package org.apache.lucene.index;

/*
 * 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.
 */

import org.apache.lucene.util.LuceneTestCase;
import org.apache.lucene.util.TestUtil;
import org.apache.lucene.util.TestUtil;
import org.apache.lucene.store.ByteArrayDataInput;
import org.apache.lucene.store.ByteArrayDataOutput;
import org.apache.lucene.store.DataInput;
import org.apache.lucene.store.IndexInput;
import org.apache.lucene.store.IndexOutput;
import org.apache.lucene.store.RAMDirectory;

import org.junit.AfterClass;
import org.junit.BeforeClass;

import java.io.IOException;
import java.util.Random;

public class TestIndexInput extends LuceneTestCase {

  static final byte[] READ_TEST_BYTES = new byte[] { 
    (byte) 0x80, 0x01,
    (byte) 0xFF, 0x7F,
    (byte) 0x80, (byte) 0x80, 0x01,
    (byte) 0x81, (byte) 0x80, 0x01,
    (byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0x07,
    (byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0x0F,
    (byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0x07,
    (byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0x7F,
    0x06, 'L', 'u', 'c', 'e', 'n', 'e',

    // 2-byte UTF-8 (U+00BF "INVERTED QUESTION MARK") 
    0x02, (byte) 0xC2, (byte) 0xBF,
    0x0A, 'L', 'u', (byte) 0xC2, (byte) 0xBF, 
          'c', 'e', (byte) 0xC2, (byte) 0xBF, 
          'n', 'e',

    // 3-byte UTF-8 (U+2620 "SKULL AND CROSSBONES") 
    0x03, (byte) 0xE2, (byte) 0x98, (byte) 0xA0,
    0x0C, 'L', 'u', (byte) 0xE2, (byte) 0x98, (byte) 0xA0,
          'c', 'e', (byte) 0xE2, (byte) 0x98, (byte) 0xA0,
          'n', 'e',

    // surrogate pairs
    // (U+1D11E "MUSICAL SYMBOL G CLEF")
    // (U+1D160 "MUSICAL SYMBOL EIGHTH NOTE")
    0x04, (byte) 0xF0, (byte) 0x9D, (byte) 0x84, (byte) 0x9E,
    0x08, (byte) 0xF0, (byte) 0x9D, (byte) 0x84, (byte) 0x9E, 
          (byte) 0xF0, (byte) 0x9D, (byte) 0x85, (byte) 0xA0, 
    0x0E, 'L', 'u',
          (byte) 0xF0, (byte) 0x9D, (byte) 0x84, (byte) 0x9E,
          'c', 'e', 
          (byte) 0xF0, (byte) 0x9D, (byte) 0x85, (byte) 0xA0, 
          'n', 'e',  

    // null bytes
    0x01, 0x00,
    0x08, 'L', 'u', 0x00, 'c', 'e', 0x00, 'n', 'e',
    
    // tests for Exceptions on invalid values
    (byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0x17,
    (byte) 0x01, // guard value
    (byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0xFF,
    (byte) 0x01, // guard value
  };
  
  static final int COUNT = RANDOM_MULTIPLIER * 65536;
  static int[] INTS;
  static long[] LONGS;
  static byte[] RANDOM_TEST_BYTES;
  
  @BeforeClass
  public static void beforeClass() throws IOException {
    Random random = random();
    INTS = new int[COUNT];
    LONGS = new long[COUNT];
    RANDOM_TEST_BYTES = new byte[COUNT * (5 + 4 + 9 + 8)];
    final ByteArrayDataOutput bdo = new ByteArrayDataOutput(RANDOM_TEST_BYTES);
    for (int i = 0; i < COUNT; i++) {
      final int i1 = INTS[i] = random.nextInt();
      bdo.writeVInt(i1);
      bdo.writeInt(i1);

      final long l1;
      if (rarely()) {
        // a long with lots of zeroes at the end
        l1 = LONGS[i] = TestUtil.nextLong(random, 0, Integer.MAX_VALUE) << 32;
      } else {
        l1 = LONGS[i] = TestUtil.nextLong(random, 0, Long.MAX_VALUE);
      }
      bdo.writeVLong(l1);
      bdo.writeLong(l1);
    }
  }

