package org.djutils.serialization;
   
   import java.io.IOException;
   
   import org.djunits.unit.Unit;
   import org.djutils.decoderdumper.Decoder;
   import org.djutils.serialization.serializers.ArrayOrMatrixSerializer;
   import org.djutils.serialization.serializers.BasicPrimitiveArrayOrMatrixSerializer;
   import org.djutils.serialization.serializers.FixedSizeObjectSerializer;
  import org.djutils.serialization.serializers.ObjectSerializer;
  import org.djutils.serialization.serializers.Pointer;
  import org.djutils.serialization.serializers.Serializer;
  
  /**
   * Decoder for inspection of serialized data.
   * <p>
   * Copyright (c) 2013-2023 Delft University of Technology, PO Box 5, 2600 AA, Delft, the Netherlands. All rights reserved. <br>
   * BSD-style license. See <a href="https://djutils.org/docs/current/djutils/licenses.html">DJUTILS License</a>.
   * <p>
   * @version $Revision$, $LastChangedDate$, by $Author$, initial version Jan 3, 2019 <br>
   * @author <a href="https://www.tudelft.nl/averbraeck">Alexander Verbraeck</a>
   * @author <a href="https://www.tudelft.nl/staff/p.knoppers/">Peter Knoppers</a>
   */
  public class SerialDataDecoder implements Decoder
  {
      /** The endian util to use to decode multi-byte values. */
      private final EndianUtil endianUtil;
  
      /** Type of the data that is currently being decoded. */
      private byte currentFieldType;
  
      /** The serializer for the <code>currentFieldType</code>. */
      private Serializer<?> currentSerializer = null;
  
      /** Position in the data of the <code>dataElementBytes</code>. */
      private int positionInData = -1;
  
      /** Position in the dataElementBytes where the next input byte shall be store. */
      private int nextDataElementByte = -1;
  
      /** Collects the bytes that constitute the current data element. */
      private byte[] dataElementBytes = new byte[0];
  
      /** Size of the data that is currently being decode. */
      private int totalDataSize = -1;
  
      /** Number of rows in an array or matrix. */
      private int rowCount;
  
      /** Number of columns in a matrix. */
      private int columnCount;
  
      /** Row of matrix or array that we are now reading. */
      private int currentRow;
  
      /** Column of matrix that we are now reading. */
      private int currentColumn;
  
      /** Djunits display unit. */
      private Unit<?> displayUnit;
  
      /** String builder for current output line. */
      private StringBuilder buffer = new StringBuilder();
  
      /**
       * Construct a new SerialDataDecoder.
       * @param endianUtil EndianUtil; the endian util to use to decode multi-byte values
       */
      public SerialDataDecoder(final EndianUtil endianUtil)
      {
          this.endianUtil = endianUtil;
      }
  
      /** {@inheritDoc} */
      @Override
      public final String getResult()
      {
          String result = this.buffer.toString();
          this.buffer.setLength(0);
          return result;
      }
  
      /** {@inheritDoc} */
      @Override
      public final int getMaximumWidth()
      {
          return 80;
      }
  
