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

namespace ProjectM.Tests
{
    /// <summary>
    /// Plain-Entities EditMode tests for <see cref="HazardExplosionSystem"/> (Exploding_Barrels_Build_Spec).
    /// Pins the review-hardened contract: an ELAPSED fuse radius-damages LIVING enemies AND players
    /// (friendly fire) with SourceNetworkId = -1 (the environment convention — a player id would score
    /// Charger whiff-punishes) and destroys the barrel exactly once; a dead player in radius gets NOTHING
    /// (the BossAISystem slam filter, copied verbatim); out-of-radius targets get nothing; an UN-ELAPSED
    /// fuse does nothing. Also pins the pop-site half via ResourceHarvestSystem: an explosive (Variant 3)
    /// clutter pop lights the fuse (Remaining -> 0, BarrelFuse added, entity ALIVE) instead of destroying,
    /// and a lit barrel is unhittable.
    /// </summary>
    public class HazardExplosionSystemTests
    {
        const uint T0 = 1000;

        static (World world, SimulationSystemGroup group) MakeWorld(string name)
        {
            var world = new World(name);
            var group = world.GetOrCreateSystemManaged<SimulationSystemGroup>();
            group.AddSystemToUpdateList(world.GetOrCreateSystem<HazardExplosionSystem>());
            group.SortSystems();
            world.SetTime(new TimeData(elapsedTime: 0f, deltaTime: 1f / 60f));
            var nt = world.EntityManager.CreateEntity(typeof(NetworkTime));
            world.EntityManager.SetComponentData(nt, new NetworkTime { ServerTick = new NetworkTick(T0) });
            return (world, group);
        }

        static Entity MakeBarrel(EntityManager em, float3 pos, uint explodeTick)
        {
            var e = em.CreateEntity();
            em.AddComponentData(e, LocalTransform.FromPosition(pos));
            em.AddComponentData(e, new BlightClutter { Remaining = 0, Variant = 3, ScrapResourceId = ResourceId.Biomass, ScrapPerHit = 2f });
            em.AddComponentData(e, new BarrelFuse { ExplodeTick = explodeTick });
            return e;
        }

        static Entity MakePlayer(EntityManager em, float3 pos, float health, byte region)
        {
            var e = em.CreateEntity();
            em.AddComponentData(e, LocalTransform.FromPosition(pos));
            em.AddComponentData(e, new PlayerTag());
            em.AddComponentData(e, new Health { Current = health, Max = 130f });
            em.AddComponentData(e, new RegionTag { Region = region });
            em.AddBuffer<DamageEvent>(e);
            return e;
        }

        static Entity MakeEnemy(EntityManager em, float3 pos, float health)
        {
            var e = em.CreateEntity();
            em.AddComponentData(e, LocalTransform.FromPosition(pos));
            em.AddComponentData(e, new EnemyTag());
            em.AddComponentData(e, new Health { Current = health, Max = 30f });
            em.AddBuffer<DamageEvent>(e);
            return e;
        }

        [Test]
        public void Elapsed_Fuse_Damages_Living_Player_And_Enemy_And_Destroys_Barrel()
        {
            var (world, group) = MakeWorld("BoomBoth");
            using (world)
            {
                var em = world.EntityManager;
                var barrel = MakeBarrel(em, new float3(10, 1, 10), explodeTick: T0); // due exactly now
                var player = MakePlayer(em, new float3(11, 1, 10), health: 100f, region: RegionId.Expedition);
                var enemy = MakeEnemy(em, new float3(10, 1, 12), health: 30f);

                group.Update();

                Assert.IsFalse(em.Exists(barrel), "An elapsed fuse destroys the barrel.");
                var pd = em.GetBuffer<DamageEvent>(player);
                Assert.AreEqual(1, pd.Length, "Friendly fire: the living expedition player in radius is hit.");
                Assert.AreEqual(Tuning.BarrelExplodeDamage, pd[0].Amount);
                Assert.AreEqual(-1, pd[0].SourceNetworkId, "Environment convention: never a player id (Charger punish scoring).");
                Assert.AreNotEqual(0u, pd[0].SourceTick, "SourceTick stamped at detonation (the authored-tick contract).");
                Assert.AreEqual(1, em.GetBuffer<DamageEvent>(enemy).Length, "The living enemy in radius is hit too (the bait mechanic).");
            }
        }

