//===========================================================================

#ifndef BSON_H_
#define BSON_H_

//===========================================================================

#ifdef __arm__
#define USE_MISALIGNED_MEMORY_ACCESS 0
#else
#define USE_MISALIGNED_MEMORY_ACCESS 1
#endif

const int _is_bigendian = 1;
#define is_bigendian() ((*(char *)&_is_bigendian) == 0)

#include "nan.h"
#include <node.h>
#include <node_object_wrap.h>
#include <v8.h>

#if defined(_MSC_VER)
#include <intrin.h>
#endif

using Nan::ObjectWrap;
using Nan::Persistent;
using v8::Array;
using v8::Date;
using v8::Function;
using v8::FunctionTemplate;
using v8::Int32;
using v8::Integer;
using v8::Local;
using v8::Number;
using v8::Object;
using v8::RegExp;
using v8::String;
using v8::Uint32;
using v8::Value;

const int preLoadedIndex = 10000;

#define NanStr(x) (Unmaybe(Nan::New<String>(x)))
#define NanHas(obj, key) (Nan::Has(obj, NanKey(key)).FromJust())
#define NanGet(obj, key) (Unmaybe(Nan::Get(obj, NanKey(key))))
#define NanEquals(a, b) (Unmaybe(Nan::Equals(a, b)))
#define NanToString(obj) (Unmaybe(obj->ToString(Nan::GetCurrentContext())))
#define NanToObject(obj) (Unmaybe(obj->ToObject(Nan::GetCurrentContext())))

#if NODE_MAJOR_VERSION >= 12
#define NanUtf8Length(obj) (obj->Utf8Length(v8::Isolate::GetCurrent()))
#else
#define NanUtf8Length(obj) (obj->Utf8Length())
#endif
// Unmaybe overloading to conviniently convert from Local/MaybeLocal/Maybe to
// Local/plain value
template <class T> inline Local<T> Unmaybe(Local<T> h) { return h; }
template <class T> inline Local<T> Unmaybe(Nan::MaybeLocal<T> h) {
  assert(!h.IsEmpty());
  return h.ToLocalChecked();
}

template <class T> inline T Unmaybe(Nan::Maybe<T> h) {
  assert(h.IsJust());
  return h.FromJust();
}
// NanKey overloading to conviniently convert to a propert key for object/array
inline int NanKey(int i) { return i; }
inline Local<String> NanKey(const char *s) { return NanStr(s); }
inline Local<String> NanKey(const std::string &s) { return NanStr(s); }
inline Local<String> NanKey(const Local<String> &s) { return s; }
inline Local<String> NanKey(const Nan::Persistent<String> &s) {
  return NanStr(s);
}
template <class T, class U> inline T NanTo(Local<U> h) {
  return Nan::To<T>(h).ToChecked();
}

// Extracts a C string from a V8 Utf8Value.
inline const char *ToCString(const v8::String::Utf8Value &value) {
  return *value ? *value : "<string conversion failed>";
}
inline int NanWriteUtf8(const v8::Local<v8::String> str, char *buffer) {
#if NODE_MAJOR_VERSION >= 12
  return str->WriteUtf8(v8::Isolate::GetCurrent(), buffer);
#else
  return str->WriteUtf8(buffer);
#endif
}
inline int NanWrite(const v8::Local<v8::String> str, uint16_t *buffer,
                    int start = 0, int length = -1) {
#if NODE_MAJOR_VERSION >= 12
  return str->Write(v8::Isolate::GetCurrent(), buffer, start, length);
#else
  return str->Write(buffer, start, length);
#endif
}

