#nullable enable

using System.Diagnostics;
using Demo2.Domain;
using Demo2.ECS;
using Demo2.Runtime;
using NUnit.Framework;
using Unity.Collections;
using Unity.Entities;
using UnityEngine;

namespace Demo2.Tests
{
    public sealed class Demo2EcsTests
    {
        [Test]
        public void SameSeedAndCommands_RemainIdenticalForTenThousandTicks()
        {
            using var left = new Demo2EcsWorld(20260817, Demo2BuiltInContent.BuildRules());
            using var right = new Demo2EcsWorld(20260817, Demo2BuiltInContent.BuildRules());
            left.SetPhase(Demo2Phase.Production);
            right.SetPhase(Demo2Phase.Production);

            for (var tick = 0; tick < 10_000; tick++)
            {
                left.Tick();
                right.Tick();
            }

            var leftState = left.EntityManager.GetComponentData<Demo2SimulationState>(left.Singleton);
            var rightState = right.EntityManager.GetComponentData<Demo2SimulationState>(right.Singleton);
            Assert.That(leftState.Tick, Is.EqualTo(10_000));
            Assert.That(leftState.StateHash, Is.EqualTo(rightState.StateHash));
        }

        [Test]
        public void SnapshotRestore_ContinuesWithTheSameHash()
        {
            using var source = new Demo2EcsWorld(42, Demo2BuiltInContent.BuildRules());
            source.SetPhase(Demo2Phase.Production);
            for (var tick = 0; tick < 500; tick++) source.Tick();
            var snapshot = source.CaptureSnapshot(new[] { "production.dense-ammo" });

            using var restored = new Demo2EcsWorld(999, Demo2BuiltInContent.BuildRules());
            restored.RestoreSnapshot(snapshot);
            for (var tick = 0; tick < 200; tick++)
            {
                source.Tick();
                restored.Tick();
            }

            var sourceState = source.EntityManager.GetComponentData<Demo2SimulationState>(source.Singleton);
            var restoredState = restored.EntityManager.GetComponentData<Demo2SimulationState>(restored.Singleton);
            Assert.That(restoredState.StateHash, Is.EqualTo(sourceState.StateHash));
        }

        [Test]
        public void BuildCommands_AreIdempotentAndRemovalRefundsBeforeEntityDestruction()
        {
            using var service = new Demo2GameService();
            service.StartNewGame(17);
            var command = new Demo2BuildCommand
            {
                Sequence = 1,
                IdempotencyToken = "test-place",
                PlayerId = "test",
                Kind = Demo2MachineKind.Conveyor,
                X = 1,
                Y = 1
            };

            var accepted = service.SubmitBuild(command);
            var duplicate = service.SubmitBuild(command);
            var removed = service.BuildLocal(Demo2MachineKind.Conveyor, 1, 1, remove: true);

            Assert.That(accepted.Accepted, Is.True);
            Assert.That(duplicate.Accepted && duplicate.Duplicate, Is.True);
            Assert.That(removed.Accepted, Is.True);
            Assert.That(removed.Refund, Is.EqualTo(5));
        }

        [Test]
        public void MultipleTurrets_LoadWithoutSingletonExceptions()
        {
            using var world = new Demo2EcsWorld(31);
            var manager = world.EntityManager;
            var state = manager.GetComponentData<Demo2SimulationState>(world.Singleton);
            var turret = Demo2EcsFactory.CreateMachine(manager, ++state.NextStableId, Demo2MachineKind.Turret, 22, 10, 0, 0);
            manager.AddComponentData(turret, new Demo2TurretAmmo());
            Demo2EcsFactory.CreateMaterial(manager, ++state.NextStableId, Demo2MaterialKind.Ammo, 0, 19, 0, 9);
            manager.SetComponentData(world.Singleton, state);
            world.SetPhase(Demo2Phase.Production);

            world.Tick();

            var query = manager.CreateEntityQuery(typeof(Demo2TurretAmmo));
            using var ammo = query.ToComponentDataArray<Demo2TurretAmmo>(Allocator.Temp);
            long total = 0;
            for (var i = 0; i < ammo.Length; i++) total += ammo[i].Value;
            Assert.That(total, Is.EqualTo(9));
        }

        [Test]
        [Category("Demo2Performance")]
        public void StressTick_HandlesTenThousandItemsAndOneThousandMachines()
        {
            using var world = new Demo2EcsWorld(77);
            var manager = world.EntityManager;
            var state = manager.GetComponentData<Demo2SimulationState>(world.Singleton);
            for (var i = 0; i < 1_000; i++)
                Demo2EcsFactory.CreateMachine(manager, ++state.NextStableId, Demo2MachineKind.Conveyor, i % Demo2Protocol.GridWidth, (i / Demo2Protocol.GridWidth) % 10, 0, 0);
            for (var i = 0; i < 10_000; i++)
                Demo2EcsFactory.CreateMaterial(manager, ++state.NextStableId, Demo2MaterialKind.IronOre, i % Demo2Protocol.GridWidth, 19, 0, 1);
            manager.SetComponentData(world.Singleton, state);
            world.SetPhase(Demo2Phase.Production);
            var before = System.GC.GetAllocatedBytesForCurrentThread();
            var stopwatch = Stopwatch.StartNew();

            world.Tick();

            stopwatch.Stop();
            var allocated = System.GC.GetAllocatedBytesForCurrentThread() - before;
            using var entities = manager.GetAllEntities(Allocator.Temp);
            UnityEngine.Debug.Log($"[Demo2 Benchmark] entities={entities.Length} tickMs={stopwatch.Elapsed.TotalMilliseconds:0.00} managedBytes={allocated}");
            Assert.That(entities.Length, Is.GreaterThanOrEqualTo(11_000));
            Assert.That(stopwatch.ElapsedMilliseconds, Is.LessThan(10_000));
            Assert.That(allocated, Is.LessThanOrEqualTo(4096));
        }
    }
}