      /** {@inheritDoc} */
      @Override
      public final boolean append(final int address, final byte theByte) throws IOException
      {
          boolean result = false;
          if (null == this.currentSerializer)
          {
              // We are expecting a field type byte
              this.currentFieldType = theByte;
              this.currentSerializer = TypedMessage.PRIMITIVE_DATA_DECODERS.get(this.currentFieldType);
             if (null == this.currentSerializer)
             {
                 this.buffer.append(String.format("Bad field type %02x - resynchronizing", this.currentFieldType));
                 result = true;
                 // May eventually re-synchronize, but that could take a lot of data.
             }
             else
             {
                 this.buffer.append(this.currentSerializer.dataClassName() + (this.currentSerializer.getNumberOfDimensions() > 0
                         || this.currentSerializer.dataClassName().startsWith("Djunits") ? " " : ": "));
                 this.positionInData = 1;
                 this.totalDataSize = 1; // to be adjusted
                 this.columnCount = 0;
                 this.rowCount = 0;
                 this.displayUnit = null;
                 if (this.currentSerializer.dataClassName().startsWith("String_"))
                 {
                     prepareForDataElement(4);
                     this.totalDataSize += 4;
                 }
                 else if (this.currentSerializer.dataClassName().contentEquals("Djunits_vector_array"))
                 {
                     prepareForDataElement(8);
                     this.totalDataSize += 8;
                 }
                 else if (this.currentSerializer.getNumberOfDimensions() > 0)
                 {
                     int size = this.currentSerializer.getNumberOfDimensions() * 4;
                     prepareForDataElement(size);
                     this.totalDataSize += size;
                 }
                 else if (this.currentSerializer instanceof ObjectSerializer)
                 {
                     try
                     {
                         int size;
                         if (this.currentSerializer.dataClassName().startsWith("Djunits"))
                         {
                             // We won't get away calling the size method with null here
                             // Prepare to get the display unit; requires at least two more bytes
                             size = 2;
                             this.displayUnit = null;
                         }
                         else
                         {
                             size = this.currentSerializer.size(null);
                         }
                         prepareForDataElement(size);
                         this.totalDataSize += size;
                     }
                     catch (SerializationException e)
                     {
                         e.printStackTrace();
                     }
                 }
                 else
                 {
                     try
                     {
                         int size = this.currentSerializer.size(null);
                         this.totalDataSize += size;
                         prepareForDataElement(size);
                     }
                     catch (SerializationException e)
                     {
                         e.printStackTrace(); // Cannot happen
                     }
                 }
             }
             return result;
         }
         if (this.nextDataElementByte < this.dataElementBytes.length)
         {
             this.dataElementBytes[this.nextDataElementByte] = theByte;
         }
         this.nextDataElementByte++;
         this.positionInData++;
         if (this.nextDataElementByte == this.dataElementBytes.length)
         {
             if (this.currentSerializer.dataClassName().startsWith("String_"))
             {
                 int elementSize = this.currentSerializer.dataClassName().endsWith("8") ? 1 : 2;
                 if (this.columnCount == 0) // re-using columnCount to store number of characters
                 {
                     this.columnCount = this.endianUtil.decodeInt(this.dataElementBytes, 0);
                     prepareForDataElement(elementSize);
                     this.totalDataSize += this.columnCount * elementSize;
                 }
                 else
                 {
                     if (1 == elementSize)
                     {
                         if (this.dataElementBytes[0] > 32 && this.dataElementBytes[0] < 127)
                         {
                             this.buffer.append((char) this.dataElementBytes[0]); // safe to print
                         }
                         else
                         {
                             this.buffer.append("."); // not safe to print
                         }
                     }
                     else
                     {
                         char character = this.endianUtil.decodeChar(this.dataElementBytes, 0);
                         if (Character.isAlphabetic(character))
                         {
                             this.buffer.append(character); // safe to print
                         }
                         else
                         {
                             this.buffer.append("."); // not safe to print
                         }
                     }
                 }
                 this.currentColumn = 0;
                 this.nextDataElementByte = 0;
             }
             else if (this.currentSerializer.dataClassName().contentEquals("Djunits_vector_array"))
             {
                 if (this.rowCount == 0)
                 {
                     this.rowCount = this.endianUtil.decodeInt(this.dataElementBytes, 0);
                     this.columnCount = this.endianUtil.decodeInt(this.dataElementBytes, 4);
                     this.currentRow = -1; // indicates we are parsing the units
                     this.currentColumn = 0;
                     prepareForDataElement(2);
                     this.totalDataSize += 2;
                 }
                 else if (this.currentRow < 0)
                 {
                     // parse one unit
                     TypedMessage.getUnit(this.dataElementBytes, new Pointer(), this.endianUtil);
                     this.displayUnit = TypedMessage.getUnit(this.dataElementBytes, new Pointer(), this.endianUtil);
                     this.buffer.append("unit for column " + this.currentColumn + ": ");
                     this.buffer.append(this.displayUnit);
                     this.currentColumn++;
                     if (this.currentColumn < this.columnCount)
                     {
                         prepareForDataElement(2);
                         this.totalDataSize += 2;
                         this.buffer.append(", ");
                     }
                     else
                     {
                         // Done with the units; prepare to parse the values
                         this.currentRow = 0;
                         this.currentColumn = 0;
                         prepareForDataElement(8);
                         this.totalDataSize += 8 * this.columnCount * this.rowCount;
                     }
                 }
                 else
                 {
                     // process one double value
                     this.buffer.append(String.format("value at row %d column %d: ", this.currentRow, this.currentColumn));
                     this.buffer.append(this.endianUtil.decodeDouble(this.dataElementBytes, 0));
                     this.positionInData = 0;
                     this.currentColumn++;
                     if (this.currentColumn >= this.columnCount)
                     {
                         this.currentColumn = 0;
