/*
    * ====================================================================
    * 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.
   * ====================================================================
   *
   * This software consists of voluntary contributions made by many
   * individuals on behalf of the Apache Software Foundation.  For more
   * information on the Apache Software Foundation, please see
   * <http://www.apache.org/>.
   *
   */
  
  package org.apache.hc.client5.http.impl.cache;
  
  import java.io.File;
  import java.io.FileInputStream;
  import java.io.FileOutputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStream;
  import java.nio.charset.StandardCharsets;
  import java.util.Collections;
  import java.util.Date;
  import java.util.Map;
  
  import org.apache.hc.client5.http.cache.HttpCacheEntry;
  import org.apache.hc.client5.http.cache.HttpCacheEntrySerializer;
  import org.apache.hc.client5.http.cache.HttpCacheStorageEntry;
  import org.apache.hc.client5.http.cache.Resource;
  import org.apache.hc.client5.http.cache.ResourceIOException;
  import org.apache.hc.core5.http.Header;
  import org.apache.hc.core5.http.message.BasicHeader;
  
  import static org.junit.Assert.assertArrayEquals;
  import static org.junit.Assert.assertEquals;
  import static org.junit.Assert.assertNull;
  import static org.junit.Assert.fail;
  
  class HttpByteArrayCacheEntrySerializerTestUtils {
      private final static String TEST_RESOURCE_DIR = "src/test/resources/";
      static final String TEST_STORAGE_KEY = "xyzzy";
  
      /**
       * Template for incrementally building a new HttpCacheStorageEntry test object, starting from defaults.
       */
      static class HttpCacheStorageEntryTestTemplate {
          Resource resource;
          Date requestDate;
          Date responseDate;
          int responseCode;
          Header[] responseHeaders;
          Map<String, String> variantMap;
          String storageKey;
  
          /**
           * Return a new HttpCacheStorageEntryTestTemplate instance with all default values.
           *
           * @return new HttpCacheStorageEntryTestTemplate instance
           */
          static HttpCacheStorageEntryTestTemplate makeDefault() {
              return new HttpCacheStorageEntryTestTemplate(DEFAULT_HTTP_CACHE_STORAGE_ENTRY_TEST_TEMPLATE);
          }
  
          /**
           * Convert this template to a HttpCacheStorageEntry object.
           * @return HttpCacheStorageEntry object
           */
          HttpCacheStorageEntry toEntry() {
              return new HttpCacheStorageEntry(storageKey,
                      new HttpCacheEntry(
                              requestDate,
                              responseDate,
                              responseCode,
                              responseHeaders,
                              resource,
                              variantMap));
          }
  
          /**
           * Create a new template with all null values.
           */
          private HttpCacheStorageEntryTestTemplate() {
          }
  
         /**
          * Create a new template values copied from the given template
          *
          * @param src Template to copy values from
          */
         private HttpCacheStorageEntryTestTemplate(final HttpCacheStorageEntryTestTemplate src) {
             this.resource = src.resource;
             this.requestDate = src.requestDate;
             this.responseDate = src.responseDate;
             this.responseCode = src.responseCode;
             this.responseHeaders = src.responseHeaders;
             this.variantMap = src.variantMap;
             this.storageKey = src.storageKey;
         }
     }
 
     /**
      * Template with all default values.
      *
      * Used by HttpCacheStorageEntryTestTemplate#makeDefault()
      */
     private static final HttpCacheStorageEntryTestTemplate DEFAULT_HTTP_CACHE_STORAGE_ENTRY_TEST_TEMPLATE = new HttpCacheStorageEntryTestTemplate();
     static {
         DEFAULT_HTTP_CACHE_STORAGE_ENTRY_TEST_TEMPLATE.resource = new HeapResource("Hello World".getBytes(StandardCharsets.UTF_8));
         DEFAULT_HTTP_CACHE_STORAGE_ENTRY_TEST_TEMPLATE.requestDate = new Date(165214800000L);
         DEFAULT_HTTP_CACHE_STORAGE_ENTRY_TEST_TEMPLATE.responseDate = new Date(2611108800000L);
         DEFAULT_HTTP_CACHE_STORAGE_ENTRY_TEST_TEMPLATE.responseCode = 200;
         DEFAULT_HTTP_CACHE_STORAGE_ENTRY_TEST_TEMPLATE.responseHeaders = new Header[]{
                 new BasicHeader("Content-type", "text/html"),
                 new BasicHeader("Cache-control", "public, max-age=31536000"),
         };
         DEFAULT_HTTP_CACHE_STORAGE_ENTRY_TEST_TEMPLATE.variantMap = Collections.emptyMap();
         DEFAULT_HTTP_CACHE_STORAGE_ENTRY_TEST_TEMPLATE.storageKey = TEST_STORAGE_KEY;
     }
 
