#include "test_harness.h"
#include <TestProject/RNG/model/DriftModel.h>
using json = nlohmann::json;

TEST(drift_basic) {
  DriftModel m(json{{"drift_rate", 0.1f}}, 0.0f);
  CHECK_FLOAT_EQ(m.evaluate(0), 0.0f, 0.001f);
  CHECK_FLOAT_EQ(m.evaluate(10), 1.0f, 0.001f);
}

TEST(drift_default_rate_is_zero) {
  DriftModel m(json::object(), 42.0f);
  CHECK_FLOAT_EQ(m.evaluate(0), 42.0f, 0.001f);
  CHECK_FLOAT_EQ(m.evaluate(1000), 42.0f, 0.001f);
}

TEST(drift_negative_rate) {
  DriftModel m(json{{"drift_rate", -0.5f}}, 100.0f);
  CHECK_FLOAT_EQ(m.evaluate(10), 95.0f, 0.001f);
}

TEST(drift_with_period) {
  // period_ms=100 → 5 ticks per period
  DriftModel m(json{{"drift_rate", 1.0f}, {"period_ms", 100}}, 0.0f);
  CHECK_FLOAT_EQ(m.evaluate(0), 0.0f, 0.001f);
  CHECK_FLOAT_EQ(m.evaluate(4), 4.0f, 0.001f);
  CHECK_FLOAT_EQ(m.evaluate(5), 0.0f, 0.001f); // wraps
}