#include <doctest/doctest.h>

#include <chrono>
#include <thread>
#include <vector>

#include "secsgem/gem/ept_state.hpp"

using namespace secsgem::gem;

TEST_CASE("EPT: initial state is NonScheduledTime") {
  EptStateMachine ept;
  CHECK(ept.state() == EptState::NonScheduledTime);
}

TEST_CASE("EPT: every event transitions to exactly its target state") {
  EptStateMachine ept;
  CHECK(ept.on_event(EptEvent::EnterStandby));
  CHECK(ept.state() == EptState::Standby);
  CHECK(ept.on_event(EptEvent::EnterProductive));
  CHECK(ept.state() == EptState::Productive);
  CHECK(ept.on_event(EptEvent::EnterUnscheduledDown));
  CHECK(ept.state() == EptState::UnscheduledDowntime);
  CHECK(ept.on_event(EptEvent::EnterEngineering));
  CHECK(ept.state() == EptState::Engineering);
  CHECK(ept.on_event(EptEvent::EnterScheduledDown));
  CHECK(ept.state() == EptState::ScheduledDowntime);
  CHECK(ept.on_event(EptEvent::EnterNonScheduled));
  CHECK(ept.state() == EptState::NonScheduledTime);
}

TEST_CASE("EPT: change handler reports dwell time") {
  EptStateMachine ept;
  std::vector<std::pair<EptState, std::chrono::milliseconds>> transitions;
  ept.set_state_change_handler(
      [&](EptState, EptState to, EptEvent, std::chrono::milliseconds dwell) {
        transitions.emplace_back(to, dwell);
      });

  std::this_thread::sleep_for(std::chrono::milliseconds(5));
  ept.on_event(EptEvent::EnterStandby);
  std::this_thread::sleep_for(std::chrono::milliseconds(5));
  ept.on_event(EptEvent::EnterProductive);

  REQUIRE(transitions.size() == 2);
  CHECK(transitions[0].first == EptState::Standby);
  CHECK(transitions[0].second.count() >= 1);  // dwelled in NonScheduledTime
  CHECK(transitions[1].first == EptState::Productive);
  CHECK(transitions[1].second.count() >= 1);  // dwelled in Standby
}

TEST_CASE("EPT: same-state event is a no-op (no handler call)") {
  EptStateMachine ept;
  ept.on_event(EptEvent::EnterStandby);
  int calls = 0;
  ept.set_state_change_handler(
      [&](EptState, EptState, EptEvent, std::chrono::milliseconds) { ++calls; });
  CHECK(ept.on_event(EptEvent::EnterStandby));  // already in Standby
  CHECK(calls == 0);
}