package org.msgpack.jruby;

import java.math.BigInteger; import java.nio.ByteBuffer; import java.util.Arrays;

import org.jruby.Ruby; import org.jruby.RubyObject; import org.jruby.RubyModule; import org.jruby.RubyNil; import org.jruby.RubyBoolean; import org.jruby.RubyNumeric; import org.jruby.RubyBignum; import org.jruby.RubyInteger; import org.jruby.RubyFixnum; import org.jruby.RubyFloat; import org.jruby.RubyString; import org.jruby.RubySymbol; import org.jruby.RubyArray; import org.jruby.RubyHash; import org.jruby.RubyEncoding; import org.jruby.runtime.builtin.IRubyObject; import org.jruby.util.ByteList;

import org.jcodings.Encoding; import org.jcodings.specific.UTF8Encoding;

import static org.msgpack.jruby.Types.*;

public class Encoder {

private static final int CACHE_LINE_SIZE = 64;
private static final int ARRAY_HEADER_SIZE = 24;

private final Ruby runtime;
private final Encoding binaryEncoding;
private final Encoding utf8Encoding;
private final boolean compatibilityMode;
private final ExtensionRegistry registry;
private final Packer packer;

public boolean hasSymbolExtType;
private boolean hasBigintExtType;
private boolean recursiveExtension;

private ByteBuffer buffer;

public Encoder(Ruby runtime, Packer packer, boolean compatibilityMode, ExtensionRegistry registry, boolean hasSymbolExtType, boolean hasBigintExtType) {
  this.packer = packer;
  this.runtime = runtime;
  this.buffer = ByteBuffer.allocate(CACHE_LINE_SIZE - ARRAY_HEADER_SIZE);
  this.binaryEncoding = runtime.getEncodingService().getAscii8bitEncoding();
  this.utf8Encoding = UTF8Encoding.INSTANCE;
  this.compatibilityMode = compatibilityMode;
  this.registry = registry;
  this.hasSymbolExtType = hasSymbolExtType;
  this.hasBigintExtType = hasBigintExtType;
}

public boolean isCompatibilityMode() {
  return compatibilityMode;
}

private void ensureRemainingCapacity(int c) {
  if (buffer.remaining() < c) {
    int newLength = Math.max(buffer.capacity() + (buffer.capacity() >> 1), buffer.capacity() + c);
    newLength += CACHE_LINE_SIZE - ((ARRAY_HEADER_SIZE + newLength) % CACHE_LINE_SIZE);
    buffer = ByteBuffer.allocate(newLength).put(buffer.array(), 0, buffer.position());
  }
}

private IRubyObject readRubyString() {
  if (recursiveExtension) {
    // If recursiveExtension is true, it means we re-entered encode, so we MUST NOT flush the buffer.
        // Instead we return an empty string to act as a null object for the caller. The buffer will actually
        // be flushed once we're done serializing the recursive extension.
        // All other method that consume the buffer should do so through readRubyString or implement the same logic.
    return runtime.newString();
  } else {
    IRubyObject str = runtime.newString(new ByteList(buffer.array(), 0, buffer.position(), binaryEncoding, false));
    buffer.clear();
    return str;
  }
}

public IRubyObject encode(IRubyObject object) {
  appendObject(object);
  return readRubyString();
}

public IRubyObject encode(IRubyObject object, IRubyObject destination) {
  appendObject(object, destination);
  return readRubyString();
}

public IRubyObject encodeArrayHeader(int size) {
  appendArrayHeader(size);
  return readRubyString();
}

public IRubyObject encodeMapHeader(int size) {
  appendHashHeader(size);
  return readRubyString();
}

public IRubyObject encodeBinHeader(int size) {
  appendStringHeader(size, true);
  return readRubyString();
}

public IRubyObject encodeFloat32(RubyNumeric numeric) {
  appendFloat32(numeric);
  return readRubyString();
}

