/*
    * 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.bcel.generic;
  
  import java.io.ByteArrayInputStream;
  import java.io.ByteArrayOutputStream;
  import java.io.DataInput;
  import java.io.DataInputStream;
  import java.io.DataOutputStream;
  import java.io.IOException;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.stream.Collectors;
  
  import org.apache.bcel.classfile.AnnotationEntry;
  import org.apache.bcel.classfile.Attribute;
  import org.apache.bcel.classfile.ConstantUtf8;
  import org.apache.bcel.classfile.ElementValuePair;
  import org.apache.bcel.classfile.RuntimeInvisibleAnnotations;
  import org.apache.bcel.classfile.RuntimeInvisibleParameterAnnotations;
  import org.apache.bcel.classfile.RuntimeVisibleAnnotations;
  import org.apache.bcel.classfile.RuntimeVisibleParameterAnnotations;
  import org.apache.bcel.util.Args;
  import org.apache.commons.lang3.ArrayUtils;
  import org.apache.commons.lang3.stream.Streams;
  
  /**
   * Generates annotation entries.
   *
   * @since 6.0
   */
  public class AnnotationEntryGen {
  
      static final AnnotationEntryGen[] EMPTY_ARRAY = {};
  
      /**
       * Converts a list of AnnotationGen objects into a set of attributes that can be attached to the class file.
       *
       * @param cp The constant pool gen where we can create the necessary name refs.
       * @param annotationEntryGens An array of AnnotationGen objects.
       */
      static Attribute[] getAnnotationAttributes(final ConstantPoolGen cp, final AnnotationEntryGen[] annotationEntryGens) {
          if (ArrayUtils.isEmpty(annotationEntryGens)) {
              return Attribute.EMPTY_ARRAY;
          }
  
          try {
              int countVisible = 0;
              int countInvisible = 0;
  
              // put the annotations in the right output stream
              for (final AnnotationEntryGen a : annotationEntryGens) {
                  if (a.isRuntimeVisible()) {
                      countVisible++;
                  } else {
                      countInvisible++;
                  }
              }
  
              final ByteArrayOutputStream rvaBytes = new ByteArrayOutputStream();
              final ByteArrayOutputStream riaBytes = new ByteArrayOutputStream();
              try (DataOutputStream rvaDos = new DataOutputStream(rvaBytes); DataOutputStream riaDos = new DataOutputStream(riaBytes)) {
  
                  rvaDos.writeShort(countVisible);
                  riaDos.writeShort(countInvisible);
  
                  // put the annotations in the right output stream
                  for (final AnnotationEntryGen a : annotationEntryGens) {
                      if (a.isRuntimeVisible()) {
                          a.dump(rvaDos);
                      } else {
                          a.dump(riaDos);
                      }
                  }
              }
  
              final byte[] rvaData = rvaBytes.toByteArray();
              final byte[] riaData = riaBytes.toByteArray();
  
              int rvaIndex = -1;
              int riaIndex = -1;
  
              if (rvaData.length > 2) {
                 rvaIndex = cp.addUtf8("RuntimeVisibleAnnotations");
             }
             if (riaData.length > 2) {
                 riaIndex = cp.addUtf8("RuntimeInvisibleAnnotations");
             }
 
             final List<Attribute> newAttributes = new ArrayList<>();
             if (rvaData.length > 2) {
                 newAttributes
                     .add(new RuntimeVisibleAnnotations(rvaIndex, rvaData.length, new DataInputStream(new ByteArrayInputStream(rvaData)), cp.getConstantPool()));
             }
             if (riaData.length > 2) {
                 newAttributes.add(
                     new RuntimeInvisibleAnnotations(riaIndex, riaData.length, new DataInputStream(new ByteArrayInputStream(riaData)), cp.getConstantPool()));
             }
 
             return newAttributes.toArray(Attribute.EMPTY_ARRAY);
         } catch (final IOException e) {
             System.err.println("IOException whilst processing annotations");
             e.printStackTrace();
         }
         return null;
     }
 
