/*
 * SimpleArray_ByteBuffer.java
 *
 * Copyright (C) 2020 easye
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 * As a special exception, the copyright holders of this library give you
 * permission to link this library with independent modules to produce an
 * executable, regardless of the license terms of these independent
 * modules, and to copy and distribute the resulting executable under
 * terms of your choice, provided that you also meet, for each linked
 * independent module, the terms and conditions of the license of that
 * module.  An independent module is a module which is not derived from
 * or based on this library.  If you modify this library, you may extend
 * this exception to your version of the library, but you are not
 * obligated to do so.  If you do not wish to do so, delete this
 * exception statement from your version.
 */

package org.armedbear.lisp;

import static org.armedbear.lisp.Lisp.*;

import java.nio.ByteBuffer;

public final class SimpleArray_ByteBuffer
  extends AbstractArray
{
  private final int[] dimv;
  private final int totalSize;
  final ByteBuffer data;
  private boolean directAllocation;

  public SimpleArray_ByteBuffer(int[] dimv) {
    this(dimv, false);
  }

  public SimpleArray_ByteBuffer(int[] dimv, boolean directAllocation) {
    this.dimv = dimv;
    this.directAllocation = directAllocation;
    totalSize = computeTotalSize(dimv);
    if (directAllocation) { 
      data = ByteBuffer.allocateDirect(totalSize);
    } else {
      data = ByteBuffer.allocate(totalSize);
    }
  }

  public SimpleArray_ByteBuffer(int[] dimv, LispObject initialContents) {
    this(dimv, initialContents, false);
  }

  public SimpleArray_ByteBuffer(int[] dimv, LispObject initialContents, boolean directAllocation) {
    this.dimv = dimv;
    final int rank = dimv.length;
    this.directAllocation = directAllocation;
    LispObject rest = initialContents;
    for (int i = 0; i < rank; i++) {
      dimv[i] = rest.length();
      rest = rest.elt(0);
    }
    totalSize = computeTotalSize(dimv);
    if (directAllocation) {
      data = ByteBuffer.allocateDirect(totalSize);
    } else {
      data = ByteBuffer.allocate(totalSize);
    }
    setInitialContents(0, dimv, initialContents, 0);
  }

  public SimpleArray_ByteBuffer(int rank, LispObject initialContents) {
    this(rank, initialContents, false);
  }
  
  public SimpleArray_ByteBuffer(int rank, LispObject initialContents, boolean directAllocation) {
    if (rank < 2) {
      Debug.assertTrue(false);
    }
    dimv = new int[rank];
    LispObject rest = initialContents;
    for (int i = 0; i < rank; i++) {
      dimv[i] = rest.length();
      if (rest == NIL || rest.length() == 0)
        break;
      rest = rest.elt(0);
    }
    totalSize = computeTotalSize(dimv);
    if (directAllocation) {
      data = ByteBuffer.allocateDirect(totalSize);
    } else {
      data = ByteBuffer.allocate(totalSize);
    }
    setInitialContents(0, dimv, initialContents, 0);
  }

  private int setInitialContents(int axis, int[] dims, LispObject contents,
                                 int index) {
    if (dims.length == 0) {
      try {
        data.put(index, coerceToJavaByte(contents));
      } catch (IndexOutOfBoundsException e) {
        error(new LispError("Bad initial contents for array."));
        return -1;
      }
      ++index;
    } else {
      int dim = dims[0];
      if (dim != contents.length()) {
        error(new LispError("Bad initial contents for array."));
        return -1;
      }
      int[] newDims = new int[dims.length-1];
      for (int i = 1; i < dims.length; i++)
        newDims[i-1] = dims[i];
      if (contents.listp()) {
        for (int i = contents.length();i-- > 0;) {
          LispObject content = contents.car();
          index
            = setInitialContents(axis + 1, newDims, content, index);
          contents = contents.cdr();
        }
      } else {
        AbstractVector v = checkVector(contents);
        final int length = v.length();
        for (int i = 0; i < length; i++) {
          LispObject content = v.AREF(i);
          index
            = setInitialContents(axis + 1, newDims, content, index);
        }
      }
    }
    return index;
  }

  @Override
  public LispObject typeOf() {
    return list(Symbol.SIMPLE_ARRAY, UNSIGNED_BYTE_8, getDimensions());
  }

  @Override
  public LispObject classOf() {
    return BuiltInClass.SIMPLE_ARRAY;
  }

  @Override
  public LispObject typep(LispObject typeSpecifier) {
    if (typeSpecifier == Symbol.SIMPLE_ARRAY)
      return T;
    if (typeSpecifier == BuiltInClass.SIMPLE_ARRAY)
      return T;
    return super.typep(typeSpecifier);
  }

  @Override
  public int getRank() {
    return dimv.length;
  }

  @Override
  public LispObject getDimensions() {
    LispObject result = NIL;
    for (int i = dimv.length; i-- > 0;)
      result = new Cons(Fixnum.getInstance(dimv[i]), result);
    return result;
  }

