/*
 * Copyright (C) 2023 Mikhail Burakov. This file is part of streamer.
 *
 * streamer is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * streamer 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with streamer.  If not, see <https://www.gnu.org/licenses/>.
 */

#include "gpu.h"

#include <EGL/egl.h>
#include <EGL/eglext.h>
#include <GLES2/gl2.h>
#include <GLES2/gl2ext.h>
#include <GLES3/gl32.h>
#include <drm_fourcc.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#ifndef USE_EGL_MESA_PLATFORM_SURFACELESS
#include <fcntl.h>
#include <gbm.h>
#endif  // USE_EGL_MESA_PLATFORM_SURFACELESS

#include "toolbox/utils.h"

#define _(...) __VA_ARGS__
#define LOOKUP_FUNCTION(a, b, c)              \
  gpu_context->b = (a)eglGetProcAddress(#b);  \
  if (!gpu_context->b) {                      \
    LOG("Failed to look up " #b " function"); \
    goto c;                                   \
  }

// TODO(mburakov): It should be theoretically possible to do everything in a
// single pass using a compute shader and GLES3. Unfortunately my test machine
// reports the primary framebuffer as multiplane. This is probably the reason
// why texture created from it can not be sampled using imageLoad in a compute
// shader even though it's still RGB. Fallback to GLES2 and per-plane textures
// for now, and figure out details later.

extern const char _binary_vertex_glsl_start[];
extern const char _binary_vertex_glsl_end[];
extern const char _binary_luma_glsl_start[];
extern const char _binary_luma_glsl_end[];
extern const char _binary_chroma_glsl_start[];
extern const char _binary_chroma_glsl_end[];

struct GpuContext {
#ifndef USE_EGL_MESA_PLATFORM_SURFACELESS
  int render_node;
  struct gbm_device* device;
#endif  // USE_EGL_MESA_PLATFORM_SURFACELESS
  EGLDisplay display;
  EGLContext context;
  PFNEGLQUERYDMABUFFORMATSEXTPROC eglQueryDmaBufFormatsEXT;
  PFNEGLQUERYDMABUFMODIFIERSEXTPROC eglQueryDmaBufModifiersEXT;
  PFNGLEGLIMAGETARGETTEXTURE2DOESPROC glEGLImageTargetTexture2DOES;
  GLuint program_luma;
  GLuint program_chroma;
  GLint sample_offsets;
  GLuint framebuffer;
  GLuint vertices;
};

struct GpuFrameImpl {
  struct GpuFrame size;
  int dmabuf_fds[4];
  EGLImage images[2];
  GLuint textures[2];
};

static const char* EglErrorString(EGLint error) {
  static const char* const egl_error_strings[] = {
      "EGL_SUCCESS",       "EGL_NOT_INITIALIZED",     "EGL_BAD_ACCESS",
      "EGL_BAD_ALLOC",     "EGL_BAD_ATTRIBUTE",       "EGL_BAD_CONFIG",
      "EGL_BAD_CONTEXT",   "EGL_BAD_CURRENT_SURFACE", "EGL_BAD_DISPLAY",
      "EGL_BAD_MATCH",     "EGL_BAD_NATIVE_PIXMAP",   "EGL_BAD_NATIVE_WINDOW",
      "EGL_BAD_PARAMETER", "EGL_BAD_SURFACE",         "EGL_CONTEXT_LOST",
  };
  return EGL_SUCCESS <= error && error <= EGL_CONTEXT_LOST
             ? egl_error_strings[error - EGL_SUCCESS]
             : "???";
}

static const char* GlErrorString(GLenum error) {
  static const char* const gl_error_strings[] = {
      "GL_INVALID_ENUM",
      "GL_INVALID_VALUE",
      "GL_INVALID_OPERATION",
      "GL_STACK_OVERFLOW",
      "GL_STACK_UNDERFLOW",
      "GL_OUT_OF_MEMORY",
      "GL_INVALID_FRAMEBUFFER_OPERATION",
      "GL_CONTEXT_LOST",
  };
  if (error == GL_NO_ERROR) return "GL_NO_ERROR";
  return GL_INVALID_ENUM <= error && error <= GL_CONTEXT_LOST
             ? gl_error_strings[error - GL_INVALID_ENUM]
             : "???";
}

