/*
 * notes: by srl295
 *  - When in NODE_HAVE_SMALL_ICU mode, ICU is linked against "stub" (null) data
 *     ( stubdata/libicudata.a ) containing nothing, no data, and it's also
 *    linked against a "small" data file which the SMALL_ICUDATA_ENTRY_POINT
 *    macro names. That's the "english+root" data.
 *
 *    If icu_data_path is non-null, the user has provided a path and we assume
 *    it goes somewhere useful. We set that path in ICU, and exit.
 *    If icu_data_path is null, they haven't set a path and we want the
 *    "english+root" data.  We call
 *       udata_setCommonData(SMALL_ICUDATA_ENTRY_POINT,...)
 *    to load up the english+root data.
 *
 *  - when NOT in NODE_HAVE_SMALL_ICU mode, ICU is linked directly with its full
 *    data. All of the variables and command line options for changing data at
 *    runtime are disabled, as they wouldn't fully override the internal data.
 *    See:  http://bugs.icu-project.org/trac/ticket/10924
 */


#include "node_i18n.h"

#if defined(NODE_HAVE_I18N_SUPPORT)

#include "node.h"
#include "node_buffer.h"
#include "env.h"
#include "env-inl.h"
#include "util.h"
#include "util-inl.h"
#include "v8.h"

#include <unicode/utypes.h>
#include <unicode/putil.h>
#include <unicode/uchar.h>
#include <unicode/udata.h>
#include <unicode/uidna.h>
#include <unicode/ucnv.h>
#include <unicode/utf8.h>
#include <unicode/utf16.h>
#include <unicode/timezone.h>
#include <unicode/ulocdata.h>
#include <unicode/uvernum.h>
#include <unicode/uversion.h>
#include <unicode/ustring.h>

#ifdef NODE_HAVE_SMALL_ICU
/* if this is defined, we have a 'secondary' entry point.
   compare following to utypes.h defs for U_ICUDATA_ENTRY_POINT */
#define SMALL_ICUDATA_ENTRY_POINT \
  SMALL_DEF2(U_ICU_VERSION_MAJOR_NUM, U_LIB_SUFFIX_C_NAME)
#define SMALL_DEF2(major, suff) SMALL_DEF(major, suff)
#ifndef U_LIB_SUFFIX_C_NAME
#define SMALL_DEF(major, suff) icusmdt##major##_dat
#else
#define SMALL_DEF(major, suff) icusmdt##suff##major##_dat
#endif

extern "C" const char U_DATA_API SMALL_ICUDATA_ENTRY_POINT[];
#endif

namespace node {

using v8::Context;
using v8::FunctionCallbackInfo;
using v8::Isolate;
using v8::Local;
using v8::MaybeLocal;
using v8::Object;
using v8::String;
using v8::Value;

namespace i18n {

template <typename T>
MaybeLocal<Object> ToBufferEndian(Environment* env, MaybeStackBuffer<T>* buf) {
  MaybeLocal<Object> ret = Buffer::New(env, buf);
  if (ret.IsEmpty())
    return ret;

  static_assert(sizeof(T) == 1 || sizeof(T) == 2,
                "Currently only one- or two-byte buffers are supported");
  if (sizeof(T) > 1 && IsBigEndian()) {
    SPREAD_BUFFER_ARG(ret.ToLocalChecked(), retbuf);
    SwapBytes16(retbuf_data, retbuf_length);
  }

  return ret;
}

struct Converter {
  explicit Converter(const char* name, const char* sub = NULL)
      : conv(nullptr) {
    UErrorCode status = U_ZERO_ERROR;
    conv = ucnv_open(name, &status);
    CHECK(U_SUCCESS(status));
    if (sub != NULL) {
      ucnv_setSubstChars(conv, sub, strlen(sub), &status);
    }
  }

  ~Converter() {
    ucnv_close(conv);
  }

  UConverter* conv;
};

