/**********************************************************************

  Audacity: A Digital Audio Editor

  ExportPCM.cpp

  Dominic Mazzoni

**********************************************************************/

#include "../Audacity.h"
#include "ExportPCM.h"

#include <wx/defs.h>

#include <wx/choice.h>
#include <wx/dynlib.h>
#include <wx/filename.h>
#include <wx/intl.h>
#include <wx/timer.h>
#include <wx/msgdlg.h>
#include <wx/progdlg.h>
#include <wx/string.h>
#include <wx/textctrl.h>
#include <wx/window.h>

#include "sndfile.h"

#include "../FileFormats.h"
#include "../Internat.h"
#include "../Mix.h"
#include "../Prefs.h"
#include "../Project.h"
#include "../ShuttleGui.h"
#include "../Tags.h"
#include "../Track.h"
#include "../ondemand/ODManager.h"

#include "Export.h"

#ifdef USE_LIBID3TAG
   #include <id3tag.h>
   // DM: the following functions were supposed to have been
   // included in id3tag.h - should be fixed in the next release
   // of mad.
   extern "C" {
      struct id3_frame *id3_frame_new(char const *);
      id3_length_t id3_latin1_length(id3_latin1_t const *);
      void id3_latin1_decode(id3_latin1_t const *, id3_ucs4_t *);
   }
#endif

struct
{
   int format;
   const wxChar *name;
   const wxChar *desc;
}
static const kFormats[] =
{
   { SF_FORMAT_AIFF | SF_FORMAT_PCM_16,   wxT("AIFF"),   XO("AIFF (Apple) signed 16-bit PCM")    },
   { SF_FORMAT_WAV | SF_FORMAT_PCM_16,    wxT("WAV"),    XO("WAV (Microsoft) signed 16-bit PCM") },
   { SF_FORMAT_WAV | SF_FORMAT_FLOAT,     wxT("WAVFLT"), XO("WAV (Microsoft) 32-bit float PCM")  },
// { SF_FORMAT_WAV | SF_FORMAT_GSM610,    wxT("GSM610"), XO("GSM 6.10 WAV (mobile)")             },
};

//----------------------------------------------------------------------------
// Statics
//----------------------------------------------------------------------------

static int ReadExportFormatPref()
{
#if defined(__WXMAC__)
   return gPrefs->Read(wxT("/FileFormats/ExportFormat_SF1"),
                       (long int)(SF_FORMAT_AIFF | SF_FORMAT_PCM_16));
#else
   return gPrefs->Read(wxT("/FileFormats/ExportFormat_SF1"),
                       (long int)(SF_FORMAT_WAV | SF_FORMAT_PCM_16));
#endif
}

static void WriteExportFormatPref(int format)
{
   gPrefs->Write(wxT("/FileFormats/ExportFormat_SF1"), (long int)format);
   gPrefs->Flush();
}

//----------------------------------------------------------------------------
// ExportPCMOptions Class
//----------------------------------------------------------------------------

#define ID_HEADER_CHOICE           7102
#define ID_ENCODING_CHOICE         7103

class ExportPCMOptions final : public wxPanelWrapper
{
public:

   ExportPCMOptions(wxWindow *parent, int format);
   virtual ~ExportPCMOptions();

   void PopulateOrExchange(ShuttleGui & S);
   bool TransferDataToWindow();
   bool TransferDataFromWindow();

   void OnHeaderChoice(wxCommandEvent & evt);

private:

   bool ValidatePair(int format);
   int GetFormat();

private:

   wxArrayString mHeaderNames;
   wxArrayString mEncodingNames;
   wxChoice *mHeaderChoice;
   wxChoice *mEncodingChoice;
   int mHeaderFromChoice;
   int mEncodingFromChoice;
   wxArrayInt mEncodingFormats;

   DECLARE_EVENT_TABLE()
};

BEGIN_EVENT_TABLE(ExportPCMOptions, wxPanelWrapper)
   EVT_CHOICE(ID_HEADER_CHOICE, ExportPCMOptions::OnHeaderChoice)
END_EVENT_TABLE()

