#include <simloop.h>

#include <test.h>
#include <timer.h>

/// At time/frame 0:
///   1. An initial render is always triggered.
///   2. No update is triggered (not enough time passed).
TEST_CASE(simloop_initial_render) {
  Timer   timer   = {};
  Simloop simloop = simloop_make(
      &(SimloopArgs){.update_fps = 10, .max_render_fps = 0, .timer = &timer});
  SimloopOut simout;

  simloop_update(&simloop, &simout);

  TEST_TRUE(simout.should_render);
  TEST_TRUE(!simout.should_update);
  TEST_EQUAL(simout.frame, 0);
}

/// The initial render is not re-triggered if there is a render frame rate cap
/// and time does not advance.
TEST_CASE(simloop_initial_render_not_retriggered) {
  Timer   timer   = {};
  Simloop simloop = simloop_make(
      &(SimloopArgs){.update_fps = 10, .max_render_fps = 10, .timer = &timer});
  SimloopOut simout;

  simloop_update(&simloop, &simout);

  TEST_TRUE(simout.should_render);
  TEST_TRUE(!simout.should_update);
  TEST_EQUAL(simout.frame, 0);

  for (int i = 0; i < 10; i++) {
    // Note that time does not advance.
    simloop_update(&simloop, &simout);
    TEST_TRUE(!simout.should_render);
    TEST_TRUE(!simout.should_update);
    TEST_EQUAL(simout.frame, 0);
  }
}

/// A simulation loop with no render frame cap:
///   1. Updates based on the desired update frame rate.
///   2. Renders at every loop.
TEST_CASE(simloop_no_render_frame_cap) {
  constexpr int    UPDATE_FPS    = 10;
  const time_delta EXPECT_UPDATE = sec_to_time_delta(1.0 / (double)UPDATE_FPS);
  const time_delta STEP          = sec_to_time_delta(1);
  const time_delta SIM_TIME_SEC  = sec_to_time_delta(30);

  Timer      timer   = {};
  Simloop    simloop = simloop_make(&(SimloopArgs){
         .update_fps = UPDATE_FPS, .max_render_fps = 0, .timer = &timer});
  SimloopOut simout;

  for (time_delta t = 0; t < SIM_TIME_SEC; t += STEP) {
    timer_advance(&timer, t);
    simloop_update(&simloop, &simout);
    TEST_TRUE(simout.should_render);
    TEST_EQUAL((t > 0) && ((t % EXPECT_UPDATE) == 0), simout.should_update);
  }
}

/// A simulation loop with a render frame cap:
///   1. Updates based on the desired update frame rate.
///   2. Renders based on the desired render frame rate.
TEST_CASE(simloop_with_render_frame_cap) {
  constexpr int    UPDATE_FPS    = 10;
  constexpr int    RENDER_FPS    = 5;
  const time_delta EXPECT_UPDATE = sec_to_time_delta(1.0 / (double)UPDATE_FPS);
  const time_delta EXPECT_RENDER = sec_to_time_delta(1.0 / (double)RENDER_FPS);
  const time_delta STEP          = sec_to_time_delta(0.1);
  const time_delta SIM_TIME_SEC  = sec_to_time_delta(30);

  Timer      timer   = {};
  Simloop    simloop = simloop_make(&(SimloopArgs){
         .update_fps = UPDATE_FPS, .max_render_fps = RENDER_FPS, .timer = &timer});
  SimloopOut simout;

  for (time_delta t = 0; t < SIM_TIME_SEC; t += STEP) {
    timer_advance(&timer, t);
    simloop_update(&simloop, &simout);
    // Also expecting initial render at t=0.
    TEST_EQUAL((t % EXPECT_RENDER) == 0, simout.should_render);
    TEST_EQUAL((t > 0) && ((t % EXPECT_UPDATE) == 0), simout.should_update);
  }
}

int main() { return 0; }