/*
    * 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.csv.perf;
  
  import java.io.BufferedReader;
  import java.io.File;
  import java.io.FileNotFoundException;
  import java.io.FileOutputStream;
  import java.io.FileReader;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStream;
  import java.io.Reader;
  import java.util.zip.GZIPInputStream;
  
  import org.apache.commons.csv.CSVFormat;
  import org.apache.commons.csv.CSVParser;
  import org.apache.commons.csv.CSVRecord;
  import org.apache.commons.io.FileUtils;
  import org.apache.commons.io.IOUtils;
  import org.junit.jupiter.api.BeforeAll;
  import org.junit.jupiter.api.Test;
  
  /**
   * Tests performance.
   *
   * To run this test, use: mvn test -Dtest=PerformanceTest
   */
  class PerformanceTest {
  
      private static final String TEST_RESRC = "org/apache/commons/csv/perf/worldcitiespop.txt.gz";
  
      private static final File BIG_FILE = new File(FileUtils.getTempDirectoryPath(), "worldcitiespop.txt");
  
      @BeforeAll
      public static void setUpClass() throws FileNotFoundException, IOException {
          if (BIG_FILE.exists()) {
              System.out.println(String.format("Found test fixture %s: %,d bytes.", BIG_FILE, BIG_FILE.length()));
              return;
          }
          System.out.println("Decompressing test fixture to: " + BIG_FILE + "...");
          try (InputStream input = new GZIPInputStream(PerformanceTest.class.getClassLoader().getResourceAsStream(TEST_RESRC));
                  OutputStream output = new FileOutputStream(BIG_FILE)) {
              IOUtils.copy(input, output);
              System.out.println(String.format("Decompressed test fixture %s: %,d bytes.", BIG_FILE, BIG_FILE.length()));
          }
      }
  
      private final int max = 10;
  
      private BufferedReader createBufferedReader() throws IOException {
          return new BufferedReader(new FileReader(BIG_FILE));
      }
  
      private long parse(final Reader reader, final boolean traverseColumns) throws IOException {
          final CSVFormat format = CSVFormat.DEFAULT.builder().setIgnoreSurroundingSpaces(false).get();
          long recordCount = 0;
          try (CSVParser parser = format.parse(reader)) {
              for (final CSVRecord record : parser) {
                  recordCount++;
                  if (traverseColumns) {
                      for (@SuppressWarnings("unused")
                      final String value : record) {
                          // do nothing for now
                      }
                  }
              }
          }
          return recordCount;
      }
  
      private void println(final String s) {
          System.out.println(s);
      }
  
      private long readLines(final BufferedReader in) throws IOException {
          long count = 0;
          while (in.readLine() != null) {
              count++;
          }
          return count;
      }
 
     public long testParseBigFile(final boolean traverseColumns) throws Exception {
         final long startMillis = System.currentTimeMillis();
         try (BufferedReader reader = createBufferedReader()) {
             final long count = parse(reader, traverseColumns);
             final long totalMillis = System.currentTimeMillis() - startMillis;
             println(
                 String.format("File parsed in %,d milliseconds with Commons CSV: %,d lines.", totalMillis, count));
             return totalMillis;
         }
     }
 
     @Test
     void testParseBigFileRepeat() throws Exception {
         long bestTime = Long.MAX_VALUE;
         for (int i = 0; i < this.max; i++) {
             bestTime = Math.min(testParseBigFile(false), bestTime);
         }
         println(String.format("Best time out of %,d is %,d milliseconds.", this.max, bestTime));
     }
 
     @Test
     void testReadBigFile() throws Exception {
         long bestTime = Long.MAX_VALUE;
         long count;
         for (int i = 0; i < this.max; i++) {
             final long startMillis;
             try (BufferedReader in = createBufferedReader()) {
                 startMillis = System.currentTimeMillis();
                 count = readLines(in);
             }
             final long totalMillis = System.currentTimeMillis() - startMillis;
             bestTime = Math.min(totalMillis, bestTime);
             println(String.format("File read in %,d milliseconds: %,d lines.", totalMillis, count));
         }
         println(String.format("Best time out of %,d is %,d milliseconds.", this.max, bestTime));
     }
 }