     /**
      * Annotations against a class are stored in one of four attribute kinds: - RuntimeVisibleParameterAnnotations -
      * RuntimeInvisibleParameterAnnotations
      */
     static Attribute[] getParameterAnnotationAttributes(final ConstantPoolGen cp,
         final List<AnnotationEntryGen>[] /* Array of lists, array size depends on #params */ vec) {
         final int[] visCount = new int[vec.length];
         int totalVisCount = 0;
         final int[] invisCount = new int[vec.length];
         int totalInvisCount = 0;
         try {
             for (int i = 0; i < vec.length; i++) {
                 if (vec[i] != null) {
                     for (final AnnotationEntryGen element : vec[i]) {
                         if (element.isRuntimeVisible()) {
                             visCount[i]++;
                             totalVisCount++;
                         } else {
                             invisCount[i]++;
                             totalInvisCount++;
                         }
                     }
                 }
             }
             // Lets do the visible ones
             final ByteArrayOutputStream rvaBytes = new ByteArrayOutputStream();
             try (DataOutputStream rvaDos = new DataOutputStream(rvaBytes)) {
                 rvaDos.writeByte(Args.requireU1(vec.length, "vec.length")); // First goes number of parameters
                 for (int i = 0; i < vec.length; i++) {
                     rvaDos.writeShort(visCount[i]);
                     if (visCount[i] > 0) {
                         for (final AnnotationEntryGen element : vec[i]) {
                             if (element.isRuntimeVisible()) {
                                 element.dump(rvaDos);
                             }
                         }
                     }
                 }
             }
             // Lets do the invisible ones
             final ByteArrayOutputStream riaBytes = new ByteArrayOutputStream();
             try (DataOutputStream riaDos = new DataOutputStream(riaBytes)) {
                 riaDos.writeByte(Args.requireU1(vec.length, "vec.length")); // First goes number of parameters
                 for (int i = 0; i < vec.length; i++) {
                     riaDos.writeShort(invisCount[i]);
                     if (invisCount[i] > 0) {
                         for (final AnnotationEntryGen element : vec[i]) {
                             if (!element.isRuntimeVisible()) {
                                 element.dump(riaDos);
                             }
                         }
                     }
                 }
             }
             final byte[] rvaData = rvaBytes.toByteArray();
             final byte[] riaData = riaBytes.toByteArray();
             int rvaIndex = -1;
             int riaIndex = -1;
             if (totalVisCount > 0) {
                 rvaIndex = cp.addUtf8("RuntimeVisibleParameterAnnotations");
             }
             if (totalInvisCount > 0) {
                 riaIndex = cp.addUtf8("RuntimeInvisibleParameterAnnotations");
             }
             final List<Attribute> newAttributes = new ArrayList<>();
             if (totalVisCount > 0) {
                 newAttributes.add(new RuntimeVisibleParameterAnnotations(rvaIndex, rvaData.length, new DataInputStream(new ByteArrayInputStream(rvaData)),
                     cp.getConstantPool()));
             }
             if (totalInvisCount > 0) {
                 newAttributes.add(new RuntimeInvisibleParameterAnnotations(riaIndex, riaData.length, new DataInputStream(new ByteArrayInputStream(riaData)),
                     cp.getConstantPool()));
             }
             return newAttributes.toArray(Attribute.EMPTY_ARRAY);
         } catch (final IOException e) {
             System.err.println("IOException whilst processing parameter annotations");
             e.printStackTrace();
         }
         return null;
     }
 
     /**
      * Reads an AnnotationEntryGen from a DataInput.
      *
      * @param dis The data input stream.
      * @param cpool The constant pool generator.
      * @param b whether the annotation is runtime visible.
      * @return The annotation entry generator.
      * @throws IOException Thrown if an I/O error occurs.
      */
     public static AnnotationEntryGen read(final DataInput dis, final ConstantPoolGen cpool, final boolean b) throws IOException {
         final AnnotationEntryGen a = new AnnotationEntryGen(cpool);
         a.typeIndex = dis.readUnsignedShort();
         final int elemValuePairCount = dis.readUnsignedShort();
         for (int i = 0; i < elemValuePairCount; i++) {
             final int nidx = dis.readUnsignedShort();
             a.addElementNameValuePair(new ElementValuePairGen(nidx, ElementValueGen.readElementValue(dis, cpool), cpool));
         }
         a.isRuntimeVisible(b);
         return a;
     }
 
     private int typeIndex;
 
     private List<ElementValuePairGen> evs;
 
     private final ConstantPoolGen cpool;
 
     private boolean isRuntimeVisible;
 
     /**
      * Here we are taking a fixed annotation of type Annotation and building a modifiable AnnotationGen object. If the pool
      * passed in is for a different class file, then copyPoolEntries should have been passed as true as that will force us
      * to do a deep copy of the annotation and move the cpool entries across. We need to copy the type and the element name
      * value pairs and the visibility.
      *
      * @param a The annotation entry.
      * @param cpool The constant pool generator.
      * @param copyPoolEntries whether to copy pool entries.
      */
     public AnnotationEntryGen(final AnnotationEntry a, final ConstantPoolGen cpool, final boolean copyPoolEntries) {
         this.cpool = cpool;
         if (copyPoolEntries) {
             typeIndex = cpool.addUtf8(a.getAnnotationType());
         } else {
             typeIndex = a.getAnnotationTypeIndex();
         }
         isRuntimeVisible = a.isRuntimeVisible();
         evs = copyValues(a.getElementValuePairs(), cpool, copyPoolEntries);
     }
 
     private AnnotationEntryGen(final ConstantPoolGen cpool) {
         this.cpool = cpool;
     }
 