private void appendObject(IRubyObject object) {
  appendObject(object, null);
}

private void appendObject(IRubyObject object, IRubyObject destination) {
  if (object == null || object instanceof RubyNil) {
    ensureRemainingCapacity(1);
    buffer.put(NIL);
  } else if (object instanceof RubyBoolean) {
    ensureRemainingCapacity(1);
    buffer.put(((RubyBoolean) object).isTrue() ? TRUE : FALSE);
  } else if (object instanceof RubyBignum) {
    appendBignum((RubyBignum) object);
  } else if (object instanceof RubyInteger) {
    appendInteger((RubyInteger) object);
  } else if (object instanceof RubyFloat) {
    appendFloat((RubyFloat) object);
  } else if (object instanceof RubyString) {
    if (object.getType() == runtime.getString() || !tryAppendWithExtTypeLookup(object)) {
      appendString((RubyString) object);
    }
  } else if (object instanceof RubySymbol) {
    if (hasSymbolExtType) {
      appendOther(object, destination);
    } else {
      appendString(((RubySymbol) object).asString());
    }
  } else if (object instanceof RubyArray) {
    if (object.getType() == runtime.getArray() || !tryAppendWithExtTypeLookup(object)) {
      appendArray((RubyArray) object);
    }
  } else if (object instanceof RubyHash) {
    if (object.getType() == runtime.getHash() || !tryAppendWithExtTypeLookup(object)) {
      appendHash((RubyHash) object);
    }
  } else if (object instanceof ExtensionValue) {
    appendExtensionValue((ExtensionValue) object);
  } else {
    appendOther(object, destination);
  }
}

private void appendBignum(RubyBignum object) {
  BigInteger value = object.getBigIntegerValue();
  if (value.compareTo(RubyBignum.LONG_MIN) < 0 || value.compareTo(RubyBignum.LONG_MAX) > 0) {
    if (value.bitLength() > 64 || (value.bitLength() > 63 && value.signum() < 0)) {
      if (hasBigintExtType && tryAppendWithExtTypeLookup(object)) {
        return;
      }
      throw runtime.newRangeError(String.format("Cannot pack big integer: %s", value));
    }
    ensureRemainingCapacity(9);
    buffer.put(value.signum() < 0 ? INT64 : UINT64);
    byte[] b = value.toByteArray();
    buffer.put(b, b.length - 8, 8);
  } else {
    appendInteger(object);
  }
}

private void appendInteger(RubyInteger object) {
  long value = object.getLongValue();
  if (value < 0) {
    if (value < Short.MIN_VALUE) {
      if (value < Integer.MIN_VALUE) {
        ensureRemainingCapacity(9);
        buffer.put(INT64);
        buffer.putLong(value);
      } else {
        ensureRemainingCapacity(5);
        buffer.put(INT32);
        buffer.putInt((int) value);
      }
    } else if (value >= -0x20L) {
      ensureRemainingCapacity(1);
      byte b = (byte) (value | 0xe0);
      buffer.put(b);
    } else if (value < Byte.MIN_VALUE) {
      ensureRemainingCapacity(3);
      buffer.put(INT16);
      buffer.putShort((short) value);
    } else {
      ensureRemainingCapacity(2);
      buffer.put(INT8);
      buffer.put((byte) value);
    }
  } else {
    if (value < 0x10000L) {
      if (value < 128L) {
        ensureRemainingCapacity(1);
        buffer.put((byte) value);
      } else if (value < 0x100L) {
        ensureRemainingCapacity(2);
        buffer.put(UINT8);
        buffer.put((byte) value);
      } else {
        ensureRemainingCapacity(3);
        buffer.put(UINT16);
        buffer.putShort((short) value);
      }
    } else if (value < 0x100000000L) {
      ensureRemainingCapacity(5);
      buffer.put(UINT32);
      buffer.putInt((int) value);
    } else {
      ensureRemainingCapacity(9);
      buffer.put(INT64);
      buffer.putLong(value);
    }
  }
}

