/*
    * 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.jexl3.junit;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertThrows;
  import static org.junit.jupiter.api.Assertions.fail;
  
  import java.lang.reflect.Array;
  import java.math.BigDecimal;
  import java.math.BigInteger;
  import java.util.HashMap;
  import java.util.Map;
  import java.util.function.BiPredicate;
  
  import org.apache.commons.jexl3.JexlArithmetic;
  import org.apache.commons.jexl3.JexlContext;
  import org.apache.commons.jexl3.JexlEngine;
  import org.apache.commons.jexl3.JexlEvalContext;
  import org.apache.commons.jexl3.JexlException;
  import org.apache.commons.jexl3.JexlScript;
  
  /**
   * A utility class for performing JUnit based assertions using Jexl
   * expressions. This class can make it easier to do unit tests using
   * JEXL navigation expressions.
   *
   * @since 1.0
   */
  public class Asserter {
      /** Variables used during asserts. */
      private final Map<String, Object> variables = new HashMap<>();
      /** Context to use during asserts. */
      private final JexlEvalContext context = new JexlEvalContext(variables);
      /** JEXL engine to use during Asserts. */
      private final JexlEngine engine;
  
      /**
       *
       * Create an asserter.
       * @param jexl the JEXL engine to use
       */
      public Asserter(final JexlEngine jexl) {
          engine = jexl;
      }
  
      /**
       * Performs an assertion that the value of the given JEXL expression
       * evaluates to the given expected value.
       *
       * @param expression is the JEXL expression to evaluate
       * @param expected is the expected value of the expression
       * @throws Exception if the expression could not be evaluationed or an assertion
       * fails
       */
      public void assertExpression(final String expression, final Object expected, final Object... args) throws Exception {
          final JexlScript exp = engine.createScript(expression);
          final Object value = exp.execute(context, args);
          if (expected instanceof BigDecimal) {
              final JexlArithmetic jexla = engine.getArithmetic();
              assertEquals(0, ((BigDecimal) expected).compareTo(jexla.toBigDecimal(value)), () -> "expression: " + expression);
          } else if (expected instanceof BigInteger) {
              final JexlArithmetic jexla = engine.getArithmetic();
              assertEquals(0, ((BigInteger) expected).compareTo(jexla.toBigInteger(value)), () -> "expression: " + expression);
          } else if (expected != null && value != null) {
              if (expected.getClass().isArray() && value.getClass().isArray()) {
                  final int esz = Array.getLength(expected);
                  final int vsz = Array.getLength(value);
                  final String report = "expression: " + expression;
                  assertEquals(esz, vsz, () -> report + ", array size");
                  for (int i = 0; i < vsz; ++i) {
                      assertEquals(Array.get(expected, i), Array.get(value, i), report + ", value@[]" + i);
                  }
              } else {
                  assertEquals(expected, value,
                          () -> "expression: " + expression + ", " + expected.getClass().getSimpleName() + " ?= " + value.getClass().getSimpleName());
              }
          } else {
              assertEquals(expected, value, () -> "expression: " + expression);
          }
      }
  
      /**
       * Performs an assertion that the expression fails throwing an exception.
       * If matchException is not null, the exception message is expected to match it as a regexp.
      * The engine is temporarily switched to strict * verbose to maximize error detection abilities.
      * @param expression the expression that should fail
      * @param matchException the exception message pattern
      * @throws Exception if the expression did not fail or the exception did not match the expected pattern
      */
     public void failExpression(final String expression, final String matchException) throws Exception {
          failExpression(expression, matchException, String::matches);
     }
 
     public void failExpression(final String expression, final String matchException, final BiPredicate<String, String> predicate) throws Exception {
         final JexlException xjexl = assertThrows(JexlException.class, () -> engine.createScript(expression).execute(context));
         if (matchException != null && !predicate.test(xjexl.getMessage(), matchException)) {
             fail("expression: " + expression + ", expected: " + matchException + ", got " + xjexl.getMessage());
         }
     }
 
     /**
      * Retrieves the underlying JEXL context.
      * @return the JEXL context
      */
     public JexlContext getContext() {
         return context;
     }
 
     /**
      * Retrieves the underlying JEXL engine.
      * @return the JEXL engine
      */
     public JexlEngine getEngine() {
         return engine;
     }
 
     /**
      * Gets a variable of a certain name.
      *
      * @param name variable name
      * @return value variable value
      */
     public Object getVariable(final String name) {
         return variables.get(name);
     }
 
     /**
      * @return the variables map
      */
     public Map<String, Object> getVariables() {
         return variables;
     }
     /**
      * Removes a variable of a certain name from the context.
      * @param name variable name
      * @return variable value
      */
     public Object removeVariable(final String name) {
         return variables.remove(name);
     }
 
     public void setSilent(final boolean silent) {
         context.getEngineOptions().setSilent(silent);
     }
 
     public void setStrict(final boolean s) {
         context.getEngineOptions().setStrict(s);
     }
 
     public void setStrict(final boolean es, final boolean as) {
         context.getEngineOptions().setStrict(es);
         context.getEngineOptions().setStrictArithmetic(as);
     }
 
     /**
      * Puts a variable of a certain name in the context so that it can be used from
      * assertion expressions.
      *
      * @param name variable name
      * @param value variable value
      */
     public void setVariable(final String name, final Object value) {
         variables.put(name, value);
     }
 }