/**
 * Copyright (c) 2026 Dominic Masters
 * 
 * This software is released under the MIT License.
 * https://opensource.org/licenses/MIT
 */

#include "display/display.h"
#include "display/framebuffer/framebuffer.h"
#include "assert/assert.h"

errorret_t frameBufferGLInitBackBuffer(void) {
  errorOk();
}

uint32_t frameBufferGetWidth(const framebuffer_t *framebuffer) {
  if(framebuffer == NULL) {
    return 0;
  }

  if(framebuffer == &FRAMEBUFFER_BACKBUFFER) {
    #ifdef DUSK_DISPLAY_SIZE_DYNAMIC
      int32_t windowWidth, windowHeight;
      SDL_GetWindowSize(DISPLAY.window, &windowWidth, &windowHeight);
      return windowWidth;
    #else
      return DUSK_DISPLAY_WIDTH;
    #endif
  }

  return framebuffer->texture.width;
}

uint32_t frameBufferGLGetHeight(const framebuffer_t *framebuffer) {
  if(framebuffer == NULL) {
    return 0;
  }

  if(framebuffer == &FRAMEBUFFER_BACKBUFFER) {
    #ifdef DUSK_DISPLAY_SIZE_DYNAMIC
      int32_t windowWidth, windowHeight;
      SDL_GetWindowSize(DISPLAY.window, &windowWidth, &windowHeight);
      return windowHeight;
    #else
      return DUSK_DISPLAY_HEIGHT;
    #endif
  }

  return framebuffer->texture.height;
}

errorret_t frameBufferGLBind(framebuffer_t *framebuffer) {
  assertNotNull(framebuffer, "Framebuffer cannot be NULL");

  #ifdef DUSK_DISPLAY_SIZE_DYNAMIC
    if(framebuffer == &FRAMEBUFFER_BACKBUFFER) {
      glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
    } else {
      glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, framebuffer->id);
    }
    
    glViewport(
      0, 0,
      frameBufferGetWidth(framebuffer), frameBufferGetHeight(framebuffer)
    );
  #else
    glViewport(
      0, 0,
      DUSK_DISPLAY_WIDTH, DUSK_DISPLAY_HEIGHT
    );
  #endif
    
  errorChain(errorGLCheck());
  errorOk();
}

void frameBufferClear(const uint8_t flags, const color_t color) {
  GLbitfield glFlags = 0;

  if(flags & FRAMEBUFFER_CLEAR_COLOR) {
    glFlags |= GL_COLOR_BUFFER_BIT;
    glClearColor(
      color.r / 255.0f,
      color.g / 255.0f,
      color.b / 255.0f,
      color.a / 255.0f
    );
  }

  if(flags & FRAMEBUFFER_CLEAR_DEPTH) {
    glFlags |= GL_DEPTH_BUFFER_BIT;
  }

  glClear(glFlags);
}

#ifdef DUSK_DISPLAY_SIZE_DYNAMIC
  errorret_t frameBufferGLInit(
    framebuffer_t *fb,
    const uint32_t width,
    const uint32_t height
  ) {
    assertNotNull(fb, "Framebuffer cannot be NULL");
    assertTrue(width > 0 && height > 0, "W/H must be greater than 0");

    memoryZero(fb, sizeof(framebuffer_t));
    textureInit(&fb->texture, width, height, TEXTURE_FORMAT_RGBA,(texturedata_t){
      .rgbaColors = NULL
    });
    errorChain(errorGLCheck());

    glGenFramebuffersEXT(1, &fb->id);
    glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fb->id);
    errorChain(errorGLCheck());

    glFramebufferTexture2DEXT(
      GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT,
      GL_TEXTURE_2D, fb->texture.id, 0
    );
    errorChain(errorGLCheck());

    if(
      glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT) !=
      GL_FRAMEBUFFER_COMPLETE_EXT
    ) {
      assertUnreachable("Framebuffer is not complete");
    }

    glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
    errorChain(errorGLCheck());
    errorOk();
  }
  
  errorret_t frameBufferGLDispose(framebuffer_t *framebuffer) {
    assertNotNull(framebuffer, "Framebuffer cannot be NULL");

    if(framebuffer == &FRAMEBUFFER_BACKBUFFER) {
      assertUnreachable("Cannot dispose of backbuffer");
    }

    errorChain(textureDispose(&framebuffer->texture));
    glDeleteFramebuffersEXT(1, &framebuffer->id);
    errorChain(errorGLCheck());
    errorOk();
  }
#endif