////////////////////////////////////////////////////////////////////////////////
/// DISCLAIMER
///
/// Copyright 2014-2019 ArangoDB GmbH, Cologne, Germany
/// Copyright 2004-2014 triAGENS GmbH, Cologne, Germany
///
/// Licensed under the Apache License, Version 2.0 (the "License");
/// you may not use this file except in compliance with the License.
/// You may obtain a copy of the License at
///
///     http://www.apache.org/licenses/LICENSE-2.0
///
/// Unless required by applicable law or agreed to in writing, software
/// distributed under the License is distributed on an "AS IS" BASIS,
/// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
/// See the License for the specific language governing permissions and
/// limitations under the License.
///
/// Copyright holder is ArangoDB GmbH, Cologne, Germany
///
/// @author Frank Celler
/// @author Achim Brandt
////////////////////////////////////////////////////////////////////////////////

#ifndef ARANGODB_BASICS_UTF8HELPER_H
#define ARANGODB_BASICS_UTF8HELPER_H 1

#include <set>
#include "Basics/Common.h"

#include <velocypack/StringRef.h>

#include <unicode/coll.h>
#include <unicode/regex.h>
#include <unicode/ustring.h>
#include <unicode/locid.h>

namespace arangodb {
namespace basics {

#ifdef _WIN32
std::wstring toWString(std::string const& validUTF8String);
std::string fromWString(wchar_t const* validUTF16String, std::size_t size);
std::string fromWString(std::wstring const& validUTF16String);
#endif

class Utf8Helper {
  Utf8Helper(Utf8Helper const&) = delete;
  Utf8Helper& operator=(Utf8Helper const&) = delete;

 public:
  static Utf8Helper DefaultUtf8Helper;

 public:
  //////////////////////////////////////////////////////////////////////////////
  /// @brief constructor
  /// @param lang   Lowercase two-letter or three-letter ISO-639 code.
  ///     This parameter can instead be an ICU style C locale (e.g. "en_US")
  //////////////////////////////////////////////////////////////////////////////

  Utf8Helper(std::string const& lang, void* icuDataPtr);

  explicit Utf8Helper(void* icuDataPtr);

  ~Utf8Helper();

 public:
  //////////////////////////////////////////////////////////////////////////////
  ///  public functions
  //////////////////////////////////////////////////////////////////////////////

  //////////////////////////////////////////////////////////////////////////////
  /// @brief compare utf8 strings
  /// -1 : left < right
  ///  0 : left == right
  ///  1 : left > right
  //////////////////////////////////////////////////////////////////////////////

  int compareUtf8(char const* left, size_t leftLength, char const* right,
                  size_t rightLength) const;

  //////////////////////////////////////////////////////////////////////////////
  /// @brief compare utf16 strings
  /// -1 : left < right
  ///  0 : left == right
  ///  1 : left > right
  //////////////////////////////////////////////////////////////////////////////

  int compareUtf16(uint16_t const* left, size_t leftLength,
                   uint16_t const* right, size_t rightLength) const;

  //////////////////////////////////////////////////////////////////////////////
  /// @brief set collator by language
  /// @param lang   Lowercase two-letter or three-letter ISO-639 code.
  ///     This parameter can instead be an ICU style C locale (e.g. "en_US")
  /// @param icuDataPointer data file to be loaded by the application
  //////////////////////////////////////////////////////////////////////////////

  bool setCollatorLanguage(std::string const& lang, void* icuDataPointer);

  //////////////////////////////////////////////////////////////////////////////
  /// @brief get collator language
  //////////////////////////////////////////////////////////////////////////////

  std::string getCollatorLanguage();

  //////////////////////////////////////////////////////////////////////////////
  /// @brief get collator country
  //////////////////////////////////////////////////////////////////////////////

  std::string getCollatorCountry();

  //////////////////////////////////////////////////////////////////////////////
  /// @brief Lowercase the characters in a UTF-8 string.
  //////////////////////////////////////////////////////////////////////////////

  std::string toLowerCase(std::string const& src);

  //////////////////////////////////////////////////////////////////////////////
  /// @brief Lowercase the characters in a UTF-8 string.
  //////////////////////////////////////////////////////////////////////////////

  char* tolower(char const* src, int32_t srcLength, int32_t& dstLength);