// One-Shot Converters

void CopySourceBuffer(MaybeStackBuffer<UChar>* dest,
                      const char* data,
                      const size_t length,
                      const size_t length_in_chars) {
  dest->AllocateSufficientStorage(length_in_chars);
  char* dst = reinterpret_cast<char*>(**dest);
  memcpy(dst, data, length);
  if (IsBigEndian()) {
    SwapBytes16(dst, length);
  }
}

typedef MaybeLocal<Object> (*TranscodeFunc)(Environment* env,
                                            const char* fromEncoding,
                                            const char* toEncoding,
                                            const char* source,
                                            const size_t source_length,
                                            UErrorCode* status);

MaybeLocal<Object> Transcode(Environment* env,
                             const char* fromEncoding,
                             const char* toEncoding,
                             const char* source,
                             const size_t source_length,
                             UErrorCode* status) {
  *status = U_ZERO_ERROR;
  MaybeLocal<Object> ret;
  MaybeStackBuffer<char> result;
  Converter to(toEncoding, "?");
  Converter from(fromEncoding);
  const uint32_t limit = source_length * ucnv_getMaxCharSize(to.conv);
  result.AllocateSufficientStorage(limit);
  char* target = *result;
  ucnv_convertEx(to.conv, from.conv, &target, target + limit,
                 &source, source + source_length, nullptr, nullptr,
                 nullptr, nullptr, true, true, status);
  if (U_SUCCESS(*status)) {
    result.SetLength(target - &result[0]);
    ret = ToBufferEndian(env, &result);
  }
  return ret;
}

MaybeLocal<Object> TranscodeToUcs2(Environment* env,
                                   const char* fromEncoding,
                                   const char* toEncoding,
                                   const char* source,
                                   const size_t source_length,
                                   UErrorCode* status) {
  *status = U_ZERO_ERROR;
  MaybeLocal<Object> ret;
  MaybeStackBuffer<UChar> destbuf(source_length);
  Converter from(fromEncoding);
  const size_t length_in_chars = source_length * sizeof(UChar);
  ucnv_toUChars(from.conv, *destbuf, length_in_chars,
                source, source_length, status);
  if (U_SUCCESS(*status))
    ret = ToBufferEndian(env, &destbuf);
  return ret;
}

MaybeLocal<Object> TranscodeFromUcs2(Environment* env,
                                     const char* fromEncoding,
                                     const char* toEncoding,
                                     const char* source,
                                     const size_t source_length,
                                     UErrorCode* status) {
  *status = U_ZERO_ERROR;
  MaybeStackBuffer<UChar> sourcebuf;
  MaybeLocal<Object> ret;
  Converter to(toEncoding, "?");
  const size_t length_in_chars = source_length / sizeof(UChar);
  CopySourceBuffer(&sourcebuf, source, source_length, length_in_chars);
  MaybeStackBuffer<char> destbuf(length_in_chars);
  const uint32_t len = ucnv_fromUChars(to.conv, *destbuf, length_in_chars,
                                       *sourcebuf, length_in_chars, status);
  if (U_SUCCESS(*status)) {
    destbuf.SetLength(len);
    ret = ToBufferEndian(env, &destbuf);
  }
  return ret;
}

MaybeLocal<Object> TranscodeUcs2FromUtf8(Environment* env,
                                         const char* fromEncoding,
                                         const char* toEncoding,
                                         const char* source,
                                         const size_t source_length,
                                         UErrorCode* status) {
  *status = U_ZERO_ERROR;
  MaybeStackBuffer<UChar> destbuf;
  int32_t result_length;
  u_strFromUTF8(*destbuf, destbuf.capacity(), &result_length,
                source, source_length, status);
  MaybeLocal<Object> ret;
  if (U_SUCCESS(*status)) {
    destbuf.SetLength(result_length);
    ret = ToBufferEndian(env, &destbuf);
  } else if (*status == U_BUFFER_OVERFLOW_ERROR) {
    *status = U_ZERO_ERROR;
    destbuf.AllocateSufficientStorage(result_length);
    u_strFromUTF8(*destbuf, result_length, &result_length,
                  source, source_length, status);
    if (U_SUCCESS(*status)) {
      destbuf.SetLength(result_length);
      ret = ToBufferEndian(env, &destbuf);
    }
  }
  return ret;
}