//===========================================================================

enum BsonType {
  BSON_TYPE_NUMBER = 1,
  BSON_TYPE_STRING = 2,
  BSON_TYPE_OBJECT = 3,
  BSON_TYPE_ARRAY = 4,
  BSON_TYPE_BINARY = 5,
  BSON_TYPE_UNDEFINED = 6,
  BSON_TYPE_OID = 7,
  BSON_TYPE_BOOLEAN = 8,
  BSON_TYPE_DATE = 9,
  BSON_TYPE_NULL = 10,
  BSON_TYPE_REGEXP = 11,
  BSON_TYPE_DBPOINTER = 12,
  BSON_TYPE_CODE = 13,
  BSON_TYPE_SYMBOL = 14,
  BSON_TYPE_CODE_W_SCOPE = 15,
  BSON_TYPE_INT = 16,
  BSON_TYPE_TIMESTAMP = 17,
  BSON_TYPE_LONG = 18,
  BSON_TYPE_DECIMAL128 = 19,
  BSON_TYPE_MAX_KEY = 0x7f,
  BSON_TYPE_MIN_KEY = 0xff
};

//===========================================================================

template <typename T> class BSONSerializer;

class BSON : public Nan::ObjectWrap {
public:
  BSON();
  ~BSON();

  static void Initialize(Local<Object> target);
  static NAN_METHOD(BSONDeserializeStream);

  // JS based objects
  static NAN_METHOD(BSONSerialize);
  static NAN_METHOD(BSONDeserialize);

  // Calculate size of function
  static NAN_METHOD(CalculateObjectSize);
  static NAN_METHOD(SerializeWithBufferAndIndex);

  // Constructor used for creating new BSON objects from C++
  static Persistent<FunctionTemplate> constructor_template;

  // Get the data
  static void initializeStatics();

  // Static cache
  static Nan::Persistent<Integer> indexes[preLoadedIndex];
  static Nan::Persistent<String> indexesStrings[preLoadedIndex];
  static bool initialized;

public:
  Persistent<Object> buffer;
  size_t maxBSONSize;

  // Long type cached labels
  Nan::Persistent<String> LONG_CLASS_NAME_STR;
  Nan::Persistent<String> LONG_LOW_PROPERTY_NAME_STR;
  Nan::Persistent<String> LONG_HIGH_PROPERTY_NAME_STR;
  Nan::Persistent<String> TIMESTAMP_CLASS_NAME_STR;
  Nan::Persistent<String> OBJECT_ID_CLASS_NAME_STR;
  Nan::Persistent<String> OBJECT_ID_ID_PROPERTY_NAME_STR;
  Nan::Persistent<String> BINARY_CLASS_NAME_STR;
  Nan::Persistent<String> DECIMAL128_CLASS_NAME_STR;
  Nan::Persistent<String> DOUBLE_CLASS_NAME_STR;
  Nan::Persistent<String> INT32_CLASS_NAME_STR;
  Nan::Persistent<String> SYMBOL_CLASS_NAME_STR;
  Nan::Persistent<String> CODE_CLASS_NAME_STR;
  Nan::Persistent<String> DBREF_CLASS_NAME_STR;
  Nan::Persistent<String> REGEXP_CLASS_NAME_STR;
  Nan::Persistent<String> MIN_KEY_CLASS_NAME_STR;
  Nan::Persistent<String> MAX_KEY_CLASS_NAME_STR;
  Nan::Persistent<String> BINARY_POSITION_PROPERTY_NAME_STR;
  Nan::Persistent<String> BINARY_BUFFER_PROPERTY_NAME_STR;
  Nan::Persistent<String> BINARY_SUBTYPE_PROPERTY_NAME_STR;
  Nan::Persistent<String> DECIMAL128_VALUE_PROPERTY_NAME_STR;
  Nan::Persistent<String> DOUBLE_VALUE_PROPERTY_NAME_STR;
  Nan::Persistent<String> INT32_VALUE_PROPERTY_NAME_STR;
  Nan::Persistent<String> SYMBOL_VALUE_PROPERTY_NAME_STR;
  Nan::Persistent<String> CODE_CODE_PROPERTY_NAME_STR;
  Nan::Persistent<String> CODE_SCOPE_PROPERTY_NAME_STR;
  Nan::Persistent<String> DBREF_NAMESPACE_PROPERTY_NAME_STR;
  Nan::Persistent<String> DBREF_OID_PROPERTY_NAME_STR;
  Nan::Persistent<String> DBREF_DB_PROPERTY_NAME_STR;
  Nan::Persistent<String> DBREF_FIELDS_PROPERTY_NAME_STR;
  Nan::Persistent<String> REGEX_PATTERN_PROPERTY_NAME_STR;
  Nan::Persistent<String> REGEX_OPTIONS_PROPERTY_NAME_STR;
  Nan::Persistent<String> MAP_NAME_STR;