#define DEFINE_CHECK_BUILDABLE_FUNCTION(postfix, err_msg, getter_fn, \
                                        status_enum, logger_fn)      \
  static bool CheckBuildable##postfix(GLuint buildable) {            \
    GLenum error = glGetError();                                     \
    if (error != GL_NO_ERROR) {                                      \
      LOG(err_msg " (%s)", GlErrorString(error));                    \
      return false;                                                  \
    }                                                                \
    GLint status;                                                    \
    getter_fn(buildable, status_enum, &status);                      \
    if (status != GL_TRUE) {                                         \
      GLint log_length;                                              \
      getter_fn(buildable, GL_INFO_LOG_LENGTH, &log_length);         \
      char message[log_length];                                      \
      memset(message, 0, sizeof(message));                           \
      logger_fn(buildable, log_length, NULL, message);               \
      LOG("%s", message);                                            \
      return false;                                                  \
    }                                                                \
    return true;                                                     \
  }

DEFINE_CHECK_BUILDABLE_FUNCTION(Shader, "Failed to compile shader",
                                glGetShaderiv, GL_COMPILE_STATUS,
                                glGetShaderInfoLog)
DEFINE_CHECK_BUILDABLE_FUNCTION(Program, "Failed to link program",
                                glGetProgramiv, GL_LINK_STATUS,
                                glGetProgramInfoLog)

static bool HasExtension(const char* haystack, const char* needle) {
  bool result = !!strstr(haystack, needle);
  if (!result) LOG("Unsupported extension %s", needle);
  return result;
}

static GLuint CreateGlProgram(const char* vs_begin, const char* vs_end,
                              const char* fs_begin, const char* fs_end) {
  GLuint program = 0;
  GLuint vertex = glCreateShader(GL_VERTEX_SHADER);
  if (!vertex) {
    LOG("Failed to create vertex shader (%s)", GlErrorString(glGetError()));
    goto bail_out;
  }
  GLsizei size = (GLsizei)(vs_end - vs_begin);
  glShaderSource(vertex, 1, &vs_begin, &size);
  glCompileShader(vertex);
  if (!CheckBuildableShader(vertex)) goto delete_vs;

  GLuint fragment = glCreateShader(GL_FRAGMENT_SHADER);
  if (!fragment) {
    LOG("Failed to create fragment shader (%s)", GlErrorString(glGetError()));
    goto delete_vs;
  }
  size = (GLsizei)(fs_end - fs_begin);
  glShaderSource(fragment, 1, &fs_begin, &size);
  glCompileShader(fragment);
  if (!CheckBuildableShader(fragment)) goto delete_fs;

  program = glCreateProgram();
  if (!program) {
    LOG("Failed to create shader program (%s)", GlErrorString(glGetError()));
    goto delete_fs;
  }
  glAttachShader(program, vertex);
  glAttachShader(program, fragment);
  glLinkProgram(program);
  if (!CheckBuildableProgram(program)) {
    glDeleteProgram(program);
    program = 0;
    goto delete_fs;
  }

delete_fs:
  glDeleteShader(fragment);
delete_vs:
  glDeleteShader(vertex);
bail_out:
  return program;
}

static const GLfloat* GetColorspaceMatrix(enum YuvColorspace colorspace) {
  static const GLfloat rec601[] = {
      _(0.299f, 0.587f, 0.114f),
      _(-0.168736f, -0.331264f, 0.5f),
      _(0.5f, -0.418688f, -0.081312f),
  };
  static const GLfloat rec709[] = {
      _(0.2126f, 0.7152f, 0.0722f),
      _(-0.1146f, -0.3854f, 0.5f),
      _(0.5f, -0.4542f, -0.0458f),
  };
  switch (colorspace) {
    case kItuRec601:
      return rec601;
    case kItuRec709:
      return rec709;
    default:
      __builtin_unreachable();
  }
}

static const GLfloat* GetRangeVectors(enum YuvRange range) {
  static const GLfloat narrow[] = {
      _(16.f / 255.f, 16.f / 255.f, 16.f / 255.f),
      _((235.f - 16.f) / 255.f, (240.f - 16.f) / 255.f, (240.f - 16.f) / 255.f),
  };
  static const GLfloat full[] = {
      _(0.f, 0.f, 0.f),
      _(1.f, 1.f, 1.f),
  };
  switch (range) {
    case kNarrowRange:
      return narrow;
    case kFullRange:
      return full;
    default:
      __builtin_unreachable();
  }
}

static bool SetupCommonUniforms(GLuint program, enum YuvColorspace colorspace,
                                enum YuvRange range) {
  struct {
    const char* name;
    GLint location;
  } uniforms[] = {
      {.name = "img_input"},
      {.name = "colorspace"},
      {.name = "ranges"},
  };

