// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
// See the LICENCE file in the repository root for full licence text.

using System;
using System.Collections.Generic;
using System.Linq;
using Moq;
using NUnit.Framework;
using osu.Game.Rulesets.Mods;
using osu.Game.Rulesets.Osu.Mods;
using osu.Game.Utils;

namespace osu.Game.Tests.Mods
{
    [TestFixture]
    public class ModUtilsTest
    {
        [Test]
        public void TestModIsCompatibleByItself()
        {
            var mod = new Mock<Mod>();
            Assert.That(ModUtils.CheckCompatibleSet(new[] { mod.Object }));
        }

        [Test]
        public void TestIncompatibleThroughTopLevel()
        {
            var mod1 = new Mock<Mod>();
            var mod2 = new Mock<Mod>();

            mod1.Setup(m => m.IncompatibleMods).Returns(new[] { mod2.Object.GetType() });

            // Test both orderings.
            Assert.That(ModUtils.CheckCompatibleSet(new[] { mod1.Object, mod2.Object }), Is.False);
            Assert.That(ModUtils.CheckCompatibleSet(new[] { mod2.Object, mod1.Object }), Is.False);
        }

        [Test]
        public void TestIncompatibleThroughMultiMod()
        {
            var mod1 = new Mock<Mod>();

            // The nested mod.
            var mod2 = new Mock<Mod>();
            mod2.Setup(m => m.IncompatibleMods).Returns(new[] { mod1.Object.GetType() });

            var multiMod = new MultiMod(new MultiMod(mod2.Object));

            // Test both orderings.
            Assert.That(ModUtils.CheckCompatibleSet(new[] { multiMod, mod1.Object }), Is.False);
            Assert.That(ModUtils.CheckCompatibleSet(new[] { mod1.Object, multiMod }), Is.False);
        }

        [Test]
        public void TestAllowedThroughMostDerivedType()
        {
            var mod = new Mock<Mod>();
            Assert.That(ModUtils.CheckAllowed(new[] { mod.Object }, new[] { mod.Object.GetType() }));
        }

        [Test]
        public void TestNotAllowedThroughBaseType()
        {
            var mod = new Mock<Mod>();
            Assert.That(ModUtils.CheckAllowed(new[] { mod.Object }, new[] { typeof(Mod) }), Is.False);
        }

        // test incompatible pair.
        [TestCase(new[] { typeof(OsuModDoubleTime), typeof(OsuModHalfTime) }, new[] { typeof(OsuModDoubleTime), typeof(OsuModHalfTime) })]
        // test incompatible pair with derived class.
        [TestCase(new[] { typeof(OsuModNightcore), typeof(OsuModHalfTime) }, new[] { typeof(OsuModNightcore), typeof(OsuModHalfTime) })]
        // test system mod.
        [TestCase(new[] { typeof(OsuModDoubleTime), typeof(OsuModTouchDevice) }, new[] { typeof(OsuModTouchDevice) })]
        // test valid.
        [TestCase(new[] { typeof(OsuModDoubleTime), typeof(OsuModHardRock) }, null)]
        public void TestInvalidModScenarios(Type[] input, Type[] expectedInvalid)
        {
            List<Mod> inputMods = new List<Mod>();
            foreach (var t in input)
                inputMods.Add((Mod)Activator.CreateInstance(t));

            bool isValid = ModUtils.CheckValidForGameplay(inputMods, out var invalid);

            Assert.That(isValid, Is.EqualTo(expectedInvalid == null));

            if (isValid)
                Assert.IsNull(invalid);
            else
                Assert.That(invalid?.Select(t => t.GetType()), Is.EquivalentTo(expectedInvalid));
        }
    }
}