using System.Numerics;
using AcDream.Core.Combat;
using AcDream.UI.Abstractions.Panels.Debug;

namespace AcDream.UI.Abstractions.Tests.Panels.Debug;

/// <summary>
/// Tests for the Phase I.2 <see cref="DebugVM"/> — read-through ViewModel
/// for the migrated debug panel. Verifies the combat-event subscription
/// (replacing the old <c>DebugOverlay.BindCombat</c>), the toast ring
/// cap, and that the diagnostic-flag bools round-trip without affecting
/// the rest of the VM.
/// </summary>
public sealed class DebugVMTests
{
    /// <summary>
    /// Build a minimal <see cref="DebugVM"/> with safe defaults for every
    /// constructor source. Tests that don't care about a particular source
    /// just leave it stubbed out.
    /// </summary>
    private static DebugVM NewVm(CombatState? combat = null)
    {
        combat ??= new CombatState();
        return new DebugVM(
            getPlayerPosition: () => Vector3.Zero,
            getPlayerHeadingDeg: () => 0f,
            getPlayerCellId: () => 0u,
            getPlayerOnGround: () => true,
            getInPlayerMode: () => false,
            getInFlyMode: () => false,
            getVerticalVelocity: () => 0f,
            getEntityCount: () => 0,
            getAnimatedCount: () => 0,
            getLandblocksVisible: () => 0,
            getLandblocksTotal: () => 0,
            getShadowObjectCount: () => 0,
            getNearestObjDist: () => float.PositiveInfinity,
            getNearestObjLabel: () => "-",
            getColliding: () => false,
            getDebugWireframes: () => false,
            getStreamingRadius: () => 2,
            getMouseSensitivity: () => 1f,
            getChaseDistance: () => 0f,
            getRmbOrbit: () => false,
            getHourName: () => "Dawnsong",
            getDayFraction: () => 0.25f,
            getWeather: () => "Clear",
            getActiveLights: () => 0,
            getRegisteredLights: () => 0,
            getParticleCount: () => 0,
            getFps: () => 60f,
            getFrameMs: () => 16.7f,
            combat: combat);
    }

    [Fact]
    public void Constructor_ThrowsOnNullCombat()
    {
        Assert.Throws<ArgumentNullException>(() => new DebugVM(
            getPlayerPosition: () => Vector3.Zero,
            getPlayerHeadingDeg: () => 0f,
            getPlayerCellId: () => 0u,
            getPlayerOnGround: () => true,
            getInPlayerMode: () => false,
            getInFlyMode: () => false,
            getVerticalVelocity: () => 0f,
            getEntityCount: () => 0,
            getAnimatedCount: () => 0,
            getLandblocksVisible: () => 0,
            getLandblocksTotal: () => 0,
            getShadowObjectCount: () => 0,
            getNearestObjDist: () => 0f,
            getNearestObjLabel: () => "-",
            getColliding: () => false,
            getDebugWireframes: () => false,
            getStreamingRadius: () => 0,
            getMouseSensitivity: () => 1f,
            getChaseDistance: () => 0f,
            getRmbOrbit: () => false,
            getHourName: () => "",
            getDayFraction: () => 0f,
            getWeather: () => "",
            getActiveLights: () => 0,
            getRegisteredLights: () => 0,
            getParticleCount: () => 0,
            getFps: () => 0f,
            getFrameMs: () => 0f,
            combat: null!));
    }

    [Fact]
    public void ReadThrough_PullsLiveValuesPerAccess_NoCache()
    {
        // The VM does NOT cache; every property read goes through the
        // backing Func<T>. Mutating an external box between two reads
        // must surface immediately.
        int counter = 0;
        var vm = new DebugVM(
            getPlayerPosition: () => Vector3.Zero,
            getPlayerHeadingDeg: () => 0f,
            getPlayerCellId: () => 0u,
            getPlayerOnGround: () => true,
            getInPlayerMode: () => false,
            getInFlyMode: () => false,
            getVerticalVelocity: () => 0f,
            getEntityCount: () => ++counter,
            getAnimatedCount: () => 0,
            getLandblocksVisible: () => 0,
            getLandblocksTotal: () => 0,
            getShadowObjectCount: () => 0,
            getNearestObjDist: () => 0f,
            getNearestObjLabel: () => "-",
            getColliding: () => false,
            getDebugWireframes: () => false,
            getStreamingRadius: () => 0,
            getMouseSensitivity: () => 1f,
            getChaseDistance: () => 0f,
            getRmbOrbit: () => false,
            getHourName: () => "",
            getDayFraction: () => 0f,
            getWeather: () => "",
            getActiveLights: () => 0,
            getRegisteredLights: () => 0,
            getParticleCount: () => 0,
            getFps: () => 0f,
            getFrameMs: () => 0f,
            combat: new CombatState());

        Assert.Equal(1, vm.EntityCount);
        Assert.Equal(2, vm.EntityCount);
        Assert.Equal(3, vm.EntityCount);
    }