     /**
      * Test serializing and deserializing the given object with the given factory.
      * <p>
      * Compares fields to ensure the deserialized object is equivalent to the original object.
      *
      * @param serializer Factory for creating serializers
      * @param httpCacheStorageEntry    Original object to serialize and test against
      * @throws Exception if anything goes wrong
      */
     static void testWithCache(final HttpCacheEntrySerializer<byte[]> serializer, final HttpCacheStorageEntry httpCacheStorageEntry) throws Exception {
         final byte[] testBytes = serializer.serialize(httpCacheStorageEntry);
         verifyHttpCacheEntryFromBytes(serializer, httpCacheStorageEntry, testBytes);
     }
 
     /**
      * Verify that the given bytes deserialize to the given storage key and an equivalent cache entry.
      *
      * @param serializer Deserializer
      * @param httpCacheStorageEntry Cache entry to verify
      * @param testBytes Bytes to deserialize
      * @throws Exception if anything goes wrong
      */
     static void verifyHttpCacheEntryFromBytes(final HttpCacheEntrySerializer<byte[]> serializer, final HttpCacheStorageEntry httpCacheStorageEntry, final byte[] testBytes) throws Exception {
         final HttpCacheStorageEntry testEntry = httpCacheStorageEntryFromBytes(serializer, testBytes);
 
         assertCacheEntriesEqual(httpCacheStorageEntry, testEntry);
     }
 
     /**
      * Verify that the given test file deserializes to a cache entry equivalent to the one given.
      *
      * @param serializer Deserializer
      * @param httpCacheStorageEntry    Cache entry to verify
      * @param testFileName  Name of test file to deserialize
      * @param reserializeFiles If true, test files will be regenerated and saved to disk
      * @throws Exception if anything goes wrong
      */
     static void verifyHttpCacheEntryFromTestFile(final HttpCacheEntrySerializer<byte[]> serializer,
                                                  final HttpCacheStorageEntry httpCacheStorageEntry,
                                                  final String testFileName,
                                                  final boolean reserializeFiles) throws Exception {
         if (reserializeFiles) {
             final File toFile = makeTestFileObject(testFileName);
             saveEntryToFile(serializer, httpCacheStorageEntry, toFile);
         }
 
         final byte[] bytes = readTestFileBytes(testFileName);
 
         verifyHttpCacheEntryFromBytes(serializer, httpCacheStorageEntry, bytes);
     }
 
     /**
      * Get the bytes of the given test file.
      *
      * @param testFileName Name of test file to get bytes from
      * @return Bytes from the given test file
      * @throws Exception if anything goes wrong
      */
     static byte[] readTestFileBytes(final String testFileName) throws Exception {
         final File testFile = makeTestFileObject(testFileName);
         try(final FileInputStream testStream = new FileInputStream(testFile)) {
             return readFullyStrict(testStream, testFile.length());
         }
     }
 
     /**
      * Create a new cache object from the given bytes.
      *
      * @param serializer Deserializer
      * @param testBytes         Bytes to deserialize
      * @return Deserialized object
      */
     static HttpCacheStorageEntry httpCacheStorageEntryFromBytes(final HttpCacheEntrySerializer<byte[]> serializer, final byte[] testBytes) throws ResourceIOException {
         return serializer.deserialize(testBytes);
     }
 
