using AcDream.Plugin.Abstractions;

namespace AcDream.Plugins.MossTank.Tests;

public sealed class MossTankPanelTests
{
    [Fact]
    public void RetainedLabelReads_UseUpdateSideSnapshotsWithoutAllocating()
    {
        var automation = new FakeAutomation
        {
            CurrentHealth = 90,
            MaxHealth = 100,
            CurrentStamina = 80,
            MaxStamina = 110,
            CurrentMana = 70,
            MaxMana = 120,
            Skills =
            [
                new PluginSkillInfo(1, "Life Magic", PluginSkillTraining.Trained, 300),
                new PluginSkillInfo(2, "War Magic", PluginSkillTraining.Specialized, 350),
                new PluginSkillInfo(3, "Run", PluginSkillTraining.Untrained, 100),
            ],
            Attributes =
            [
                new PluginAttributeInfo(0, "Strength", 100),
                new PluginAttributeInfo(1, "Endurance", 100),
            ],
            KnownSelfBuffs =
            [
                Spell(1, 10, "Increases the caster's Life Magic skill by 10 points."),
            ],
        };
        var panel = new MossTankPanel(new FakeHost(automation));

        panel.OnTick(0.0);

        Assert.Equal("Health 90/100   Stam 80/110   Mana 70/120", panel.Vitals);
        Assert.Equal("2 attributes, 2 trained skills, 1 buff lines", panel.Coverage);
        string expectedVitals = panel.Vitals;
        string expectedCoverage = panel.Coverage;

        _ = panel.Vitals;
        _ = panel.Coverage;
        long before = GC.GetAllocatedBytesForCurrentThread();
        bool sameReferences = true;
        for (int i = 0; i < 10_000; i++)
        {
            sameReferences &= ReferenceEquals(expectedVitals, panel.Vitals);
            sameReferences &= ReferenceEquals(expectedCoverage, panel.Coverage);
        }
        long allocated = GC.GetAllocatedBytesForCurrentThread() - before;

        Assert.True(sameReferences);
        Assert.Equal(0, allocated);
        Assert.Equal(1, automation.KnownSelfBuffReads);
    }

    [Fact]
    public void UpdateTick_RefreshesRareCoverageAndChangedVitals()
    {
        var automation = new FakeAutomation
        {
            CurrentHealth = 90,
            MaxHealth = 100,
            CurrentStamina = 80,
            MaxStamina = 110,
            CurrentMana = 70,
            MaxMana = 120,
            Skills =
            [
                new PluginSkillInfo(1, "Life Magic", PluginSkillTraining.Trained, 300),
            ],
            Attributes = [new PluginAttributeInfo(0, "Strength", 100)],
            KnownSelfBuffs =
            [
                Spell(1, 10, "Increases the caster's Life Magic skill by 10 points."),
            ],
        };
        var panel = new MossTankPanel(new FakeHost(automation));
        panel.OnTick(0.0);

        automation.CurrentHealth = 75;
        automation.Skills =
        [
            new PluginSkillInfo(1, "Life Magic", PluginSkillTraining.Trained, 300),
            new PluginSkillInfo(2, "War Magic", PluginSkillTraining.Specialized, 350),
        ];
        panel.OnTick(0.5);

        Assert.StartsWith("Health 75/100", panel.Vitals, StringComparison.Ordinal);
        Assert.Equal("1 attributes, 1 trained skills, 1 buff lines", panel.Coverage);

        panel.OnTick(0.5);
        Assert.Equal("1 attributes, 2 trained skills, 1 buff lines", panel.Coverage);

        automation.KnownSelfBuffs =
        [
            Spell(1, 10, "Increases the caster's Life Magic skill by 10 points."),
            Spell(2, 11, "Increases the caster's War Magic skill by 10 points."),
        ];
        panel.OnTick(0.0);

