/*
Looking Glass - KVM FrameRelay (KVMFR) Client
Copyright (C) 2017-2019 Geoffrey McRae <geoff@hostfission.com>
https://looking-glass.hostfission.com

This program is free software; you can redistribute it and/or modify it under
cahe terms of the GNU General Public License as published by the Free Software
Foundation; either version 2 of the License, or (at your option) any later
version.

This program 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
this program; if not, write to the Free Software Foundation, Inc., 59 Temple
Place, Suite 330, Boston, MA 02111-1307 USA
*/

#include "desktop.h"
#include "common/debug.h"
#include "common/option.h"
#include "common/locking.h"

#include "texture.h"
#include "shader.h"
#include "model.h"

#include <stdlib.h>
#include <string.h>

#include "interface/app.h"

// these headers are auto generated by cmake
#include "desktop.vert.h"
#include "desktop_rgb.frag.h"
#include "desktop_yuv.frag.h"

struct DesktopShader
{
  EGL_Shader * shader;
  GLint uDesktopPos;
  GLint uDesktopSize;
  GLint uNearest;
  GLint uNV, uNVGain;
};

struct EGL_Desktop
{
  EGL_Texture          * texture;
  struct DesktopShader * shader; // the active shader
  EGL_Model            * model;

  // shader instances
  struct DesktopShader shader_generic;
  struct DesktopShader shader_yuv;

  // internals
  LG_Lock              updateLock;
  enum EGL_PixelFormat pixFmt;
  unsigned int         width, height;
  unsigned int         pitch;
  const FrameBuffer  * frame;
  bool                 update;

  // night vision
  KeybindHandle kbNV;
  int   nvMax;
  int   nvGain;
};

// forwards
void egl_desktop_toggle_nv(SDL_Scancode key, void * opaque);

static bool egl_init_desktop_shader(
  struct DesktopShader * shader,
  const char * vertex_code  , size_t vertex_size,
  const char * fragment_code, size_t fragment_size
)
{
  if (!egl_shader_init(&shader->shader))
    return false;

  if (!egl_shader_compile(shader->shader,
        vertex_code  , vertex_size,
        fragment_code, fragment_size))
  {
    return false;
  }

  shader->uDesktopPos  = egl_shader_get_uniform_location(shader->shader, "position");
  shader->uDesktopSize = egl_shader_get_uniform_location(shader->shader, "size"    );
  shader->uNearest     = egl_shader_get_uniform_location(shader->shader, "nearest" );
  shader->uNV          = egl_shader_get_uniform_location(shader->shader, "nv"      );
  shader->uNVGain      = egl_shader_get_uniform_location(shader->shader, "nvGain"  );

  return true;
}

bool egl_desktop_init(EGL_Desktop ** desktop)
{
  *desktop = (EGL_Desktop *)malloc(sizeof(EGL_Desktop));
  if (!*desktop)
  {
    DEBUG_ERROR("Failed to malloc EGL_Desktop");
    return false;
  }

  memset(*desktop, 0, sizeof(EGL_Desktop));

  if (!egl_texture_init(&(*desktop)->texture))
  {
    DEBUG_ERROR("Failed to initialize the desktop texture");
    return false;
  }

  if (!egl_init_desktop_shader(
    &(*desktop)->shader_generic,
    b_shader_desktop_vert    , b_shader_desktop_vert_size,
    b_shader_desktop_rgb_frag, b_shader_desktop_rgb_frag_size))
  {
    DEBUG_ERROR("Failed to initialize the generic desktop shader");
    return false;
  }

  if (!egl_init_desktop_shader(
    &(*desktop)->shader_yuv,
    b_shader_desktop_vert    , b_shader_desktop_vert_size,
    b_shader_desktop_yuv_frag, b_shader_desktop_yuv_frag_size))
  {
    DEBUG_ERROR("Failed to initialize the yuv desktop shader");
    return false;
  }

  if (!egl_model_init(&(*desktop)->model))
  {
    DEBUG_ERROR("Failed to initialize the desktop model");
    return false;
  }

  egl_model_set_default((*desktop)->model);
  egl_model_set_texture((*desktop)->model, (*desktop)->texture);

  LG_LOCK_INIT((*desktop)->updateLock);

  (*desktop)->kbNV = app_register_keybind(SDL_SCANCODE_N, egl_desktop_toggle_nv, *desktop);

