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

#include "dusktest.h"
#include <SDL2/SDL.h>

// Mocks
static uint64_t SDL_GETTICKS_TICKS = 0;
static bool_t SDL_GETTICKS_CALLED = false;

uint64_t SDL_GetTicks64(void) {
  SDL_GETTICKS_CALLED = true;
  return SDL_GETTICKS_TICKS;
}

// Mocked includes
#include "util/memory.h"
#include "time/time.h"

// Tests
static void test_timeInit(void **state) {
  (void)state;
  
  // Fill time with garbage
  memorySet(&TIME, 0xFF, sizeof(TIME));

  // Init
  timeInit();

  // Inital struct is set.
  assert_float_equal(TIME.time, TIME_STEP, 0.0001f);
  assert_float_equal(TIME.delta, TIME_STEP, 0.0001f);
  assert_float_equal(TIME.dynamicTime, TIME_STEP, 0.0001f);
  assert_float_equal(TIME.dynamicDelta, TIME_STEP, 0.0001f);
  assert_false(TIME.dynamicUpdate);
}

static void test_timeUpdate(void **state) {
  (void)state;

  // Init first
  timeInit();

  // First time update, calls SDL_GetTicks
  SDL_GETTICKS_TICKS = 14; // Simulate 15ms elapsed (just barely not one step)
  SDL_GETTICKS_CALLED = false;
  timeUpdate();
  assert_true(SDL_GETTICKS_CALLED);
  assert_true(TIME.dynamicUpdate);
  assert_float_equal(TIME.dynamicDelta, 0.014f, 0.0001f);
  assert_float_equal(TIME.dynamicTime, TIME_STEP + TIME.dynamicDelta, 0.0001f);
  assert_float_equal(TIME.delta, TIME_STEP, 0.0001f); // Not changed
  assert_float_equal(TIME.time, TIME_STEP, 0.0001f); // Not changed

  // Simulate total 16ms elapsed (2ms more)
  SDL_GETTICKS_TICKS = 16;
  SDL_GETTICKS_CALLED = false;
  timeUpdate();
  assert_true(SDL_GETTICKS_CALLED);
  assert_false(TIME.dynamicUpdate);
  assert_float_equal(TIME.dynamicDelta, 0.002f, 0.0001f);
  assert_float_equal(TIME.dynamicTime, TIME_STEP * 2, 0.0001f);
  assert_float_equal(TIME.delta, TIME_STEP, 0.0001f);
  assert_float_equal(TIME.time, TIME_STEP * 2, 0.0001f); // Stepped once

  // Second test, half step (16 + 8)
  SDL_GETTICKS_TICKS = 24;
  SDL_GETTICKS_CALLED = false;
  timeUpdate();
  assert_true(SDL_GETTICKS_CALLED);
  assert_true(TIME.dynamicUpdate);
  assert_float_equal(TIME.dynamicDelta, 0.008f, 0.0001f);
  assert_float_equal(TIME.dynamicTime, TIME_STEP + 0.024f, 0.0001f);
  assert_float_equal(TIME.delta, TIME_STEP, 0.0001f);
  assert_float_equal(TIME.time, TIME_STEP * 2, 0.0001f);// Unchanged.

  // Third test, another half step, leading to non dynamic update
  SDL_GETTICKS_TICKS = 32;
  SDL_GETTICKS_CALLED = false;
  timeUpdate();
  assert_true(SDL_GETTICKS_CALLED);
  assert_false(TIME.dynamicUpdate);
  assert_float_equal(TIME.dynamicDelta, 0.008f, 0.0001f);
  assert_float_equal(TIME.dynamicTime, TIME_STEP + 0.032f, 0.0001f);
  assert_float_equal(TIME.delta, TIME_STEP, 0.0001f); 
  assert_float_equal(TIME.time, TIME_STEP * 3, 0.0001f);

  // Fourth test, large jump, should only step once
  SDL_GETTICKS_TICKS = 100; // Simulate 100ms elapsed
  SDL_GETTICKS_CALLED = false;
  timeUpdate();
  assert_true(SDL_GETTICKS_CALLED);
  assert_false(TIME.dynamicUpdate);
  assert_float_equal(TIME.dynamicDelta, 0.068f, 0.0001f);
  assert_float_equal(TIME.dynamicTime, TIME_STEP + 0.100f, 0.0001f);
  assert_float_equal(TIME.delta, TIME_STEP, 0.0001f); 
  assert_float_equal(TIME.time, TIME_STEP * 4, 0.0001f);

  // Fifth test, despite a small time passing the game should be trying to catch
  // and running extra ticks
  SDL_GETTICKS_TICKS = 104; // Simulate 4ms elapsed
  SDL_GETTICKS_CALLED = false;
  timeUpdate();
  assert_true(SDL_GETTICKS_CALLED);
  assert_false(TIME.dynamicUpdate);
  assert_float_equal(TIME.dynamicDelta, 0.004f, 0.0001f);
  assert_float_equal(TIME.dynamicTime, TIME_STEP + 0.104f, 0.0001f);
  assert_float_equal(TIME.delta, TIME_STEP, 0.0001f); 
  assert_float_equal(TIME.time, TIME_STEP * 5, 0.0001f);
}

int main(int argc, char **argv) {
  const struct CMUnitTest tests[] = {
    cmocka_unit_test(test_timeInit),
    cmocka_unit_test(test_timeUpdate),
  };
  return cmocka_run_group_tests(tests, NULL, NULL);
}