                         this.currentRow++;
                     }
                     this.buffer.append(" ");
                     this.nextDataElementByte = 0;
                 }
             }
             else if (this.currentSerializer.dataClassName().startsWith("Djunits"))
             {
                 if (this.currentSerializer.getNumberOfDimensions() > 0 && 0 == this.rowCount)
                 {
                     this.columnCount = this.endianUtil.decodeInt(this.dataElementBytes, 0);
                     this.currentRow = 0;
                     this.currentColumn = 0;
                     if (this.dataElementBytes.length == 8)
                     {
                         this.rowCount = this.columnCount;
                         this.columnCount = this.endianUtil.decodeInt(this.dataElementBytes, 4);
                         this.buffer.append(String.format("height %d, width %d", this.rowCount, this.columnCount));
                     }
                     else
                     {
                         this.rowCount = 1;
                         this.buffer.append(String.format("length %d", this.columnCount));
                     }
                     // Prepare for the unit.
                     prepareForDataElement(2);
                     this.totalDataSize += 2;
                     this.buffer.append(", ");
                     return false;
                 }
                 else if (null == this.displayUnit)
                 {
                     this.displayUnit = TypedMessage.getUnit(this.dataElementBytes, new Pointer(), this.endianUtil);
                     this.buffer.append("unit " + this.displayUnit);
                     int numberOfDimensions = this.currentSerializer.getNumberOfDimensions();
                     int elementSize = this.currentSerializer.dataClassName().contains("Float") ? 4 : 8;
                     this.totalDataSize += elementSize * (0 == numberOfDimensions ? 1 : this.rowCount * this.columnCount);
                     prepareForDataElement(elementSize);
                     if (0 == numberOfDimensions)
                     {
                         this.buffer.append(": ");
                     }
                     else
                     {
                         result = true;
                     }
                 }
                 else
                 {
                     // get one value
                     int dimensions = this.currentSerializer.getNumberOfDimensions();
                     if (dimensions == 1)
                     {
                         this.buffer.append(String.format("value at index %d: ", this.currentColumn));
                     }
                     else if (dimensions == 2)
                     {
                         this.buffer.append(String.format("value at row %d column %d: ", this.currentRow, this.currentColumn));
                     }
                     // else dimension == 0
                     if (dimensions > 0)
                     {
                         this.currentColumn++;
                         if (this.currentColumn >= this.columnCount)
                         {
                             this.currentColumn = 0;
                             this.currentRow++;
                         }
                     }
                     this.buffer.append(this.dataElementBytes.length == 4 ? this.endianUtil.decodeFloat(this.dataElementBytes, 0)
                             : this.endianUtil.decodeDouble(this.dataElementBytes, 0));
                     this.nextDataElementByte = 0;
                     result = true;
                 }
             }
             else if (this.currentSerializer instanceof FixedSizeObjectSerializer)
             {
                 try
                 {
                     Object value = this.currentSerializer.deSerialize(this.dataElementBytes, new Pointer(), this.endianUtil);
                     this.buffer.append(value.toString());
                 }
                 catch (SerializationException e)
                 {
                     this.buffer.append("Error deserializing data");
                 }
             }
             else if (this.currentSerializer.getNumberOfDimensions() > 0)
             {
                 if (this.rowCount == 0)
                 {
                     // Got the height and width of a matrix, or length of an array
                     this.columnCount = this.endianUtil.decodeInt(this.dataElementBytes, 0);
                     this.currentRow = 0;
                     this.currentColumn = 0;
                     if (this.dataElementBytes.length == 8)
                     {
                         this.rowCount = this.columnCount;
                         this.columnCount = this.endianUtil.decodeInt(this.dataElementBytes, 4);
                         this.buffer.append(String.format("height %d, width %d", this.rowCount, this.columnCount));
                     }
                     else
                     {
                         this.rowCount = 1;
                         this.buffer.append(String.format("length %d", this.columnCount));
                     }
                     int elementSize = -1;
                     if (this.currentSerializer instanceof ArrayOrMatrixSerializer<?, ?>)
                     {
                         elementSize = ((ArrayOrMatrixSerializer<?, ?>) this.currentSerializer).getElementSize();
                     }
                     else if (this.currentSerializer instanceof BasicPrimitiveArrayOrMatrixSerializer)
                     {
                         elementSize = ((BasicPrimitiveArrayOrMatrixSerializer<?>) this.currentSerializer).getElementSize();
                     }
                     else
                     {
                         throw new RuntimeException("Unhandled type of array or matrix serializer");
                     }
                     this.totalDataSize += elementSize * this.rowCount * this.columnCount;
                     prepareForDataElement(elementSize);
                     // System.out.println("Selecting element size " + elementSize + " for serializer "
                     // + this.currentSerializer.dataClassName());
                 }
                 else
                 {
                     // Got one data element
                     if (this.currentSerializer.getNumberOfDimensions() == 1)
                     {
                         this.buffer.append(String.format("value at index %d: ", this.currentColumn));
                     }
                     else // 2 dimensions
                     {
                         this.buffer.append(String.format("value at row %d column %d: ", this.currentRow, this.currentColumn));
                     }
                     if (this.currentSerializer instanceof ArrayOrMatrixSerializer<?, ?>)
                     {
                         Object value = ((ArrayOrMatrixSerializer<?, ?>) this.currentSerializer)
                                 .deSerializeElement(this.dataElementBytes, 0, this.endianUtil);
                         this.buffer.append(value.toString());
                     }
                     else if (this.currentSerializer instanceof BasicPrimitiveArrayOrMatrixSerializer)
                     {
                         // It looks like we'll have to do this ourselves.
                         BasicPrimitiveArrayOrMatrixSerializer<?> basicPrimitiveArraySerializer =
                                 (BasicPrimitiveArrayOrMatrixSerializer<?>) this.currentSerializer;
                         switch (basicPrimitiveArraySerializer.fieldType())
                         {
                             case FieldTypes.BYTE_8_ARRAY:
                             case FieldTypes.BYTE_8_MATRIX:
                                 this.buffer.append(String.format("%02x", this.dataElementBytes[0]));
                                 break;
 
