/*
    * 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.file;
  
  import java.io.IOException;
  import java.nio.charset.Charset;
  import java.nio.charset.StandardCharsets;
  import java.nio.charset.UnsupportedCharsetException;
  import java.util.Base64;
  import java.util.Locale;
  
  import org.apache.commons.io.Charsets;
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.htmlunit.corejs.javascript.Function;
  import org.htmlunit.corejs.javascript.ScriptableObject;
  import org.htmlunit.corejs.javascript.typedarrays.NativeArrayBuffer;
  import org.htmlunit.javascript.JavaScriptEngine;
  import org.htmlunit.javascript.configuration.JsxClass;
  import org.htmlunit.javascript.configuration.JsxConstant;
  import org.htmlunit.javascript.configuration.JsxConstructor;
  import org.htmlunit.javascript.configuration.JsxFunction;
  import org.htmlunit.javascript.configuration.JsxGetter;
  import org.htmlunit.javascript.configuration.JsxSetter;
  import org.htmlunit.javascript.host.event.Event;
  import org.htmlunit.javascript.host.event.EventTarget;
  import org.htmlunit.javascript.host.event.ProgressEvent;
  import org.htmlunit.protocol.data.DataURLConnection;
  import org.htmlunit.util.MimeType;
  import org.htmlunit.util.StringUtils;
  
  /**
   * A JavaScript object for {@code FileReader}.
   *
   * @author Ahmed Ashour
   * @author Ronald Brill
   * @author Lai Quang Duong
   */
  @JsxClass
  public class FileReader extends EventTarget {
  
      private static final Log LOG = LogFactory.getLog(FileReader.class);
  
      /** No data has been loaded yet. */
      @JsxConstant
      public static final int EMPTY = 0;
  
      /** Data is currently being loaded. */
      @JsxConstant
      public static final int LOADING = 1;
  
      /** The entire read request has been completed. */
      @JsxConstant
      public static final int DONE = 2;
  
      private int readyState_ = EMPTY;
      private Object result_;
  
      /**
       * JavaScript constructor.
       */
      @Override
      @JsxConstructor
      public void jsConstructor() {
          super.jsConstructor();
      }
  
      /**
       * Returns the current state of the reading operation.
       *
       * @return {@value #EMPTY}, {@value #LOADING}, or {@value #DONE}
       */
      @JsxGetter
      public int getReadyState() {
          return readyState_;
      }
  
      /**
       * Returns the file's contents.
       * @return the file's contents
       */
      @JsxGetter
      public Object getResult() {
          return result_;
      }
  
      /**
      * Reads the contents of the specified {@link Blob} or {@link File}.
      * @param object the {@link Blob} or {@link File} from which to read
      * @throws IOException if an error occurs
      */
     @JsxFunction
     public void readAsDataURL(final Object object) throws IOException {
         readyState_ = LOADING;
 
         if (!(object instanceof Blob blob)) {
             throw JavaScriptEngine.typeError(
                     "FileReader.readAsDataURL: Argument 1 does not implement interface Blob.");
         }
 
         result_ = DataURLConnection.DATA_PREFIX;
 
         final byte[] bytes = blob.getBytes();
         fireEvent(new ProgressEvent(this, Event.TYPE_LOAD_START, true, 0, bytes.length));
         fireEvent(new ProgressEvent(this, Event.TYPE_PROGRESS, true, bytes.length, bytes.length));
 
         final String value = new String(Base64.getEncoder().encode(bytes), StandardCharsets.US_ASCII);
 
         String contentType = blob.getType();
         if (StringUtils.isEmptyOrNull(contentType)) {
             contentType = MimeType.APPLICATION_OCTET_STREAM;
         }
 
         result_ += contentType + ";base64," + value;
         readyState_ = DONE;
 
         fireEvent(new ProgressEvent(this, Event.TYPE_LOAD, true, bytes.length, bytes.length));
         fireEvent(new ProgressEvent(this, Event.TYPE_LOAD_END, true, bytes.length, bytes.length));
     }
 
     /**
      * Reads the contents of the specified {@link Blob} or {@link File}.
      * @param object the {@link Blob} or {@link File} from which to read
      */
     @JsxFunction
     public void readAsArrayBuffer(final Object object) {
         readyState_ = LOADING;
 
         if (!(object instanceof Blob blob)) {
             throw JavaScriptEngine.typeError(
                     "FileReader.readAsArrayBuffer: Argument 1 does not implement interface Blob.");
         }
 
         final byte[] bytes = blob.getBytes();
         fireEvent(new ProgressEvent(this, Event.TYPE_LOAD_START, true, 0, bytes.length));
         fireEvent(new ProgressEvent(this, Event.TYPE_PROGRESS, true, bytes.length, bytes.length));
 
         final NativeArrayBuffer buffer = new NativeArrayBuffer(bytes.length);
         System.arraycopy(bytes, 0, buffer.getBuffer(), 0, bytes.length);
         buffer.setParentScope(getParentScope());
         buffer.setPrototype(ScriptableObject.getClassPrototype(getParentScope(), buffer.getClassName()));
 
         result_ = buffer;
         readyState_ = DONE;
 
         fireEvent(new ProgressEvent(this, Event.TYPE_LOAD, true, bytes.length, bytes.length));
         fireEvent(new ProgressEvent(this, Event.TYPE_LOAD_END, true, bytes.length, bytes.length));
     }
 
