using NUnit.Framework;
using ProjectM.Server;
using ProjectM.Simulation;
using Unity.Core;
using Unity.Entities;
using Unity.Mathematics;
using Unity.Transforms;

namespace ProjectM.Tests
{
    /// <summary>
    /// Regression test for the <see cref="ExpeditionFieldSystem"/> teardown region-filter. When the last player
    /// leaves the expedition the field is cleared — but that teardown must destroy ONLY RegionTag{Expedition}
    /// nodes, never the permanent RegionTag{Base} home-base mining field. Before the fix the unfiltered teardown
    /// wiped every ResourceNode on the empty edge (a despawn storm beside base players that broke the core loop).
    /// </summary>
    public class ExpeditionFieldTeardownTests
    {
        [Test]
        public void Expedition_Empty_Edge_Destroys_Only_Expedition_Nodes_Base_Field_Survives()
        {
            var world = new World("ExpeditionTeardown");
            using (world)
            {
                var group = world.GetOrCreateSystemManaged<SimulationSystemGroup>();
                group.AddSystemToUpdateList(world.GetOrCreateSystem<ExpeditionFieldSystem>());
                group.SortSystems();
                world.SetTime(new TimeData(elapsedTime: 0f, deltaTime: 1f / 60f));
                var em = world.EntityManager;

                // Cycle director: was occupied last tick, nobody out there now => the occupied->empty edge fires.
                var cycle = em.CreateEntity(typeof(CycleState), typeof(CycleRuntime));
                em.SetComponentData(cycle, new CycleState { Phase = CyclePhase.Calm, CycleNumber = 1 });
                em.SetComponentData(cycle, new CycleRuntime { PrevExpeditionOccupied = 1 });

                // Spawner singleton (required); null prefab so the spawn branch is inert.
                var spawnerE = em.CreateEntity(typeof(ResourceFieldSpawner));
                em.SetComponentData(spawnerE, new ResourceFieldSpawner { Prefab = Entity.Null, Count = 5, Radius = 10f });

                var baseNode = em.CreateEntity(typeof(LocalTransform), typeof(ResourceNode), typeof(RegionTag));
                em.SetComponentData(baseNode, LocalTransform.FromPosition(new float3(20, 0, 0)));
                em.SetComponentData(baseNode, new ResourceNode { ResourceId = ResourceId.Ore, Remaining = 30, HarvestPerHit = 5f });
                em.SetComponentData(baseNode, new RegionTag { Region = RegionId.Base });

                var expNode = em.CreateEntity(typeof(LocalTransform), typeof(ResourceNode), typeof(RegionTag));
                em.SetComponentData(expNode, LocalTransform.FromPosition(new float3(1020, 0, 0)));
                em.SetComponentData(expNode, new ResourceNode { ResourceId = ResourceId.Aether, Remaining = 30, HarvestPerHit = 5f });
                em.SetComponentData(expNode, new RegionTag { Region = RegionId.Expedition });

                group.Update();

                Assert.IsTrue(em.Exists(baseNode), "The permanent base mining field survives the expedition teardown.");
                Assert.IsFalse(em.Exists(expNode), "Only the expedition node is cleared when the last player leaves.");
            }
        }
    }
}