  @Override
  public int getDimension(int n) {
    try {
      return dimv[n];
    } catch (ArrayIndexOutOfBoundsException e) {
      error(new TypeError("Bad array dimension " + n + "."));
      return -1;
    }
  }

  @Override
  public LispObject getElementType() {
    return UNSIGNED_BYTE_8;
  }

  @Override
  public int getTotalSize() {
    return totalSize;
  }

  @Override
  public boolean isAdjustable() {
    return false;
  }

  @Override
  public LispObject AREF(int index) {
    try {
      return coerceFromJavaByte(data.get(index));
    } catch (IndexOutOfBoundsException e) {
      return error(new TypeError("Bad row major index " + index + "."));
    }
  }

  @Override
  public void aset(int index, LispObject newValue) {
    try {
      data.put(index, coerceToJavaByte(newValue));
    } catch (IndexOutOfBoundsException e) {
      error(new TypeError("Bad row major index " + index + "."));
    }
  }

  @Override
  public int getRowMajorIndex(int[] subscripts) {
    final int rank = dimv.length;
    if (rank != subscripts.length) {
      StringBuffer sb = new StringBuffer("Wrong number of subscripts (");
      sb.append(subscripts.length);
      sb.append(") for array of rank ");
      sb.append(rank);
      sb.append('.');
      program_error(sb.toString());
    }
    int sum = 0;
    int size = 1;
    for (int i = rank; i-- > 0;) {
      final int dim = dimv[i];
      final int lastSize = size;
      size *= dim;
      int n = subscripts[i];
      if (n < 0 || n >= dim) {
        StringBuffer sb = new StringBuffer("Invalid index ");
        sb.append(n);
        sb.append(" for array ");
        sb.append(this);
        sb.append('.');
        program_error(sb.toString());
      }
      sum += n * lastSize;
    }
    return sum;
  }

  @Override
  public LispObject get(int[] subscripts) {
    try {
      return coerceFromJavaByte(data.get(getRowMajorIndex(subscripts)));
    } catch (IndexOutOfBoundsException e) {
      return error(new TypeError("Bad row major index " +
                                 getRowMajorIndex(subscripts) + "."));
    }
  }

  @Override
  public void set(int[] subscripts, LispObject newValue) {
    try {
      data.put(getRowMajorIndex(subscripts),coerceToJavaByte(newValue));
    } catch (IndexOutOfBoundsException e) {
      error(new TypeError("Bad row major index " +
                          getRowMajorIndex(subscripts) + "."));
    }
  }

  @Override
  public void fill(LispObject obj) {
    if (!(obj instanceof Fixnum)) {
      type_error(obj, Symbol.FIXNUM);
      // Not reached.
      return;
    }
    int n = ((Fixnum) obj).value;
    if (n < 0 || n > 255) {
      type_error(obj, UNSIGNED_BYTE_8);
      // Not reached.
      return;
    }
    for (int i = totalSize; i-- > 0;)
      data.put(i, (byte) n);
  }

  @Override
  public String printObject() {
    if (Symbol.PRINT_READABLY.symbolValue() != NIL) {
      error(new PrintNotReadable(list(Keyword.OBJECT, this)));
      // Not reached.
      return null;
    }
    return printObject(dimv);
  }

  public AbstractArray adjustArray(int[] dimv, LispObject initialElement,
                                   LispObject initialContents) {
    if (initialContents != null)
      return new SimpleArray_ByteBuffer(dimv, initialContents);
    for (int i = 0; i < dimv.length; i++) {
      if (dimv[i] != this.dimv[i]) {
        SimpleArray_ByteBuffer newArray
          = new SimpleArray_ByteBuffer(dimv);
        if (initialElement != null)
          newArray.fill(initialElement);
        copyArray(this, newArray);
        return newArray;
      }
    }
    // New dimensions are identical to old dimensions.
    return this;
  }

  // Copy a1 to a2 for index tuples that are valid for both arrays.
  static void copyArray(AbstractArray a1, AbstractArray a2) {
    Debug.assertTrue(a1.getRank() == a2.getRank());
    int[] subscripts = new int[a1.getRank()];
    int axis = 0;
    copySubArray(a1, a2, subscripts, axis);
  }

  private static void copySubArray(AbstractArray a1, AbstractArray a2,
                                   int[] subscripts, int axis) {
    if (axis < subscripts.length) {
      final int limit
        = Math.min(a1.getDimension(axis), a2.getDimension(axis));
      for (int i = 0; i < limit; i++) {
        subscripts[axis] = i;
        copySubArray(a1, a2, subscripts, axis + 1);
      }
    } else {
      int i1 = a1.getRowMajorIndex(subscripts);
      int i2 = a2.getRowMajorIndex(subscripts);
      a2.aset(i2, a1.AREF(i1));
    }
  }

  public AbstractArray adjustArray(int[] dimv, AbstractArray displacedTo,
                                   int displacement) {
    return new ComplexArray(dimv, displacedTo, displacement);
  }
}
