using PkmnLib.Dynamic.Models;
using PkmnLib.Plugin.Gen7.Scripts.Moves;
using PkmnLib.Static;

namespace PkmnLib.Plugin.Gen7.Tests.Scripts.Moves;

/// <summary>
/// Tests for the <see cref="Eruption"/> move script.
/// Gen VII Bulbapedia behavior: "Eruption deals damage. It has 150 base power at maximum HP, but its base
/// power decreases linearly with the user's remaining HP", following ⌊150 × HPcurrent / HPmax⌋ with a
/// minimum of 1.
/// </summary>
public class EruptionTests
{
    private static (Eruption script, IExecutingMove move, IPokemon target) CreateTestSetup(uint currentHealth,
        uint maxHealth)
    {
        var script = new Eruption();
        var move = Substitute.For<IExecutingMove>();
        var user = Substitute.For<IPokemon>();
        user.CurrentHealth.Returns(currentHealth);
        user.BoostedStats.Returns(new StatisticSet<uint>(maxHealth, 1, 1, 1, 1, 1));
        move.User.Returns(user);
        var target = Substitute.For<IPokemon>();
        return (script, move, target);
    }

    /// <summary>
    /// Bulbapedia: "It has 150 base power at maximum HP, but its base power decreases linearly with the
    /// user's remaining HP" — power = ⌊150 × HPcurrent / HPmax⌋, with integer truncation.
    /// </summary>
    [Test, Arguments(100u, 100u, (ushort)150), Arguments(300u, 300u, (ushort)150), Arguments(50u, 100u, (ushort)75),
     Arguments(75u, 100u, (ushort)112), Arguments(33u, 100u, (ushort)49), Arguments(150u, 300u, (ushort)75)]
    public async Task ChangeBasePower_ScalesWithUserCurrentHp(uint currentHealth, uint maxHealth, ushort expectedPower)
    {
        // Arrange
        var (script, move, target) = CreateTestSetup(currentHealth, maxHealth);
        ushort basePower = 150;

        // Act
        script.ChangeBasePower(move, target, 0, ref basePower);

        // Assert
        await Assert.That(basePower).IsEqualTo(expectedPower);
    }

    /// <summary>
    /// Bulbapedia: "if this calculation yields a value below 1, the move's power becomes 1 instead."
    /// </summary>
    [Test, Arguments(1u, 300u), Arguments(1u, 151u)]
    public async Task ChangeBasePower_UserAtVeryLowHp_PowerIsAtLeastOne(uint currentHealth, uint maxHealth)
    {
        // Arrange
        var (script, move, target) = CreateTestSetup(currentHealth, maxHealth);
        ushort basePower = 150;

        // Act
        script.ChangeBasePower(move, target, 0, ref basePower);

        // Assert
        await Assert.That(basePower).IsEqualTo((ushort)1);
    }
}