private void appendFloat(RubyFloat object) {
  double value = object.getDoubleValue();
  //TODO: msgpack-ruby original does encode this value as Double, not float
  // float f = (float) value;
  // if (Double.compare(f, value) == 0) {
  //   ensureRemainingCapacity(5);
  //   buffer.put(FLOAT32);
  //   buffer.putFloat(f);
  // } else {
    ensureRemainingCapacity(9);
    buffer.put(FLOAT64);
    buffer.putDouble(value);
  // }
}

private void appendFloat32(RubyNumeric object) {
  float value = (float) object.getDoubleValue();
  ensureRemainingCapacity(5);
  buffer.put(FLOAT32);
  buffer.putFloat(value);
}

private void appendStringHeader(int length, boolean binary) {
  if (length < 32 && !binary) {
    ensureRemainingCapacity(1 + length);
    buffer.put((byte) (length | FIXSTR));
  } else if (length <= 0xff && !compatibilityMode) {
    ensureRemainingCapacity(2 + length);
    buffer.put(binary ? BIN8 : STR8);
    buffer.put((byte) length);
  } else if (length <= 0xffff) {
    ensureRemainingCapacity(3 + length);
    buffer.put(binary ? BIN16 : STR16);
    buffer.putShort((short) length);
  } else {
    ensureRemainingCapacity(5 + length);
    buffer.put(binary ? BIN32 : STR32);
    buffer.putInt(length);
  }
}

private void appendString(RubyString object) {
  Encoding encoding = object.getEncoding();
  boolean binary = !compatibilityMode && encoding == binaryEncoding;
  if (encoding != utf8Encoding && encoding != binaryEncoding) {
    object = (RubyString)(object).encode(runtime.getCurrentContext(), runtime.getEncodingService().getEncoding(utf8Encoding));
  }
  ByteList bytes = object.getByteList();
  int length = bytes.length();
  appendStringHeader(length, binary);
  buffer.put(bytes.unsafeBytes(), bytes.begin(), length);
}

private void appendArray(RubyArray<?> object) {
  appendArrayHeader(object);
  appendArrayElements(object);
}

private void appendArrayHeader(RubyArray<?> object) {
  appendArrayHeader(object.size());
}

private void appendArrayHeader(int size) {
  if (size < 16) {
    ensureRemainingCapacity(1);
    buffer.put((byte) (size | 0x90));
  } else if (size < 0x10000) {
    ensureRemainingCapacity(3);
    buffer.put(ARY16);
    buffer.putShort((short) size);
  } else {
    ensureRemainingCapacity(5);
    buffer.put(ARY32);
    buffer.putInt(size);
  }
}

private void appendArrayElements(RubyArray<?> object) {
  int size = object.size();
  for (int i = 0; i < size; i++) {
    appendObject(object.eltOk(i));
  }
}

private void appendHash(RubyHash object) {
  appendHashHeader(object);
  appendHashElements(object);
}

private void appendHashHeader(RubyHash object) {
  appendHashHeader(object.size());
}

private void appendHashHeader(int size) {
  if (size < 16) {
    ensureRemainingCapacity(1);
    buffer.put((byte) (size | 0x80));
  } else if (size < 0x10000) {
    ensureRemainingCapacity(3);
    buffer.put(MAP16);
    buffer.putShort((short) size);
  } else {
    ensureRemainingCapacity(5);
    buffer.put(MAP32);
    buffer.putInt(size);
  }
}

private void appendHashElements(RubyHash object) {
  int size = object.size();
  HashVisitor visitor = new HashVisitor(size);
  object.visitAll(visitor);
  if (visitor.remain != 0) {
    object.getRuntime().newConcurrencyError("Hash size changed while packing");
  }
}

private class HashVisitor extends RubyHash.Visitor {
  public int remain;