  for (size_t i = 0; i < LENGTH(uniforms); i++) {
    uniforms[i].location = glGetUniformLocation(program, uniforms[i].name);
    if (uniforms[i].location == -1) {
      LOG("Failed to locate %s uniform (%s)", uniforms[i].name,
          GlErrorString(glGetError()));
      return false;
    }
  }

  glUseProgram(program);
  glUniform1i(uniforms[0].location, 0);
  glUniformMatrix3fv(uniforms[1].location, 1, GL_TRUE,
                     GetColorspaceMatrix(colorspace));
  glUniform3fv(uniforms[2].location, 2, GetRangeVectors(range));
  GLenum error = glGetError();
  if (error != GL_NO_ERROR) {
    LOG("Failed to set img_input uniform (%s)", GlErrorString(glGetError()));
    return false;
  }
  return true;
}

struct GpuContext* GpuContextCreate(enum YuvColorspace colorspace,
                                    enum YuvRange range) {
  struct GpuContext* gpu_context = malloc(sizeof(struct GpuContext));
  if (!gpu_context) {
    LOG("Failed to allocate gpu context (%s)", strerror(errno));
    return NULL;
  }
  *gpu_context = (struct GpuContext){
#ifndef USE_EGL_MESA_PLATFORM_SURFACELESS
      .render_node = -1,
#endif  // USE_EGL_MESA_PLATFORM_SURFACELESS
      .display = EGL_NO_DISPLAY,
      .context = EGL_NO_CONTEXT,
      .sample_offsets = -1,
  };

  const char* egl_ext = eglQueryString(EGL_NO_DISPLAY, EGL_EXTENSIONS);
  if (!egl_ext) {
    LOG("Failed to query platformless egl extensions (%s)",
        EglErrorString(eglGetError()));
    goto rollback_gpu_context;
  }

  LOG("EGL_EXTENSIONS: %s", egl_ext);
  // TODO(mburakov): Quite surprisingly EGL_MESA_platform_surfaceless does not
  // provide support for AMD_FMT_MOD_TILE_VER_GFX11 dmabuf modifier on my AMD
  // system. For comparison, on my Intel system all the modifiers ever found on
  // framebuffers are reported as supported by EGL. Maybe that's because the
  // support for RDNA3 is still quite young in MESA.
#ifndef USE_EGL_MESA_PLATFORM_SURFACELESS
  if (!HasExtension(egl_ext, "EGL_MESA_platform_gbm"))
    goto rollback_gpu_context;
  gpu_context->render_node = open("/dev/dri/renderD128", O_RDWR);
  if (gpu_context->render_node == -1) {
    LOG("Failed to open render node (%s)", strerror(errno));
    goto rollback_gpu_context;
  }
  gpu_context->device = gbm_create_device(gpu_context->render_node);
  if (!gpu_context->device) {
    LOG("Failed to create gbm device (%s)", strerror(errno));
    goto rollback_render_node;
  }
  gpu_context->display =
      eglGetPlatformDisplay(EGL_PLATFORM_GBM_MESA, gpu_context->device, NULL);
#else   // USE_EGL_MESA_PLATFORM_SURFACELESS
  if (!HasExtension(egl_ext, "EGL_MESA_platform_surfaceless"))
    goto rollback_gpu_context;
  gpu_context->display =
      eglGetPlatformDisplay(EGL_PLATFORM_SURFACELESS_MESA, NULL, NULL);
#endif  // USE_EGL_MESA_PLATFORM_SURFACELESS
  if (gpu_context->display == EGL_NO_DISPLAY) {
    LOG("Failed to get egl display (%s)", EglErrorString(eglGetError()));
#ifndef USE_EGL_MESA_PLATFORM_SURFACELESS
    goto rollback_device;
#else   // USE_EGL_MESA_PLATFORM_SURFACELESS
    goto rollback_gpu_context;
#endif  // USE_EGL_MESA_PLATFORM_SURFACELESS
  }

  EGLint major, minor;
  if (!eglInitialize(gpu_context->display, &major, &minor)) {
    LOG("Failed to initialize egl display (%s)", EglErrorString(eglGetError()));
    goto rollback_display;
  }

  LOG("Initialized EGL %d.%d", major, minor);
  egl_ext = eglQueryString(gpu_context->display, EGL_EXTENSIONS);
  if (!egl_ext) {
    LOG("Failed to query egl extensions (%s)", EglErrorString(eglGetError()));
    goto rollback_display;
  }

