//==============================================================================
// RichEdit 2.0 windowless drawing routines

// For some reason I'm getting the wrong IID from riched20.lib
const IID IID_ITextServices = { 0x8d33f740, 0xcf58, 0x11ce,
                                        {0xa8, 0x9d, 0x00, 0xaa,
                                         0x00, 0x6c, 0xad, 0xc5}};

ITextServices *g_pts = NULL;
int g_x_per_inch = 96;
int g_y_per_inch = 96;

HRESULT RichEdit_GetTextServices(ITextServices **ppts) {
  HRESULT hr = E_OUTOFMEMORY;
  if (g_pts == NULL) {

    // Put this initialization somewhere...
    HDC hdcScreen = GetDC(NULL);
    g_x_per_inch = GetDeviceCaps(hdcScreen, LOGPIXELSX);
    g_y_per_inch = GetDeviceCaps(hdcScreen, LOGPIXELSY);
    ReleaseDC(NULL, hdcScreen);
    // End of screen initialization...

    TextHost *host = new TextHost();
    if (host) {
      IUnknown *punkTS;
      hr = CreateTextServices(NULL, host, &punkTS);
      if (SUCCEEDED(hr)) {
        // you would think that CreateTextServices would AddRef the host
        // pointer we just passed it, but alas its COM support it poor.
        host->AddRef();

        hr = punkTS->QueryInterface(IID_ITextServices, (void **)&g_pts);
        if (SUCCEEDED(hr)) {
          // nothing to do
        }
        punkTS->Release();
      }
      host->Release();
    }
  }
  if (g_pts) {
    hr = g_pts->QueryInterface(IID_ITextServices, (void **)ppts);
  }
  return hr;
}

#define Y_PER_INCH  1440    // TWIPS conversion

void RichEdit_SetFont(ITextServices *pts, HFONT font, COLORREF color) {
  LOGFONT lf;
  if (GetObject(font, sizeof(lf), &lf)) {
    CHARFORMAT2W char_format;
    memset(&char_format, 0, sizeof(char_format));
    char_format.cbSize = sizeof(char_format);
    char_format.yHeight = -lf.lfHeight * Y_PER_INCH / g_y_per_inch;
    char_format.crTextColor = color;
    char_format.dwEffects = CFM_EFFECTS | CFE_AUTOBACKCOLOR;
    char_format.dwEffects &= ~(CFE_PROTECTED | CFE_LINK | CFE_AUTOCOLOR);

    if(lf.lfWeight < FW_BOLD) {
      char_format.dwEffects &= ~CFE_BOLD;
    }

    if(!lf.lfItalic) {
      char_format.dwEffects &= ~CFE_ITALIC;
    }

    if(!lf.lfUnderline) {
      char_format.dwEffects &= ~CFE_UNDERLINE;
    }

    if(!lf.lfStrikeOut) {
      char_format.dwEffects &= ~CFE_STRIKEOUT;
    }

    char_format.dwMask = CFM_ALL | CFM_BACKCOLOR | CFM_STYLE | CFM_COLOR;
    char_format.bCharSet = lf.lfCharSet;
    char_format.bPitchAndFamily = lf.lfPitchAndFamily;

    memcpy(char_format.szFaceName, lf.lfFaceName, sizeof(char_format.szFaceName));

    LRESULT lResult;
    pts->TxSendMessage(EM_SETCHARFORMAT, 0, (LPARAM)&char_format, &lResult);
  }
}

#define HIMETRIC_PER_INCH   2540    // 2540 units per inch

void RichEdit_MeasureText(HDC hdc, HFONT hfont, const CString &text, int width,
                          SIZE *psize) {
  psize->cx = 0;
  psize->cy = 0;

  ITextServices *pts;
  HRESULT hr = RichEdit_GetTextServices(&pts);
  if (SUCCEEDED(hr)) {

    // Set the right font
    RichEdit_SetFont(pts, hfont, RGB(0xFF,0xFF,0xFF));

    // Set the right text
    pts->TxSetText(L"");

