#pragma once

#include "gdkcolorstateprivate.h"
#include "gdkcolorprivate.h"

#include "gdkmemoryformatprivate.h"
#include "gdkmemorytexture.h"

#include "gdkrectangleprivate.h"

#include <cairo.h>
#include <graphene.h>
#include <math.h>

static inline cairo_format_t
gdk_cairo_format_for_depth (GdkMemoryDepth depth)
{
  switch (depth)
    {
      case GDK_MEMORY_NONE:
      case GDK_MEMORY_U8:
        return CAIRO_FORMAT_ARGB32;

      case GDK_MEMORY_FLOAT16:
      case GDK_MEMORY_FLOAT32:
        return CAIRO_FORMAT_RGBA128F;

      case GDK_N_DEPTHS:
      default:
        g_return_val_if_reached (CAIRO_FORMAT_ARGB32);
    }
}

static inline GdkMemoryFormat
gdk_cairo_format_to_memory_format (cairo_format_t format)
{
  GdkMemoryFormat result;

  if (!gdk_memory_format_find_by_cairo_format (format, &result))
    result = GDK_MEMORY_DEFAULT;

  return result;
}

static inline cairo_format_t
gdk_cairo_format_for_content (cairo_content_t content)
{
  switch (content)
    {
      case CAIRO_CONTENT_COLOR:
        return CAIRO_FORMAT_RGB24;
      case CAIRO_CONTENT_ALPHA:
        return CAIRO_FORMAT_A8;
      case CAIRO_CONTENT_COLOR_ALPHA:
        return CAIRO_FORMAT_ARGB32;
      default:
        g_return_val_if_reached (CAIRO_FORMAT_ARGB32);
    }
}

static inline void
gdk_cairo_set_source_color (cairo_t        *cr,
                            GdkColorState  *ccs,
                            const GdkColor *color)
{
  float c[4];
  gdk_color_to_float (color, ccs, c);
  cairo_set_source_rgba (cr, c[0], c[1], c[2], c[3]);
}

static inline void
gdk_cairo_set_source_rgba_ccs (cairo_t       *cr,
                               GdkColorState *ccs,
                               const GdkRGBA *rgba)
{
  GdkColor c;
  gdk_color_init_from_rgba (&c, rgba);
  gdk_cairo_set_source_color (cr, ccs, &c);
  gdk_color_finish (&c);
}

static inline void
gdk_cairo_pattern_add_color_stop_rgba_ccs (cairo_pattern_t *pattern,
                                           GdkColorState   *ccs,
                                           double           offset,
                                           const GdkRGBA   *rgba)
{
  float color[4];

  gdk_color_state_from_rgba (ccs, rgba, color);
  cairo_pattern_add_color_stop_rgba (pattern, offset, color[0], color[1], color[2], color[3]);
}

static inline void
gdk_cairo_pattern_add_color_stop_color (cairo_pattern_t *pattern,
                                        GdkColorState   *ccs,
                                        double           offset,
                                        const GdkColor  *color)
{
  float values[4];

  gdk_color_to_float (color, ccs, values);
  cairo_pattern_add_color_stop_rgba (pattern, offset, values[0], values[1], values[2], values[3]);
}

static inline void
gdk_cairo_rect (cairo_t               *cr,
                const graphene_rect_t *rect)
{
  cairo_rectangle (cr,
                   rect->origin.x, rect->origin.y,
                   rect->size.width, rect->size.height);
}

static inline void
gdk_cairo_surface_convert_color_state (cairo_surface_t *surface,
                                       GdkColorState   *source,
                                       GdkColorState   *target)
{
  cairo_surface_t *image_surface;
  int status, width, height;

  if (gdk_color_state_equal (source, target))
    return;

  image_surface = cairo_surface_map_to_image (surface, NULL);

  status = cairo_surface_status (image_surface);
  width = cairo_image_surface_get_width (image_surface);
  height = cairo_image_surface_get_height (image_surface);

  if (status == CAIRO_STATUS_SUCCESS && width > 0 && height > 0)
    {
      gdk_memory_convert_color_state (cairo_image_surface_get_data (image_surface),
                                      &GDK_MEMORY_LAYOUT_SIMPLE (
                                          gdk_cairo_format_to_memory_format (cairo_image_surface_get_format (image_surface)),
                                          width,
                                          height,
                                          cairo_image_surface_get_stride (image_surface)),
                                      source,
                                      target);
    }