  LOG("EGL_EXTENSIONS: %s", egl_ext);
  if (!HasExtension(egl_ext, "EGL_KHR_surfaceless_context") ||
      !HasExtension(egl_ext, "EGL_KHR_no_config_context") ||
      !HasExtension(egl_ext, "EGL_EXT_image_dma_buf_import") ||
      !HasExtension(egl_ext, "EGL_EXT_image_dma_buf_import_modifiers"))
    goto rollback_display;
  LOOKUP_FUNCTION(PFNEGLQUERYDMABUFFORMATSEXTPROC, eglQueryDmaBufFormatsEXT,
                  rollback_display)
  LOOKUP_FUNCTION(PFNEGLQUERYDMABUFMODIFIERSEXTPROC, eglQueryDmaBufModifiersEXT,
                  rollback_display)

  if (!eglBindAPI(EGL_OPENGL_ES_API)) {
    LOG("Failed to bind egl api (%s)", EglErrorString(eglGetError()));
    goto rollback_display;
  }

  static const EGLint context_attribs[] = {
      _(EGL_CONTEXT_MAJOR_VERSION, 3),
      _(EGL_CONTEXT_MINOR_VERSION, 1),
      EGL_NONE,
  };
  gpu_context->context = eglCreateContext(
      gpu_context->display, EGL_NO_CONFIG_KHR, EGL_NO_CONTEXT, context_attribs);
  if (gpu_context->context == EGL_NO_CONTEXT) {
    LOG("Failed to create egl context (%s)", EglErrorString(eglGetError()));
    goto rollback_display;
  }

  if (!eglMakeCurrent(gpu_context->display, EGL_NO_SURFACE, EGL_NO_SURFACE,
                      gpu_context->context)) {
    LOG("Failed to make egl context current (%s)",
        EglErrorString(eglGetError()));
    goto rollback_context;
  }

  const char* gl_ext = (const char*)glGetString(GL_EXTENSIONS);
  if (!gl_ext) {
    LOG("Failed to get gl extensions (%s)", GlErrorString(glGetError()));
    goto rollback_context;
  }

  LOG("GL_EXTENSIONS: %s", gl_ext);
  if (!HasExtension(gl_ext, "GL_OES_EGL_image")) goto rollback_context;
  LOOKUP_FUNCTION(PFNGLEGLIMAGETARGETTEXTURE2DOESPROC,
                  glEGLImageTargetTexture2DOES, rollback_context)

  gpu_context->program_luma =
      CreateGlProgram(_binary_vertex_glsl_start, _binary_vertex_glsl_end,
                      _binary_luma_glsl_start, _binary_luma_glsl_end);
  if (!gpu_context->program_luma ||
      !SetupCommonUniforms(gpu_context->program_luma, colorspace, range)) {
    LOG("Failed to create luma program");
    goto rollback_context;
  }

  gpu_context->program_chroma =
      CreateGlProgram(_binary_vertex_glsl_start, _binary_vertex_glsl_end,
                      _binary_chroma_glsl_start, _binary_chroma_glsl_end);
  if (!gpu_context->program_chroma ||
      !SetupCommonUniforms(gpu_context->program_chroma, colorspace, range)) {
    LOG("Failed to create chroma program");
    goto rollback_program_luma;
  }
  gpu_context->sample_offsets =
      glGetUniformLocation(gpu_context->program_chroma, "sample_offsets");
  if (gpu_context->sample_offsets == -1) {
    LOG("Failed to find sample_offsets uniform (%s)",
        GlErrorString(glGetError()));
    goto rollback_program_chroma;
  }

  glGenFramebuffers(1, &gpu_context->framebuffer);
  glBindFramebuffer(GL_FRAMEBUFFER, gpu_context->framebuffer);
  glGenBuffers(1, &gpu_context->vertices);
  glBindBuffer(GL_ARRAY_BUFFER, gpu_context->vertices);
  static const GLfloat vertices[] = {0, 0, 1, 0, 1, 1, 0, 1};
  glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
  glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 0, NULL);
  glEnableVertexAttribArray(0);
  GLenum error = glGetError();
  if (error != GL_NO_ERROR) {
    LOG("Failed to create gl objects (%s)", GlErrorString(glGetError()));
    goto rollback_buffers;
  }
  return gpu_context;

rollback_buffers:
  if (gpu_context->vertices) glDeleteBuffers(1, &gpu_context->vertices);
  if (gpu_context->framebuffer)
    glDeleteFramebuffers(1, &gpu_context->framebuffer);
rollback_program_chroma:
  glDeleteProgram(gpu_context->program_chroma);
rollback_program_luma:
  glDeleteProgram(gpu_context->program_luma);
rollback_context:
  eglMakeCurrent(gpu_context->display, EGL_NO_SURFACE, EGL_NO_SURFACE,
                 EGL_NO_CONTEXT);
  eglDestroyContext(gpu_context->display, gpu_context->context);
rollback_display:
  eglTerminate(gpu_context->display);
#ifndef USE_EGL_MESA_PLATFORM_SURFACELESS
rollback_device:
  gbm_device_destroy(gpu_context->device);
rollback_render_node:
  close(gpu_context->render_node);
#endif  // USE_EGL_MESA_PLATFORM_SURFACELESS
rollback_gpu_context:
  free(gpu_context);
  return NULL;
}