     /**
      * Assert that the given objects are equivalent
      *
      * @param expected Expected cache entry object
      * @param actual   Actual cache entry object
      * @throws Exception if anything goes wrong
      */
     static void assertCacheEntriesEqual(final HttpCacheStorageEntry expected, final HttpCacheStorageEntry actual) throws Exception {
         assertEquals(expected.getKey(), actual.getKey());
 
         final HttpCacheEntry expectedContent = expected.getContent();
         final HttpCacheEntry actualContent = actual.getContent();
 
         assertEquals(expectedContent.getRequestDate(), actualContent.getRequestDate());
         assertEquals(expectedContent.getResponseDate(), actualContent.getResponseDate());
         assertEquals(expectedContent.getStatus(), actualContent.getStatus());
 
         assertArrayEquals(expectedContent.getVariantMap().keySet().toArray(), actualContent.getVariantMap().keySet().toArray());
         for (final String key : expectedContent.getVariantMap().keySet()) {
             assertEquals("Expected same variantMap values for key '" + key + "'",
                     expectedContent.getVariantMap().get(key), actualContent.getVariantMap().get(key));
         }
 
         // Verify that the same headers are present on the expected and actual content.
         for(final Header expectedHeader: expectedContent.getHeaders()) {
             final Header actualHeader = actualContent.getFirstHeader(expectedHeader.getName());
 
             if (actualHeader == null) {
                 if (expectedHeader.getName().equalsIgnoreCase("content-length")) {
                     // This header is added by the cache implementation, and can be safely ignored
                 } else {
                     fail("Expected header " + expectedHeader.getName() + " was not found");
                 }
             } else {
                 assertEquals(expectedHeader.getName(), actualHeader.getName());
                 assertEquals(expectedHeader.getValue(), actualHeader.getValue());
             }
         }
 
         if (expectedContent.getResource() == null) {
             assertNull("Expected null resource", actualContent.getResource());
         } else {
             final byte[] expectedBytes = readFullyStrict(
                     expectedContent.getResource().getInputStream(),
                     (int) expectedContent.getResource().length()
             );
             final byte[] actualBytes = readFullyStrict(
                     actualContent.getResource().getInputStream(),
                     (int) actualContent.getResource().length()
             );
             assertArrayEquals(expectedBytes, actualBytes);
         }
     }
 
     /**
      * Get a File object for the given test file.
      *
      * @param testFileName Name of test file
      * @return File for this test file
      */
     static File makeTestFileObject(final String testFileName) {
         return new File(TEST_RESOURCE_DIR + testFileName);
     }
 
     /**
      * Save the given cache entry serialized to the given file.
      *
      * @param serializer Serializer
      * @param httpCacheStorageEntry Cache entry to serialize and save
      * @param outFile Output file to write to
      * @throws Exception if anything goes wrong
      */
     static void saveEntryToFile(final HttpCacheEntrySerializer<byte[]> serializer, final HttpCacheStorageEntry httpCacheStorageEntry, final File outFile) throws Exception {
         final byte[] bytes = serializer.serialize(httpCacheStorageEntry);
 
         try (OutputStream out = new FileOutputStream(outFile)) {
             out.write(bytes);
         }
     }
 
     /**
      * Copy bytes from the given input stream to the given destination buffer until the buffer is full,
      * or end-of-file is reached, and return the number of bytes read.
      *
      * @param src Input stream to read from
      * @param dest Output buffer to write to
      * @return Number of bytes read
      * @throws IOException if an I/O error occurs
      */
     private static int readFully(final InputStream src, final byte[] dest) throws IOException {
         final int destPos = 0;
         final int length = dest.length;
         int totalBytesRead = 0;
         int lastBytesRead;
 
         while (totalBytesRead < length && (lastBytesRead = src.read(dest, destPos + totalBytesRead, length - totalBytesRead)) != -1) {
             totalBytesRead += lastBytesRead;
         }
         return totalBytesRead;
     }
 
     /**
      * Copy bytes from the given input stream to a new buffer until the given length is reached,
      * and returns the new buffer.  If end-of-file is reached first, an IOException is thrown
      *
      * @param src Input stream to read from
      * @param length Maximum bytes to read
      * @return All bytes from file
      * @throws IOException if an I/O error occurs or end-of-file is reached before the requested
      *                     number of bytes have been read
      */
     static byte[] readFullyStrict(final InputStream src, final long length) throws IOException {
         if (length > Integer.MAX_VALUE) {
             throw new IllegalArgumentException(String.format("Length %d is too large to fit in an array", length));
         }
         final int intLength = (int) length;
         final byte[] dest = new byte[intLength];
         final int bytesRead = readFully(src, dest);
 
         if (bytesRead == intLength) {
             return dest;
         } else {
             throw new IOException(String.format("Expected to read %d bytes but only got %d", intLength, bytesRead));
         }
     }
 }