  public HashVisitor(int size) {
    remain = size;
  }

  public void visit(IRubyObject key, IRubyObject value) {
    if (remain-- > 0) {
      appendObject(key);
      appendObject(value);
    }
  }
}

private void appendExt(int type, ByteList payloadBytes) {
  int payloadSize = payloadBytes.length();
  int outputSize = 0;
  boolean fixSize = payloadSize == 1 || payloadSize == 2 || payloadSize == 4 || payloadSize == 8 || payloadSize == 16;
  if (fixSize) {
    outputSize = 2 + payloadSize;
  } else if (payloadSize < 0x100) {
    outputSize = 3 + payloadSize;
  } else if (payloadSize < 0x10000) {
    outputSize = 4 + payloadSize;
  } else {
    outputSize = 6 + payloadSize;
  }
  ensureRemainingCapacity(outputSize);
  if (payloadSize == 1) {
    buffer.put(FIXEXT1);
  } else if (payloadSize == 2) {
    buffer.put(FIXEXT2);
  } else if (payloadSize == 4) {
    buffer.put(FIXEXT4);
  } else if (payloadSize == 8) {
    buffer.put(FIXEXT8);
  } else if (payloadSize == 16) {
    buffer.put(FIXEXT16);
  } else if (payloadSize < 0x100) {
    buffer.put(VAREXT8);
    buffer.put((byte) payloadSize);
  } else if (payloadSize < 0x10000) {
    buffer.put(VAREXT16);
    buffer.putShort((short) payloadSize);
  } else {
    buffer.put(VAREXT32);
    buffer.putInt(payloadSize);
  }
  buffer.put((byte) type);
  buffer.put(payloadBytes.unsafeBytes(), payloadBytes.begin(), payloadSize);
}

private void appendExtensionValue(ExtensionValue object) {
  long type = ((RubyFixnum)object.get_type()).getLongValue();
  if (type < -128 || type > 127) {
    throw object.getRuntime().newRangeError(String.format("integer %d too big to convert to `signed char'", type));
  }
  ByteList payloadBytes = ((RubyString)object.payload()).getByteList();
  appendExt((int) type, payloadBytes);
}

private boolean tryAppendWithExtTypeLookup(IRubyObject object) {
  if (registry != null) {
    ExtensionRegistry.ExtensionEntry entry = registry.lookupExtensionForObject(object);
    if (entry != null) {
      IRubyObject proc = entry.getPackerProc();
      int type = entry.getTypeId();

      if (entry.isRecursive()) {
        ByteBuffer oldBuffer = buffer;
        buffer = ByteBuffer.allocate(CACHE_LINE_SIZE - ARRAY_HEADER_SIZE);
        boolean previousRecursiveExtension = recursiveExtension;
        recursiveExtension = true;

        ByteList payload;
        try {
          IRubyObject args[] = { object, packer };
          proc.callMethod(runtime.getCurrentContext(), "call", args);
          payload = new ByteList(buffer.array(), 0, buffer.position(), binaryEncoding, false);
        } finally {
          recursiveExtension = previousRecursiveExtension;
          buffer = oldBuffer;
        }
        appendExt(type, payload);
      } else {
        RubyString bytes = proc.callMethod(runtime.getCurrentContext(), "call", object).asString();
        appendExt(type, bytes.getByteList());
      }
      return true;
    }
  }
  return false;
}

private void appendOther(IRubyObject object, IRubyObject destination) {
  if (!tryAppendWithExtTypeLookup(object)) { appendCustom(object, destination); }
}

private void appendCustom(IRubyObject object, IRubyObject destination) {
  if (destination == null) {
    IRubyObject result = object.callMethod(runtime.getCurrentContext(), "to_msgpack");
    ByteList bytes = result.asString().getByteList();
    int length = bytes.length();
    ensureRemainingCapacity(length);
    buffer.put(bytes.unsafeBytes(), bytes.begin(), length);
  } else {
    object.callMethod(runtime.getCurrentContext(), "to_msgpack", destination);
  }
}

}