/**
 * Copyright (c) 2025 Dominic Masters
 * 
 * This software is released under the MIT License.
 * https://opensource.org/licenses/MIT
 */

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

framebuffer_t FRAMEBUFFER_BACKBUFFER = {0};
const framebuffer_t *FRAMEBUFFER_BOUND = &FRAMEBUFFER_BACKBUFFER;

void frameBufferInitBackbuffer() {
  memoryZero(&FRAMEBUFFER_BACKBUFFER, sizeof(framebuffer_t));

  FRAMEBUFFER_BACKBUFFER.id = -1;
  FRAMEBUFFER_BOUND = &FRAMEBUFFER_BACKBUFFER;
}

#if DISPLAY_SIZE_DYNAMIC == 1
  void frameBufferInit(
    framebuffer_t *framebuffer,
    const uint32_t width,
    const uint32_t height
  ) {
    #if DISPLAY_SDL2 == 1
      assertNotNull(framebuffer, "Framebuffer cannot be NULL");
      assertTrue(width > 0 && height > 0, "W/H must be greater than 0");

      memoryZero(framebuffer, sizeof(framebuffer_t));
      textureInit(&framebuffer->texture, width, height, GL_RGBA,(texturedata_t){
        .rgba = { .colors = NULL }
      });

      glGenFramebuffersEXT(1, &framebuffer->id);
      glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, framebuffer->id);

      glFramebufferTexture2DEXT(
        GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT,
        GL_TEXTURE_2D, framebuffer->texture.id, 0
      );

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

      glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
    #endif
  }
#endif

int32_t frameBufferGetWidth(const framebuffer_t *framebuffer) {
  #if DISPLAY_SDL2
    if(framebuffer == &FRAMEBUFFER_BACKBUFFER) {
      #if DISPLAY_SIZE_DYNAMIC == 0
        return DISPLAY_WIDTH;
      #else
        int32_t windowWidth, windowHeight;
        SDL_GetWindowSize(DISPLAY.window, &windowWidth, &windowHeight);
        return windowWidth;
      #endif
    }

    return framebuffer->texture.width;
  #endif
}

int32_t frameBufferGetHeight(const framebuffer_t *framebuffer) {
  #if DISPLAY_SDL2
    if(framebuffer == &FRAMEBUFFER_BACKBUFFER) {
      #if DISPLAY_SIZE_DYNAMIC == 0
        return DISPLAY_HEIGHT;
      #else
        int32_t windowWidth, windowHeight;
        SDL_GetWindowSize(DISPLAY.window, &windowWidth, &windowHeight);
        return windowHeight;
      #endif
    }

    return framebuffer->texture.height;
  #endif
}

void frameBufferBind(const framebuffer_t *framebuffer) {
  if(framebuffer == NULL) {
    #if DISPLAY_SDL2
      frameBufferBind(&FRAMEBUFFER_BACKBUFFER);
    #endif

    FRAMEBUFFER_BOUND = &FRAMEBUFFER_BACKBUFFER;
    return;
  }

  // Bind the framebuffer for rendering
  #if DISPLAY_SDL2
    if(framebuffer == &FRAMEBUFFER_BACKBUFFER) {
      #if PSP

      #else
        glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
      #endif
    } else {
      #if PSP
        assertUnreachable("Framebuffers not supported on PSP");
      #else
        glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, framebuffer->id);
      #endif
    }
    
    glViewport(
      0, 0,
      frameBufferGetWidth(framebuffer), frameBufferGetHeight(framebuffer)
    );
  #endif

  FRAMEBUFFER_BOUND = framebuffer;
}

void frameBufferClear(uint8_t flags, color_t color) {
  #if DISPLAY_SDL2
    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);
  #endif
}

void frameBufferDispose(framebuffer_t *framebuffer) {
  assertNotNull(framebuffer, "Framebuffer cannot be NULL");

  #if DISPLAY_SDL2
    if(framebuffer == &FRAMEBUFFER_BACKBUFFER) {
      assertUnreachable("Cannot dispose of backbuffer");
    }

    #if DISPLAY_SIZE_DYNAMIC == 0
      assertUnreachable("Dynamic size framebuffers not supported");
    #else
      textureDispose(&framebuffer->texture);
      glDeleteFramebuffersEXT(1, &framebuffer->id);
    #endif
  #endif
}