  @AfterClass
  public static void afterClass() {
    INTS = null;
    LONGS = null;
    RANDOM_TEST_BYTES = null;
  }

  private void checkReads(DataInput is, Class<? extends Exception> expectedEx) throws IOException {
    assertEquals(128,is.readVInt());
    assertEquals(16383,is.readVInt());
    assertEquals(16384,is.readVInt());
    assertEquals(16385,is.readVInt());
    assertEquals(Integer.MAX_VALUE, is.readVInt());
    assertEquals(-1, is.readVInt());
    assertEquals((long) Integer.MAX_VALUE, is.readVLong());
    assertEquals(Long.MAX_VALUE, is.readVLong());
    assertEquals("Lucene",is.readString());

    assertEquals("\u00BF",is.readString());
    assertEquals("Lu\u00BFce\u00BFne",is.readString());

    assertEquals("\u2620",is.readString());
    assertEquals("Lu\u2620ce\u2620ne",is.readString());

    assertEquals("\uD834\uDD1E",is.readString());
    assertEquals("\uD834\uDD1E\uD834\uDD60",is.readString());
    assertEquals("Lu\uD834\uDD1Ece\uD834\uDD60ne",is.readString());
    
    assertEquals("\u0000",is.readString());
    assertEquals("Lu\u0000ce\u0000ne",is.readString());
    
    try {
      is.readVInt();
      fail("Should throw " + expectedEx.getName());
    } catch (Exception e) {
      assertTrue(e.getMessage().startsWith("Invalid vInt"));
      assertTrue(expectedEx.isInstance(e));
    }
    assertEquals(1, is.readVInt()); // guard value
    
    try {
      is.readVLong();
      fail("Should throw " + expectedEx.getName());
    } catch (Exception e) {
      assertTrue(e.getMessage().startsWith("Invalid vLong"));
      assertTrue(expectedEx.isInstance(e));
    }
    assertEquals(1L, is.readVLong()); // guard value
  }
  
  private void checkRandomReads(DataInput is) throws IOException {
    for (int i = 0; i < COUNT; i++) {
      assertEquals(INTS[i], is.readVInt());
      assertEquals(INTS[i], is.readInt());
      assertEquals(LONGS[i], is.readVLong());
      assertEquals(LONGS[i], is.readLong());
    }
  }

  // this test only checks BufferedIndexInput because MockIndexInput extends BufferedIndexInput
  public void testBufferedIndexInputRead() throws IOException {
    IndexInput is = new MockIndexInput(READ_TEST_BYTES);
    checkReads(is, IOException.class);
    is.close();
    is = new MockIndexInput(RANDOM_TEST_BYTES);
    checkRandomReads(is);
    is.close();
  }

  // this test checks the raw IndexInput methods as it uses RAMIndexInput which extends IndexInput directly
  public void testRawIndexInputRead() throws IOException {
    Random random = random();
    final RAMDirectory dir = new RAMDirectory();
    IndexOutput os = dir.createOutput("foo", newIOContext(random));
    os.writeBytes(READ_TEST_BYTES, READ_TEST_BYTES.length);
    os.close();
    IndexInput is = dir.openInput("foo", newIOContext(random));
    checkReads(is, IOException.class);
    is.close();
    
    os = dir.createOutput("bar", newIOContext(random));
    os.writeBytes(RANDOM_TEST_BYTES, RANDOM_TEST_BYTES.length);
    os.close();
    is = dir.openInput("bar", newIOContext(random));
    checkRandomReads(is);
    is.close();
    dir.close();
  }

  public void testByteArrayDataInput() throws IOException {
    ByteArrayDataInput is = new ByteArrayDataInput(READ_TEST_BYTES);
    checkReads(is, RuntimeException.class);
    is = new ByteArrayDataInput(RANDOM_TEST_BYTES);
    checkRandomReads(is);
  }

}
