using AcDream.Core.Player;

namespace AcDream.Core.Tests.Player;

/// <summary>
/// Tests for <see cref="LocalPlayerState"/> — the cache that retains
/// stamina / mana absolute + max values from <c>PlayerDescription
/// (0x0013)</c>'s embedded <c>CreatureProfile</c>. Health stays in
/// <see cref="AcDream.Core.Combat.CombatState"/>; this class only
/// covers the vitals that don't have a dedicated delta opcode in
/// our currently-wired event set.
/// </summary>
public sealed class LocalPlayerStateTests
{
    [Fact]
    public void Defaults_AllVitalsNull_PercentsNull()
    {
        var s = new LocalPlayerState();

        Assert.Null(s.CurrentStamina);
        Assert.Null(s.MaxStamina);
        Assert.Null(s.CurrentMana);
        Assert.Null(s.MaxMana);
        Assert.Null(s.StaminaPercent);
        Assert.Null(s.ManaPercent);
    }

    [Fact]
    public void OnPlayerDescription_PopulatesFields_FromValidValues()
    {
        var s = new LocalPlayerState();

        s.OnPlayerDescription(currentStamina: 50, maxStamina: 100,
                              currentMana: 150, maxMana: 200);

        Assert.Equal(50u, s.CurrentStamina);
        Assert.Equal(100u, s.MaxStamina);
        Assert.Equal(150u, s.CurrentMana);
        Assert.Equal(200u, s.MaxMana);
    }

    [Fact]
    public void StaminaPercent_IsCurrentOverMax_InZeroToOneRange()
    {
        var s = new LocalPlayerState();
        s.OnPlayerDescription(currentStamina: 50, maxStamina: 100,
                              currentMana: null, maxMana: null);

        Assert.Equal(0.5f, s.StaminaPercent!.Value, precision: 3);
    }

    [Fact]
    public void ManaPercent_IsCurrentOverMax_InZeroToOneRange()
    {
        var s = new LocalPlayerState();
        s.OnPlayerDescription(currentStamina: null, maxStamina: null,
                              currentMana: 75, maxMana: 100);

        Assert.Equal(0.75f, s.ManaPercent!.Value, precision: 3);
    }

    [Fact]
    public void StaminaPercent_NullWhenMaxIsZero_AvoidsDivByZero()
    {
        var s = new LocalPlayerState();
        s.OnPlayerDescription(currentStamina: 0, maxStamina: 0,
                              currentMana: null, maxMana: null);

        Assert.Null(s.StaminaPercent);
    }

    [Fact]
    public void ManaPercent_NullWhenMaxIsZero_AvoidsDivByZero()
    {
        var s = new LocalPlayerState();
        s.OnPlayerDescription(currentStamina: null, maxStamina: null,
                              currentMana: 0, maxMana: 0);

        Assert.Null(s.ManaPercent);
    }

    [Fact]
    public void StaminaPercent_Null_WhenOnlyCurrentKnown()
    {
        var s = new LocalPlayerState();
        s.OnPlayerDescription(currentStamina: 50, maxStamina: null,
                              currentMana: null, maxMana: null);
        // Max never received → percent indeterminate.
        Assert.Null(s.StaminaPercent);
    }

    [Fact]
    public void StaminaPercent_Null_WhenOnlyMaxKnown()
    {
        var s = new LocalPlayerState();
        s.OnPlayerDescription(currentStamina: null, maxStamina: 100,
                              currentMana: null, maxMana: null);
        // Current never received → percent indeterminate.
        Assert.Null(s.StaminaPercent);
    }

    [Fact]
    public void StaminaPercent_ClampsToOne_WhenCurrentExceedsMax()
    {
        var s = new LocalPlayerState();
        // Server can momentarily report current > max during buff transitions.
        s.OnPlayerDescription(currentStamina: 150, maxStamina: 100,
                              currentMana: null, maxMana: null);

        Assert.Equal(1f, s.StaminaPercent!.Value);
    }

    [Fact]
    public void Changed_EventFires_WhenAnyVitalUpdates()
    {
        var s = new LocalPlayerState();
        int fires = 0;
        s.Changed += _ => fires++;

        s.OnPlayerDescription(currentStamina: 50, maxStamina: 100,
                              currentMana: 75, maxMana: 200);

        Assert.Equal(1, fires);
    }

    [Fact]
    public void OnPlayerDescription_PreservesPreviousField_WhenIncomingValueIsNull()
    {
        // CreatureProfile occasionally has nullable fields if the server
        // sends a partial profile — the cache should preserve known-good
        // values rather than wipe them. Stamina set first, then a Mana-only
        // update should not clear Stamina.
        var s = new LocalPlayerState();
        s.OnPlayerDescription(currentStamina: 50, maxStamina: 100,
                              currentMana: null, maxMana: null);
        s.OnPlayerDescription(currentStamina: null, maxStamina: null,
                              currentMana: 75, maxMana: 200);

        Assert.Equal(50u, s.CurrentStamina);
        Assert.Equal(100u, s.MaxStamina);
        Assert.Equal(75u, s.CurrentMana);
        Assert.Equal(200u, s.MaxMana);
    }
}