static void DumpEglImageParams(const EGLAttrib* attribs) {
  for (; *attribs != EGL_NONE; attribs += 2) {
    switch (attribs[0]) {
      case EGL_HEIGHT:
        LOG("\tEGL_HEIGHT: %ld", attribs[1]);
        break;
      case EGL_WIDTH:
        LOG("\tEGL_WIDTH: %ld", attribs[1]);
        break;
      case EGL_LINUX_DRM_FOURCC_EXT:
        LOG("\tEGL_LINUX_DRM_FOURCC_EXT: %.4s", (const char*)&attribs[1]);
        break;
      case EGL_DMA_BUF_PLANE0_FD_EXT:
      case EGL_DMA_BUF_PLANE1_FD_EXT:
      case EGL_DMA_BUF_PLANE2_FD_EXT:
        LOG("\tEGL_DMA_BUF_PLANE%ld_FD_EXT: %ld",
            (attribs[0] - EGL_DMA_BUF_PLANE0_FD_EXT) / 3, attribs[1]);
        break;
      case EGL_DMA_BUF_PLANE0_OFFSET_EXT:
      case EGL_DMA_BUF_PLANE1_OFFSET_EXT:
      case EGL_DMA_BUF_PLANE2_OFFSET_EXT:
        LOG("\tEGL_DMA_BUF_PLANE%ld_OFFSET_EXT: %ld",
            (attribs[0] - EGL_DMA_BUF_PLANE0_OFFSET_EXT) / 3, attribs[1]);
        break;
      case EGL_DMA_BUF_PLANE0_PITCH_EXT:
      case EGL_DMA_BUF_PLANE1_PITCH_EXT:
      case EGL_DMA_BUF_PLANE2_PITCH_EXT:
        LOG("\tEGL_DMA_BUF_PLANE%ld_PITCH_EXT: %ld",
            (attribs[0] - EGL_DMA_BUF_PLANE0_PITCH_EXT) / 3, attribs[1]);
        break;
      case EGL_DMA_BUF_PLANE3_FD_EXT:
        LOG("\tEGL_DMA_BUF_PLANE3_FD_EXT: %ld", attribs[1]);
        break;
      case EGL_DMA_BUF_PLANE3_OFFSET_EXT:
        LOG("\tEGL_DMA_BUF_PLANE3_OFFSET_EXT: %ld", attribs[1]);
        break;
      case EGL_DMA_BUF_PLANE3_PITCH_EXT:
        LOG("\tEGL_DMA_BUF_PLANE3_PITCH_EXT: %ld", attribs[1]);
        break;
      case EGL_DMA_BUF_PLANE0_MODIFIER_LO_EXT:
      case EGL_DMA_BUF_PLANE0_MODIFIER_HI_EXT:
      case EGL_DMA_BUF_PLANE1_MODIFIER_LO_EXT:
      case EGL_DMA_BUF_PLANE1_MODIFIER_HI_EXT:
      case EGL_DMA_BUF_PLANE2_MODIFIER_LO_EXT:
      case EGL_DMA_BUF_PLANE2_MODIFIER_HI_EXT:
      case EGL_DMA_BUF_PLANE3_MODIFIER_LO_EXT:
      case EGL_DMA_BUF_PLANE3_MODIFIER_HI_EXT:
        LOG("\tEGL_DMA_BUF_PLANE%ld_MODIFIER_%s_EXT: 0x%08lx",
            (attribs[0] - EGL_DMA_BUF_PLANE0_MODIFIER_LO_EXT) / 2,
            attribs[0] & 1 ? "LO" : "HI", attribs[1]);
        break;
    }
  }
}