ExportPCMOptions::ExportPCMOptions(wxWindow *parent, int selformat)
:  wxPanelWrapper(parent, wxID_ANY)
{
   int format;

   if (selformat < 0 || selformat >= WXSIZEOF(kFormats))
   {
      format = ReadExportFormatPref();
   }
   else
   {
      format = kFormats[selformat].format;
   }

   mHeaderFromChoice = 0;
   for (int i = 0, num = sf_num_headers(); i < num; i++) {
      mHeaderNames.Add(sf_header_index_name(i));
      if ((format & SF_FORMAT_TYPEMASK) == (int)sf_header_index_to_type(i))
         mHeaderFromChoice = i;
   }

   mEncodingFromChoice = 0;
   for (int i = 0, sel = 0, num = sf_num_encodings(); i < num; i++) {
      int enc = sf_encoding_index_to_subtype(i);
      int fmt = (format & SF_FORMAT_TYPEMASK) | enc;
      bool valid = ValidatePair(fmt);
      if (valid)
      {
         mEncodingNames.Add(sf_encoding_index_name(i));
         mEncodingFormats.Add(enc);
         if ((format & SF_FORMAT_SUBMASK) == (int)sf_encoding_index_to_subtype(i))
            mEncodingFromChoice = sel;
         else
            sel++;
      }
   }

   ShuttleGui S(this, eIsCreatingFromPrefs);
   PopulateOrExchange(S);

   TransferDataToWindow();
   TransferDataFromWindow();
}

ExportPCMOptions::~ExportPCMOptions()
{
   TransferDataFromWindow();
}

void ExportPCMOptions::PopulateOrExchange(ShuttleGui & S)
{
   S.StartVerticalLay();
   {
      S.StartHorizontalLay(wxCENTER);
      {
         S.StartMultiColumn(2, wxCENTER);
         {
            S.SetStretchyCol(1);
            mHeaderChoice = S.Id(ID_HEADER_CHOICE)
               .AddChoice(_("Header:"),
                          mHeaderNames[mHeaderFromChoice],
                          &mHeaderNames);
            mEncodingChoice = S.Id(ID_ENCODING_CHOICE)
               .AddChoice(_("Encoding:"),
                          mEncodingNames[mEncodingFromChoice],
                          &mEncodingNames);
         }
         S.EndMultiColumn();
      }
      S.EndHorizontalLay();
   }
   S.EndVerticalLay();

   return;
}

///
///
bool ExportPCMOptions::TransferDataToWindow()
{
   return true;
}

///
///
bool ExportPCMOptions::TransferDataFromWindow()
{
   ShuttleGui S(this, eIsSavingToPrefs);
   PopulateOrExchange(S);

   gPrefs->Flush();

   WriteExportFormatPref(GetFormat());

   return true;
}

void ExportPCMOptions::OnHeaderChoice(wxCommandEvent & WXUNUSED(evt))
{
   int format = sf_header_index_to_type(mHeaderChoice->GetSelection());
   mEncodingNames.Clear();
   mEncodingChoice->Clear();
   mEncodingFormats.Clear();
   int sel = wxNOT_FOUND;
   int i,j;

   int sfnum = sf_num_simple_formats();
   wxArrayInt sfs;

   for (i = 0; i < sfnum; i++)
   {
      SF_FORMAT_INFO *fi = sf_simple_format(i);
      sfs.Add(fi->format);
   }

   int num = sf_num_encodings();
   for (i = 0; i < num; i++)
   {
      int enc = sf_encoding_index_to_subtype(i);
      int fmt = format | enc;
      bool valid  = ValidatePair(fmt);
      if (valid)
      {
         const auto name = sf_encoding_index_name(i);
         mEncodingNames.Add(name);
         mEncodingChoice->Append(name);
         mEncodingFormats.Add(enc);
         for (j = 0; j < sfnum; j++)
         {
            int enc = sfs[j];
            if ((sel == wxNOT_FOUND) && (fmt == enc))
            {
               sel = mEncodingFormats.GetCount()-1;
               break;
            }
         }
      }
   }

   if (sel == wxNOT_FOUND) sel = 0;
   mEncodingFromChoice = sel;
   mEncodingChoice->SetSelection(sel);
   ValidatePair(GetFormat());

   TransferDataFromWindow();
}

int ExportPCMOptions::GetFormat()
{
   int hdr = sf_header_index_to_type(mHeaderChoice->GetSelection());
   int sel = mEncodingChoice->GetSelection();
   int enc = mEncodingFormats[sel];
   return hdr | enc;
}