private:
  static NAN_METHOD(New);
  static Local<Value> deserialize(BSON *bson, char *data, uint32_t dataLength,
                                  uint32_t startIndex, bool is_array_item);

  // BSON type instantiate functions
  Nan::Persistent<Function> longConstructor;
  Nan::Persistent<Function> objectIDConstructor;
  Nan::Persistent<Function> int32Constructor;
  Nan::Persistent<Function> decimalConstructor;
  Nan::Persistent<Function> binaryConstructor;
  Nan::Persistent<Function> codeConstructor;
  Nan::Persistent<Function> regexpConstructor;
  Nan::Persistent<Function> dbrefConstructor;
  Nan::Persistent<Function> symbolConstructor;
  Nan::Persistent<Function> doubleConstructor;
  Nan::Persistent<Function> timestampConstructor;
  Nan::Persistent<Function> minKeyConstructor;
  Nan::Persistent<Function> maxKeyConstructor;

  Local<Object> GetSerializeObject(const Local<Value> &object);

  template <typename T> friend class BSONSerializer;
  friend class BSONDeserializer;
};

//===========================================================================

class CountStream {
public:
  CountStream() : depth(0), count(0) {}

  void WriteByte(int value) { ++count; }
  void WriteByte(const Local<Object> &, const Local<String> &) { ++count; }
  void WriteBool(const Local<Value> &value) { ++count; }
  void WriteInt32(int32_t value) { count += 4; }
  void WriteInt32(const Local<Value> &value) { count += 4; }
  void WriteInt32(const Local<Object> &object, const Local<String> &key) {
    count += 4;
  }
  void WriteInt64(int64_t value) { count += 8; }
  void WriteInt64(const Local<Value> &value) { count += 8; }
  void WriteDouble(double value) { count += 8; }
  void WriteDouble(const Local<Value> &value) { count += 8; }
  void WriteDouble(const Local<Object> &, const Local<String> &) { count += 8; }
  void WriteUInt32String(uint32_t name) {
    char buffer[32];
    count += sprintf(buffer, "%u", name) + 1;
  }
  void WriteLengthPrefixedString(const Local<String> &value) {
    count += NanUtf8Length(value) + 5;
  }
  void WriteObjectId(const Local<Object> &object, const Local<String> &key) {
    count += 12;
  }
  void WriteString(const Local<String> &value) {
    count += NanUtf8Length(value) + 1;
  } // This returns the number of bytes exclusive of the NULL terminator
  void WriteData(const char *data, size_t length) { count += length; }

  void *BeginWriteType() {
    ++count;
    return NULL;
  }
  void CommitType(void *, BsonType) {}
  void *BeginWriteSize() {
    count += 4;
    return NULL;
  }
  void CommitSize(void *) {}
  bool BeginDocument() {
    depth = depth + 1;
    if (depth >= 256)
      return false;
    return true;
  }
  void EndDocument() { depth = depth - 1; }

  size_t GetSerializeSize() const { return count; }

  // Do nothing. CheckKey is implemented for DataStream
  void CheckKey(const Local<String> &) {}
  void CheckForIllegalString(const Local<String> &) {}

  uint32_t depth; // keeps track of recursive depth

private:
  size_t count;
};

const size_t MAX_BSON_SIZE(1024 * 1024 * 17);

