/*============================================================================
  KWSys - Kitware System Library
  Copyright 2000-2016 Kitware, Inc., Insight Software Consortium

  Distributed under the OSI-approved BSD License (the "License");
  see accompanying file Copyright.txt for details.

  This software is distributed WITHOUT ANY WARRANTY; without even the
  implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  See the License for more information.
============================================================================*/
#ifndef @KWSYS_NAMESPACE@_ConsoleBuf_hxx
#define @KWSYS_NAMESPACE@_ConsoleBuf_hxx

#include <@KWSYS_NAMESPACE@/Configure.hxx>
#include <@KWSYS_NAMESPACE@/Encoding.hxx>
#include <string>
#include <cstring>
#include <sstream>
#include <streambuf>
#include <iostream>
#include <stdexcept>

#if defined(_WIN32)
#  include <windows.h>
#  if __cplusplus >= 201103L
#    include <system_error>
#  endif
#endif

namespace @KWSYS_NAMESPACE@
{
#if defined(_WIN32)

  template<class CharT, class Traits = std::char_traits<CharT> >
  class @KWSYS_NAMESPACE@_EXPORT BasicConsoleBuf :
      public std::basic_streambuf<CharT, Traits> {
    public:
      typedef typename Traits::int_type int_type;
      typedef typename Traits::char_type char_type;

      class Manager {
        public:
          Manager(std::basic_ios<CharT, Traits> &ios, const bool err = false)
            : m_consolebuf(0)
          {
            m_ios = &ios;
            try {
              m_consolebuf = new BasicConsoleBuf<CharT, Traits>(err);
              m_streambuf = m_ios->rdbuf(m_consolebuf);
            } catch (const std::runtime_error& ex) {
              std::cerr << "Failed to create ConsoleBuf!" << std::endl
                        << ex.what() << std::endl;
            };
          }

          ~Manager()
          {
            if (m_consolebuf) {
              delete m_consolebuf;
              m_ios->rdbuf(m_streambuf);
            }
          }

        private:
          std::basic_ios<CharT, Traits> *m_ios;
          std::basic_streambuf<CharT, Traits> *m_streambuf;
          BasicConsoleBuf<CharT, Traits> *m_consolebuf;
      };

      BasicConsoleBuf(const bool err = false) :
        flush_on_newline(true),
        input_pipe_codepage(0),
        output_pipe_codepage(0),
        input_file_codepage(CP_UTF8),
        output_file_codepage(CP_UTF8),
        m_consolesCodepage(0)
      {
        m_hInput = ::GetStdHandle(STD_INPUT_HANDLE);
        checkHandle(true, "STD_INPUT_HANDLE");
        if (!setActiveInputCodepage()) {
          throw std::runtime_error("setActiveInputCodepage failed!");
        }
        m_hOutput = err ? ::GetStdHandle(STD_ERROR_HANDLE) :
                          ::GetStdHandle(STD_OUTPUT_HANDLE);
        checkHandle(false, err ? "STD_ERROR_HANDLE" : "STD_OUTPUT_HANDLE");
        if (!setActiveOutputCodepage()) {
          throw std::runtime_error("setActiveOutputCodepage failed!");
        }
        _setg();
        _setp();
      }

      ~BasicConsoleBuf() throw()
      {
        sync();
      }

      bool activateCodepageChange()
      {
        return setActiveInputCodepage() && setActiveOutputCodepage();
      }

    protected:
      virtual int sync() {
        bool success = true;
        if (m_hInput && m_isConsoleInput &&
            ::FlushConsoleInputBuffer(m_hInput) == 0) {
          success = false;
        }
        if (m_hOutput && !m_obuffer.empty()) {
          const std::wstring wbuffer = getBuffer(m_obuffer);
          if (m_isConsoleOutput) {
            DWORD charsWritten;
            success = ::WriteConsoleW(m_hOutput, wbuffer.c_str(),
                                      (DWORD)wbuffer.size(), &charsWritten,
                                      NULL) == 0 ? false : true;
          } else {
            DWORD bytesWritten;
            std::string buffer;
            success = encodeOutputBuffer(wbuffer, buffer);
            if (success) {
              success = ::WriteFile(m_hOutput, buffer.c_str(),
                                    (DWORD)buffer.size(), &bytesWritten,
                                     NULL) == 0 ? false : true;
            }
          }
        }
        m_ibuffer.clear();
        m_obuffer.clear();
        _setg();
        _setp();
        return success ? 0 : -1;
      }