/// Calls a libsndfile library function to determine whether the user's
/// choice of sample encoding (e.g. pcm 16-bit or GSM 6.10 compression)
/// is compatible with their choice of file format (e.g. WAV, AIFF)
/// and enables/disables the OK button accordingly.
bool ExportPCMOptions::ValidatePair(int format)
{
   SF_INFO info;
   memset(&info, 0, sizeof(info));
   info.frames = 0;
   info.samplerate = 44100;
   info.channels = 1;
   info.format = format;
   info.sections = 1;
   info.seekable = 0;

   return sf_format_check(&info) != 0 ? true : false;
}

//----------------------------------------------------------------------------
// ExportPCM Class
//----------------------------------------------------------------------------

class ExportPCM final : public ExportPlugin
{
public:

   ExportPCM();

   // Required

   wxWindow *OptionsCreate(wxWindow *parent, int format);
   int Export(AudacityProject *project,
               int channels,
               const wxString &fName,
               bool selectedOnly,
               double t0,
               double t1,
               MixerSpec *mixerSpec = NULL,
               const Tags *metadata = NULL,
               int subformat = 0) override;
   // optional
   wxString GetExtension(int index);
   bool CheckFileName(wxFileName &filename, int format) override;

private:

   char *AdjustString(const wxString & wxStr, int sf_format);
   bool AddStrings(AudacityProject *project, SNDFILE *sf, const Tags *tags, int sf_format);
   void AddID3Chunk(wxString fName, const Tags *tags, int sf_format);

};

ExportPCM::ExportPCM()
:  ExportPlugin()
{

   SF_INFO si;

   si.samplerate = 0;
   si.channels = 0;

   int format; // the index of the format we are setting up at the moment

   // Add the "special" formats first
   for (size_t i = 0; i < WXSIZEOF(kFormats); i++)
   {
      format = AddFormat() - 1;

      si.format = kFormats[i].format;
      for (si.channels = 1; sf_format_check(&si); si.channels++){};
      wxString ext = sf_header_extension(si.format);

      SetFormat(kFormats[i].name, format);
      SetCanMetaData(true, format);
      SetDescription(wxGetTranslation(kFormats[i].desc), format);
      AddExtension(ext, format);
      SetMaxChannels(si.channels - 1, format);
   }

   // Then add the generic libsndfile formats
   format = AddFormat() - 1;  // store the index = 1 less than the count
   SetFormat(wxT("LIBSNDFILE"), format);
   SetCanMetaData(true, format);
   SetDescription(_("Other uncompressed files"), format);
   wxArrayString allext = sf_get_all_extensions();
   wxString wavext = sf_header_extension(SF_FORMAT_WAV);   // get WAV ext.
#if defined(wxMSW)
   // On Windows make sure WAV is at the beginning of the list of all possible
   // extensions for this format
   allext.Remove(wavext);
   allext.Insert(wavext, 0);
#endif
   SetExtensions(allext, format);
   SetMaxChannels(255, format);
}

/**
 *
 * @param subformat Control whether we are doing a "preset" export to a popular
 * file type, or giving the user full control over libsndfile.
 */
int ExportPCM::Export(AudacityProject *project,
                       int numChannels,
                       const wxString &fName,
                       bool selectionOnly,
                       double t0,
                       double t1,
                       MixerSpec *mixerSpec,
                       const Tags *metadata,
                       int subformat)
{
   double       rate = project->GetRate();
   const TrackList   *tracks = project->GetTracks();
   int sf_format;

   if (subformat < 0 || subformat >= WXSIZEOF(kFormats))
   {
      sf_format = ReadExportFormatPref();
   }
   else
   {
      sf_format = kFormats[subformat].format;
   }

   int updateResult = eProgressSuccess;
   {
      wxFile f;   // will be closed when it goes out of scope
      SFFile       sf; // wraps f

      wxString     formatStr;
      SF_INFO      info;
      int          err;

      //This whole operation should not occur while a file is being loaded on OD,
      //(we are worried about reading from a file being written to,) so we block.
      //Furthermore, we need to do this because libsndfile is not threadsafe.
      formatStr = SFCall<wxString>(sf_header_name, sf_format & SF_FORMAT_TYPEMASK);

      // Use libsndfile to export file

      info.samplerate = (unsigned int)(rate + 0.5);
      info.frames = (unsigned int)((t1 - t0)*rate + 0.5);
      info.channels = numChannels;
      info.format = sf_format;
      info.sections = 1;
      info.seekable = 0;

