#include "zeroerr/assert.h"
#include "zeroerr/unittest.h"

#include "particles/Particles.h"
#include "particles/ParticleEmitter.h"
#include "particles/ParticleSystem.h"
#include "filesystem/Filesystem.h"

#include <cmath>
#include <cstring>
#include <string>

using namespace eve::particles;

TEST_CASE("particles.newEmitter.ecsView") {
    auto *mod = Particles::create();
    int before = mod->getEmitterCount();
    ParticleEmitter *e = mod->newEmitter(64);
    REQUIRE(e != nullptr);
    CHECK_EQ(e->getBufferSize(), 64);
    CHECK_EQ(e->getCount(), 0);
    CHECK_EQ(mod->getEmitterCount(), before + 1);
    CHECK(e->config()->entity == e);
}

TEST_CASE("particles.emitter.emitAndLifetime") {
    auto *mod = Particles::create();
    ParticleEmitter *e = mod->newEmitter(32);
    e->setParticleLifetime(1.f, 1.f);
    e->setSpeed(0.f, 0.f);
    e->emit(10);
    CHECK_EQ(e->getCount(), 10);

    ParticleSimSystem::update(0.5f);
    CHECK_EQ(e->getCount(), 10);

    ParticleSimSystem::update(0.6f);
    CHECK_EQ(e->getCount(), 0);
}

TEST_CASE("particles.emitter.emissionRate") {
    auto *mod = Particles::create();
    ParticleEmitter *e = mod->newEmitter(100);
    e->setParticleLifetime(10.f, 10.f);
    e->setEmissionRate(50.f);
    e->setSpeed(0.f, 0.f);
    e->start();
    ParticleSimSystem::update(0.2f); // ~10 particles
    CHECK_GE(e->getCount(), 9);
    CHECK_LE(e->getCount(), 11);
}

TEST_CASE("particles.emitter.startStopPause") {
    auto *mod = Particles::create();
    ParticleEmitter *e = mod->newEmitter(16);
    e->setEmissionRate(100.f);
    e->setParticleLifetime(5.f, 5.f);
    CHECK(e->isStopped());

    e->start();
    CHECK(e->isActive());
    e->pause();
    CHECK(e->isPaused());
    CHECK(!e->isActive());
    int c0 = e->getCount();
    ParticleSimSystem::update(1.f);
    CHECK_EQ(e->getCount(), c0);

    e->start();
    e->stop();
    CHECK(e->isStopped());
}

TEST_CASE("particles.emitter.motion") {
    auto *mod = Particles::create();
    ParticleEmitter *e = mod->newEmitter(8);
    e->setPosition(0.f, 0.f);
    e->setParticleLifetime(2.f, 2.f);
    e->setDirection(0.f);
    e->setSpread(0.f);
    e->setSpeed(100.f, 100.f);
    e->setLinearAcceleration(0.f, 0.f, 0.f, 0.f);
    e->emit(1);
    ParticleSimSystem::update(0.1f);
    CHECK_EQ(e->getCount(), 1);
}

TEST_CASE("particles.emitter.applyPreset") {
    auto *mod = Particles::create();
    ParticleEmitter *e = mod->newEmitter(64);
    e->applyPreset("spark");
    CHECK_GT(e->getEmissionRate(), 0.f);
    e->applyPreset("smoke");
    CHECK_GT(e->getEmissionRate(), 0.f);
    e->applyPreset("fire");
    CHECK_GT(e->getEmissionRate(), 0.f);
    e->applyPreset("unknown");
    CHECK_GT(e->getEmissionRate(), 0.f);
}

TEST_CASE("particles.system.updateAll") {
    auto *mod = Particles::create();
    ParticleEmitter *a = mod->newEmitter(16);
    ParticleEmitter *b = mod->newEmitter(16);
    a->setParticleLifetime(1.f, 1.f);
    b->setParticleLifetime(1.f, 1.f);
    a->emit(3);
    b->emit(5);
    ParticleSimSystem::update(2.f);
    CHECK_EQ(a->getCount(), 0);
    CHECK_EQ(b->getCount(), 0);
}

TEST_CASE("particles.module.updateForwardsToSystem") {
    auto *mod = Particles::create();
    ParticleEmitter *e = mod->newEmitter(16);
    e->setParticleLifetime(1.f, 1.f);
    e->emit(4);
    mod->update(2.f);
    CHECK_EQ(e->getCount(), 0);
}

TEST_CASE("particles.emitter.reset") {
    auto *mod = Particles::create();
    ParticleEmitter *e = mod->newEmitter(16);
    e->setParticleLifetime(5.f, 5.f);
    e->emit(8);
    CHECK_EQ(e->getCount(), 8);
    e->reset();
    CHECK_EQ(e->getCount(), 0);
}

