#include <cogl/cogl.h>
#include <cogl/cogl-gles2.h>
#include <string.h>

#include "test-utils.h"

typedef struct _TestState
{
  CoglTexture *offscreen_texture;
  CoglOffscreen *offscreen;
  CoglGLES2Context *gles2_ctx;
  const CoglGLES2Vtable *gles2;
} TestState;

static void
test_push_pop_single_context (void)
{
  CoglTexture *offscreen_texture;
  CoglOffscreen *offscreen;
  CoglPipeline *pipeline;
  CoglGLES2Context *gles2_ctx;
  const CoglGLES2Vtable *gles2;
  GError *error = NULL;

  offscreen_texture = COGL_TEXTURE (
    cogl_texture_2d_new_with_size (ctx,
                                   cogl_framebuffer_get_width (fb),
                                   cogl_framebuffer_get_height (fb),
                                   COGL_PIXEL_FORMAT_ANY,
                                   NULL));
  offscreen = cogl_offscreen_new_to_texture (offscreen_texture);

  pipeline = cogl_pipeline_new (ctx);
  cogl_pipeline_set_layer_texture (pipeline, 0, offscreen_texture);

  gles2_ctx = cogl_gles2_context_new (ctx, &error);
  if (!gles2_ctx)
    g_error ("Failed to create GLES2 context: %s\n", error->message);

  gles2 = cogl_gles2_context_get_vtable (gles2_ctx);

  /* Clear onscreen to 0xffff00 using GLES2 */

  if (!cogl_push_gles2_context (ctx,
                                gles2_ctx,
                                fb,
                                fb,
                                &error))
    {
      g_error ("Failed to push gles2 context: %s\n", error->message);
    }

  gles2->glClearColor (1, 1, 0, 1);
  gles2->glClear (GL_COLOR_BUFFER_BIT);

  cogl_pop_gles2_context (ctx);

  test_utils_check_pixel (fb, 0, 0, 0xffff00ff);

  /* Clear offscreen to 0xff0000 using GLES2 and then copy the result
   * onscreen.
   *
   * If we fail to bind the new context here then we'd probably end up
   * clearing onscreen to 0xff0000 and copying 0xffff00 to onscreen
   * instead.
   */

  if (!cogl_push_gles2_context (ctx,
                                gles2_ctx,
                                COGL_FRAMEBUFFER (offscreen),
                                COGL_FRAMEBUFFER (offscreen),
                                &error))
    {
      g_error ("Failed to push gles2 context: %s\n", error->message);
    }

  gles2->glClearColor (1, 0, 0, 1);
  gles2->glClear (GL_COLOR_BUFFER_BIT);

  cogl_pop_gles2_context (ctx);

  cogl_framebuffer_draw_rectangle (fb,
                                   pipeline,
                                   -1, 1, 1, -1);
  /* NB: Cogl doesn't automatically support mid-scene modifications
   * of textures and so we explicitly flush the drawn rectangle to the
   * framebuffer now otherwise it may be batched until after the
   * offscreen texture has been modified again. */
  cogl_flush ();

  /* Clear the offscreen framebuffer to blue using GLES2 before
   * reading back from the onscreen framebuffer in case we mistakenly
   * read from the offscreen framebuffer and get a false positive
   */
  if (!cogl_push_gles2_context (ctx,
                                gles2_ctx,
                                COGL_FRAMEBUFFER (offscreen),
                                COGL_FRAMEBUFFER (offscreen),
                                &error))
    {
      g_error ("Failed to push gles2 context: %s\n", error->message);
    }

  gles2->glClearColor (0, 0, 1, 1);
  gles2->glClear (GL_COLOR_BUFFER_BIT);

  cogl_pop_gles2_context (ctx);

  test_utils_check_pixel (fb, 0, 0, 0xff0000ff);

  /* Now copy the offscreen blue clear to the onscreen framebufer and
   * check that too */
  cogl_framebuffer_draw_rectangle (fb,
                                   pipeline,
                                   -1, 1, 1, -1);

  test_utils_check_pixel (fb, 0, 0, 0x0000ffff);

  if (!cogl_push_gles2_context (ctx,
                                gles2_ctx,
                                fb,
                                fb,
                                &error))
    {
      g_error ("Failed to push gles2 context: %s\n", error->message);
    }

  gles2->glClearColor (1, 0, 1, 1);
  gles2->glClear (GL_COLOR_BUFFER_BIT);

  cogl_pop_gles2_context (ctx);

  test_utils_check_pixel (fb, 0, 0, 0xff00ffff);


  cogl_object_unref (gles2_ctx);

  cogl_object_unref (pipeline);
}

static void
create_gles2_context (CoglTexture **offscreen_texture,
                      CoglOffscreen **offscreen,
                      CoglPipeline **pipeline,
                      CoglGLES2Context **gles2_ctx,
                      const CoglGLES2Vtable **gles2)
{
  GError *error = NULL;