     /**
      * Constructs an AnnotationEntryGen.
      *
      * @param type The object type.
      * @param elements The element value pairs.
      * @param vis whether the annotation is visible.
      * @param cpool The constant pool generator.
      */
     public AnnotationEntryGen(final ObjectType type, final List<ElementValuePairGen> elements, final boolean vis, final ConstantPoolGen cpool) {
         this.cpool = cpool;
         this.typeIndex = cpool.addUtf8(type.getSignature());
         evs = elements;
         isRuntimeVisible = vis;
     }
 
     /**
      * Adds an element name value pair.
      *
      * @param evp The element value pair generator.
      */
     public void addElementNameValuePair(final ElementValuePairGen evp) {
         if (evs == null) {
             evs = new ArrayList<>();
         }
         evs.add(evp);
     }
 
     private List<ElementValuePairGen> copyValues(final ElementValuePair[] in, final ConstantPoolGen cpool, final boolean copyPoolEntries) {
         return Streams.of(in).map(nvp -> new ElementValuePairGen(nvp, cpool, copyPoolEntries)).collect(Collectors.toList());
     }
 
     /**
      * Dumps this annotation entry to a DataOutputStream.
      *
      * @param dos The data output stream.
      * @throws IOException Thrown if an I/O error occurs.
      */
     public void dump(final DataOutputStream dos) throws IOException {
         dos.writeShort(typeIndex); // u2 index of type name in cpool
         dos.writeShort(Args.requireU2(evs.size(), "evs.size()")); // u2 element_value pair count
         for (final ElementValuePairGen envp : evs) {
             envp.dump(dos);
         }
     }
 
     /**
      * Retrieves an immutable version of this AnnotationGen.
      *
      * @return An immutable version of this AnnotationGen.
      */
     public AnnotationEntry getAnnotation() {
         final AnnotationEntry a = new AnnotationEntry(typeIndex, cpool.getConstantPool(), isRuntimeVisible);
         for (final ElementValuePairGen element : evs) {
             a.addElementNameValuePair(element.getElementNameValuePair());
         }
         return a;
     }
 
     /**
      * Gets the type index.
      *
      * @return The type index.
      */
     public int getTypeIndex() {
         return typeIndex;
     }
 
     /**
      * Gets the type name.
      *
      * @return The type name.
      */
     public final String getTypeName() {
         return getTypeSignature(); // BCELBUG: Should I use this instead?
         // Utility.signatureToString(getTypeSignature());
     }
 
     /**
      * Gets the type signature.
      *
      * @return The type signature.
      */
     public final String getTypeSignature() {
         // ConstantClass c = (ConstantClass) cpool.getConstant(typeIndex);
         final ConstantUtf8 utf8 = (ConstantUtf8) cpool.getConstant(typeIndex/* c.getNameIndex() */);
         return utf8.getBytes();
     }
 
     /**
      * Returns list of ElementNameValuePair objects.
      *
      * @return list of ElementNameValuePair objects.
      */
     public List<ElementValuePairGen> getValues() {
         return evs;
     }
 
     /**
      * Gets whether this annotation is runtime visible.
      *
      * @return true if this annotation is runtime visible.
      */
     public boolean isRuntimeVisible() {
         return isRuntimeVisible;
     }
 
     private void isRuntimeVisible(final boolean b) {
         isRuntimeVisible = b;
     }
 
     /**
      * Returns a short string representation of this annotation.
      *
      * @return A short string representation of this annotation.
      */
     public String toShortString() {
         final StringBuilder s = new StringBuilder();
         s.append("@").append(getTypeName()).append("(");
         for (int i = 0; i < evs.size(); i++) {
             s.append(evs.get(i));
             if (i + 1 < evs.size()) {
                 s.append(",");
             }
         }
         s.append(")");
         return s.toString();
     }
 
     @Override
     public String toString() {
         final StringBuilder s = new StringBuilder(32); // CHECKSTYLE IGNORE MagicNumber
         s.append("AnnotationGen:[").append(getTypeName()).append(" #").append(evs.size()).append(" {");
         for (int i = 0; i < evs.size(); i++) {
             s.append(evs.get(i));
             if (i + 1 < evs.size()) {
                 s.append(",");
             }
         }
         s.append("}]");
         return s.toString();
     }
 
 }