     /**
      * Reads the contents of the specified {@link Blob} or {@link File}.
      * When the read operation is complete, the readyState is changed to DONE,
      * the loaded event is triggered, and the result attribute contains the
      * contents of the file as a text string.
      * @param object the {@link Blob} or {@link File} from which to read
      * @param encoding the encoding
      */
     @JsxFunction
     public void readAsText(final Object object, final Object encoding) {
         readyState_ = LOADING;
 
         if (!(object instanceof Blob blob)) {
             throw JavaScriptEngine.typeError(
                     "FileReader.readAsText: Argument 1 does not implement interface Blob.");
         }
 
         Charset charset = StandardCharsets.UTF_8;
         if (encoding != null && !JavaScriptEngine.isUndefined(encoding)) {
             final String encAsString = JavaScriptEngine.toString(encoding);
             if (StringUtils.isNotBlank(encAsString)) {
                 try {
                     charset = Charsets.toCharset(encAsString.trim().toLowerCase(Locale.ROOT));
                 }
                 catch (final UnsupportedCharsetException e) {
                     if (LOG.isWarnEnabled()) {
                         LOG.warn("FileReader readAsText was called with an unsupported encoding '"
                                     + encoding + "'. Using UTF-8 instead.");
                     }
                 }
             }
         }
 
         final byte[] bytes = blob.getBytes();
         fireEvent(new ProgressEvent(this, Event.TYPE_LOAD_START, true, 0, bytes.length));
         fireEvent(new ProgressEvent(this, Event.TYPE_PROGRESS, true, bytes.length, bytes.length));
 
         result_ = new String(bytes, charset);
         readyState_ = DONE;
 
         fireEvent(new ProgressEvent(this, Event.TYPE_LOAD, true, bytes.length, bytes.length));
         fireEvent(new ProgressEvent(this, Event.TYPE_LOAD_END, true, bytes.length, bytes.length));
     }
 
     /**
      * Returns the {@code onloadstart} event handler for this {@link FileReader}.
      * @return the {@code onloadstart} event handler for this {@link FileReader}
      */
     @JsxGetter
     public Function getOnloadstart() {
         return getEventHandler(Event.TYPE_LOAD_START);
     }
 
     /**
      * Sets the {@code onloadstart} event handler for this {@link FileReader}.
      * @param onloadstart the {@code onloadstart} event handler for this {@link FileReader}
      */
     @JsxSetter
     public void setOnloadstart(final Object onloadstart) {
         setEventHandler(Event.TYPE_LOAD_START, onloadstart);
     }
 
     /**
      * Returns the {@code onprogress} event handler for this {@link FileReader}.
      * @return the {@code onprogress} event handler for this {@link FileReader}
      */
     @JsxGetter
     public Function getOnprogress() {
         return getEventHandler(Event.TYPE_PROGRESS);
     }
 
     /**
      * Sets the {@code onprogress} event handler for this {@link FileReader}.
      * @param onprogress the {@code onprogress} event handler for this {@link FileReader}
      */
     @JsxSetter
     public void setOnprogress(final Object onprogress) {
         setEventHandler(Event.TYPE_PROGRESS, onprogress);
     }
 
     /**
      * Returns the {@code onload} event handler for this {@link FileReader}.
      * @return the {@code onload} event handler for this {@link FileReader}
      */
     @JsxGetter
     public Function getOnload() {
         return getEventHandler(Event.TYPE_LOAD);
     }
 
     /**
      * Sets the {@code onload} event handler for this {@link FileReader}.
      * @param onload the {@code onload} event handler for this {@link FileReader}
      */
     @JsxSetter
     public void setOnload(final Object onload) {
         setEventHandler(Event.TYPE_LOAD, onload);
     }
 
     /**
      * Returns the {@code onloadend} event handler for this {@link FileReader}.
      * @return the {@code onloadend} event handler for this {@link FileReader}
      */
     @JsxGetter
     public Function getOnloadend() {
         return getEventHandler(Event.TYPE_LOAD_END);
     }
 
     /**
      * Sets the {@code onloadend} event handler for this {@link FileReader}.
      * @param onloadend the {@code onloadend} event handler for this {@link FileReader}
      */
     @JsxSetter
     public void setOnloadend(final Object onloadend) {
         setEventHandler(Event.TYPE_LOAD_END, onloadend);
     }
 
     /**
      * Returns the {@code onerror} event handler for this {@link FileReader}.
      * @return the {@code onerror} event handler for this {@link FileReader}
      */
     @JsxGetter
     public Function getOnerror() {
         return getEventHandler(Event.TYPE_ERROR);
     }
 
     /**
      * Sets the {@code onerror} event handler for this {@link FileReader}.
      * @param onerror the {@code onerror} event handler for this {@link FileReader}
      */
     @JsxSetter
     public void setOnerror(final Object onerror) {
         setEventHandler(Event.TYPE_ERROR, onerror);
     }
 }