    [Fact]
    public void DamageTaken_AppendsErrorEvent()
    {
        var combat = new CombatState();
        var vm = NewVm(combat);

        combat.OnVictimNotification(
            attackerName: "Drudge", attackerGuid: 0x10u,
            damageType: 0u, damage: 12u, hitQuadrant: 0u,
            critical: 0u, attackType: 0u);

        var events = vm.CombatEvents.ToList();
        Assert.Single(events);
        Assert.Equal(CombatEventKind.Error, events[0].Kind);
        Assert.Contains("Drudge", events[0].Text);
        Assert.Contains("12", events[0].Text);
    }

    [Fact]
    public void DamageDealt_AppendsInfoEvent()
    {
        var combat = new CombatState();
        var vm = NewVm(combat);

        combat.OnAttackerNotification(
            defenderName: "Drudge", damageType: 0u,
            damage: 8u, damagePercent: 0.1f);

        var events = vm.CombatEvents.ToList();
        Assert.Single(events);
        Assert.Equal(CombatEventKind.Info, events[0].Kind);
        Assert.Contains("Drudge", events[0].Text);
    }

    [Fact]
    public void EvadedIncoming_AppendsWarnEvent()
    {
        var combat = new CombatState();
        var vm = NewVm(combat);

        combat.OnEvasionDefenderNotification("Mosswart");

        var events = vm.CombatEvents.ToList();
        Assert.Single(events);
        Assert.Equal(CombatEventKind.Warn, events[0].Kind);
        Assert.Contains("Mosswart", events[0].Text);
    }

    [Fact]
    public void CombatEventRing_CapsAtMax_DropsOldest()
    {
        var combat = new CombatState();
        var vm = NewVm(combat);

        // Pump well past the cap (25). The oldest entries must drop out.
        for (int i = 0; i < 40; i++)
        {
            combat.OnAttackerNotification(
                defenderName: $"Foe{i}", damageType: 0u,
                damage: (uint)i, damagePercent: 0.1f);
        }

        var events = vm.CombatEvents.ToList();
        Assert.Equal(DebugVM.MaxCombatEvents, events.Count);
        // The newest entry must still be present.
        Assert.Contains(events, e => e.Text.Contains("Foe39"));
        // The oldest must have dropped.
        Assert.DoesNotContain(events, e => e.Text.Contains("Foe0,") || e.Text == "Foe0");
        Assert.DoesNotContain(events, e => e.Text.Contains("Foe5"));
    }

    [Fact]
    public void Toast_RingCapsAtMaxRecent()
    {
        var vm = NewVm();

        for (int i = 0; i < 30; i++)
            vm.AddToast($"toast-{i}");

        var toasts = vm.RecentToasts.ToList();
        Assert.Equal(DebugVM.MaxRecentToasts, toasts.Count);
        Assert.Contains(toasts, t => t.Text == "toast-29");
        Assert.DoesNotContain(toasts, t => t.Text == "toast-0");
    }

    [Fact]
    public void Toast_PreservesKind()
    {
        var vm = NewVm();
        vm.AddToast("warning!", ToastKind.Warn);
        vm.AddToast("error!", ToastKind.Error);

        var toasts = vm.RecentToasts.ToList();
        Assert.Equal(2, toasts.Count);
        Assert.Contains(toasts, t => t.Text == "warning!" && t.Kind == ToastKind.Warn);
        Assert.Contains(toasts, t => t.Text == "error!" && t.Kind == ToastKind.Error);
    }

    [Fact]
    public void DiagnosticFlags_DefaultFalse_RoundTripIndependently()
    {
        var vm = NewVm();
        Assert.False(vm.DumpMotion);
        Assert.False(vm.DumpVitals);
        Assert.False(vm.DumpOpcodes);
        Assert.False(vm.DumpSky);

        vm.DumpMotion = true;
        Assert.True(vm.DumpMotion);
        Assert.False(vm.DumpVitals);
        Assert.False(vm.DumpOpcodes);
        Assert.False(vm.DumpSky);

        vm.DumpSky = true;
        vm.DumpMotion = false;
        Assert.False(vm.DumpMotion);
        Assert.True(vm.DumpSky);
    }

    [Fact]
    public void ToggleFlags_DoNotAffectCombatRing()
    {
        var combat = new CombatState();
        var vm = NewVm(combat);

        combat.OnAttackerNotification("X", 0u, 1u, 0.1f);
        Assert.Single(vm.CombatEvents);

        vm.DumpMotion = true;
        vm.DumpVitals = true;
        Assert.Single(vm.CombatEvents);
    }

    [Fact]
    public void ActionHooks_InvokeSuppliedDelegates()
    {
        // The panel needs to invoke "cycle time", "cycle weather", "toggle
        // collision wires" actions when the corresponding Button is
        // clicked. The VM exposes these as Action; the panel calls them.
        int timeHits = 0, weatherHits = 0, wireHits = 0;
        var vm = NewVm();
        vm.CycleTimeOfDay = () => timeHits++;
        vm.CycleWeather = () => weatherHits++;
        vm.ToggleCollisionWires = () => wireHits++;

        vm.CycleTimeOfDay?.Invoke();
        vm.CycleTimeOfDay?.Invoke();
        vm.CycleWeather?.Invoke();
        vm.ToggleCollisionWires?.Invoke();

        Assert.Equal(2, timeHits);
        Assert.Equal(1, weatherHits);
        Assert.Equal(1, wireHits);
    }
}