static bool IsFourccSupported(struct GpuContext* gpu_context, uint32_t fourcc) {
  EGLint num_formats;
  if (!gpu_context->eglQueryDmaBufFormatsEXT(gpu_context->display, 0, NULL,
                                             &num_formats)) {
    LOG("Faield to get number of supported dmabuf formats (%s)",
        EglErrorString(eglGetError()));
    return false;
  }
  EGLint formats[num_formats];
  if (!gpu_context->eglQueryDmaBufFormatsEXT(gpu_context->display, num_formats,
                                             formats, &num_formats)) {
    LOG("Failed to get supported dmabuf formats (%s)",
        EglErrorString(eglGetError()));
    return false;
  }
  for (int i = 0; i < num_formats; i++) {
    if ((uint32_t)formats[i] == fourcc) return true;
  }
  LOG("Format %.4s is unsupported by egl", (const char*)&fourcc);
  LOG("Supported formats are:");
  for (int i = 0; i < num_formats; i++) {
    LOG("\t%.4s", (const char*)&formats[i]);
  }
  return false;
}

static bool IsModifierSupported(struct GpuContext* gpu_context, uint32_t fourcc,
                                uint64_t modifier) {
  EGLint num_modifiers;
  if (!gpu_context->eglQueryDmaBufModifiersEXT(
          gpu_context->display, (GLint)fourcc, 0, NULL, NULL, &num_modifiers)) {
    LOG("Failed to get number of supported dmabuf modifiers (%s)",
        EglErrorString(eglGetError()));
    return false;
  }
  EGLuint64KHR modifiers[num_modifiers];
  EGLBoolean external_only[num_modifiers];
  if (!gpu_context->eglQueryDmaBufModifiersEXT(
          gpu_context->display, (GLint)fourcc, num_modifiers, modifiers,
          external_only, &num_modifiers)) {
    LOG("Failed to get supported dmabuf modifiers (%s)",
        EglErrorString(eglGetError()));
    return false;
  }
  for (int i = 0; i < num_modifiers; i++) {
    if (modifiers[i] == modifier && !external_only[i]) return true;
  }
  LOG("Modifier 0x%016lx for format %.4s is unsupported by egl", modifier,
      (const char*)&fourcc);
  LOG("Supported modifiers for format %.4s are:", (const char*)&fourcc);
  for (int i = 0; i < num_modifiers; i++) {
    LOG("\t0x%016lx%s", modifiers[i],
        external_only[i] ? " (external only)" : "");
  }
  return false;
}

static EGLImage CreateEglImage(struct GpuContext* gpu_context, uint32_t width,
                               uint32_t height, uint32_t fourcc, size_t nplanes,
                               const struct GpuFramePlane* planes) {
  static const EGLAttrib attrib_keys[] = {
      EGL_DMA_BUF_PLANE0_FD_EXT,          EGL_DMA_BUF_PLANE0_OFFSET_EXT,
      EGL_DMA_BUF_PLANE0_PITCH_EXT,       EGL_DMA_BUF_PLANE0_MODIFIER_LO_EXT,
      EGL_DMA_BUF_PLANE0_MODIFIER_HI_EXT, EGL_DMA_BUF_PLANE1_FD_EXT,
      EGL_DMA_BUF_PLANE1_OFFSET_EXT,      EGL_DMA_BUF_PLANE1_PITCH_EXT,
      EGL_DMA_BUF_PLANE1_MODIFIER_LO_EXT, EGL_DMA_BUF_PLANE1_MODIFIER_HI_EXT,
      EGL_DMA_BUF_PLANE2_FD_EXT,          EGL_DMA_BUF_PLANE2_OFFSET_EXT,
      EGL_DMA_BUF_PLANE2_PITCH_EXT,       EGL_DMA_BUF_PLANE2_MODIFIER_LO_EXT,
      EGL_DMA_BUF_PLANE2_MODIFIER_HI_EXT, EGL_DMA_BUF_PLANE3_FD_EXT,
      EGL_DMA_BUF_PLANE3_OFFSET_EXT,      EGL_DMA_BUF_PLANE3_PITCH_EXT,
      EGL_DMA_BUF_PLANE3_MODIFIER_LO_EXT, EGL_DMA_BUF_PLANE3_MODIFIER_HI_EXT,
  };

  EGLAttrib attrib_list[7 + LENGTH(attrib_keys) * 2] = {
      _(EGL_HEIGHT, height),
      _(EGL_WIDTH, width),
      _(EGL_LINUX_DRM_FOURCC_EXT, fourcc),
  };

  EGLAttrib* pairs = &attrib_list[6];
  const EGLAttrib* key = &attrib_keys[0];
  for (size_t i = 0; i < nplanes; i++) {
    if (planes[i].dmabuf_fd == -1) break;
    *pairs++ = *key++;
    *pairs++ = planes[i].dmabuf_fd;
    *pairs++ = *key++;
    *pairs++ = planes[i].offset;
    *pairs++ = *key++;
    *pairs++ = planes[i].pitch;
    *pairs++ = *key++;
    *pairs++ = planes[i].modifier & UINT32_MAX;
    *pairs++ = *key++;
    *pairs++ = planes[i].modifier >> 32;
  }