        Assert.Equal("1 attributes, 2 trained skills, 2 buff lines", panel.Coverage);
    }

    private static PluginSpellInfo Spell(uint id, uint family, string description) => new(
        id,
        $"Spell {id}",
        family,
        Tier: 1,
        Difficulty: 10,
        ManaCost: 5,
        DurationSeconds: 60f,
        School: 1,
        description,
        IsSelfTargeted: true,
        IsBeneficial: true);

    private sealed class FakeHost(IAutomationSurface automation) : IPluginHost
    {
        public bool HasUi => false;
        public IPluginLogger Log { get; } = new FakeLogger();
        public IGameState State { get; } = new FakeState();
        public IEvents Events { get; } = new FakeEvents();
        public ISelectionService Selection { get; } = new FakeSelection();
        public IUiRegistry Ui => NoOpUiRegistry.Instance;
        public IAutomationSurface Automation { get; } = automation;
    }

    private sealed class FakeAutomation
        : IAutomationSurface, ICharacterInfo, ISpellCatalog, IMagicCommands, IPluginChat
    {
        private IReadOnlyList<PluginSpellInfo> _knownSelfBuffs = [];

        public bool IsAvailable { get; set; } = true;
        public ICharacterInfo Character => this;
        public ISpellCatalog Spells => this;
        public IMagicCommands Magic => this;
        public IPluginChat Chat => this;
        public bool IsInWorld => IsAvailable;
        public uint ObjectId { get; set; } = 1;
        public uint CurrentHealth { get; set; }
        public uint MaxHealth { get; set; }
        public uint CurrentStamina { get; set; }
        public uint MaxStamina { get; set; }
        public uint CurrentMana { get; set; }
        public uint MaxMana { get; set; }
        public IReadOnlyList<PluginSkillInfo> Skills { get; set; } = [];
        public IReadOnlyList<PluginAttributeInfo> Attributes { get; set; } = [];
        public IReadOnlyList<PluginActiveEnchantment> ActiveEnchantments { get; set; } = [];

        public int KnownSelfBuffReads { get; private set; }

        public IReadOnlyList<PluginSpellInfo> KnownSelfBuffs
        {
            get
            {
                KnownSelfBuffReads++;
                return _knownSelfBuffs;
            }
            set => _knownSelfBuffs = value;
        }

        public bool TryGetSkill(uint skillId, out PluginSkillInfo skill)
        {
            foreach (PluginSkillInfo candidate in Skills)
            {
                if (candidate.SkillId == skillId)
                {
                    skill = candidate;
                    return true;
                }
            }
            skill = default;
            return false;
        }

        public bool TryGet(uint spellId, out PluginSpellInfo info)
        {
            foreach (PluginSpellInfo candidate in _knownSelfBuffs)
            {
                if (candidate.SpellId == spellId)
                {
                    info = candidate;
                    return true;
                }
            }
            info = default;
            return false;
        }

        public bool IsCasting => false;
        public PluginCastGate EvaluateGate(uint spellId) => PluginCastGate.Ready;
        public bool Cast(uint spellId) => true;
        public void PostSystemMessage(string text) { }
    }

    private sealed class FakeLogger : IPluginLogger
    {
        public void Info(string message) { }
        public void Warn(string message) { }
        public void Error(string message, Exception? exception = null) { }
    }

    private sealed class FakeState : IGameState
    {
        public IReadOnlyList<WorldEntitySnapshot> Entities => [];
    }

    private sealed class FakeEvents : IEvents
    {
        public event Action<WorldEntitySnapshot> EntitySpawned
        {
            add { }
            remove { }
        }

        public event Action<double> Tick
        {
            add { }
            remove { }
        }
    }

    private sealed class FakeSelection : ISelectionService
    {
        public uint? SelectedObjectId { get; private set; }
        public uint? PreviousObjectId { get; private set; }

        public event Action<SelectionChangedEvent> Changed
        {
            add { }
            remove { }
        }

        public bool Select(uint objectId)
        {
            PreviousObjectId = SelectedObjectId;
            SelectedObjectId = objectId;
            return true;
        }

        public bool Clear()
        {
            PreviousObjectId = SelectedObjectId;
            SelectedObjectId = null;
            return true;
        }
    }
}