/*
 * Copyright (C) 2019 Red Hat Inc.
 *
 * 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, see <http://www.gnu.org/licenses/>.
 */

#include "config.h"

#include "clutter/clutter-paint-context-private.h"

#include "clutter/clutter-color-state.h"
#include "clutter/clutter-frame.h"
#include "clutter/clutter-stage-view-private.h"

struct _ClutterPaintContext
{
  grefcount ref_count;

  ClutterPaintFlag paint_flags;

  GList *framebuffers;

  ClutterStageView *view;
  ClutterFrame *frame;

  MtkRegion *redraw_clip;
  GArray *clip_frusta;

  GList *target_color_states;
  GList *color_states;

  ClutterColorState *framebuffer_color_state;
};

G_DEFINE_BOXED_TYPE (ClutterPaintContext, clutter_paint_context,
                     clutter_paint_context_ref,
                     clutter_paint_context_unref)

ClutterPaintContext *
clutter_paint_context_new_for_view (ClutterStageView *view,
                                    const MtkRegion  *redraw_clip,
                                    GArray           *clip_frusta,
                                    ClutterPaintFlag  paint_flags)
{
  ClutterPaintContext *paint_context;
  ClutterColorState *target_color_state;
  CoglFramebuffer *framebuffer;

  paint_context = g_new0 (ClutterPaintContext, 1);
  g_ref_count_init (&paint_context->ref_count);
  paint_context->view = view;
  paint_context->redraw_clip = mtk_region_copy (redraw_clip);
  paint_context->clip_frusta = g_array_ref (clip_frusta);
  paint_context->paint_flags = paint_flags;
  g_set_object (&paint_context->framebuffer_color_state,
                clutter_stage_view_get_color_state (view));

  target_color_state = paint_context->framebuffer_color_state;
  clutter_paint_context_push_target_color_state (paint_context,
                                                 target_color_state);

  framebuffer = clutter_stage_view_get_framebuffer (view);
  clutter_paint_context_push_framebuffer (paint_context, framebuffer);

  return paint_context;
}

/**
 * clutter_paint_context_new_for_framebuffer: (skip)
 */
ClutterPaintContext *
clutter_paint_context_new_for_framebuffer (CoglFramebuffer   *framebuffer,
                                           const MtkRegion   *redraw_clip,
                                           ClutterPaintFlag   paint_flags,
                                           ClutterColorState *color_state)
{
  ClutterPaintContext *paint_context;
  ClutterColorState *target_color_state;

  paint_context = g_new0 (ClutterPaintContext, 1);
  g_ref_count_init (&paint_context->ref_count);
  paint_context->paint_flags = paint_flags;
  g_set_object (&paint_context->framebuffer_color_state, color_state);

  target_color_state = paint_context->framebuffer_color_state;
  clutter_paint_context_push_target_color_state (paint_context,
                                                 target_color_state);

  if (redraw_clip)
    paint_context->redraw_clip = mtk_region_copy (redraw_clip);

  clutter_paint_context_push_framebuffer (paint_context, framebuffer);

  return paint_context;
}

ClutterPaintContext *
clutter_paint_context_ref (ClutterPaintContext *paint_context)
{
  g_ref_count_inc (&paint_context->ref_count);
  return paint_context;
}

static void
clutter_paint_context_dispose (ClutterPaintContext *paint_context)
{
  if (paint_context->framebuffer_color_state)
    {
      clutter_paint_context_pop_target_color_state (paint_context);
      g_clear_object (&paint_context->framebuffer_color_state);
    }

  g_warn_if_fail (!paint_context->color_states);
  g_warn_if_fail (!paint_context->target_color_states);
  g_list_free_full (paint_context->framebuffers, g_object_unref);
  paint_context->framebuffers = NULL;
  g_clear_pointer (&paint_context->redraw_clip, mtk_region_unref);
  g_clear_pointer (&paint_context->clip_frusta, g_array_unref);
  g_clear_pointer (&paint_context->frame, clutter_frame_unref);
}

void
clutter_paint_context_unref (ClutterPaintContext *paint_context)
{
  if (g_ref_count_dec (&paint_context->ref_count))
    {
      clutter_paint_context_dispose (paint_context);
      g_free (paint_context);
    }
}

void
clutter_paint_context_destroy (ClutterPaintContext *paint_context)
{
  clutter_paint_context_dispose (paint_context);
  clutter_paint_context_unref (paint_context);
}

void
clutter_paint_context_push_framebuffer (ClutterPaintContext *paint_context,
                                        CoglFramebuffer     *framebuffer)
{
  paint_context->framebuffers = g_list_prepend (paint_context->framebuffers,
                                                g_object_ref (framebuffer));
}

void
clutter_paint_context_pop_framebuffer (ClutterPaintContext *paint_context)
{
  g_return_if_fail (paint_context->framebuffers);

  g_object_unref (paint_context->framebuffers->data);
  paint_context->framebuffers =
    g_list_delete_link (paint_context->framebuffers,
                        paint_context->framebuffers);
}

const MtkRegion *
clutter_paint_context_get_redraw_clip (ClutterPaintContext *paint_context)
{
  return paint_context->redraw_clip;
}

const GArray *
clutter_paint_context_get_clip_frusta (ClutterPaintContext *paint_context)
{
  return paint_context->clip_frusta;
}