  *pairs = EGL_NONE;
  if (!IsFourccSupported(gpu_context, fourcc)) goto failure;
  for (size_t i = 0; i < nplanes; i++) {
    if (!IsModifierSupported(gpu_context, fourcc, planes[i].modifier))
      goto failure;
  }
  EGLImage image = eglCreateImage(gpu_context->display, EGL_NO_CONFIG_KHR,
                                  EGL_LINUX_DMA_BUF_EXT, NULL, attrib_list);
  if (image == EGL_NO_IMAGE) {
    LOG("Failed to create egl image (%s)", EglErrorString(eglGetError()));
    goto failure;
  }
  return image;

failure:
  LOG("Attributes list for failed egl image:");
  DumpEglImageParams(attrib_list);
  return EGL_NO_IMAGE;
}

static GLuint CreateTexture(struct GpuContext* gpu_context, EGLImage image) {
  GLuint texture = 0;
  glGenTextures(1, &texture);
  glBindTexture(GL_TEXTURE_2D, texture);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
  gpu_context->glEGLImageTargetTexture2DOES(GL_TEXTURE_2D, image);

  GLenum error = glGetError();
  if (error != GL_NO_ERROR) {
    LOG("Failed to create texture (%s)", GlErrorString(error));
    glDeleteTextures(1, &texture);
    return 0;
  }
  return texture;
}

struct GpuFrame* GpuContextCreateFrame(struct GpuContext* gpu_context,
                                       uint32_t width, uint32_t height,
                                       uint32_t fourcc, size_t nplanes,
                                       const struct GpuFramePlane* planes) {
  struct GpuFrameImpl* gpu_frame_impl = malloc(sizeof(struct GpuFrameImpl));
  if (!gpu_frame_impl) {
    LOG("Failed to allocate gpu frame (%s)", strerror(errno));
    return NULL;
  }
  *gpu_frame_impl = (struct GpuFrameImpl){
      .size.width = width,
      .size.height = height,
      .dmabuf_fds = {-1, -1, -1, -1},
      .images = {EGL_NO_IMAGE, EGL_NO_IMAGE},
  };

  if (fourcc == DRM_FORMAT_NV12) {
    gpu_frame_impl->images[0] = CreateEglImage(gpu_context, width, height,
                                               DRM_FORMAT_R8, 1, &planes[0]);
    if (gpu_frame_impl->images[0] == EGL_NO_IMAGE) {
      LOG("Failed to create luma plane image");
      goto rollback_gpu_frame;
    }
    gpu_frame_impl->images[1] = CreateEglImage(
        gpu_context, width / 2, height / 2, DRM_FORMAT_GR88, 1, &planes[1]);
    if (gpu_frame_impl->images[1] == EGL_NO_IMAGE) {
      LOG("Failed to create chroma plane image");
      goto rollback_images;
    }
  } else {
    gpu_frame_impl->images[0] =
        CreateEglImage(gpu_context, width, height, fourcc, nplanes, planes);
    if (gpu_frame_impl->images[0] == EGL_NO_IMAGE) {
      LOG("Failed to create multiplanar image");
      goto rollback_gpu_frame;
    }
  }

  for (size_t i = 0; i < LENGTH(gpu_frame_impl->images); i++) {
    if (gpu_frame_impl->images[i] == EGL_NO_IMAGE) break;
    gpu_frame_impl->textures[i] =
        CreateTexture(gpu_context, gpu_frame_impl->images[i]);
    if (!gpu_frame_impl->textures[i]) {
      LOG("Failed to create texture");
      goto rollback_textures;
    }
  }

  for (size_t i = 0; i < nplanes; i++)
    gpu_frame_impl->dmabuf_fds[i] = planes[i].dmabuf_fd;
  return (struct GpuFrame*)gpu_frame_impl;

rollback_textures:
  for (size_t i = LENGTH(gpu_frame_impl->textures); i; i--) {
    if (gpu_frame_impl->textures[i - 1])
      glDeleteTextures(1, &gpu_frame_impl->textures[i - 1]);
  }
rollback_images:
  for (size_t i = LENGTH(gpu_frame_impl->images); i; i--) {
    if (gpu_frame_impl->images[i - 1] != EGL_NO_IMAGE)
      eglDestroyImage(gpu_context->device, gpu_frame_impl->images[i - 1]);
  }
rollback_gpu_frame:
  free(gpu_frame_impl);
  return NULL;
}