  *offscreen_texture = COGL_TEXTURE (
    cogl_texture_2d_new_with_size (ctx,
                                   cogl_framebuffer_get_width (fb),
                                   cogl_framebuffer_get_height (fb),
                                   COGL_PIXEL_FORMAT_ANY,
                                   NULL));
  *offscreen = cogl_offscreen_new_to_texture (*offscreen_texture);

  *pipeline = cogl_pipeline_new (ctx);
  cogl_pipeline_set_layer_texture (*pipeline, 0, *offscreen_texture);

  *gles2_ctx = cogl_gles2_context_new (ctx, NULL);
  if (!*gles2_ctx)
    g_error ("Failed to create GLES2 context: %s\n", error->message);

  *gles2 = cogl_gles2_context_get_vtable (*gles2_ctx);
}

static void
test_push_pop_multi_context (void)
{
  CoglTexture *offscreen_texture0;
  CoglOffscreen *offscreen0;
  CoglPipeline *pipeline0;
  CoglGLES2Context *gles2_ctx0;
  const CoglGLES2Vtable *gles20;
  CoglTexture *offscreen_texture1;
  CoglOffscreen *offscreen1;
  CoglPipeline *pipeline1;
  CoglGLES2Context *gles2_ctx1;
  const CoglGLES2Vtable *gles21;
  GError *error = NULL;

  create_gles2_context (&offscreen_texture0,
                        &offscreen0,
                        &pipeline0,
                        &gles2_ctx0,
                        &gles20);

  create_gles2_context (&offscreen_texture1,
                        &offscreen1,
                        &pipeline1,
                        &gles2_ctx1,
                        &gles21);

  cogl_framebuffer_clear4f (fb, COGL_BUFFER_BIT_COLOR, 1, 1, 1, 1);

  if (!cogl_push_gles2_context (ctx,
                                gles2_ctx0,
                                COGL_FRAMEBUFFER (offscreen0),
                                COGL_FRAMEBUFFER (offscreen0),
                                &error))
    {
      g_error ("Failed to push gles2 context 0: %s\n", error->message);
    }

  gles20->glClearColor (1, 0, 0, 1);
  gles20->glClear (GL_COLOR_BUFFER_BIT);

  if (!cogl_push_gles2_context (ctx,
                                gles2_ctx1,
                                COGL_FRAMEBUFFER (offscreen1),
                                COGL_FRAMEBUFFER (offscreen1),
                                &error))
    {
      g_error ("Failed to push gles2 context 1: %s\n", error->message);
    }

  gles21->glClearColor (0, 1, 0, 1);
  gles21->glClear (GL_COLOR_BUFFER_BIT);

  cogl_pop_gles2_context (ctx);
  cogl_pop_gles2_context (ctx);

  test_utils_check_pixel (fb, 0, 0, 0xffffffff);

  cogl_framebuffer_draw_rectangle (fb,
                                   pipeline0,
                                   -1, 1, 1, -1);

  test_utils_check_pixel (fb, 0, 0, 0xff0000ff);

  cogl_framebuffer_draw_rectangle (fb,
                                   pipeline1,
                                   -1, 1, 1, -1);

  test_utils_check_pixel (fb, 0, 0, 0x00ff00ff);
}

static GLuint
create_gles2_framebuffer (const CoglGLES2Vtable *gles2,
                          int width,
                          int height)
{
  GLuint texture_handle;
  GLuint fbo_handle;
  GLenum status;

  gles2->glGenTextures (1, &texture_handle);
  gles2->glGenFramebuffers (1, &fbo_handle);

  gles2->glBindTexture (GL_TEXTURE_2D, texture_handle);
  gles2->glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
  gles2->glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
  gles2->glTexImage2D (GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA,
                       GL_UNSIGNED_BYTE, NULL);
  gles2->glBindTexture (GL_TEXTURE_2D, 0);

  gles2->glBindFramebuffer (GL_FRAMEBUFFER, fbo_handle);
  gles2->glFramebufferTexture2D (GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
                                 GL_TEXTURE_2D, texture_handle, 0);