/**
 * clutter_paint_context_get_framebuffer:
 * @paint_context: The #ClutterPaintContext
 *
 * Returns: (transfer none): The #CoglFramebuffer used for drawing
 */
CoglFramebuffer *
clutter_paint_context_get_framebuffer (ClutterPaintContext *paint_context)
{
  g_return_val_if_fail (paint_context->framebuffers, NULL);

  return paint_context->framebuffers->data;
}

CoglFramebuffer *
clutter_paint_context_get_base_framebuffer (ClutterPaintContext *paint_context)
{
  return g_list_last (paint_context->framebuffers)->data;
}

/**
 * clutter_paint_context_get_stage_view: (skip)
 */
ClutterStageView *
clutter_paint_context_get_stage_view (ClutterPaintContext *paint_context)
{
  return paint_context->view;
}

/**
 * clutter_paint_context_is_drawing_off_stage: (skip)
 *
 * Return %TRUE if the paint context is currently drawing off stage.
 * This happens if there are any framebuffers pushed, and the base framebuffer
 * comes from the stage view.
 */
gboolean
clutter_paint_context_is_drawing_off_stage (ClutterPaintContext *paint_context)
{
  if (g_list_length (paint_context->framebuffers) > 1)
    return TRUE;

  return !paint_context->view;
}

/**
 * clutter_paint_context_get_paint_flags: (skip)
 */
ClutterPaintFlag
clutter_paint_context_get_paint_flags (ClutterPaintContext *paint_context)
{
  return paint_context->paint_flags;
}

void
clutter_paint_context_assign_frame (ClutterPaintContext *paint_context,
                                    ClutterFrame        *frame)
{
  g_assert (paint_context != NULL);
  g_assert (paint_context->frame == NULL);
  g_assert (frame != NULL);

  paint_context->frame = clutter_frame_ref (frame);
}

/**
 * clutter_paint_context_get_frame: (skip)
 * @paint_context: The #ClutterPaintContext
 *
 * Retrieves the #ClutterFrame assigned to @paint_context, if any. A frame is
 * only assigned when the paint context is created as part of a frame scheduled
 * by the frame clock, and won't be assigned e.g. on offscreen paints.
 *
 * Returns: (transfer none)(nullable): The #ClutterFrame associated with the
 *   @paint_context, or %NULL
 */
ClutterFrame *
clutter_paint_context_get_frame (ClutterPaintContext *paint_context)
{
  return paint_context->frame;
}

void
clutter_paint_context_push_target_color_state (ClutterPaintContext *paint_context,
                                               ClutterColorState   *color_state)
{
  paint_context->target_color_states =
    g_list_prepend (paint_context->target_color_states, color_state);
}

void
clutter_paint_context_pop_target_color_state (ClutterPaintContext *paint_context)
{
  g_return_if_fail (paint_context->target_color_states);

  paint_context->target_color_states =
    g_list_delete_link (paint_context->target_color_states,
                        paint_context->target_color_states);
}

void
clutter_paint_context_push_color_state (ClutterPaintContext *paint_context,
                                        ClutterColorState   *color_state)
{
  paint_context->color_states = g_list_prepend (paint_context->color_states,
                                                color_state);
}

void
clutter_paint_context_pop_color_state (ClutterPaintContext *paint_context)
{
  g_return_if_fail (paint_context->color_states);

  paint_context->color_states =
    g_list_delete_link (paint_context->color_states,
                        paint_context->color_states);
}

/**
 * clutter_paint_context_get_target_color_state: (skip)
 */
ClutterColorState *
clutter_paint_context_get_target_color_state (ClutterPaintContext *paint_context)
{
  return CLUTTER_COLOR_STATE (paint_context->target_color_states->data);
}

/**
  * clutter_paint_context_get_color_state: (skip)
  */
ClutterColorState *
clutter_paint_context_get_color_state (ClutterPaintContext *paint_context)
{
  g_return_val_if_fail (paint_context->color_states, NULL);

  return CLUTTER_COLOR_STATE (paint_context->color_states->data);
}