static bool GpuFrameConvertImpl(GLuint from, GLuint to) {
  glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                         to, 0);
  GLenum framebuffer_status = glCheckFramebufferStatus(GL_FRAMEBUFFER);
  if (framebuffer_status != GL_FRAMEBUFFER_COMPLETE) {
    LOG("Framebuffer is incomplete (0x%x)", framebuffer_status);
    return false;
  }

  glBindTexture(GL_TEXTURE_2D, from);
  glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
  GLenum error = glGetError();
  if (error != GL_NO_ERROR) {
    LOG("Failed to convert plane (%s)", GlErrorString(error));
    return false;
  }
  return true;
}

bool GpuContextConvertFrame(struct GpuContext* gpu_context,
                            const struct GpuFrame* from,
                            const struct GpuFrame* to) {
  const struct GpuFrameImpl* from_impl = (const void*)from;
  const struct GpuFrameImpl* to_impl = (const void*)to;

  glUseProgram(gpu_context->program_luma);
  glViewport(0, 0, (GLsizei)to->width, (GLsizei)to->height);
  if (!GpuFrameConvertImpl(from_impl->textures[0], to_impl->textures[0])) {
    LOG("Failed to convert luma plane");
    return false;
  }

  const GLfloat sample_offsets[] = {
      _(0.f, 0.f),
      _(1.f / (GLfloat)from->width, 0.f),
      _(0.f, 1.f / (GLfloat)from->height),
      _(1.f / (GLfloat)from->width, 1.f / (GLfloat)from->height),
  };

  glUseProgram(gpu_context->program_chroma);
  glUniform2fv(gpu_context->sample_offsets, 4, sample_offsets);
  glViewport(0, 0, (GLsizei)to->width / 2, (GLsizei)to->height / 2);
  if (!GpuFrameConvertImpl(from_impl->textures[0], to_impl->textures[1])) {
    LOG("Failed to convert chroma plane");
    return false;
  }

  EGLSync sync = eglCreateSync(gpu_context->display, EGL_SYNC_FENCE, NULL);
  if (sync == EGL_NO_SYNC) {
    LOG("Failed to create egl fence sync (%s)", EglErrorString(eglGetError()));
    return false;
  }
  eglClientWaitSync(gpu_context->display, sync, 0, EGL_FOREVER);
  eglDestroySync(gpu_context->display, sync);
  return true;
}

void GpuContextDestroyFrame(struct GpuContext* gpu_context,
                            struct GpuFrame* gpu_frame) {
  struct GpuFrameImpl* gpu_frame_impl = (void*)gpu_frame;
  for (size_t i = LENGTH(gpu_frame_impl->textures); i; i--) {
    if (gpu_frame_impl->textures[i - 1])
      glDeleteTextures(1, &gpu_frame_impl->textures[i - 1]);
  }
  for (size_t i = LENGTH(gpu_frame_impl->images); i; i--) {
    if (gpu_frame_impl->images[i - 1] != EGL_NO_IMAGE)
      eglDestroyImage(gpu_context->device, gpu_frame_impl->images[i - 1]);
  }
  CloseUniqueFds(gpu_frame_impl->dmabuf_fds);
  free(gpu_frame_impl);
}

void GpuContextDestroy(struct GpuContext* gpu_context) {
  glDeleteBuffers(1, &gpu_context->vertices);
  glDeleteFramebuffers(1, &gpu_context->framebuffer);
  glDeleteProgram(gpu_context->program_chroma);
  glDeleteProgram(gpu_context->program_luma);
  eglMakeCurrent(gpu_context->display, EGL_NO_SURFACE, EGL_NO_SURFACE,
                 EGL_NO_CONTEXT);
  eglDestroyContext(gpu_context->display, gpu_context->context);
  eglTerminate(gpu_context->display);
#ifndef USE_EGL_MESA_PLATFORM_SURFACELESS
  gbm_device_destroy(gpu_context->device);
  close(gpu_context->render_node);
#endif  // USE_EGL_MESA_PLATFORM_SURFACELESS
  free(gpu_context);
}

void CloseUniqueFds(int fds[4]) {
  // TODO(mburakov): Meh, but still better than looping...
  if (fds[3] != -1 && fds[3] != fds[2] && fds[3] != fds[1] && fds[3] != fds[0])
    close(fds[3]);
  if (fds[2] != -1 && fds[2] != fds[1] && fds[2] != fds[0]) close(fds[2]);
  if (fds[1] != -1 && fds[1] != fds[0]) close(fds[1]);
  if (fds[0] != -1) close(fds[0]);
}