MaybeLocal<Object> TranscodeUtf8FromUcs2(Environment* env,
                                         const char* fromEncoding,
                                         const char* toEncoding,
                                         const char* source,
                                         const size_t source_length,
                                         UErrorCode* status) {
  *status = U_ZERO_ERROR;
  MaybeLocal<Object> ret;
  const size_t length_in_chars = source_length / sizeof(UChar);
  int32_t result_length;
  MaybeStackBuffer<UChar> sourcebuf;
  MaybeStackBuffer<char> destbuf;
  CopySourceBuffer(&sourcebuf, source, source_length, length_in_chars);
  u_strToUTF8(*destbuf, destbuf.capacity(), &result_length,
              *sourcebuf, length_in_chars, status);
  if (U_SUCCESS(*status)) {
    destbuf.SetLength(result_length);
    ret = ToBufferEndian(env, &destbuf);
  } else if (*status == U_BUFFER_OVERFLOW_ERROR) {
    *status = U_ZERO_ERROR;
    destbuf.AllocateSufficientStorage(result_length);
    u_strToUTF8(*destbuf, result_length, &result_length, *sourcebuf,
                length_in_chars, status);
    if (U_SUCCESS(*status)) {
      destbuf.SetLength(result_length);
      ret = ToBufferEndian(env, &destbuf);
    }
  }
  return ret;
}

const char* EncodingName(const enum encoding encoding) {
  switch (encoding) {
    case ASCII: return "us-ascii";
    case LATIN1: return "iso8859-1";
    case UCS2: return "utf16le";
    case UTF8: return "utf-8";
    default: return NULL;
  }
}

bool SupportedEncoding(const enum encoding encoding) {
  switch (encoding) {
    case ASCII:
    case LATIN1:
    case UCS2:
    case UTF8: return true;
    default: return false;
  }
}

void Transcode(const FunctionCallbackInfo<Value>&args) {
  Environment* env = Environment::GetCurrent(args);
  Isolate* isolate = env->isolate();
  UErrorCode status = U_ZERO_ERROR;
  MaybeLocal<Object> result;

  THROW_AND_RETURN_UNLESS_BUFFER(env, args[0]);
  SPREAD_BUFFER_ARG(args[0], ts_obj);
  const enum encoding fromEncoding = ParseEncoding(isolate, args[1], BUFFER);
  const enum encoding toEncoding = ParseEncoding(isolate, args[2], BUFFER);

  if (SupportedEncoding(fromEncoding) && SupportedEncoding(toEncoding)) {
    TranscodeFunc tfn = &Transcode;
    switch (fromEncoding) {
      case ASCII:
      case LATIN1:
        if (toEncoding == UCS2)
          tfn = &TranscodeToUcs2;
        break;
      case UTF8:
        if (toEncoding == UCS2)
          tfn = &TranscodeUcs2FromUtf8;
        break;
      case UCS2:
        switch (toEncoding) {
          case UCS2:
            tfn = &Transcode;
            break;
          case UTF8:
            tfn = &TranscodeUtf8FromUcs2;
            break;
          default:
            tfn = TranscodeFromUcs2;
        }
        break;
      default:
        // This should not happen because of the SupportedEncoding checks
        ABORT();
    }

    result = tfn(env, EncodingName(fromEncoding), EncodingName(toEncoding),
                 ts_obj_data, ts_obj_length, &status);
  } else {
    status = U_ILLEGAL_ARGUMENT_ERROR;
  }

  if (result.IsEmpty())
    return args.GetReturnValue().Set(status);

  return args.GetReturnValue().Set(result.ToLocalChecked());
}

static void ICUErrorName(const FunctionCallbackInfo<Value>& args) {
  Environment* env = Environment::GetCurrent(args);
  UErrorCode status = static_cast<UErrorCode>(args[0]->Int32Value());
  args.GetReturnValue().Set(
      String::NewFromUtf8(env->isolate(),
                          u_errorName(status),
                          v8::NewStringType::kNormal).ToLocalChecked());
}