  //////////////////////////////////////////////////////////////////////////////
  /// @brief Uppercase the characters in a UTF-8 string.
  //////////////////////////////////////////////////////////////////////////////

  std::string toUpperCase(std::string const& src);

  //////////////////////////////////////////////////////////////////////////////
  /// @brief Uppercase the characters in a UTF-8 string.
  //////////////////////////////////////////////////////////////////////////////

  char* toupper(char const* src, int32_t srcLength, int32_t& dstLength);

  //////////////////////////////////////////////////////////////////////////////
  /// @brief returns the words of a UTF-8 string.
  //////////////////////////////////////////////////////////////////////////////

  bool tokenize(std::set<std::string>& words, arangodb::velocypack::StringRef const& text,
                size_t minimalWordLength, size_t maximalWordLength, bool lowerCase);

  //////////////////////////////////////////////////////////////////////////////
  /// @brief builds a regex matcher for the specified pattern
  //////////////////////////////////////////////////////////////////////////////

  icu::RegexMatcher* buildMatcher(std::string const&);

  //////////////////////////////////////////////////////////////////////////////
  /// @brief whether or not value matches a regex
  //////////////////////////////////////////////////////////////////////////////

  bool matches(icu::RegexMatcher*, char const* pattern, size_t patternLength,
               bool partial, bool& error);

  std::string replace(icu::RegexMatcher*, char const* pattern, size_t patternLength,
                      char const* replacement, size_t replacementLength,
                      bool partial, bool& error);

  // append an UTF8 to a string. This will append 1 to 4 bytes.
  static void appendUtf8Character(std::string& result, uint32_t ch) {
    if (ch <= 0x7f) {
      result.push_back((uint8_t)ch);
    } else {
      if (ch <= 0x7ff) {
        result.push_back((uint8_t)((ch >> 6) | 0xc0));
      } else {
        if (ch <= 0xffff) {
          result.push_back((uint8_t)((ch >> 12) | 0xe0));
        } else {
          result.push_back((uint8_t)((ch >> 18) | 0xf0));
          result.push_back((uint8_t)(((ch >> 12) & 0x3f) | 0x80));
        }
        result.push_back((uint8_t)(((ch >> 6) & 0x3f) | 0x80));
      }
      result.push_back((uint8_t)((ch & 0x3f) | 0x80));
    }
  }

 private:
  icu::Collator* _coll;
};
}  // namespace basics
}  // namespace arangodb

////////////////////////////////////////////////////////////////////////////////
/// @brief convert a utf-8 string to a uchar (utf-16)
////////////////////////////////////////////////////////////////////////////////

UChar* TRI_Utf8ToUChar(char const* utf8, size_t inLength, size_t* outLength);
UChar* TRI_Utf8ToUChar(char const* utf8, size_t inLength, UChar* buffer, size_t bufferSize,
                       size_t* outLength);

////////////////////////////////////////////////////////////////////////////////
/// @brief convert a uchar (utf-16) to a utf-8 string
////////////////////////////////////////////////////////////////////////////////

char* TRI_UCharToUtf8(UChar const* uchar, size_t inLength, size_t* outLength);

////////////////////////////////////////////////////////////////////////////////
/// @brief normalize an utf8 string (NFC)
////////////////////////////////////////////////////////////////////////////////

char* TRI_normalize_utf8_to_NFC(char const* utf8, size_t inLength, size_t* outLength);

////////////////////////////////////////////////////////////////////////////////
/// @brief normalize an utf16 string (NFC) and export it to utf8
////////////////////////////////////////////////////////////////////////////////

char* TRI_normalize_utf16_to_NFC(uint16_t const* utf16, size_t inLength, size_t* outLength);

////////////////////////////////////////////////////////////////////////////////
/// @brief compare two utf8 strings
////////////////////////////////////////////////////////////////////////////////

static inline int TRI_compare_utf8(char const* left, size_t leftLength,
                                   char const* right, size_t rightLength) {
  return arangodb::basics::Utf8Helper::DefaultUtf8Helper.compareUtf8(left, leftLength,
                                                                     right, rightLength);
}

////////////////////////////////////////////////////////////////////////////////
/// @brief Lowercase the characters in a UTF-8 string
////////////////////////////////////////////////////////////////////////////////

char* TRI_tolower_utf8(char const* src, int32_t srcLength, int32_t* dstLength);

#endif