/*
    * 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
    *
    *      https://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.parser;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertFalse;
  import static org.junit.jupiter.api.Assertions.assertNotNull;
  import static org.junit.jupiter.api.Assertions.assertThrows;
  
  import org.apache.commons.jexl3.JexlException;
  import org.apache.commons.jexl3.JexlFeatures;
  import org.junit.jupiter.api.Test;
  
  /**
   */
  class ParserTest {
      static final JexlFeatures FEATURES = new JexlFeatures();
      public ParserTest() {}
  
      /**
       * Test the escaped control characters.
       */
      @Test
      void testControlCharacters() {
          // Both '' and "" are valid JEXL string
          // The array of tuples where the first element is an expected result and the second element is a test string.
          final String[][] strings = {
              new String[] {"a\nb\tc", "'a\nb\tc'"}, // we still honor the actual characters
              new String[] {"a\nb\tc", "'a\\nb\\tc'"},
              new String[] {"a\nb\tc", "\"a\\nb\\tc\""},
              new String[] {"\b\t\n\f\r", "'\\b\\t\\n\\f\\r'"},
              new String[] {"'hi'", "'\\'hi\\''"},
              new String[] {"\"hi\"", "'\"hi\"'"},
              new String[] {"\"hi\"", "'\"hi\"'"},
          };
          for(final String[] pair: strings) {
              final String output = StringParser.buildString(pair[1], true);
              assertEquals(pair[0], output);
          }
      }
  
      /**
       * Test unicode escape sequences: only 4 hex digits (0-9, a-f, A-F) form a unicode char;
       * an out-of-range digit (g/h/...) is not a valid escape and passes through literally.
       */
      @Test
      void testUnicodeEscape() {
          // valid unicode escapes decode to the expected character
          assertEquals("A", StringParser.buildString("'\\u0041'", true));
          assertEquals(String.valueOf((char) 0x00ff), StringParser.buildString("'\\u00ff'", true));
          assertEquals(String.valueOf((char) 0x00ff), StringParser.buildString("'\\u00FF'", true));
          assertEquals("Z9", StringParser.buildString("'\\u005a\\u0039'", true));
          // out-of-range hex digits ('g'/'h'/'G'/'H') are NOT consumed as a unicode escape:
          // the escape is not recognized, so the '\\u' is re-emitted followed by the raw characters.
          assertEquals("\\ug000", StringParser.buildString("'\\ug000'", true));
          assertEquals("\\u00fh", StringParser.buildString("'\\u00fh'", true));
          assertEquals("\\uH000", StringParser.buildString("'\\uH000'", true));
      }
  
      @Test
      void testErrorAmbiguous() throws Exception {
          final Parser parser = new Parser(";");
          assertThrows(JexlException.Ambiguous.class, () -> parser.parse(null, FEATURES, "x = 1 y = 5", null), "should have failed on ambiguous statement");
      }
  
      @Test
      void testErrorAssign() throws Exception {
          final String[] ops = { "=", "+=", "-=", "/=", "*=", "^=", "&=", "|=" };
          for (final String op : ops) {
              final Parser parser = new Parser(";");
              final JexlException.Parsing xparse = assertThrows(JexlException.Parsing.class, () -> parser.parse(null, FEATURES, "foo() " + op + " 1;", null),
                      () -> "should have failed on invalid assignment " + op);
              assertNotNull(xparse.getDetail());
              assertNotNull(xparse.toString());
          }
      }
  
      @Test
      void testIdentifierEscape() {
          final String[] ids = {"a\\ b", "a\\ b\\ c", "a\\'b\\\"c", "a\\ \\ c"};
          for(final String id : ids) {
              final String esc0 = StringParser.unescapeIdentifier(id);
              assertFalse(esc0.contains("\\"));
              final String esc1 = StringParser.escapeIdentifier(esc0);
              assertEquals(id, esc1);
         }
     }
 
     /**
      * See if we can parse simple scripts
      */
     @Test
     void testParse() throws Exception {
         final Parser parser = new Parser(";");
         JexlNode sn;
         sn = parser.parse(null, FEATURES, "foo = 1;", null);
         assertNotNull(sn, "parsed node is null");
 
         sn = parser.parse(null, FEATURES, "foo = \"bar\";", null);
         assertNotNull(sn, "parsed node is null");
 
         sn = parser.parse(null, FEATURES, "foo = 'bar';", null);
         assertNotNull(sn, "parsed node is null");
     }
 }