      // If we can't export exactly the format they requested,
      // try the default format for that header type...
      if (!sf_format_check(&info))
         info.format = (info.format & SF_FORMAT_TYPEMASK);
      if (!sf_format_check(&info)) {
         wxMessageBox(_("Cannot export audio in this format."));
         return false;
      }

      if (f.Open(fName, wxFile::write)) {
         // Even though there is an sf_open() that takes a filename, use the one that
         // takes a file descriptor since wxWidgets can open a file with a Unicode name and
         // libsndfile can't (under Windows).
         sf.reset(SFCall<SNDFILE*>(sf_open_fd, f.fd(), SFM_WRITE, &info, FALSE));
         //add clipping for integer formats.  We allow floats to clip.
         sf_command(sf.get(), SFC_SET_CLIPPING, NULL, sf_subtype_is_integer(sf_format)?SF_TRUE:SF_FALSE) ;
      }

      if (!sf) {
         wxMessageBox(wxString::Format(_("Cannot export audio to %s"),
                                       fName.c_str()));
         return false;
      }
      // Retrieve tags if not given a set
      if (metadata == NULL)
         metadata = project->GetTags();

      // Install the metata at the beginning of the file (except for
      // WAV and WAVEX formats)
      if ((sf_format & SF_FORMAT_TYPEMASK) != SF_FORMAT_WAV &&
          (sf_format & SF_FORMAT_TYPEMASK) != SF_FORMAT_WAVEX) {
         if (!AddStrings(project, sf.get(), metadata, sf_format)) {
            return false;
         }
      }

      sampleFormat format;
      if (sf_subtype_more_than_16_bits(info.format))
         format = floatSample;
      else
         format = int16Sample;

      int maxBlockLen = 44100 * 5;

      const WaveTrackConstArray waveTracks =
      tracks->GetWaveTrackConstArray(selectionOnly, false);
      {
         auto mixer = CreateMixer(waveTracks,
                                  tracks->GetTimeTrack(),
                                  t0, t1,
                                  info.channels, maxBlockLen, true,
                                  rate, format, true, mixerSpec);

         ProgressDialog progress(wxFileName(fName).GetName(),
                                 selectionOnly ?
                                 wxString::Format(_("Exporting the selected audio as %s"),
                                                  formatStr.c_str()) :
                                 wxString::Format(_("Exporting the entire project as %s"),
                                                  formatStr.c_str()));

         while (updateResult == eProgressSuccess) {
            sampleCount samplesWritten;
            sampleCount numSamples = mixer->Process(maxBlockLen);

            if (numSamples == 0)
               break;

            samplePtr mixed = mixer->GetBuffer();

            if (format == int16Sample)
               samplesWritten = SFCall<sf_count_t>(sf_writef_short, sf.get(), (short *)mixed, numSamples);
            else
               samplesWritten = SFCall<sf_count_t>(sf_writef_float, sf.get(), (float *)mixed, numSamples);

            if (samplesWritten != numSamples) {
               char buffer2[1000];
               sf_error_str(sf.get(), buffer2, 1000);
               wxMessageBox(wxString::Format(
                                             /* i18n-hint: %s will be the error message from libsndfile, which
                                              * is usually something unhelpful (and untranslated) like "system
                                              * error" */
                                             _("Error while writing %s file (disk full?).\nLibsndfile says \"%s\""),
                                             formatStr.c_str(),
                                             wxString::FromAscii(buffer2).c_str()));
               break;
            }
            
            updateResult = progress.Update(mixer->MixGetCurrentTime() - t0, t1 - t0);
         }
      }
      
      // Install the WAV metata in a "LIST" chunk at the end of the file
      if ((sf_format & SF_FORMAT_TYPEMASK) == SF_FORMAT_WAV ||
          (sf_format & SF_FORMAT_TYPEMASK) == SF_FORMAT_WAVEX) {
         if (!AddStrings(project, sf.get(), metadata, sf_format)) {
            return false;
         }
      }
   }

   if (((sf_format & SF_FORMAT_TYPEMASK) == SF_FORMAT_AIFF) ||
       ((sf_format & SF_FORMAT_TYPEMASK) == SF_FORMAT_WAV))
      AddID3Chunk(fName, metadata, sf_format);

   return updateResult;
}

char *ExportPCM::AdjustString(const wxString & wxStr, int sf_format)
{
   bool b_aiff = false;
   if ((sf_format & SF_FORMAT_TYPEMASK) == SF_FORMAT_AIFF)
         b_aiff = true;    // Apple AIFF file