        [Test]
        public void Dead_Player_And_Out_Of_Radius_Targets_Get_Nothing()
        {
            var (world, group) = MakeWorld("BoomFilters");
            using (world)
            {
                var em = world.EntityManager;
                MakeBarrel(em, new float3(10, 1, 10), explodeTick: T0);
                var deadPlayer = MakePlayer(em, new float3(10.5f, 1, 10), health: 0f, region: RegionId.Expedition);
                var farEnemy = MakeEnemy(em, new float3(10 + Tuning.BarrelExplodeRadius + 1f, 1, 10), health: 30f);

                group.Update();

                Assert.AreEqual(0, em.GetBuffer<DamageEvent>(deadPlayer).Length, "A dead player in radius gets NOTHING (the boss-slam filter).");
                Assert.AreEqual(0, em.GetBuffer<DamageEvent>(farEnemy).Length, "Out of radius gets nothing.");
            }
        }

        [Test]
        public void Unelapsed_Fuse_Does_Nothing()
        {
            var (world, group) = MakeWorld("BoomWait");
            using (world)
            {
                var em = world.EntityManager;
                var barrel = MakeBarrel(em, new float3(10, 1, 10), explodeTick: T0 + 30); // still burning
                var player = MakePlayer(em, new float3(10.5f, 1, 10), health: 100f, region: RegionId.Expedition);

                group.Update();

                Assert.IsTrue(em.Exists(barrel), "A burning fuse leaves the barrel alive.");
                Assert.AreEqual(0, em.GetBuffer<DamageEvent>(player).Length, "No damage before detonation.");
            }
        }

        // ---- pop-site half (ResourceHarvestSystem drives the fuse, never a direct destroy) ----

        static (World world, SimulationSystemGroup group) MakeHarvestWorld(string name)
        {
            var world = new World(name);
            var group = world.GetOrCreateSystemManaged<SimulationSystemGroup>();
            group.AddSystemToUpdateList(world.GetOrCreateSystem<ResourceHarvestSystem>());
            group.SortSystems();
            world.SetTime(new TimeData(elapsedTime: 0f, deltaTime: 1f / 60f));
            var em = world.EntityManager;
            var ledger = em.CreateEntity(typeof(ResourceLedger));
            em.AddBuffer<StorageEntry>(ledger);
            var nt = em.CreateEntity(typeof(NetworkTime));
            em.SetComponentData(nt, new NetworkTime { ServerTick = new NetworkTick(T0) });
            return (world, group);
        }

        [Test]
        public void Explosive_Pop_Lights_The_Fuse_Instead_Of_Destroying_And_Is_Unhittable()
        {
            var (world, group) = MakeHarvestWorld("PopFuse");
            using (world)
            {
                var em = world.EntityManager;
                var barrel = em.CreateEntity();
                em.AddComponentData(barrel, LocalTransform.FromPosition(new float3(10, 1, 10)));
                em.AddComponentData(barrel, new HitRadius { Value = 1f });
                em.AddComponentData(barrel, new BlightClutter { Remaining = 2, Variant = 3, ScrapResourceId = ResourceId.Biomass, ScrapPerHit = 2f });
                var proj = em.CreateEntity();
                em.AddComponentData(proj, LocalTransform.FromPosition(new float3(10, 1, 10)));
                em.AddComponentData(proj, new Projectile { Direction = new float2(1, 0), LastStep = 5f });

                group.Update();

                Assert.IsTrue(em.Exists(barrel), "An explosive pop LIGHTS THE FUSE — the barrel survives the hit.");
                Assert.AreEqual(0, em.GetComponentData<BlightClutter>(barrel).Remaining, "Remaining=0 is the replicated fuse cue.");
                Assert.IsTrue(em.HasComponent<BarrelFuse>(barrel), "The fuse component schedules detonation.");
                Assert.AreEqual(TickUtil.NonZero(T0 + Tuning.BarrelFuseTicks), em.GetComponentData<BarrelFuse>(barrel).ExplodeTick);
                Assert.IsFalse(em.Exists(proj), "The popping projectile is consumed.");

                // A lit barrel is unhittable: a second projectile flies through (no target on the segment).
                var proj2 = em.CreateEntity();
                em.AddComponentData(proj2, LocalTransform.FromPosition(new float3(10, 1, 10)));
                em.AddComponentData(proj2, new Projectile { Direction = new float2(0, 1), LastStep = 5f });
                group.Update();
                Assert.IsTrue(em.Exists(proj2), "A lit-fuse barrel is not a harvest target — the shot passes through.");
                Assert.IsTrue(em.Exists(barrel), "Still alive until detonation.");
            }
        }
    }
}