      virtual int_type underflow() {
        if (this->gptr() >= this->egptr()) {
          if (!m_hInput) {
            _setg(true);
            return Traits::eof();
          }
          if (m_isConsoleInput) {
            wchar_t wbuffer[128];
            DWORD charsRead;
            if (::ReadConsoleW(m_hInput, wbuffer, (sizeof(wbuffer) / sizeof(wbuffer[0])) - 1,
                               &charsRead, NULL) == 0 || charsRead == 0) {
              _setg(true);
              return Traits::eof();
            }
            wbuffer[charsRead] = L'\0';
            setBuffer(wbuffer, m_ibuffer);
          } else {
            std::wstring totalBuffer;
            std::wstring wbuffer;
            char buffer[128];
            DWORD bytesRead;
            while (::ReadFile(m_hInput, buffer, (sizeof(buffer) / sizeof(buffer[0])) - 1,
                              &bytesRead, NULL) == 0) {
              if (::GetLastError() == ERROR_MORE_DATA) {
                buffer[bytesRead] = '\0';
                if (decodeInputBuffer(buffer, wbuffer)) {
                  totalBuffer += wbuffer;
                  continue;
                }
              }
              _setg(true);
              return Traits::eof();
            }
            buffer[bytesRead] = '\0';
            if (!decodeInputBuffer(buffer, wbuffer)) {
              _setg(true);
              return Traits::eof();
            }
            totalBuffer += wbuffer;
            setBuffer(totalBuffer, m_ibuffer);
          }
          _setg();
        }
        return Traits::to_int_type(*this->gptr());
      }

      virtual int_type overflow(int_type ch = Traits::eof()) {
        if (!Traits::eq_int_type(ch, Traits::eof())) {
          char_type chr = Traits::to_char_type(ch);
          m_obuffer += chr;
          if ((flush_on_newline && Traits::eq(chr, '\n')) ||
              Traits::eq_int_type(ch, 0x00)) {
            sync();
          }
          return ch;
        }
        sync();
        return Traits::eof();
      }

    public:
      bool flush_on_newline;
      UINT input_pipe_codepage;
      UINT output_pipe_codepage;
      UINT input_file_codepage;
      UINT output_file_codepage;