   // We must convert the string to 7 bit ASCII
   size_t  sz = wxStr.length();
   if(sz == 0)
      return NULL;
   // Size for secure malloc in case of local wide char usage
   size_t  sr = (sz+4) * 2;

   char *pDest = (char *)malloc(sr);
   if (!pDest)
      return NULL;
   char *pSrc = (char *)malloc(sr);
   if (!pSrc)
   {
      free(pDest);
      return NULL;
   }
   memset(pDest, 0, sr);
   memset(pSrc, 0, sr);

   if(wxStr.mb_str(wxConvISO8859_1))
      strncpy(pSrc, wxStr.mb_str(wxConvISO8859_1), sz);
   else if(wxStr.mb_str())
      strncpy(pSrc, wxStr.mb_str(), sz);
   else {
      free(pDest);
      free(pSrc);
      return NULL;
   }

   char *pD = pDest;
   char *pS = pSrc;
   unsigned char c;

   // ISO Latin to 7 bit ascii conversion table (best approximation)
   static char aASCII7Table[256] = {
      0x00, 0x5f, 0x5f, 0x5f, 0x5f, 0x5f, 0x5f, 0x5f,
      0x5f, 0x09, 0x0a, 0x5f, 0x0d, 0x5f, 0x5f, 0x5f,
      0x5f, 0x5f, 0x5f, 0x5f, 0x5f, 0x5f, 0x5f, 0x5f,
      0x5f, 0x5f, 0x5f, 0x5f, 0x5f, 0x5f, 0x5f, 0x5f,
      0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27,
      0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f,
      0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37,
      0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f,
      0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47,
      0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f,
      0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57,
      0x58, 0x59, 0x5a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f,
      0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67,
      0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f,
      0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77,
      0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f,
      0x45, 0x20, 0x2c, 0x53, 0x22, 0x2e, 0x2b, 0x2b,
      0x5e, 0x25, 0x53, 0x28, 0x4f, 0x20, 0x5a, 0x20,
      0x20, 0x27, 0x27, 0x22, 0x22, 0x2e, 0x2d, 0x5f,
      0x22, 0x54, 0x73, 0x29, 0x6f, 0x20, 0x7a, 0x59,
      0x20, 0x21, 0x63, 0x4c, 0x6f, 0x59, 0x7c, 0x53,
      0x22, 0x43, 0x61, 0x22, 0x5f, 0x2d, 0x43, 0x2d,
      0x6f, 0x7e, 0x32, 0x33, 0x27, 0x75, 0x50, 0x27,
      0x2c, 0x31, 0x6f, 0x22, 0x5f, 0x5f, 0x5f, 0x3f,
      0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x43,
      0x45, 0x45, 0x45, 0x45, 0x49, 0x49, 0x49, 0x49,
      0x44, 0x4e, 0x4f, 0x4f, 0x4f, 0x4f, 0x4f, 0x78,
      0x4f, 0x55, 0x55, 0x55, 0x55, 0x59, 0x70, 0x53,
      0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x63,
      0x65, 0x65, 0x65, 0x65, 0x69, 0x69, 0x69, 0x69,
      0x64, 0x6e, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x2f,
      0x6f, 0x75, 0x75, 0x75, 0x75, 0x79, 0x70, 0x79
   };

   size_t i;
   for(i = 0; i < sr; i++) {
      c = (unsigned char) *pS++;
      *pD++ = aASCII7Table[c];
      if(c == 0)
         break;
   }
   *pD = '\0';

   free(pSrc);

   if(b_aiff) {
      int len = (int)strlen(pDest);
      if((len % 2) != 0) {
         // In case of an odd length string, add a space char
         strcat(pDest, " ");
      }
   }

   return pDest;
}

bool ExportPCM::AddStrings(AudacityProject * WXUNUSED(project), SNDFILE *sf, const Tags *tags, int sf_format)
{
   if (tags->HasTag(TAG_TITLE)) {
      char * ascii7Str = AdjustString(tags->GetTag(TAG_TITLE), sf_format);
      if (ascii7Str) {
         sf_set_string(sf, SF_STR_TITLE, ascii7Str);
         free(ascii7Str);
      }
   }

   if (tags->HasTag(TAG_ALBUM)) {
      char * ascii7Str = AdjustString(tags->GetTag(TAG_ALBUM), sf_format);
      if (ascii7Str) {
         sf_set_string(sf, SF_STR_ALBUM, ascii7Str);
         free(ascii7Str);
      }
   }