    PARAFORMAT pf;
    ZeroMemory(&pf, sizeof(pf));
    pf.cbSize = sizeof(pf);
    pf.dwMask = PFM_ALIGNMENT;
    pf.wAlignment = PFA_LEFT;
    LRESULT lresult;
    pts->TxSendMessage(EM_SETPARAFORMAT, NULL, (LPARAM)&pf, &lresult);

    pts->TxSetText(text);
  
    // Now do the measurement
    SIZEL size_long = { LONG_MAX, LONG_MAX };
    LONG width_long = LONG_MAX;
    if (width != INT_MAX && g_x_per_inch != 0) {
      // TxGetNaturalSize takes sizes in MM_HIMETRIC
      width_long = (width * HIMETRIC_PER_INCH + g_x_per_inch - 1) 
                   / g_x_per_inch;
    }
    LONG height_long = LONG_MAX;

    // *** Mapping mode freak-out time ***
    //
    // Ok, here is the deal.  RichEdit likes to measure the size of your
    // font in MM_HIMETRIC mode, it does this to gain accuracy.  But the
    // rendering code in "TxDraw" isn't as nice.  It tries to clip the 
    // text to the bounding rectangle that is passed to it, and when it
    // is doing that measurement, it does it in MM_TEXT mode.  Due to
    // rounding errors, the two will be different - in a bad way.
    // It is nearly impossible to get TxDraw to do the right thing, so
    // instead we cripple the TxGetNaturalSize.  We apply a transform
    // such that the font will be scaled down and measured as if it were
    // only as big in MM_HIMETRIC as it eventually is in MM_TEXT later.  Ugh.
    SetMapMode(hdc, MM_ANISOTROPIC);
    // Yes RichEdit hard-codes this HIMETRIC_PER_INCH value too
    SetWindowExtEx(hdc, HIMETRIC_PER_INCH, HIMETRIC_PER_INCH, NULL);
    SetViewportExtEx(hdc, g_x_per_inch, g_y_per_inch, NULL);

    hr = pts->TxGetNaturalSize(DVASPECT_CONTENT, hdc, NULL, NULL, 
          TXTNS_FITTOCONTENT, &size_long, &width_long, &height_long);

    // Restore mapping mode to something sane
    SetMapMode(hdc, MM_TEXT);
    //
    // *** End mapping mode freak-out time ***

    if (SUCCEEDED(hr)) {
      // TxGetNaturalSize gives back width and height in terms of MM_HIMETRIC
      // (2540 units per inch).  Let's round up to nearest pixel
      psize->cx = ((width_long * g_x_per_inch + HIMETRIC_PER_INCH - 1) 
                   / HIMETRIC_PER_INCH);
      psize->cy = ((height_long * g_y_per_inch + HIMETRIC_PER_INCH - 1) 
                   / HIMETRIC_PER_INCH);
    }
    pts->Release();
  }
}

void RichEdit_DrawText(HDC hdc, const RECT *rect, HFONT hfont, COLORREF color,
                       const CString &text, bool centered) {
  RECTL rc = { rect->left, rect->top, rect->right, rect->bottom};

  ITextServices *pts;
  HRESULT hr = RichEdit_GetTextServices(&pts);
  if (SUCCEEDED(hr)) {
    // Set the right font
    RichEdit_SetFont(pts, hfont, color);

    // Set the right text
    pts->TxSetText(L"");

    PARAFORMAT pf;
    ZeroMemory(&pf, sizeof(pf));
    pf.cbSize = sizeof(pf);
    pf.dwMask = PFM_ALIGNMENT;
    if (centered) {
      pf.wAlignment = PFA_CENTER;
    } else {
      pf.wAlignment = PFA_LEFT;
    }
    LRESULT lresult;
    pts->TxSendMessage(EM_SETPARAFORMAT, NULL, (LPARAM)&pf, &lresult);

    pts->TxSetText(text);

    // Now draw the text
    pts->TxDraw(DVASPECT_CONTENT, 0, NULL, NULL, hdc, NULL,
		&rc, NULL, NULL, NULL, NULL, TXTVIEW_INACTIVE);
    pts->Release();
  }
}

void RichEdit_CleanupGlobals() {
  if (g_pts) {
    g_pts->Release();
    g_pts = NULL;
  }
}