  (*desktop)->nvMax  = option_get_int("egl", "nvGainMax");
  (*desktop)->nvGain = option_get_int("egl", "nvGain"   );

  return true;
}


void egl_desktop_toggle_nv(SDL_Scancode key, void * opaque)
{
  EGL_Desktop * desktop = (EGL_Desktop *)opaque;
  if (desktop->nvGain++ == desktop->nvMax)
    desktop->nvGain = 0;

       if (desktop->nvGain == 0) app_alert(LG_ALERT_INFO, "NV Disabled");
  else if (desktop->nvGain == 1) app_alert(LG_ALERT_INFO, "NV Enabled");
  else app_alert(LG_ALERT_INFO, "NV Gain + %d", desktop->nvGain - 1);
}

void egl_desktop_free(EGL_Desktop ** desktop)
{
  if (!*desktop)
    return;

  LG_LOCK_FREE((*desktop)->updateLock);

  egl_texture_free(&(*desktop)->texture              );
  egl_shader_free (&(*desktop)->shader_generic.shader);
  egl_shader_free (&(*desktop)->shader_yuv.shader    );
  egl_model_free  (&(*desktop)->model                );

  app_release_keybind(&(*desktop)->kbNV);

  free(*desktop);
  *desktop = NULL;
}

bool egl_desktop_prepare_update(EGL_Desktop * desktop, const bool sourceChanged, const LG_RendererFormat format, const FrameBuffer * frame)
{
  if (sourceChanged)
  {
    LG_LOCK(desktop->updateLock);
    switch(format.type)
    {
      case FRAME_TYPE_BGRA:
        desktop->pixFmt = EGL_PF_BGRA;
        desktop->shader = &desktop->shader_generic;
        break;

      case FRAME_TYPE_RGBA:
        desktop->pixFmt = EGL_PF_RGBA;
        desktop->shader = &desktop->shader_generic;
        break;

      case FRAME_TYPE_RGBA10:
        desktop->pixFmt = EGL_PF_RGBA10;
        desktop->shader = &desktop->shader_generic;
        break;

      case FRAME_TYPE_YUV420:
        desktop->pixFmt = EGL_PF_YUV420;
        desktop->shader = &desktop->shader_yuv;
        break;

      default:
        DEBUG_ERROR("Unsupported frame format");
        LG_UNLOCK(desktop->updateLock);
        return false;
    }

    desktop->width  = format.width;
    desktop->height = format.height;
    desktop->pitch  = format.pitch;
    desktop->frame  = frame;
    desktop->update = true;

    /* defer the actual update as the format has changed and we need to issue GL commands first */
    LG_UNLOCK(desktop->updateLock);
    return true;
  }

  /* update the texture now */
  return egl_texture_update_from_frame(desktop->texture, frame);
}

void egl_desktop_perform_update(EGL_Desktop * desktop, const bool sourceChanged)
{
  if (sourceChanged)
  {
    LG_LOCK(desktop->updateLock);
    if (!egl_texture_setup(
      desktop->texture,
      desktop->pixFmt,
      desktop->width,
      desktop->height,
      desktop->pitch,
      true // streaming texture
    ))
    {
      DEBUG_ERROR("Failed to setup the desktop texture");
      LG_UNLOCK(desktop->updateLock);
      return;
    }
    LG_UNLOCK(desktop->updateLock);
  }

  if (desktop->update)
  {
    desktop->update = false;
    egl_texture_update_from_frame(desktop->texture, desktop->frame);
  }
}

bool egl_desktop_render(EGL_Desktop * desktop, const float x, const float y, const float scaleX, const float scaleY, const bool nearest)
{
  if (!desktop->shader)
    return false;

  if (egl_texture_process(desktop->texture) != EGL_TEX_STATUS_OK)
    return false;

  const struct DesktopShader * shader = desktop->shader;
  egl_shader_use(shader->shader);
  glUniform4f(shader->uDesktopPos , x, y, scaleX, scaleY);
  glUniform1i(shader->uNearest    , nearest ? 1 : 0);
  glUniform2f(shader->uDesktopSize, desktop->width, desktop->height);

  if (desktop->nvGain)
  {
    glUniform1i(shader->uNV, 1);
    glUniform1f(shader->uNVGain, (float)desktop->nvGain);
  }
  else
    glUniform1i(shader->uNV, 0);

  egl_model_render(desktop->model);
  return true;
}