   if (tags->HasTag(TAG_ARTIST)) {
      char * ascii7Str = AdjustString(tags->GetTag(TAG_ARTIST), sf_format);
      if (ascii7Str) {
         sf_set_string(sf, SF_STR_ARTIST, ascii7Str);
         free(ascii7Str);
      }
   }

   if (tags->HasTag(TAG_COMMENTS)) {
      char * ascii7Str = AdjustString(tags->GetTag(TAG_COMMENTS), sf_format);
      if (ascii7Str) {
         sf_set_string(sf, SF_STR_COMMENT, ascii7Str);
         free(ascii7Str);
      }
   }

   if (tags->HasTag(TAG_YEAR)) {
      char * ascii7Str = AdjustString(tags->GetTag(TAG_YEAR), sf_format);
      if (ascii7Str) {
         sf_set_string(sf, SF_STR_DATE, ascii7Str);
         free(ascii7Str);
      }
   }

   if (tags->HasTag(TAG_GENRE)) {
      char * ascii7Str = AdjustString(tags->GetTag(TAG_GENRE), sf_format);
      if (ascii7Str) {
         sf_set_string(sf, SF_STR_GENRE, ascii7Str);
         free(ascii7Str);
      }
   }

   if (tags->HasTag(TAG_COPYRIGHT)) {
      char * ascii7Str = AdjustString(tags->GetTag(TAG_COPYRIGHT), sf_format);
      if (ascii7Str) {
         sf_set_string(sf, SF_STR_COPYRIGHT, ascii7Str);
         free(ascii7Str);
      }
   }

   if (tags->HasTag(TAG_SOFTWARE)) {
      char * ascii7Str = AdjustString(tags->GetTag(TAG_SOFTWARE), sf_format);
      if (ascii7Str) {
         sf_set_string(sf, SF_STR_SOFTWARE, ascii7Str);
         free(ascii7Str);
      }
   }

   if (tags->HasTag(TAG_TRACK)) {
      char * ascii7Str = AdjustString(tags->GetTag(TAG_TRACK), sf_format);
      if (ascii7Str) {
         sf_set_string(sf, SF_STR_TRACKNUMBER, ascii7Str);
         free(ascii7Str);
      }
   }

   return true;
}

void ExportPCM::AddID3Chunk(wxString fName, const Tags *tags, int sf_format)
{
#ifdef USE_LIBID3TAG
   struct id3_tag *tp = id3_tag_new();

   for (const auto &pair : tags->GetRange()) {
      const auto &n = pair.first;
      const auto &v = pair.second;
      const char *name = "TXXX";

      if (n.CmpNoCase(TAG_TITLE) == 0) {
         name = ID3_FRAME_TITLE;
      }
      else if (n.CmpNoCase(TAG_ARTIST) == 0) {
         name = ID3_FRAME_ARTIST;
      }
      else if (n.CmpNoCase(TAG_ALBUM) == 0) {
         name = ID3_FRAME_ALBUM;
      }
      else if (n.CmpNoCase(TAG_YEAR) == 0) {
         name = ID3_FRAME_YEAR;
      }
      else if (n.CmpNoCase(TAG_GENRE) == 0) {
         name = ID3_FRAME_GENRE;
      }
      else if (n.CmpNoCase(TAG_COMMENTS) == 0) {
         name = ID3_FRAME_COMMENT;
      }
      else if (n.CmpNoCase(TAG_TRACK) == 0) {
         name = ID3_FRAME_TRACK;
      }
      else if (n.CmpNoCase(wxT("composer")) == 0) {
         name = "TCOM";
      }

      struct id3_frame *frame = id3_frame_new(name);

      if (!n.IsAscii() || !v.IsAscii()) {
         id3_field_settextencoding(id3_frame_field(frame, 0), ID3_FIELD_TEXTENCODING_UTF_16);
      }
      else {
         id3_field_settextencoding(id3_frame_field(frame, 0), ID3_FIELD_TEXTENCODING_ISO_8859_1);
      }

      id3_ucs4_t *ucs4 =
         id3_utf8_ucs4duplicate((id3_utf8_t *) (const char *) v.mb_str(wxConvUTF8));