TEST_CASE("particles.emitter.bufferCap") {
    auto *mod = Particles::create();
    ParticleEmitter *e = mod->newEmitter(4);
    e->setParticleLifetime(10.f, 10.f);
    e->emit(100);
    CHECK_EQ(e->getCount(), 4);
}

TEST_CASE("particles.renderSystem.skipsInvisible") {
    auto *mod = Particles::create();
    ParticleEmitter *e = mod->newEmitter(8);
    e->setParticleLifetime(5.f, 5.f);
    e->emit(3);
    e->setVisible(false);
    // No Graphics — render should early-out safely.
    ParticleRenderSystem::render(nullptr);
    CHECK_EQ(e->getCount(), 3);
}

TEST_CASE("particles.config.applyJsonText") {
    auto *mod = Particles::create();
    ParticleEmitter *e = mod->newEmitter(32);
    const char *json = R"({
      "preset": "spark",
      "x": 12.5,
      "y": 34,
      "emissionRate": 40,
      "particleLifetime": [0.5, 1.5],
      "speed": [10, 20],
      "colorStart": [1, 0, 0, 1],
      "colorEnd": [0, 0, 1, 0],
      "layer": 3,
      "autoStart": true
    })";
    CHECK(e->applyConfig(json));
    CHECK(std::abs(e->getX() - 12.5f) < 1e-4f);
    CHECK(std::abs(e->getY() - 34.f) < 1e-4f);
    CHECK(std::abs(e->getEmissionRate() - 40.f) < 1e-4f);
    CHECK(std::abs(e->getParticleLifetimeMin() - 0.5f) < 1e-4f);
    CHECK(std::abs(e->getParticleLifetimeMax() - 1.5f) < 1e-4f);
    CHECK_EQ(e->getLayer(), 3);
    CHECK(e->isActive());
}

TEST_CASE("particles.config.applyInvalid") {
    auto *mod = Particles::create();
    ParticleEmitter *e = mod->newEmitter(8);
    CHECK(!e->applyConfig("{bad"));
    CHECK(!e->applyConfig("[1,2,3]"));
}

TEST_CASE("particles.config.loadFileAndHotReload") {
    auto *fs = eve::filesystem::Filesystem::create();
    REQUIRE(fs->setIdentity("ev_ut_particles_cfg", true));
    REQUIRE(fs->setupWriteDirectory());

    const char *name = "fx_spark.json";
    const char *json1 = R"({"emissionRate":11,"x":1,"y":2,"particleLifetime":[1,1]})";
    fs->write(name, json1, std::strlen(json1));

    auto *mod = Particles::create();
    ParticleEmitter *e = mod->newEmitter(16);
    CHECK(e->loadConfig(name));
    CHECK_EQ(e->getConfigPath(), std::string(name));
    CHECK(std::abs(e->getEmissionRate() - 11.f) < 1e-4f);
    CHECK(e->getAutoReload());

    // Force stale modtime so poll reloads without waiting on FS resolution.
    e->resource()->modtime = 0;
    const char *json2 = R"({"emissionRate":77,"x":9,"y":8,"particleLifetime":[2,2]})";
    fs->write(name, json2, std::strlen(json2));

    CHECK_EQ(ParticleConfigSystem::poll(), 1);
    CHECK(std::abs(e->getEmissionRate() - 77.f) < 1e-4f);
    CHECK(std::abs(e->getX() - 9.f) < 1e-4f);

    e->setAutoReload(false);
    e->resource()->modtime = 0;
    const char *json3 = R"({"emissionRate":1})";
    fs->write(name, json3, std::strlen(json3));
    CHECK_EQ(ParticleConfigSystem::poll(), 0);
    CHECK(std::abs(e->getEmissionRate() - 77.f) < 1e-4f);

    CHECK(e->reloadConfig());
    CHECK(std::abs(e->getEmissionRate() - 1.f) < 1e-4f);
}

TEST_CASE("particles.config.newEmitterFromFile") {
    auto *fs = eve::filesystem::Filesystem::create();
    REQUIRE(fs->setIdentity("ev_ut_particles_fromfile", true));
    REQUIRE(fs->setupWriteDirectory());

    const char *name = "fx_fromfile.json";
    const char *json = R"({"buffer":48,"preset":"smoke","emissionRate":25,"autoStart":true})";
    fs->write(name, json, std::strlen(json));

    auto *mod = Particles::create();
    ParticleEmitter *e = mod->newEmitterFromFile(name);
    REQUIRE(e != nullptr);
    CHECK_EQ(e->getBufferSize(), 48);
    CHECK(std::abs(e->getEmissionRate() - 25.f) < 1e-4f);
    CHECK(e->isActive());
    CHECK_EQ(e->getConfigPath(), std::string(name));
}