    private:
      HANDLE m_hInput;
      HANDLE m_hOutput;
      std::basic_string<char_type> m_ibuffer;
      std::basic_string<char_type> m_obuffer;
      bool m_isConsoleInput;
      bool m_isConsoleOutput;
      UINT m_activeInputCodepage;
      UINT m_activeOutputCodepage;
      UINT m_consolesCodepage;
      void checkHandle(bool input, std::string handleName) {
        if ((input && m_hInput == INVALID_HANDLE_VALUE) ||
            (!input && m_hOutput == INVALID_HANDLE_VALUE)) {
          std::string errmsg = "GetStdHandle(" + handleName +
                               ") returned INVALID_HANDLE_VALUE";
#if __cplusplus >= 201103L
          throw std::system_error(::GetLastError(),
                                  std::system_category(), errmsg);
#else
          throw std::runtime_error(errmsg);
#endif
        }
      }
      UINT getConsolesCodepage() {
        if (!m_consolesCodepage) {
          m_consolesCodepage = GetConsoleCP();
          if (!m_consolesCodepage) {
            m_consolesCodepage = GetACP();
          }
        }
        return m_consolesCodepage;
      }
      bool setActiveInputCodepage() {
        m_isConsoleInput = false;
        switch (GetFileType(m_hInput)) {
          case FILE_TYPE_DISK:
            m_activeInputCodepage = input_file_codepage;
            break;
          case FILE_TYPE_CHAR:
            m_isConsoleInput = true;
            break;
          case FILE_TYPE_PIPE:
            m_activeInputCodepage = input_pipe_codepage;
            break;
          default:
            return false;
        }
        if (!m_isConsoleInput && m_activeInputCodepage == 0) {
          m_activeInputCodepage = getConsolesCodepage();
        }
        return true;
      }
      bool setActiveOutputCodepage() {
        m_isConsoleOutput = false;
        switch (GetFileType(m_hOutput)) {
          case FILE_TYPE_DISK:
            m_activeOutputCodepage = output_file_codepage;
            break;
          case FILE_TYPE_CHAR:
            m_isConsoleOutput = true;
            break;
          case FILE_TYPE_PIPE:
            m_activeOutputCodepage = output_pipe_codepage;
            break;
          default:
            return false;
        }
        if (!m_isConsoleOutput && m_activeOutputCodepage == 0) {
           m_activeOutputCodepage = getConsolesCodepage();
        }
        return true;
      }
      void _setg(bool empty = false) {
        if (!empty) {
          this->setg((char_type *)m_ibuffer.data(),
                     (char_type *)m_ibuffer.data(),
                     (char_type *)m_ibuffer.data() + m_ibuffer.size());
        } else {
          this->setg((char_type *)m_ibuffer.data(),
                     (char_type *)m_ibuffer.data() + m_ibuffer.size(),
                     (char_type *)m_ibuffer.data() + m_ibuffer.size());
        }
      }
      void _setp() {
        this->setp((char_type *)m_obuffer.data(),
                   (char_type *)m_obuffer.data() + m_obuffer.size());
      }
      bool encodeOutputBuffer(const std::wstring wbuffer,
                              std::string &buffer) {
        const int length = WideCharToMultiByte(m_activeOutputCodepage, 0,
                                               wbuffer.c_str(),
                                               (int)wbuffer.size(), NULL, 0,
                                               NULL, NULL);
        char *buf = new char[length + 1];
        const bool success = WideCharToMultiByte(m_activeOutputCodepage, 0,
                                                 wbuffer.c_str(),
                                                 (int)wbuffer.size(), buf,
                                                 length, NULL, NULL) > 0
                             ? true : false;
        buf[length] = '\0';
        buffer = buf;
        delete[] buf;
        return success;
      }
      bool decodeInputBuffer(const char *buffer, std::wstring &wbuffer) {
        int actualCodepage = m_activeInputCodepage;
        const char BOM_UTF8[] = { char(0xEF), char(0xBB), char(0xBF) };
        if (std::memcmp(buffer, BOM_UTF8, sizeof(BOM_UTF8)) == 0) {
          // PowerShell uses UTF-8 with BOM for pipes
          actualCodepage = CP_UTF8;
          buffer += sizeof(BOM_UTF8);
        }
        const int wlength = MultiByteToWideChar(actualCodepage, 0, buffer,
                                                -1, NULL, 0);
        wchar_t *wbuf = new wchar_t[wlength];
        const bool success = MultiByteToWideChar(actualCodepage, 0, buffer,
                                                 -1, wbuf, wlength) > 0
                             ? true : false;
        wbuffer = wbuf;
        delete[] wbuf;
        return success;
      }
      std::wstring getBuffer(const std::basic_string<char> buffer) {
        return Encoding::ToWide(buffer);
      }
      std::wstring getBuffer(const std::basic_string<wchar_t> buffer) {
        return buffer;
      }
      void setBuffer(const std::wstring wbuffer,
                     std::basic_string<char> &target) {
        target = Encoding::ToNarrow(wbuffer);
      }
      void setBuffer(const std::wstring wbuffer,
                     std::basic_string<wchar_t> &target) {
        target = wbuffer;
      }

  }; // BasicConsoleBuf class

  typedef BasicConsoleBuf<char>    ConsoleBuf;
  typedef BasicConsoleBuf<wchar_t> WConsoleBuf;

#endif
} // KWSYS_NAMESPACE

#endif