  cairo_surface_mark_dirty (image_surface);
  cairo_surface_unmap_image (surface, image_surface);
  /* https://gitlab.freedesktop.org/cairo/cairo/-/merge_requests/487 */
  cairo_surface_mark_dirty (surface);
}

static inline cairo_region_t *
gdk_cairo_region_scale_grow (const cairo_region_t *region,
                             double                scale_x,
                             double                scale_y)
{
  cairo_region_t *result;

  result = cairo_region_create ();
  for (int i = 0; i < cairo_region_num_rectangles (region); i++)
    {
      cairo_rectangle_int_t rect;
      cairo_region_get_rectangle (region, i, &rect);
      cairo_region_union_rectangle (result, &(cairo_rectangle_int_t) {
                                      .x = (int) floor (rect.x * scale_x),
                                      .y = (int) floor (rect.y * scale_y),
                                      .width = (int) ceil ((rect.x + rect.width) * scale_x) - floor (rect.x * scale_x),
                                      .height = (int) ceil ((rect.y + rect.height) * scale_y) - floor (rect.y * scale_y),
                                    });
    }

  return result;
}

static inline char *
gdk_cairo_region_to_debug_string (const cairo_region_t *region)
{
  GString *string;
  cairo_rectangle_int_t extents;

  cairo_region_get_extents (region, &extents);

  string = g_string_new (NULL);
  g_string_append_printf (string, "{ %d, %d, %d, %d } (%d rects)",
                          extents.x, extents.y, extents.width, extents.height,
                          cairo_region_num_rectangles (region));

  return g_string_free (string, FALSE);
}

static inline gboolean
gdk_cairo_is_all_clipped (cairo_t *cr)
{
  double x1, y1, x2, y2;

  cairo_clip_extents (cr, &x1, &y1, &x2, &y2);
  return x1 >= x2 || y1 >= y2;
}

/* apply a rectangle that bounds @rect in
 * pixel-aligned device coordinates.
 *
 * This is useful for clipping to minimize the rectangle
 * in push_group() or when blurring.
 */
static inline void
gdk_cairo_rectangle_snap_to_grid (cairo_t               *cr,
                                  const graphene_rect_t *rect)
{
  double x0, x1, x2, x3;
  double y0, y1, y2, y3;
  double xmin, xmax, ymin, ymax;

  x0 = rect->origin.x;
  y0 = rect->origin.y;
  cairo_user_to_device (cr, &x0, &y0);
  x1 = rect->origin.x + rect->size.width;
  y1 = rect->origin.y;
  cairo_user_to_device (cr, &x1, &y1);
  x2 = rect->origin.x;
  y2 = rect->origin.y + rect->size.height;
  cairo_user_to_device (cr, &x2, &y2);
  x3 = rect->origin.x + rect->size.width;
  y3 = rect->origin.y + rect->size.height;
  cairo_user_to_device (cr, &x3, &y3);

  xmin = MIN (MIN (x0, x1), MIN (x2, x3));
  ymin = MIN (MIN (y0, y1), MIN (y2, y3));
  xmax = MAX (MAX (x0, x1), MAX (x2, x3));
  ymax = MAX (MAX (y0, y1), MAX (y2, y3));

  xmin = floor (xmin);
  ymin = floor (ymin);
  xmax = ceil (xmax);
  ymax = ceil (ymax);

  cairo_save (cr);
  cairo_identity_matrix (cr);
  cairo_rectangle (cr, xmin, ymin, xmax - xmin, ymax - ymin);
  cairo_restore (cr);
}

/**
 * gdk_cairo_create_similar_surface:
 * @cr: cairo context
 * @content: the kind of surface to create
 * @bounds: the bounds to create the surface for
 *
 * Creates a surface for offscreen rendering that isn't
 * confined by Cairo's clipping behavior. So this is
 * useful as an alternative to cairo_push_group() if
 * you want a guarantee that the whole area will be
 * created, for example when blurring and needing a larger
 * input area.
 *
 * This function will set the surface's device scale and offset.
 *
 * Once done with rendering to the returned surface, you
 * can render it to the given bounds with this code:
 * 
 * ```c
 * cairo_set_source_surface (cr, surface);
 * cairo_paint (cr);
 * ```
 * 
 * Returns: a new cairo surface 
 **/
static inline cairo_surface_t *
gdk_cairo_create_similar_surface (cairo_t               *cr,
                                  cairo_content_t        content,
                                  const graphene_rect_t *bounds)
{
  cairo_matrix_t matrix;
  double xscale, yscale, det, width, height;
  cairo_surface_t *surface;

