#include "catch.hpp"

#include "ConfigLoader.h"
#include "GameConfig.h"
#include "Simulation.h"
#include "Tick.h"
#include "TickDriver.h"

static GameConfig loadConfig()
{
    return ConfigLoader::loadFromDirectory(DOTA_FACTORY_CONFIG_DIR);
}

// ---------------------------------------------------------------------------
// Simulation
// ---------------------------------------------------------------------------

TEST_CASE("Simulation::currentTick starts at 0", "[simulation]")
{
    const Simulation sim(loadConfig());

    REQUIRE(sim.currentTick() == 0);
}

TEST_CASE("Simulation::tick increments currentTick by 1", "[simulation]")
{
    Simulation sim(loadConfig());

    sim.tick();

    REQUIRE(sim.currentTick() == 1);
}

TEST_CASE("Simulation::tick 10 times yields currentTick == 10", "[simulation]")
{
    Simulation sim(loadConfig());

    for (int i = 0; i < 10; ++i)
    {
        sim.tick();
    }

    REQUIRE(sim.currentTick() == 10);
}

TEST_CASE("Simulation::drainFireEvents returns empty initially", "[simulation]")
{
    Simulation sim(loadConfig());

    REQUIRE(sim.drainFireEvents().empty());
}

TEST_CASE("Simulation::drainFireEvents clears queue on drain", "[simulation]")
{
    Simulation sim(loadConfig());

    // First drain: empty.
    sim.drainFireEvents();

    // Second drain must also be empty (not a double-return).
    REQUIRE(sim.drainFireEvents().empty());
}

TEST_CASE("Simulation::drainSchematicDropEvents returns empty initially", "[simulation]")
{
    Simulation sim(loadConfig());

    REQUIRE(sim.drainSchematicDropEvents().empty());
}

// ---------------------------------------------------------------------------
// TickDriver
// ---------------------------------------------------------------------------

TEST_CASE("TickDriver: 0x speed never produces ticks", "[simulation]")
{
    TickDriver driver;

    REQUIRE(driver.advance(100.0, 0.0) == 0);
    REQUIRE(driver.advance(1000.0, 0.0) == 0);
}

TEST_CASE("TickDriver: exactly one tick duration at 1x produces 1 tick", "[simulation]")
{
    TickDriver driver;

    REQUIRE(driver.advance(kTickDurationMs, 1.0) == 1);
}

TEST_CASE("TickDriver: two tick durations at 1x produces 2 ticks", "[simulation]")
{
    TickDriver driver;

    REQUIRE(driver.advance(2.0 * kTickDurationMs, 1.0) == 2);
}

TEST_CASE("TickDriver: 4x speed with quarter tick duration produces 1 tick", "[simulation]")
{
    TickDriver driver;

    REQUIRE(driver.advance(kTickDurationMs / 4.0, 4.0) == 1);
}

TEST_CASE("TickDriver: 0.5x speed with double tick duration produces 1 tick", "[simulation]")
{
    TickDriver driver;

    REQUIRE(driver.advance(kTickDurationMs / 0.5, 0.5) == 1);
}

TEST_CASE("TickDriver: accumulator carries partial progress across frames", "[simulation]")
{
    TickDriver driver;

    // 60% of a tick — not enough to fire yet.
    REQUIRE(driver.advance(kTickDurationMs * 0.6, 1.0) == 0);

    // Another 60% — cumulative 120%, so exactly 1 tick fires.
    REQUIRE(driver.advance(kTickDurationMs * 0.6, 1.0) == 1);
}

TEST_CASE("TickDriver::reset clears the accumulator", "[simulation]")
{
    TickDriver driver;

    // Advance to just below one tick.
    driver.advance(kTickDurationMs * 0.9, 1.0);

    driver.reset();

    // Nothing in the accumulator: zero elapsed time should not fire.
    REQUIRE(driver.advance(0.0, 1.0) == 0);
}