class DataStream {
public:
  DataStream(char *aDestinationBuffer)
      : destinationBuffer(aDestinationBuffer), p(aDestinationBuffer), depth(0) {
  }

  void WriteByte(int value) {
    if ((size_t)((p + 1) - destinationBuffer) > MAX_BSON_SIZE)
      throw "document is larger than max bson document size of 16MB";
    *p++ = value;
  }

  void WriteByte(const Local<Object> &object, const Local<String> &key) {
    if ((size_t)((p + 1) - destinationBuffer) > MAX_BSON_SIZE)
      throw "document is larger than max bson document size of 16MB";
    *p++ = NanTo<int32_t>(NanGet(object, key));
  }

#if USE_MISALIGNED_MEMORY_ACCESS
  void WriteInt32(int32_t value) {
    if ((size_t)((p + 4) - destinationBuffer) > MAX_BSON_SIZE)
      throw "document is larger than max bson document size of 16MB";
#if defined(_MSC_VER)
    *reinterpret_cast<int32_t *>(p) =
        is_bigendian() ? _byteswap_ulong(value) : value;
#elif defined(__GNUC__)
    *reinterpret_cast<int32_t *>(p) =
        is_bigendian() ? __builtin_bswap32(value) : value;
#endif
    p += 4;
  }

  void WriteInt64(int64_t value) {
    if ((size_t)((p + 8) - destinationBuffer) > MAX_BSON_SIZE)
      throw "document is larger than max bson document size of 16MB";
#if defined(_MSC_VER)
    *reinterpret_cast<int64_t *>(p) =
        is_bigendian() ? _byteswap_uint64(value) : value;
#elif defined(__GNUC__)
    *reinterpret_cast<int64_t *>(p) =
        is_bigendian() ? __builtin_bswap64(value) : value;
#endif
    p += 8;
  }

  void WriteDouble(double value) {
    if ((size_t)((p + 8) - destinationBuffer) > MAX_BSON_SIZE)
      throw "document is larger than max bson document size of 16MB";
    *reinterpret_cast<double *>(p) = value;
    if (is_bigendian()) {
#if defined(_MSC_VER)
      *reinterpret_cast<uint64_t *>(p) =
          _byteswap_uint64(*reinterpret_cast<int64_t *>(p));
#elif defined(__GNUC__)
      *reinterpret_cast<uint64_t *>(p) =
          __builtin_bswap64(*reinterpret_cast<int64_t *>(p));
#endif
      value = *reinterpret_cast<double *>(p);
    }
    p += 8;
  }
#else
  void WriteInt32(int32_t value) {
    if ((size_t)((p + 4) - destinationBuffer) > MAX_BSON_SIZE)
      throw "document is larger than max bson document size of 16MB";
    memcpy(p, &value, 4);
    p += 4;
  }

  void WriteInt64(int64_t value) {
    if ((size_t)((p + 8) - destinationBuffer) > MAX_BSON_SIZE)
      throw "document is larger than max bson document size of 16MB";
    memcpy(p, &value, 8);
    p += 8;
  }

  void WriteDouble(double value) {
    if ((size_t)((p + 8) - destinationBuffer) > MAX_BSON_SIZE)
      throw "document is larger than max bson document size of 16MB";
    memcpy(p, &value, 8);
    p += 8;
  }
#endif
  void WriteBool(const Local<Value> &value) {
    WriteByte(NanTo<bool>(value) ? 1 : 0);
  }

  void WriteInt32(const Local<Value> &value) {
    WriteInt32(NanTo<int32_t>(value));
  }

  void WriteInt32(const Local<Object> &object, const Local<String> &key) {
    WriteInt32(NanGet(object, key));
  }

  void WriteInt64(const Local<Value> &value) {
    WriteInt64(NanTo<int64_t>(value));
  }

  void WriteDouble(const Local<Value> &value) {
    WriteDouble(NanTo<double>(value));
  }

