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

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

#include "world/overworld.h"

void cameraUIPush(void) {
  glPushMatrix();

  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();

  glViewport(0, 0, RENDER_WIDTH, RENDER_HEIGHT);

  mat4 ortho;
  glm_ortho(
    0.0f, (float_t)RENDER_WIDTH,
    (float_t)RENDER_HEIGHT, 0.0f,
    -1.0f, 1.0f,
    ortho
  );
  glLoadMatrixf((const GLfloat*)ortho);

  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity();
}

void cameraUIPop(void) {
  glPopMatrix();
}

void cameraScreenPush(void) {
  glPushMatrix();

  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();

  mat4 ortho;
  #if RENDER_USE_FRAMEBUFFER
    int32_t windowWidth, windowHeight;
    SDL_GetWindowSize(RENDER_WINDOW, &windowWidth, &windowHeight);

    glViewport(0, 0, windowWidth, windowHeight);
    glm_ortho(
      0.0f, (float_t) windowWidth,
      (float_t)windowHeight, 0.0f,
      -1.0f, 1.0f,
      ortho
    );
  #else
    glm_ortho(
      0.0f, (float_t)RENDER_WIDTH,
      (float_t)RENDER_HEIGHT, 0.0f,
      -1.0f, 1.0f,
      ortho
    );
  #endif
  glLoadMatrixf((const GLfloat*)ortho);

  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity();
}

void cameraScreenPop(void) {
  glPopMatrix();
}

void cameraOverworldPush(void) {
  glPushMatrix();
  glLoadIdentity();

  #if RENDER_USE_FRAMEBUFFER
    glViewport(0, 0, RENDER_WIDTH, RENDER_HEIGHT);
  #endif

  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();

  const float_t fov = glm_rad(75.0f);
  const float_t camOffset = 12.0f;
  const float_t aspect = (float_t)RENDER_WIDTH / (float_t)RENDER_HEIGHT;
  const float_t pixelPerfectOffset = (
    tanf((glm_rad(180) - fov) / 2.0f) *
    ((float_t)RENDER_HEIGHT/ 2.0f)
  );

  vec3 look = {
    OVERWORLD_CAMERA_X,
    OVERWORLD_CAMERA_Y,
    0.0f
  };
  vec3 eye = {
    look[0],
    look[1] + camOffset,
    look[2] + pixelPerfectOffset
  };
  vec3 up = { 0.0f, 1.0f, 0.0f };

  mat4 proj;
  glm_perspective(fov, aspect, 0.1f, 1000.0f, proj);
  
  // Flips rendering on the Y axis, so that it is still right-down even in 3D;
  proj[1][1] = -proj[1][1];

  mat4 view;
  glm_lookat(eye, look, up, view);

  mat4 pv;
  glm_mat4_mul(proj, view, pv);

  glLoadMatrixf((const GLfloat*)pv);

  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity();
}

void cameraOverworldPop(void) {
  glPopMatrix();
}