);
             return;
         }
         // Run the test
         test.runTest(mname);
     }
 
     /**
      * Runs a test.
      * @param args where args[0] is the test class name and args[1] the test class method
      * @throws Exception
      */
     public static void main(String[] args) throws Exception {
         runTest(args[0], args[1]);
     }
 }