                             case FieldTypes.SHORT_16_ARRAY:
                             case FieldTypes.SHORT_16_MATRIX:
                                 this.buffer.append(String.format("%d", this.endianUtil.decodeShort(this.dataElementBytes, 0)));
                                 break;
 
                             case FieldTypes.INT_32_ARRAY:
                             case FieldTypes.INT_32_MATRIX:
                                 this.buffer.append(String.format("%d", this.endianUtil.decodeInt(this.dataElementBytes, 0)));
                                 break;
 
                             case FieldTypes.LONG_64_ARRAY:
                             case FieldTypes.LONG_64_MATRIX:
                                 this.buffer.append(String.format("%d", this.endianUtil.decodeLong(this.dataElementBytes, 0)));
                                 break;
 
                             case FieldTypes.FLOAT_32_ARRAY:
                             case FieldTypes.FLOAT_32_MATRIX:
                                 this.buffer.append(String.format("%f", this.endianUtil.decodeFloat(this.dataElementBytes, 0)));
                                 break;
 
                             case FieldTypes.DOUBLE_64_ARRAY:
                             case FieldTypes.DOUBLE_64_MATRIX:
                                 this.buffer.append(String.format("%f", this.endianUtil.decodeDouble(this.dataElementBytes, 0)));
                                 break;
 
                             case FieldTypes.BOOLEAN_8_ARRAY:
                             case FieldTypes.BOOLEAN_8_MATRIX:
                                 this.buffer.append(0 == this.dataElementBytes[0] ? "false" : "true");
                                 break;
 
                             default:
                                 throw new RuntimeException(
                                         "Unhandled type of basicPrimitiveArraySerializer: " + basicPrimitiveArraySerializer);
                         }
                     }
                     this.nextDataElementByte = 0;
                     this.currentColumn++;
                     if (this.currentColumn == this.columnCount)
                     {
                         this.currentColumn = 0;
                         this.currentRow++;
                     }
                 }
                 // System.out.println(
                 // "Parsed 1 element; next element is for column " + this.currentColumn + ", row " + this.currentRow);
                 result = true;
             }
         }
         if (this.positionInData == this.totalDataSize)
 
         {
             this.currentSerializer = null;
             this.positionInData = -1;
             this.totalDataSize = -1;
             this.rowCount = 0;
             this.columnCount = 0;
             return true;
         }
         return result;
     }
 
     /**
      * Allocate a buffer for the next data element (or two).
      * @param dataElementSize int; size of the buffer
      */
     private void prepareForDataElement(final int dataElementSize)
     {
         this.dataElementBytes = new byte[dataElementSize];
         this.nextDataElementByte = 0;
     }
 
     /** {@inheritDoc} */
     @Override
     public final boolean ignoreForIdenticalOutputCheck()
     {
         return false;
     }
 
 }