#define TYPE_ICU "icu"
#define TYPE_UNICODE "unicode"
#define TYPE_CLDR "cldr"
#define TYPE_TZ "tz"

/**
 * This is the workhorse function that deals with the actual version info.
 * Get an ICU version.
 * @param type the type of version to get. One of VERSION_TYPES
 * @param buf optional buffer for result
 * @param status ICU error status. If failure, assume result is undefined.
 * @return version number, or NULL. May or may not be buf.
 */
static const char* GetVersion(const char* type,
                              char buf[U_MAX_VERSION_STRING_LENGTH],
                              UErrorCode* status) {
  if (!strcmp(type, TYPE_ICU)) {
    return U_ICU_VERSION;
  } else if (!strcmp(type, TYPE_UNICODE)) {
    return U_UNICODE_VERSION;
  } else if (!strcmp(type, TYPE_TZ)) {
    return TimeZone::getTZDataVersion(*status);
  } else if (!strcmp(type, TYPE_CLDR)) {
    UVersionInfo versionArray;
    ulocdata_getCLDRVersion(versionArray, status);
    if (U_SUCCESS(*status)) {
      u_versionToString(versionArray, buf);
      return buf;
    }
  }
  // Fall through - unknown type or error case
  return nullptr;
}

static void GetVersion(const FunctionCallbackInfo<Value>& args) {
  Environment* env = Environment::GetCurrent(args);
  if ( args.Length() == 0 ) {
    // With no args - return a comma-separated list of allowed values
      args.GetReturnValue().Set(
          String::NewFromUtf8(env->isolate(),
            TYPE_ICU ","
            TYPE_UNICODE ","
            TYPE_CLDR ","
            TYPE_TZ));
  } else {
    CHECK_GE(args.Length(), 1);
    CHECK(args[0]->IsString());
    Utf8Value val(env->isolate(), args[0]);
    UErrorCode status = U_ZERO_ERROR;
    char buf[U_MAX_VERSION_STRING_LENGTH] = "";  // Possible output buffer.
    const char* versionString = GetVersion(*val, buf, &status);

    if (U_SUCCESS(status) && versionString) {
      // Success.
      args.GetReturnValue().Set(
          String::NewFromUtf8(env->isolate(),
          versionString));
    }
  }
}

bool InitializeICUDirectory(const std::string& path) {
  if (path.empty()) {
    UErrorCode status = U_ZERO_ERROR;
#ifdef NODE_HAVE_SMALL_ICU
    // install the 'small' data.
    udata_setCommonData(&SMALL_ICUDATA_ENTRY_POINT, &status);
#else  // !NODE_HAVE_SMALL_ICU
    // no small data, so nothing to do.
#endif  // !NODE_HAVE_SMALL_ICU
    return (status == U_ZERO_ERROR);
  } else {
    u_setDataDirectory(path.c_str());
    return true;  // No error.
  }
}

int32_t ToUnicode(MaybeStackBuffer<char>* buf,
                  const char* input,
                  size_t length,
                  bool lenient) {
  UErrorCode status = U_ZERO_ERROR;
  uint32_t options = UIDNA_DEFAULT;
  options |= UIDNA_NONTRANSITIONAL_TO_UNICODE;
  UIDNA* uidna = uidna_openUTS46(options, &status);
  if (U_FAILURE(status))
    return -1;
  UIDNAInfo info = UIDNA_INFO_INITIALIZER;