  void WriteDouble(const Local<Object> &object, const Local<String> &key) {
    WriteDouble(NanGet(object, key));
  }

  void WriteUInt32String(uint32_t name) { p += sprintf(p, "%u", name) + 1; }

  void WriteLengthPrefixedString(const Local<String> &value) {
    int32_t length = NanUtf8Length(value) + 1;
    if ((size_t)((p + length) - destinationBuffer) > MAX_BSON_SIZE)
      throw "document is larger than max bson document size of 16MB";
    WriteInt32(length);
    WriteString(value);
  }

  void WriteObjectId(const Local<Object> &object, const Local<String> &key);

  void WriteString(const Local<String> &value) {
    if ((size_t)(p - destinationBuffer) > MAX_BSON_SIZE)
      throw "document is larger than max bson document size of 16MB";
    p += NanWriteUtf8(value, p);
  } // This returns the number of bytes inclusive of the NULL terminator.

  void WriteData(const char *data, size_t length) {
    if ((size_t)((p + length) - destinationBuffer) > MAX_BSON_SIZE)
      throw "document is larger than max bson document size of 16MB";
    memcpy(p, data, length);
    p += length;
  }

  void *BeginWriteType() {
    void *returnValue = p;
    p++;
    return returnValue;
  }

  void CommitType(void *beginPoint, BsonType value) {
    *reinterpret_cast<unsigned char *>(beginPoint) = value;
  }

  void *BeginWriteSize() {
    if ((size_t)(p - destinationBuffer) > MAX_BSON_SIZE)
      throw "document is larger than max bson document size of 16MB";
    void *returnValue = p;
    p += 4;
    return returnValue;
  }

#if USE_MISALIGNED_MEMORY_ACCESS
  void CommitSize(void *beginPoint) {
    int32_t value = (int32_t)(p - (char *)beginPoint);
#if defined(_MSC_VER)
    *reinterpret_cast<int32_t *>(beginPoint) =
        is_bigendian() ? _byteswap_ulong(value) : value;
#elif defined(__GNUC__)
    *reinterpret_cast<int32_t *>(beginPoint) =
        is_bigendian() ? __builtin_bswap32(value) : value;
#endif
  }
#else
  void CommitSize(void *beginPoint) {
    int32_t value = (int32_t)(p - (char *)beginPoint);
    memcpy(beginPoint, &value, 4);
  }
#endif

  size_t GetSerializeSize() const { return p - destinationBuffer; }

  void CheckKey(const Local<String> &keyName);
  void CheckForIllegalString(const Local<String> &keyName);

  bool BeginDocument() {
    depth = depth + 1;
    if (depth >= 256)
      return false;
    return true;
  }
  void EndDocument() { depth = depth - 1; }

public:
  char *const destinationBuffer; // base, never changes
  char *p;                       // cursor into buffer
  uint32_t depth;                // keeps track of recursive depth
};

template <typename T> class BSONSerializer : public T {
private:
  typedef T Inherited;

public:
  BSONSerializer(BSON *aBson, bool aCheckKeys, bool aSerializeFunctions,
                 bool ignoreUndefined)
      : Inherited(), checkKeys(aCheckKeys),
        serializeFunctions(aSerializeFunctions),
        ignoreUndefined(ignoreUndefined), bson(aBson) {}
  BSONSerializer(BSON *aBson, bool aCheckKeys, bool aSerializeFunctions,
                 bool ignoreUndefined, char *parentParam)
      : Inherited(parentParam), checkKeys(aCheckKeys),
        serializeFunctions(aSerializeFunctions),
        ignoreUndefined(ignoreUndefined), bson(aBson) {}

  void SerializeDocument(const Local<Value> &value);
  void SerializeArray(const Local<Value> &value);
  void SerializeValue(void *typeLocation, const Local<Value> value,
                      bool isArray);

private:
  bool checkKeys;
  bool serializeFunctions;
  bool ignoreUndefined;
  BSON *bson;
};

