using Nightborn.Core.Combat;
using NUnit.Framework;

namespace Nightborn.Core.Tests;

public class BloodEnergyEconomyTests
{
    [Test]
    public void AttackGain_ShouldIncreaseEnergy()
    {
        var sut = new BloodEnergyEconomy();
        sut.Add(sut.CalculateAttackGain(1f));

        Assert.That(sut.Current, Is.EqualTo(5f).Within(0.0001f));
    }

    [Test]
    public void Spend_WhenEnoughEnergy_ShouldSucceed()
    {
        var sut = new BloodEnergyEconomy();
        sut.Add(50f);

        var ok = sut.Spend(40f);

        Assert.That(ok, Is.True);
        Assert.That(sut.Current, Is.EqualTo(10f).Within(0.0001f));
    }

    [Test]
    public void Spend_WhenInsufficientEnergy_ShouldFailWithoutSideEffects()
    {
        var sut = new BloodEnergyEconomy();
        sut.Add(10f);

        var ok = sut.Spend(40f);

        Assert.That(ok, Is.False);
        Assert.That(sut.Current, Is.EqualTo(10f).Within(0.0001f));
    }

    [Test]
    public void Add_ShouldClampToMaxAndFireFullEvent()
    {
        var sut = new BloodEnergyEconomy();
        var fullFired = false;
        sut.OnEnergyFull += () => fullFired = true;

        sut.Add(95f);
        sut.Add(10f);

        Assert.That(sut.Current, Is.EqualTo(100f).Within(0.0001f));
        Assert.That(fullFired, Is.True);
    }

    [Test]
    public void Reset_ShouldSetEnergyToZero()
    {
        var sut = new BloodEnergyEconomy();
        sut.Add(60f);

        sut.Reset();

        Assert.That(sut.Current, Is.EqualTo(0f).Within(0.0001f));
    }

    [Test]
    public void EnergyEmpty_ShouldFireWhenReachesZero()
    {
        var sut = new BloodEnergyEconomy();
        var emptyFired = false;
        sut.OnEnergyEmpty += () => emptyFired = true;

        sut.Add(24f);
        sut.Spend(24f);

        Assert.That(emptyFired, Is.True);
    }

    [Test]
    public void SwitchCost_ShouldRespectDiscountAndMinimumCost()
    {
        var sut = new BloodEnergyEconomy();

        var discounted = sut.CalculateSwitchCost(0.4f);
        var minimum = sut.CalculateSwitchCost(1.0f);

        Assert.That(discounted, Is.EqualTo(24f).Within(0.0001f));
        Assert.That(minimum, Is.EqualTo(1f).Within(0.0001f));
    }

    [Test]
    public void UpgradeBonusReduction_ShouldClampCurrentToNewMax()
    {
        var cfg = new BloodEnergyConfig { BaseMaxEnergy = 100f };
        var sut = new BloodEnergyEconomy(cfg);
        sut.Add(80f);

        cfg.BaseMaxEnergy = 50f;
        sut.SetUpgradeBonus(0f);

        Assert.That(sut.Max, Is.EqualTo(50f).Within(0.0001f));
        Assert.That(sut.Current, Is.EqualTo(50f).Within(0.0001f));
    }

    [Test]
    public void Add_WhenDead_ShouldBeIgnored()
    {
        var sut = new BloodEnergyEconomy();
        sut.SetDead(true);

        sut.Add(10f);

        Assert.That(sut.Current, Is.EqualTo(0f).Within(0.0001f));
    }

    [Test]
    public void ProcessFrame_ShouldApplyGainBeforeSpend()
    {
        var sut = new BloodEnergyEconomy();
        sut.Add(35f);

        var spendOk = sut.ProcessFrame(gainAmount: 10f, spendAmount: 40f);

        Assert.That(spendOk, Is.True);
        Assert.That(sut.Current, Is.EqualTo(5f).Within(0.0001f));
    }

    [Test]
    public void ProcessFrame_WhenGainStillInsufficient_ShouldFailSpend()
    {
        var sut = new BloodEnergyEconomy();
        sut.Add(20f);

        var spendOk = sut.ProcessFrame(gainAmount: 5f, spendAmount: 40f);

        Assert.That(spendOk, Is.False);
        Assert.That(sut.Current, Is.EqualTo(25f).Within(0.0001f));
    }

    [Test]
    public void WaveClearBonus_ShouldCapAtTwoTimesFixedBonus()
    {
        var cfg = new BloodEnergyConfig { FixedWaveBonus = 30f };
        var sut = new BloodEnergyEconomy(cfg);

        Assert.That(sut.CalculateWaveClearBonus(1), Is.EqualTo(30f).Within(0.0001f));
        Assert.That(sut.CalculateWaveClearBonus(2), Is.EqualTo(60f).Within(0.0001f));
        Assert.That(sut.CalculateWaveClearBonus(10), Is.EqualTo(60f).Within(0.0001f));
    }

    [Test]
    public void HurtGain_ShouldClampDamageRatioToOne()
    {
        var sut = new BloodEnergyEconomy(new BloodEnergyConfig { BaseHurtGain = 12f });

        var gain = sut.CalculateHurtGain(damageTaken: 200f, maxHealth: 100f);

        Assert.That(gain, Is.EqualTo(12f).Within(0.0001f));
    }

    [Test]
    public void Add_NonPositiveAmount_ShouldNotChangeEnergyOrFireEvent()
    {
        var sut = new BloodEnergyEconomy();
        var changedCount = 0;
        sut.OnEnergyChanged += (_, _) => changedCount++;

        sut.Add(0f);
        sut.Add(-5f);

        Assert.That(sut.Current, Is.EqualTo(0f).Within(0.0001f));
        Assert.That(changedCount, Is.EqualTo(0));
    }

    [Test]
    public void Spend_NonPositiveAmount_ShouldFailAndNotChangeEnergy()
    {
        var sut = new BloodEnergyEconomy();
        sut.Add(10f);

        var zero = sut.Spend(0f);
        var negative = sut.Spend(-1f);

        Assert.That(zero, Is.False);
        Assert.That(negative, Is.False);
        Assert.That(sut.Current, Is.EqualTo(10f).Within(0.0001f));
    }
}