  status = gles2->glCheckFramebufferStatus (GL_FRAMEBUFFER);
  if (cogl_test_verbose ())
    g_print ("status for gles2 framebuffer = 0x%x %s\n",
             status, status == GL_FRAMEBUFFER_COMPLETE ? "(complete)" : "(?)");

  gles2->glBindFramebuffer (GL_FRAMEBUFFER, 0);

  return fbo_handle;
}

static void
test_gles2_read_pixels (void)
{
  CoglTexture *offscreen_texture;
  CoglOffscreen *offscreen;
  CoglPipeline *pipeline;
  CoglGLES2Context *gles2_ctx;
  const CoglGLES2Vtable *gles2;
  GError *error = NULL;
  GLubyte pixel[3];
  GLuint fbo_handle;

  create_gles2_context (&offscreen_texture,
                        &offscreen,
                        &pipeline,
                        &gles2_ctx,
                        &gles2);

  cogl_framebuffer_clear4f (fb, COGL_BUFFER_BIT_COLOR, 1, 1, 1, 1);

  if (!cogl_push_gles2_context (ctx,
                                gles2_ctx,
                                COGL_FRAMEBUFFER (offscreen),
                                COGL_FRAMEBUFFER (offscreen),
                                &error))
    {
      g_error ("Failed to push gles2 context: %s\n", error->message);
    }

  gles2->glClearColor (1, 0, 0, 1);
  gles2->glClear (GL_COLOR_BUFFER_BIT);
  gles2->glReadPixels (0, 0, 1, 1, GL_RGB, GL_UNSIGNED_BYTE, &pixel);

  g_assert (pixel[0] == 0xff);
  g_assert (pixel[1] == 0);
  g_assert (pixel[2] == 0);

  fbo_handle = create_gles2_framebuffer (gles2, 256, 256);

  gles2->glBindFramebuffer (GL_FRAMEBUFFER, fbo_handle);

  gles2->glClearColor (0, 1, 0, 1);
  gles2->glClear (GL_COLOR_BUFFER_BIT);
  gles2->glReadPixels (0, 0, 1, 1, GL_RGB, GL_UNSIGNED_BYTE, &pixel);

  g_assert (pixel[0] == 0);
  g_assert (pixel[1] == 0xff);
  g_assert (pixel[2] == 0);

  gles2->glBindFramebuffer (GL_FRAMEBUFFER, 0);

  gles2->glClearColor (0, 1, 1, 1);
  gles2->glClear (GL_COLOR_BUFFER_BIT);
  gles2->glReadPixels (0, 0, 1, 1, GL_RGB, GL_UNSIGNED_BYTE, &pixel);

  g_assert (pixel[0] == 0);
  g_assert (pixel[1] == 0xff);
  g_assert (pixel[2] == 0xff);

  cogl_pop_gles2_context (ctx);

  test_utils_check_pixel (fb, 0, 0, 0xffffffff);

  /* Bind different read and write buffers */
  if (!cogl_push_gles2_context (ctx,
                                gles2_ctx,
                                COGL_FRAMEBUFFER (offscreen),
                                fb,
                                &error))
    {
      g_error ("Failed to push gles2 context: %s\n", error->message);
    }

  gles2->glReadPixels (0, 0, 1, 1, GL_RGB, GL_UNSIGNED_BYTE, &pixel);

  g_assert (pixel[0] == 0);
  g_assert (pixel[1] == 0xff);
  g_assert (pixel[2] == 0xff);

  cogl_pop_gles2_context (ctx);

  test_utils_check_pixel (fb, 0, 0, 0xffffffff);

  /* Bind different read and write buffers (the other way around from
   * before so when we test with COGL_TEST_ONSCREEN=1 we will read
   * from an onscreen framebuffer) */
  if (!cogl_push_gles2_context (ctx,
                                gles2_ctx,
                                fb,
                                COGL_FRAMEBUFFER (offscreen),
                                &error))
    {
      g_error ("Failed to push gles2 context: %s\n", error->message);
    }

  gles2->glReadPixels (0, 0, 1, 1, GL_RGB, GL_UNSIGNED_BYTE, &pixel);

  g_assert (pixel[0] == 0xff);
  g_assert (pixel[1] == 0xff);
  g_assert (pixel[2] == 0xff);

  cogl_pop_gles2_context (ctx);
}

void
test_gles2_context (void)
{
  test_push_pop_single_context ();
  test_push_pop_multi_context ();
  test_gles2_read_pixels ();

  if (cogl_test_verbose ())
    g_print ("OK\n");
}