//===========================================================================

class BSONDeserializer {
public:
  BSONDeserializer(BSON *aBson, char *data, size_t length, bool bsonRegExp,
                   bool promoteLongs, bool promoteBuffers, bool promoteValues,
                   Local<Object> fieldsAsRaw);
  BSONDeserializer(BSONDeserializer &parentSerializer, size_t length,
                   bool bsonRegExp, bool promoteLongs, bool promoteBuffers,
                   bool promoteValues, Local<Object> fieldsAsRaw);

  Local<Value> DeserializeDocument(bool raw);

  bool HasMoreData() const { return p < pEnd; }
  Local<Value> ReadCString();
  void ReadIntegerString();
  int32_t ReadJavascriptRegexOptions();
  int32_t ReadBSONRegexOptions();
  Local<String> ReadString();
  Local<Object> ReadObjectId();

  unsigned char ReadByte() { return *reinterpret_cast<unsigned char *>(p++); }
#if USE_MISALIGNED_MEMORY_ACCESS
  int32_t ReadInt32() {
    int32_t returnValue = *reinterpret_cast<int32_t *>(p);
    p += 4;
    if (is_bigendian()) {
#if defined(_MSC_VER)
      return _byteswap_ulong(returnValue);
#elif defined(__GNUC__)
      return __builtin_bswap32(returnValue);
#endif
    } else {
      return returnValue;
    }
  }
  uint32_t ReadUInt32() {
    uint32_t returnValue = *reinterpret_cast<uint32_t *>(p);
    p += 4;
    if (is_bigendian()) {
#if defined(_MSC_VER)
      return _byteswap_ulong(returnValue);
#elif defined(__GNUC__)
      return __builtin_bswap32(returnValue);
#endif
    } else {
      return returnValue;
    }
  }
  int64_t ReadInt64() {
    int64_t returnValue = *reinterpret_cast<int64_t *>(p);
    p += 8;
    if (is_bigendian()) {
#if defined(_MSC_VER)
      return _byteswap_uint64(returnValue);
#elif defined(__GNUC__)
      return __builtin_bswap64(returnValue);
#endif
    } else {
      return returnValue;
    }
  }
  double ReadDouble() {
    double returnValue;
    if (is_bigendian()) {
#if defined(_MSC_VER)
      uint64_t tmp = _byteswap_uint64(*reinterpret_cast<uint64_t *>(p));
#elif defined(__GNUC__)
      uint64_t tmp = __builtin_bswap64(*reinterpret_cast<uint64_t *>(p));
#endif
      returnValue = *reinterpret_cast<double *>(&tmp);
    } else {
      returnValue = *reinterpret_cast<double *>(p);
    }
    p += 8;
    return returnValue;
  }
#else
  int32_t ReadInt32() {
    int32_t returnValue;
    memcpy(&returnValue, p, 4);
    p += 4;
    return returnValue;
  }
  uint32_t ReadUInt32() {
    uint32_t returnValue;
    memcpy(&returnValue, p, 4);
    p += 4;
    return returnValue;
  }
  int64_t ReadInt64() {
    int64_t returnValue;
    memcpy(&returnValue, p, 8);
    p += 8;
    return returnValue;
  }
  double ReadDouble() {
    double returnValue;
    memcpy(&returnValue, p, 8);
    p += 8;
    return returnValue;
  }
#endif

  size_t GetSerializeSize() const { return p - pStart; }

private:
  Local<Value> DeserializeArray(bool raw);
  Local<Value> DeserializeValue(BsonType type, bool raw);
  Local<Value> DeserializeDocumentInternal();
  Local<Value> DeserializeArrayInternal(bool raw);

  BSON *bson;
  char *const pStart;
  char *p;
  char *const pEnd;
  bool bsonRegExp;
  bool promoteLongs;
  bool promoteBuffers;
  bool promoteValues;
  Local<Object> fieldsAsRaw;
};

//===========================================================================

#endif // BSON_H_

//===========================================================================