/* GTK - The GIMP Toolkit
 * Copyright (C) 2010 Carlos Garnacho <carlosg@gnome.org>
 * Copyright (C) 2011 Red Hat, Inc.
 *
 * Authors: Carlos Garnacho <carlosg@gnome.org>
 *          Cosimo Cecchi <cosimoc@gnome.org>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

#include <config.h>

#include "gtkwin32themeprivate.h"

#ifdef G_OS_WIN32

#include <windows.h>
#include <cairo-win32.h>

typedef HANDLE HTHEME;

#define UXTHEME_DLL "uxtheme.dll"

static HINSTANCE uxtheme_dll = NULL;
static gboolean use_xp_theme = FALSE;

typedef HRESULT (FAR PASCAL *GetThemeSysFontFunc)           (HTHEME hTheme, int iFontID, OUT LOGFONTW *plf);
typedef int (FAR PASCAL *GetThemeSysSizeFunc)               (HTHEME hTheme, int iSizeId);
typedef COLORREF (FAR PASCAL *GetThemeSysColorFunc)         (HTHEME hTheme,
							     int iColorID);
typedef HTHEME (FAR PASCAL *OpenThemeDataFunc)              (HWND hwnd,
							     LPCWSTR pszClassList);
typedef HRESULT (FAR PASCAL *CloseThemeDataFunc)            (HTHEME theme);
typedef HRESULT (FAR PASCAL *DrawThemeBackgroundFunc)       (HTHEME hTheme, HDC hdc, int iPartId, int iStateId,
							     const RECT *pRect, const RECT *pClipRect);
typedef HRESULT (FAR PASCAL *EnableThemeDialogTextureFunc)  (HWND hwnd,
							     DWORD dwFlags);
typedef BOOL (FAR PASCAL *IsThemeActiveFunc)                (VOID);
typedef BOOL (FAR PASCAL *IsAppThemedFunc)                  (VOID);
typedef BOOL (FAR PASCAL *IsThemeBackgroundPartiallyTransparentFunc) (HTHEME hTheme,
								      int iPartId,
								      int iStateId);
typedef HRESULT (FAR PASCAL *DrawThemeParentBackgroundFunc) (HWND hwnd,
							     HDC hdc,
							     RECT *prc);
typedef HRESULT (FAR PASCAL *GetThemePartSizeFunc)          (HTHEME hTheme,
							     HDC hdc,
							     int iPartId,
							     int iStateId,
							     RECT *prc,
							     int eSize,
							     SIZE *psz);

static GetThemeSysFontFunc get_theme_sys_font = NULL;
static GetThemeSysColorFunc get_theme_sys_color = NULL;
static GetThemeSysSizeFunc get_theme_sys_metric = NULL;
static OpenThemeDataFunc open_theme_data = NULL;
static CloseThemeDataFunc close_theme_data = NULL;
static DrawThemeBackgroundFunc draw_theme_background = NULL;
static EnableThemeDialogTextureFunc enable_theme_dialog_texture = NULL;
static IsThemeActiveFunc is_theme_active = NULL;
static IsAppThemedFunc is_app_themed = NULL;
static IsThemeBackgroundPartiallyTransparentFunc is_theme_partially_transparent = NULL;
static DrawThemeParentBackgroundFunc draw_theme_parent_background = NULL;
static GetThemePartSizeFunc get_theme_part_size = NULL;

static GHashTable *hthemes_by_class = NULL;

static void
_gtk_win32_theme_init (void)
{
  char *buf;
  char dummy;
  int n, k;

  if (uxtheme_dll)
    return;

  n = GetSystemDirectory (&dummy, 0);
  if (n <= 0)
    return;

  buf = g_malloc (n + 1 + strlen (UXTHEME_DLL));
  k = GetSystemDirectory (buf, n);
  if (k == 0 || k > n)
    {
      g_free (buf);
      return;
    }

  if (!G_IS_DIR_SEPARATOR (buf[strlen (buf) -1]))
    strcat (buf, G_DIR_SEPARATOR_S);
  strcat (buf, UXTHEME_DLL);