  cairo_get_matrix (cr, &matrix);
  cairo_surface_get_device_scale (cairo_get_target (cr), &xscale, &yscale);
  det = matrix.xx * matrix.yy - matrix.xy * matrix.yx;
  if (matrix.xx != 0 || matrix.yx != 0)
    {
      width = sqrt (matrix.xx * matrix.xx + matrix.yx * matrix.yx);
      height = det / width;
    }
  else if (matrix.yx != 0 || matrix.yy != 0)
    {
      height = sqrt (matrix.yx * matrix.yx + matrix.yy * matrix.yy);
      width = det / height;
    }
  else
    {
      g_return_val_if_reached (NULL);
    }

  width = ABS (ceil (width * bounds->size.width * xscale));
  height = ABS (ceil (height * bounds->size.height * yscale));

  surface = cairo_surface_create_similar (cairo_get_group_target (cr), 
                                          content,
                                          width, height);
  xscale = width / bounds->size.width;
  yscale = height / bounds->size.height;
  cairo_surface_set_device_scale (surface, xscale, yscale);
  cairo_surface_set_device_offset (surface,
                                   - bounds->origin.x * xscale,
                                   - bounds->origin.y * yscale);

  return surface;
}

static inline void
gdk_cairo_region_union_affine (cairo_region_t       *region,
                               const cairo_region_t *sub,
                               float                 scale_x,
                               float                 scale_y,
                               float                 offset_x,
                               float                 offset_y)
{
  cairo_rectangle_int_t rect;
  int i;

  for (i = 0; i < cairo_region_num_rectangles (sub); i++)
    {
      cairo_region_get_rectangle (sub, i, &rect);
      gdk_rectangle_transform_affine (&rect, scale_x, scale_y, offset_x, offset_y, &rect);
      cairo_region_union_rectangle (region, &rect);
    }
}

/*
 * gdk_cairo_region_is_rectangle:
 * @region: a cairo region
 *
 * Checks if the region can be represented by a rectangle.
 * 
 * This rectangle can be queried with cairo_region_get_extents().
 *
 * FIXME: Should this return TRUE or FALSE for an empty region?
 * Currently I have no use case, so it returns whatever.
 *
 * Returns: true if the region is a rectangle.
 **/
static inline gboolean
gdk_cairo_region_is_rectangle (cairo_region_t *region)
{
  return cairo_region_num_rectangles (region) == 1;
}

/*
 * gdk_cairo_color_component_to_u8:
 * @v: a color component, nominally in [0, 1]
 *
 * Converts a color component to the 8 bit value cairo wants.
 *
 * Shaders divide by zero and input textures contain junk, so infinities and
 * NaN do turn up here. Infinities clamp to the ends of the range, and NaN
 * becomes 0: comparisons against NaN are all false, so it takes the same
 * branch as a negative value. Clamping before the conversion also means the
 * conversion never sees a value that a guint32 cannot represent.
 *
 * Returns: @v as a value in [0, 255]
 */
static inline guint32
gdk_cairo_color_component_to_u8 (float v)
{
  float f = roundf (v * 255.f);

  return f > 0.f ? (f < 255.f ? (guint32) f : 255) : 0;
}

/*
 * gdk_cairo_pixel_from_float:
 * @rgba: premultiplied color components, in the order red, green, blue, alpha
 *
 * Packs premultiplied float color components into the pixel format used by
 * cairo's ARGB32 surfaces.
 *
 * Returns: the packed pixel
 */
static inline guint32
gdk_cairo_pixel_from_float (const float rgba[4])
{
  return gdk_cairo_color_component_to_u8 (rgba[3]) << 24 |
         gdk_cairo_color_component_to_u8 (rgba[0]) << 16 |
         gdk_cairo_color_component_to_u8 (rgba[1]) << 8 |
         gdk_cairo_color_component_to_u8 (rgba[2]) << 0;
}

static inline void
gdk_cairo_surface_get_device_matrix (cairo_surface_t *surface,
                                     cairo_matrix_t  *matrix)
{
  cairo_surface_get_device_scale (surface, &matrix->xx, &matrix->yy);
  cairo_surface_get_device_offset (surface, &matrix->x0, &matrix->y0);
  matrix->yx = matrix->xy = 0;
}

