"istio.io/istio/pkg/test"
)

// AsBytes is a simple wrapper around os.ReadFile provided for completeness.
func AsBytes(filename string) ([]byte, error) {
	return os.ReadFile(filename)
}

// AsBytesOrFail calls AsBytes and fails the test if any errors occurred.
func AsBytesOrFail(t test.Failer, filename string) []byte {
	t.Helper()
	content, err := AsBytes(filename)
	if err != nil {
		t.Fatal(err)
	}

    // Trick the JVM to prevent it from using the hash function non-polymorphically
    result ^= Hashing.crc32().hashInt(reps).asBytes()[0];
    result ^= Hashing.adler32().hashInt(reps).asBytes()[0];
    for (int i = 0; i < reps; i++) {
      result ^= hashFunction.hashBytes(testBytes).asBytes()[0];
    }
    return result;
  }

  public abstract int bits();

  /**
   * Returns the first four bytes of {@linkplain #asBytes() this hashcode's bytes}, converted to an
   * {@code int} value in little-endian order.
   *
   * @throws IllegalStateException if {@code bits() < 32}
   */
  public abstract int asInt();

  /**
   * Returns the first eight bytes of {@linkplain #asBytes() this hashcode's bytes}, converted to a
   * {@code long} value in little-endian order.
   *

            entry("Foo.class", INSTRUMENTED_CLASS)
            entry(MarkerResource.RESOURCE_NAME, MarkerResource.TRANSFORMED.asBytes())

            versionedEntry(currentJvmMajor, "Foo.class", INSTRUMENTED_VERSIONED_CLASS)
            versionedEntry(currentJvmMajor + 1, MarkerResource.RESOURCE_NAME, MarkerResource.NOT_TRANSFORMED.asBytes())
        }

        TransformedClassPath cp = classPath((original): transformed)

        expect:

      result ^= hashFunction.newHasher().putBytes(testBytes).hash().asBytes()[0];
    }
    return result;
  }

  @Benchmark
  int hashFunction(int reps) {
    HashFunction hashFunction = hashFunctionEnum.getHashFunction();
    int result = 37;
    for (int i = 0; i < reps; i++) {
      result ^= hashFunction.hashBytes(testBytes).asBytes()[0];
    }
    return result;
  }

  @Benchmark

  public abstract int bits();

  /**
   * Returns the first four bytes of {@linkplain #asBytes() this hashcode's bytes}, converted to an
   * {@code int} value in little-endian order.
   *
   * @throws IllegalStateException if {@code bits() < 32}
   */
  public abstract int asInt();

  /**
   * Returns the first eight bytes of {@linkplain #asBytes() this hashcode's bytes}, converted to a
   * {@code long} value in little-endian order.
   *

    byte[] original = hash.asBytes();
    byte[] mutated = hash.asBytes();
    mutated[0]++;
    assertTrue(Arrays.equals(original, hash.asBytes()));
  }

  private static void assertReadableBytes(HashCode hashCode) {
    assertTrue(hashCode.bits() >= 32); // sanity
    byte[] hashBytes = hashCode.asBytes();
    int totalBytes = hashCode.bits() / 8;

    // Trick the JVM to prevent it from using the hash function non-polymorphically
    result ^= Hashing.crc32().hashInt(reps).asBytes()[0];
    result ^= Hashing.adler32().hashInt(reps).asBytes()[0];
    for (int i = 0; i < reps; i++) {
      result ^= hashFunction.hashBytes(testBytes).asBytes()[0];
    }
    return result;
  }

      public byte[] hash(Algorithm algorithm, byte[] input) {
        return algorithm.getHashFunction().hashBytes(input).asBytes();
      }
    },
    HASH_FUNCTION_VIA_HASHER() {
      @Override
      public byte[] hash(Algorithm algorithm, byte[] input) {
        return algorithm.getHashFunction().newHasher().putBytes(input).hash().asBytes();
      }
    };
    ;

    public abstract byte[] hash(Algorithm algorithm, byte[] input);
  }

      public byte[] hash(Algorithm algorithm, byte[] input) {
        return algorithm.getHashFunction().hashBytes(input).asBytes();
      }
    },
    HASH_FUNCTION_VIA_HASHER() {
      @Override
      public byte[] hash(Algorithm algorithm, byte[] input) {
        return algorithm.getHashFunction().newHasher().putBytes(input).hash().asBytes();
      }
    };
    ;

    public abstract byte[] hash(Algorithm algorithm, byte[] input);
  }