  uxtheme_dll = LoadLibrary (buf);
  g_free (buf);

  if (!uxtheme_dll)
    return;

  is_app_themed = (IsAppThemedFunc) GetProcAddress (uxtheme_dll, "IsAppThemed");
  if (is_app_themed)
    {
      is_theme_active = (IsThemeActiveFunc) GetProcAddress (uxtheme_dll, "IsThemeActive");
      open_theme_data = (OpenThemeDataFunc) GetProcAddress (uxtheme_dll, "OpenThemeData");
      close_theme_data = (CloseThemeDataFunc) GetProcAddress (uxtheme_dll, "CloseThemeData");
      draw_theme_background = (DrawThemeBackgroundFunc) GetProcAddress (uxtheme_dll, "DrawThemeBackground");
      enable_theme_dialog_texture = (EnableThemeDialogTextureFunc) GetProcAddress (uxtheme_dll, "EnableThemeDialogTexture");
      get_theme_sys_font = (GetThemeSysFontFunc) GetProcAddress (uxtheme_dll, "GetThemeSysFont");
      get_theme_sys_color = (GetThemeSysColorFunc) GetProcAddress (uxtheme_dll, "GetThemeSysColor");
      get_theme_sys_metric = (GetThemeSysSizeFunc) GetProcAddress (uxtheme_dll, "GetThemeSysSize");
      is_theme_partially_transparent = (IsThemeBackgroundPartiallyTransparentFunc) GetProcAddress (uxtheme_dll, "IsThemeBackgroundPartiallyTransparent");
      draw_theme_parent_background = (DrawThemeParentBackgroundFunc) GetProcAddress (uxtheme_dll, "DrawThemeParentBackground");
      get_theme_part_size = (GetThemePartSizeFunc) GetProcAddress (uxtheme_dll, "GetThemePartSize");
    }

  if (is_app_themed && is_theme_active)
    {
      use_xp_theme = (is_app_themed () && is_theme_active ());
    }
  else
    {
      use_xp_theme = FALSE;
    }

  hthemes_by_class = g_hash_table_new (g_str_hash, g_str_equal);
}

static HTHEME
lookup_htheme_by_classname (const char *class)
{
  HTHEME theme;
  guint16 *wclass;
  char *lower;
  
  lower = g_ascii_strdown (class, -1);

  theme = (HTHEME)  g_hash_table_lookup (hthemes_by_class, lower);
  if (theme)
    {
      g_free (lower);
      return theme;
    }

  wclass = g_utf8_to_utf16 (lower, -1, NULL, NULL, NULL);
  theme  = open_theme_data (NULL, wclass);
  g_free (wclass);

  if (theme == NULL)
    {
      g_free (lower);
      return NULL;
    }

  /* Takes ownership of lower: */
  g_hash_table_insert (hthemes_by_class, lower, theme);

  return theme;
}

#else

typedef void * HTHEME;

static void
_gtk_win32_theme_init (void)
{
}

static HTHEME
lookup_htheme_by_classname (const char *class)
{
  return NULL;
}

#endif /* G_OS_WIN32 */

G_DEFINE_BOXED_TYPE_WITH_CODE (GtkWin32ThemePart, _gtk_win32_theme_part,
			       _gtk_win32_theme_part_ref, _gtk_win32_theme_part_unref, 
			       _gtk_win32_theme_init() )

struct _GtkWin32ThemePart {
  HTHEME theme;
  int part;
  int state;

  gint ref_count;
};