  int32_t len = uidna_nameToUnicodeUTF8(uidna,
                                        input, length,
                                        **buf, buf->capacity(),
                                        &info,
                                        &status);

  if (status == U_BUFFER_OVERFLOW_ERROR) {
    status = U_ZERO_ERROR;
    buf->AllocateSufficientStorage(len);
    len = uidna_nameToUnicodeUTF8(uidna,
                                  input, length,
                                  **buf, buf->capacity(),
                                  &info,
                                  &status);
  }

  if (U_FAILURE(status) || (!lenient && info.errors != 0)) {
    len = -1;
    buf->SetLength(0);
  } else {
    buf->SetLength(len);
  }

  uidna_close(uidna);
  return len;
}

int32_t ToASCII(MaybeStackBuffer<char>* buf,
                const char* input,
                size_t length,
                bool lenient) {
  UErrorCode status = U_ZERO_ERROR;
  uint32_t options = UIDNA_DEFAULT;
  options |= UIDNA_NONTRANSITIONAL_TO_ASCII;
  UIDNA* uidna = uidna_openUTS46(options, &status);
  if (U_FAILURE(status))
    return -1;
  UIDNAInfo info = UIDNA_INFO_INITIALIZER;

  int32_t len = uidna_nameToASCII_UTF8(uidna,
                                       input, length,
                                       **buf, buf->capacity(),
                                       &info,
                                       &status);

  if (status == U_BUFFER_OVERFLOW_ERROR) {
    status = U_ZERO_ERROR;
    buf->AllocateSufficientStorage(len);
    len = uidna_nameToASCII_UTF8(uidna,
                                 input, length,
                                 **buf, buf->capacity(),
                                 &info,
                                 &status);
  }

  if (U_FAILURE(status) || (!lenient && info.errors != 0)) {
    len = -1;
    buf->SetLength(0);
  } else {
    buf->SetLength(len);
  }

  uidna_close(uidna);
  return len;
}

static void ToUnicode(const FunctionCallbackInfo<Value>& args) {
  Environment* env = Environment::GetCurrent(args);
  CHECK_GE(args.Length(), 1);
  CHECK(args[0]->IsString());
  Utf8Value val(env->isolate(), args[0]);
  // optional arg
  bool lenient = args[1]->BooleanValue(env->context()).FromJust();

  MaybeStackBuffer<char> buf;
  int32_t len = ToUnicode(&buf, *val, val.length(), lenient);

  if (len < 0) {
    return env->ThrowError("Cannot convert name to Unicode");
  }

  args.GetReturnValue().Set(
      String::NewFromUtf8(env->isolate(),
                          *buf,
                          v8::NewStringType::kNormal,
                          len).ToLocalChecked());
}

static void ToASCII(const FunctionCallbackInfo<Value>& args) {
  Environment* env = Environment::GetCurrent(args);
  CHECK_GE(args.Length(), 1);
  CHECK(args[0]->IsString());
  Utf8Value val(env->isolate(), args[0]);
  // optional arg
  bool lenient = args[1]->BooleanValue(env->context()).FromJust();

  MaybeStackBuffer<char> buf;
  int32_t len = ToASCII(&buf, *val, val.length(), lenient);

  if (len < 0) {
    return env->ThrowError("Cannot convert name to ASCII");
  }

  args.GetReturnValue().Set(
      String::NewFromUtf8(env->isolate(),
                          *buf,
                          v8::NewStringType::kNormal,
                          len).ToLocalChecked());
}