      if (strcmp(name, ID3_FRAME_COMMENT) == 0) {
         // A hack to get around iTunes not recognizing the comment.  The
         // language defaults to XXX and, since it's not a valid language,
         // iTunes just ignores the tag.  So, either set it to a valid language
         // (which one???) or just clear it.  Unfortunately, there's no supported
         // way of clearing the field, so do it directly.
         id3_field *f = id3_frame_field(frame, 1);
         memset(f->immediate.value, 0, sizeof(f->immediate.value));
         id3_field_setfullstring(id3_frame_field(frame, 3), ucs4);
      }
      else if (strcmp(name, "TXXX") == 0) {
         id3_field_setstring(id3_frame_field(frame, 2), ucs4);
         free(ucs4);

         ucs4 = id3_utf8_ucs4duplicate((id3_utf8_t *) (const char *) n.mb_str(wxConvUTF8));

         id3_field_setstring(id3_frame_field(frame, 1), ucs4);
      }
      else {
         id3_field_setstrings(id3_frame_field(frame, 1), 1, &ucs4);
      }

      free(ucs4);

      id3_tag_attachframe(tp, frame);
   }

   tp->options &= (~ID3_TAG_OPTION_COMPRESSION); // No compression

   // If this version of libid3tag supports it, use v2.3 ID3
   // tags instead of the newer, but less well supported, v2.4
   // that libid3tag uses by default.
#ifdef ID3_TAG_HAS_TAG_OPTION_ID3V2_3
   tp->options |= ID3_TAG_OPTION_ID3V2_3;
#endif

   id3_length_t len;

   len = id3_tag_render(tp, 0);
   if (len == 0) {
      id3_tag_delete(tp);
      return;
   }
   if ((len % 2) != 0) len++;   // Length must be even.
   id3_byte_t *buffer = (id3_byte_t *)malloc(len);
   if (buffer == NULL) {
      id3_tag_delete(tp);
      return;
   }
   // Zero all locations, for ending odd UTF16 content
   // correctly, i.e., two '\0's at the end.
   memset(buffer, 0, len);

   id3_tag_render(tp, buffer);

   id3_tag_delete(tp);

   wxFFile f(fName, wxT("r+b"));
   if (f.IsOpened()) {
      wxUint32 sz;

      sz = (wxUint32) len;
      f.SeekEnd(0);
      if ((sf_format & SF_FORMAT_TYPEMASK) == SF_FORMAT_WAV)
         f.Write("id3 ", 4);	// Must be lower case for foobar2000.
      else {
         f.Write("ID3 ", 4);
         sz = wxUINT32_SWAP_ON_LE(sz);
      }
      f.Write(&sz, 4);

      f.Write(buffer, len);

      sz = (wxUint32) f.Tell() - 8;
      if ((sf_format & SF_FORMAT_TYPEMASK) == SF_FORMAT_AIFF)
         sz = wxUINT32_SWAP_ON_LE(sz);

      f.Seek(4);
      f.Write(&sz, 4);

      f.Close();
   }

   free(buffer);
#endif
   return;
}

wxWindow *ExportPCM::OptionsCreate(wxWindow *parent, int format)
{
   wxASSERT(parent); // to justify safenew
   // default, full user control
   if (format < 0 || format >= WXSIZEOF(kFormats))
   {
      return safenew ExportPCMOptions(parent, format);
   }

   return ExportPlugin::OptionsCreate(parent, format);
}

wxString ExportPCM::GetExtension(int index)
{
   if (index == WXSIZEOF(kFormats)) {
      // get extension libsndfile thinks is correct for currently selected format
      return sf_header_extension(ReadExportFormatPref());
   }
   else {
      // return the default
      return ExportPlugin::GetExtension(index);
   }
}

bool ExportPCM::CheckFileName(wxFileName &filename, int format)
{
   if (format == WXSIZEOF(kFormats) &&
       IsExtension(filename.GetExt(), format)) {
      // PRL:  Bug1217
      // If the user left the extension blank, then the
      // file dialog will have defaulted the extension, beyond our control,
      // to the first in the wildcard list or (Linux) the last-saved extension,
      // ignoring what we try to do with the additional drop-down mHeaderChoice.
      // Here we can intercept file name processing and impose the correct default.
      // However this has the consequence that in case an explicit extension was typed,
      // we override it without asking.
      filename.SetExt(GetExtension(format));
   }

   return ExportPlugin::CheckFileName(filename, format);
}

movable_ptr<ExportPlugin> New_ExportPCM()
{
   return make_movable<ExportPCM>();
}