GtkWin32ThemePart *
_gtk_win32_theme_part_new (const char *class, 
			   int xp_part, int state)
{
  GtkWin32ThemePart *part;

  part = g_slice_new0 (GtkWin32ThemePart);
  part->ref_count = 1;

  part->theme = lookup_htheme_by_classname (class);
  part->part = xp_part;
  part->state = state;

  return part;
}

GtkWin32ThemePart *
_gtk_win32_theme_part_ref (GtkWin32ThemePart *part)
{
  g_return_val_if_fail (part != NULL, NULL);

  part->ref_count++;

  return part;
}

void
_gtk_win32_theme_part_unref (GtkWin32ThemePart *part)
{
  g_return_if_fail (part != NULL);

  part->ref_count--;

  if (part->ref_count == 0)
    {
      g_slice_free (GtkWin32ThemePart, part);
    }
}

int
_gtk_win32_theme_part_parse (GtkCssParser *parser, 
			     GFile *base, 
			     GValue *value)
{
  char *class;
  int xp_part, state;
  GtkWin32ThemePart *theme_part;

  if (!_gtk_css_parser_try (parser, "-gtk-win32-theme-part", TRUE))
    {
      return -1;
    }
  
  g_value_unset (value);
  g_value_init (value, GTK_TYPE_WIN32_THEME_PART);

  if (!_gtk_css_parser_try (parser, "(", TRUE))
    {
      _gtk_css_parser_error (parser,
                             "Expected '(' after '-gtk-win32-theme-part'");
      return 0;
    }
  
  class = _gtk_css_parser_try_name (parser, TRUE);
  if (class == NULL)
    {
      _gtk_css_parser_error (parser,
                             "Expected name as first argument to  '-gtk-win32-theme-part'");
      return 0;
    }

  if (! _gtk_css_parser_try (parser, ",", TRUE))
    {
      g_free (class);
      _gtk_css_parser_error (parser,
			     "Expected ','");
      return 0;
    }

  if (!_gtk_css_parser_try_int (parser, &xp_part))
    {
      g_free (class);
      _gtk_css_parser_error (parser, "Expected a valid integer value");
      return 0;
    }

  if (! _gtk_css_parser_try (parser, ",", TRUE))
    {
      g_free (class);
      _gtk_css_parser_error (parser,
			     "Expected ','");
      return 0;
    }

  if (!_gtk_css_parser_try_int (parser, &state))
    {
      g_free (class);
      _gtk_css_parser_error (parser, "Expected a valid integer value");
      return 0;
    }

  if (!_gtk_css_parser_try (parser, ")", TRUE))
    {
      g_free (class);
      _gtk_css_parser_error (parser,
			     "Expected ')'");
      return 0;
    }
  
  theme_part = _gtk_win32_theme_part_new (class, xp_part, state);
  g_free (class);
  
  g_value_take_boxed (value, theme_part);
  return 1;
}

cairo_pattern_t *
_gtk_win32_theme_part_render  (GtkWin32ThemePart  *part,
			       int                 width,
			       int                 height)
{
#ifdef G_OS_WIN32
  cairo_surface_t *surface, *image;
  cairo_pattern_t *pattern;
  cairo_matrix_t matrix;
  HDC hdc;
  RECT rect;
  HRESULT res;
  cairo_user_data_key_t key;

  surface = cairo_win32_surface_create_with_dib (CAIRO_FORMAT_ARGB32, width, height);
  hdc = cairo_win32_surface_get_dc (surface);
  
  rect.left = 0;
  rect.top = 0;
  rect.right = width;
  rect.bottom = height;

  res = draw_theme_background (part->theme, hdc, part->part, part->state, &rect, &rect);

  /* We need to return an image surface, as that is what the code expects in order
     to get the size */
  image = cairo_win32_surface_get_image (surface);
  pattern = cairo_pattern_create_for_surface (cairo_surface_reference (image));

  cairo_matrix_init_scale (&matrix,
			   width,
			   height);
  cairo_pattern_set_matrix (pattern, &matrix);

  /* We can't immediately destroy the surface, because that would free the data
     the image surface refers too. Instead we destroy it with the pattern. */
  cairo_pattern_set_user_data (pattern,
			       &key,
			       surface, (cairo_destroy_func_t) cairo_surface_destroy);

  return pattern;
#else
  GdkRGBA color;
  
  gdk_rgba_parse (&color, "pink");

  return cairo_pattern_create_rgb (color.red, color.green, color.blue);
#endif
}