// This is similar to wcwidth except that it takes the current unicode
// character properties database into consideration, allowing it to
// correctly calculate the column widths of things like emoji's and
// newer wide characters. wcwidth, on the other hand, uses a fixed
// algorithm that does not take things like emoji into proper
// consideration.
static int GetColumnWidth(UChar32 codepoint,
                          bool ambiguous_as_full_width = false) {
  if (!u_isdefined(codepoint) ||
      u_iscntrl(codepoint) ||
      u_getCombiningClass(codepoint) > 0 ||
      u_hasBinaryProperty(codepoint, UCHAR_EMOJI_MODIFIER)) {
    return 0;
  }
  // UCHAR_EAST_ASIAN_WIDTH is the Unicode property that identifies a
  // codepoint as being full width, wide, ambiguous, neutral, narrow,
  // or halfwidth.
  const int eaw = u_getIntPropertyValue(codepoint, UCHAR_EAST_ASIAN_WIDTH);
  switch (eaw) {
    case U_EA_FULLWIDTH:
    case U_EA_WIDE:
      return 2;
    case U_EA_AMBIGUOUS:
      // See: http://www.unicode.org/reports/tr11/#Ambiguous for details
      if (ambiguous_as_full_width) {
        return 2;
      }
      // Fall through if ambiguous_as_full_width if false.
    case U_EA_NEUTRAL:
      if (u_hasBinaryProperty(codepoint, UCHAR_EMOJI_PRESENTATION)) {
        return 2;
      }
      // Fall through
    case U_EA_HALFWIDTH:
    case U_EA_NARROW:
    default:
      return 1;
  }
}

// Returns the column width for the given String.
static void GetStringWidth(const FunctionCallbackInfo<Value>& args) {
  Environment* env = Environment::GetCurrent(args);
  if (args.Length() < 1)
    return;

  bool ambiguous_as_full_width = args[1]->BooleanValue();
  bool expand_emoji_sequence = args[2]->BooleanValue();

  if (args[0]->IsNumber()) {
    args.GetReturnValue().Set(
        GetColumnWidth(args[0]->Uint32Value(),
                       ambiguous_as_full_width));
    return;
  }

  TwoByteValue value(env->isolate(), args[0]);
  // reinterpret_cast is required by windows to compile
  UChar* str = reinterpret_cast<UChar*>(*value);
  static_assert(sizeof(*str) == sizeof(**value),
                "sizeof(*str) == sizeof(**value)");
  UChar32 c = 0;
  UChar32 p;
  size_t n = 0;
  uint32_t width = 0;

  while (n < value.length()) {
    p = c;
    U16_NEXT(str, n, value.length(), c);
    // Don't count individual emoji codepoints that occur within an
    // emoji sequence. This is not necessarily foolproof. Some
    // environments display emoji sequences in the appropriate
    // condensed form (as a single emoji glyph), other environments
    // may not understand an emoji sequence and will display each
    // individual emoji separately. When this happens, the width
    // calculated will be off, and there's no reliable way of knowing
    // in advance if a particular sequence is going to be supported.
    // The expand_emoji_sequence option allows the caller to skip this
    // check and count each code within an emoji sequence separately.
    if (!expand_emoji_sequence &&
        n > 0 && p == 0x200d &&  // 0x200d == ZWJ (zero width joiner)
        (u_hasBinaryProperty(c, UCHAR_EMOJI_PRESENTATION) ||
         u_hasBinaryProperty(c, UCHAR_EMOJI_MODIFIER))) {
      continue;
    }
    width += GetColumnWidth(c, ambiguous_as_full_width);
  }
  args.GetReturnValue().Set(width);
}

void Init(Local<Object> target,
          Local<Value> unused,
          Local<Context> context,
          void* priv) {
  Environment* env = Environment::GetCurrent(context);
  env->SetMethod(target, "toUnicode", ToUnicode);
  env->SetMethod(target, "toASCII", ToASCII);
  env->SetMethod(target, "getStringWidth", GetStringWidth);
  env->SetMethod(target, "getVersion", GetVersion);

  // One-shot converters
  env->SetMethod(target, "icuErrName", ICUErrorName);
  env->SetMethod(target, "transcode", Transcode);
}

}  // namespace i18n
}  // namespace node

NODE_MODULE_CONTEXT_AWARE_BUILTIN(icu, node::i18n::Init)

#endif  // NODE_HAVE_I18N_SUPPORT