/*
    * Copyright (c) 2002-2026 Gargoyle Software Inc.
    *
    * Licensed 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.htmlunit.javascript.host.crypto;
  
  import java.security.SecureRandom;
  import java.util.UUID;
  
  import org.htmlunit.corejs.javascript.typedarrays.NativeArrayBufferView;
  import org.htmlunit.corejs.javascript.typedarrays.NativeBigInt64Array;
  import org.htmlunit.corejs.javascript.typedarrays.NativeBigUint64Array;
  import org.htmlunit.corejs.javascript.typedarrays.NativeInt16Array;
  import org.htmlunit.corejs.javascript.typedarrays.NativeInt32Array;
  import org.htmlunit.corejs.javascript.typedarrays.NativeInt8Array;
  import org.htmlunit.corejs.javascript.typedarrays.NativeUint16Array;
  import org.htmlunit.corejs.javascript.typedarrays.NativeUint32Array;
  import org.htmlunit.corejs.javascript.typedarrays.NativeUint8Array;
  import org.htmlunit.corejs.javascript.typedarrays.NativeUint8ClampedArray;
  import org.htmlunit.javascript.HtmlUnitScriptable;
  import org.htmlunit.javascript.JavaScriptEngine;
  import org.htmlunit.javascript.configuration.JsxClass;
  import org.htmlunit.javascript.configuration.JsxConstructor;
  import org.htmlunit.javascript.configuration.JsxFunction;
  import org.htmlunit.javascript.configuration.JsxGetter;
  import org.htmlunit.javascript.host.Window;
  import org.htmlunit.javascript.host.dom.DOMException;
  
  /**
   * A JavaScript object for {@code Crypto}.
   *
   * @author Ahmed Ashour
   * @author Marc Guillemot
   * @author Ronald Brill
   *
   * @see <a href="https://developer.mozilla.org/en-US/docs/Web/API/Crypto">MDN Documentation</a>
   */
  @JsxClass
  public class Crypto extends HtmlUnitScriptable {
  
      static final SecureRandom RANDOM = new SecureRandom();
      private SubtleCrypto subtle_;
  
      /**
       * Creates an instance.
       */
      public Crypto() {
          super();
      }
  
      /**
       * Creates an instance.
       */
      @JsxConstructor
      public void jsConstructor() {
          throw JavaScriptEngine.typeErrorIllegalConstructor();
      }
  
      /**
       * Facility constructor.
       * @param window the owning window
       */
      public Crypto(final Window window) {
          this();
          setParentScope(getTopLevelScope(window.getParentScope()));
          setPrototype(window.getPrototype(Crypto.class));
      }
  
      /**
       * Fills array with random values.
       * @param array the array to fill
       * @return the modified array
       * @see <a href="https://developer.mozilla.org/en-US/docs/Web/API/RandomSource/getRandomValues">MDN Doc</a>
       */
      @JsxFunction
      public NativeArrayBufferView getRandomValues(final Object array) {
          if (!(array instanceof NativeArrayBufferView view)) {
              throw JavaScriptEngine.typeError(
                      "Argument 1 of Crypto.getRandomValues does not implement interface ArrayBufferView.");
          }
          if (!isIntegerArray(view)) {
              throw JavaScriptEngine.asJavaScriptException(
                      getWindow(),
                      "Failed to execute 'getRandomValues' on 'Crypto': "
                              + "The provided ArrayBufferView is of type '" + view.getClassName()
                              + "', which is not an integer array type.",
                      DOMException.TYPE_MISMATCH_ERR);
          }
  
         // a view on a detached buffer has a byte length of 0; there is nothing to fill
         // (getByteLength() still reports the original length and getByteBuffer() is null)
         if (view.getBuffer().isDetached()) {
             return view;
         }
 
         if (view.getByteLength() > 65_536) {
             throw JavaScriptEngine.asJavaScriptException(
                     getWindow(),
                     "Error: Failed to execute 'getRandomValues' on 'Crypto': "
                             + "The ArrayBufferView's byte length "
                             + "(" + view.getByteLength() + ") exceeds the number of bytes "
                             + "of entropy available via this API (65536).",
                     DOMException.QUOTA_EXCEEDED_ERR);
         }
 
         // fill the underlying bytes; writing the elements would convert (e.g. clamp) the values
         final byte[] bytes = new byte[view.getByteLength()];
         if (bytes.length > 0) {
             RANDOM.nextBytes(bytes);
             view.getBuffer().getByteBuffer().put(view.getByteOffset(), bytes);
         }
         return view;
     }
 
     private static boolean isIntegerArray(final NativeArrayBufferView view) {
         return view instanceof NativeInt8Array
                 || view instanceof NativeUint8Array
                 || view instanceof NativeUint8ClampedArray
                 || view instanceof NativeInt16Array
                 || view instanceof NativeUint16Array
                 || view instanceof NativeInt32Array
                 || view instanceof NativeUint32Array
                 || view instanceof NativeBigInt64Array
                 || view instanceof NativeBigUint64Array;
     }
 
     /**
      * Returns the {@code subtle} property.
      * @return the {@code subtle} property
      */
     @JsxGetter
     public SubtleCrypto getSubtle() {
         if (subtle_ != null) {
             return subtle_;
         }
         final SubtleCrypto subtle = new SubtleCrypto();
         subtle.setParentScope(getParentScope());
         subtle.setPrototype(getWindow().getPrototype(SubtleCrypto.class));
         subtle_ = subtle;
         return subtle_;
     }
 
     /**
      * Generates a random UUID.
      * @return a v4 UUID generated using a cryptographically secure random number generator
      */
     @JsxFunction
     public String randomUUID() {
         // java.util.UUID creates a version 4 (random) UUID using a cryptographically
         // secure random number generator, formatted with lowercase hex digits
         return UUID.randomUUID().toString();
     }
 }