// 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 System.Threading;
using NUnit.Framework;
using osu.Framework.Allocation;
using osu.Framework.Bindables;
using osu.Framework.Graphics;
using osu.Framework.MathUtils;
using osu.Framework.Screens;
using osu.Game.Rulesets.Mods;
using osu.Game.Rulesets.Osu;
using osu.Game.Rulesets.Scoring;
using osu.Game.Scoring;
using osu.Game.Screens;
using osu.Game.Screens.Play;
using osu.Game.Screens.Play.PlayerSettings;

namespace osu.Game.Tests.Visual.Gameplay
{
    public class TestScenePlayerLoader : ManualInputManagerTestScene
    {
        private TestPlayerLoader loader;
        private OsuScreenStack stack;

        [SetUp]
        public void Setup() => Schedule(() =>
        {
            InputManager.Child = stack = new OsuScreenStack { RelativeSizeAxes = Axes.Both };
            Beatmap.Value = CreateWorkingBeatmap(new OsuRuleset().RulesetInfo);
        });

        [Test]
        public void TestBlockLoadViaMouseMovement()
        {
            AddStep("load dummy beatmap", () => stack.Push(loader = new TestPlayerLoader(() => new TestPlayer(false, false))));
            AddUntilStep("wait for current", () => loader.IsCurrentScreen());
            AddRepeatStep("move mouse", () => InputManager.MoveMouseTo(loader.VisualSettings.ScreenSpaceDrawQuad.TopLeft + (loader.VisualSettings.ScreenSpaceDrawQuad.BottomRight - loader.VisualSettings.ScreenSpaceDrawQuad.TopLeft) * RNG.NextSingle()), 20);
            AddAssert("loader still active", () => loader.IsCurrentScreen());
            AddUntilStep("loads after idle", () => !loader.IsCurrentScreen());
        }

        [Test]
        public void TestLoadContinuation()
        {
            Player player = null;
            SlowLoadPlayer slowPlayer = null;

            AddStep("load dummy beatmap", () => stack.Push(loader = new TestPlayerLoader(() => player = new TestPlayer(false, false))));
            AddUntilStep("wait for current", () => loader.IsCurrentScreen());
            AddStep("mouse in centre", () => InputManager.MoveMouseTo(loader.ScreenSpaceDrawQuad.Centre));
            AddUntilStep("wait for player to be current", () => player.IsCurrentScreen());
            AddStep("load slow dummy beatmap", () =>
            {
                stack.Push(loader = new TestPlayerLoader(() => slowPlayer = new SlowLoadPlayer(false, false)));
                Scheduler.AddDelayed(() => slowPlayer.AllowLoad.Set(), 5000);
            });

            AddUntilStep("wait for player to be current", () => slowPlayer.IsCurrentScreen());
        }

        [Test]
        public void TestModReinstantiation()
        {
            TestPlayer player = null;
            TestMod gameMod = null;
            TestMod playerMod1 = null;
            TestMod playerMod2 = null;

            AddStep("load player", () =>
            {
                Mods.Value = new[] { gameMod = new TestMod() };
                stack.Push(loader = new TestPlayerLoader(() => player = new TestPlayer()));
            });

            AddUntilStep("wait for loader to become current", () => loader.IsCurrentScreen());
            AddStep("mouse in centre", () => InputManager.MoveMouseTo(loader.ScreenSpaceDrawQuad.Centre));
            AddUntilStep("wait for player to be current", () => player.IsCurrentScreen());
            AddStep("retrieve mods", () => playerMod1 = (TestMod)player.Mods.Value.Single());
            AddAssert("game mods not applied", () => gameMod.Applied == false);
            AddAssert("player mods applied", () => playerMod1.Applied);

            AddStep("restart player", () =>
            {
                var lastPlayer = player;
                player = null;
                lastPlayer.Restart();
            });

            AddUntilStep("wait for player to be current", () => player.IsCurrentScreen());
            AddStep("retrieve mods", () => playerMod2 = (TestMod)player.Mods.Value.Single());
            AddAssert("game mods not applied", () => gameMod.Applied == false);
            AddAssert("player has different mods", () => playerMod1 != playerMod2);
            AddAssert("player mods applied", () => playerMod2.Applied);
        }

        private class TestPlayerLoader : PlayerLoader
        {
            public new VisualSettings VisualSettings => base.VisualSettings;

            public TestPlayerLoader(Func<Player> createPlayer)
                : base(createPlayer)
            {
            }
        }

        private class TestMod : Mod, IApplicableToScoreProcessor
        {
            public override string Name => string.Empty;
            public override string Acronym => string.Empty;
            public override double ScoreMultiplier => 1;

            public bool Applied { get; private set; }

            public void ApplyToScoreProcessor(ScoreProcessor scoreProcessor)
            {
                Applied = true;
            }

            public ScoreRank AdjustRank(ScoreRank rank, double accuracy) => rank;
        }

        private class TestPlayer : Visual.TestPlayer
        {
            public new Bindable<IReadOnlyList<Mod>> Mods => base.Mods;

            public TestPlayer(bool allowPause = true, bool showResults = true)
                : base(allowPause, showResults)
            {
            }
        }

        protected class SlowLoadPlayer : Visual.TestPlayer
        {
            public readonly ManualResetEventSlim AllowLoad = new ManualResetEventSlim(false);

            public SlowLoadPlayer(bool allowPause = true, bool showResults = true)
                : base(allowPause, showResults)
            {
            }

            [BackgroundDependencyLoader]
            private void load()
            {
                if (!AllowLoad.Wait(TimeSpan.FromSeconds(10)))
                    throw new TimeoutException();
            }
        }
    }
}