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

#include "renderbackbuffer.h"
#include "render.h"
#include "display/spritebatch/spritebatch.h"
#include "display/camera/camera.h"

#if RENDER_USE_FRAMEBUFFER
  framebuffer_t RENDER_BACKBUFFER;
#endif

errorret_t renderBackBufferInit(void) {
  #if RENDER_USE_FRAMEBUFFER
    frameBufferInit(
      &RENDER_BACKBUFFER,
      RENDER_WIDTH,
      RENDER_HEIGHT
    );
  #else
    // No back buffer needed for window rendering
  #endif

  errorOk();
}

void renderBackBufferBind(void) {
  #if RENDER_USE_FRAMEBUFFER
    frameBufferBind(&RENDER_BACKBUFFER);
  #endif
  
  // Fill background with cornflower blue.
  glClearColor(0.392f, 0.584f, 0.929f, 1.0f);
  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
}

void renderBackBufferUnbind(void) {
  #if RENDER_USE_FRAMEBUFFER
    frameBufferBind(NULL);
  #endif
}

void renderBackBufferDraw(void) {
  #if RENDER_USE_FRAMEBUFFER
    int32_t windowWidth, windowHeight;
    SDL_GetWindowSize(RENDER_WINDOW, &windowWidth, &windowHeight);

    // Set viewport to match window size
    cameraScreenPush();
    glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    // Create a quad that is scaled to fit but maintain original aspect ratio
    int32_t renderWidth, renderHeight, renderX, renderY;
    if(RENDER_WIDTH * windowHeight > RENDER_HEIGHT * windowWidth) {
      renderWidth = windowWidth;
      renderHeight = (RENDER_HEIGHT * windowWidth) / RENDER_WIDTH;
      renderX = 0;
      renderY = (windowHeight - renderHeight) / 2;
    } else {
      renderWidth = (RENDER_WIDTH * windowHeight) / RENDER_HEIGHT;
      renderHeight = windowHeight;
      renderX = (windowWidth - renderWidth) / 2;
      renderY = 0;
    }

    // Draw the back buffer texture
    spriteBatchClear();
    spriteBatchPush(
      &RENDER_BACKBUFFER.texture,
      renderX, renderY,
      renderX+renderWidth, renderY+renderHeight,
      0xFF, 0xFF, 0xFF, 0xFF,
      0, 1, 1, 0
    );
    spriteBatchFlush();
    cameraScreenPop();
  #else
    // No back buffer to draw
  #endif
}

errorret_t renderBackBufferDispose(void) {
  #if RENDER_USE_FRAMEBUFFER
    frameBufferDispose(&RENDER_BACKBUFFER);
  #endif

  errorOk();
}