using Unity.Collections;
using Unity.Entities;
using Unity.Mathematics;
using Unity.Rendering;
using Unity.Transforms;
using UnityEngine;
using UnityEngine.Rendering;

namespace HappyForest.Prototypen
{
    // Einziges MonoBehaviour im DOTS-Setup. Aufgabe: Input lesen (Space/M/C/K),
    // die Entity-World initialisieren und Pillen-Entities spawnen/löschen.
    // Bewegung + Kollision laufen komplett in ISystem/Burst (siehe PilleMovementSystem
    // und PilleCollisionSystem) - hier passiert keine Simulationslogik mehr.
    public class PilleDotsBootstrap : MonoBehaviour
    {
        [Header("Rendering (Pflichtfelder)")]
        [SerializeField] private Mesh pilleMesh;
        [SerializeField] private Material pilleMaterial;

        [Header("Einstellungen")]
        [SerializeField] private float speed = 5f;
        [SerializeField] private float pilleRadius = 0.5f;
        [SerializeField] private float spawnHeight = 1f;
        [SerializeField] private string wallTag = "Wall";
        [SerializeField] private float actionDelay = 0.05f;

        private EntityManager entityManager;
        private Entity pilleTemplateEntity;
        private EntityQuery pilleQuery;
        private EntityQuery configQuery;

        private int pilleCount = 0;
        private float lastActionTime = 0f;
        private bool collisionEnabledCache = false;

        private Texture2D backgroundTexture;

        void Start()
        {
            if (pilleMesh == null || pilleMaterial == null)
            {
                Debug.LogError("❌ PilleDotsBootstrap: Mesh oder Material im Inspector zuweisen!");
                enabled = false;
                return;
            }

            entityManager = World.DefaultGameObjectInjectionWorld.EntityManager;

            SetupSimulationConfig();
            SetupPilleTemplate();

            pilleQuery = entityManager.CreateEntityQuery(typeof(PilleComponent), typeof(LocalTransform));
            configQuery = entityManager.CreateEntityQuery(typeof(PilleSimulationConfig));

            backgroundTexture = MakeTex(new Color(0f, 0f, 0f, 0.65f));

            Debug.Log("✅ PilleDotsBootstrap bereit! Space=Spawn M=Delete C=Spawn100 K=Kollision Toggle");
        }

        void SetupSimulationConfig()
        {
            var wallBounds = ComputeWallBounds();
            float margin = pilleRadius + 0.1f;

            var configEntity = entityManager.CreateEntity(typeof(PilleSimulationConfig));
            entityManager.SetComponentData(configEntity, new PilleSimulationConfig
            {
                BoundsMin = new float3(wallBounds.min.x + margin, spawnHeight, wallBounds.min.z + margin),
                BoundsMax = new float3(wallBounds.max.x - margin, spawnHeight, wallBounds.max.z - margin),
                PlayHeight = spawnHeight,
                PilleRadius = pilleRadius,
                PilleCollisionEnabled = false
            });
        }

        Bounds ComputeWallBounds()
        {
            var walls = GameObject.FindGameObjectsWithTag(wallTag);
            if (walls.Length == 0)
            {
                Debug.LogWarning($"⚠️ Keine GameObjects mit Tag '{wallTag}' gefunden. Nutze Standard-Grenzen (50x100).");
                return new Bounds(Vector3.zero, new Vector3(50, 10, 100));
            }

            Bounds combined = default;
            bool first = true;

            foreach (var wall in walls)
            {
                var rend = wall.GetComponent<Renderer>();
                if (rend == null) continue;

                if (first) { combined = rend.bounds; first = false; }
                else combined.Encapsulate(rend.bounds);
            }

            Debug.Log($"✅ Feld-Grenzen aus '{wallTag}'-Objekten berechnet: Min={combined.min} Max={combined.max}");
            return combined;
        }

        void SetupPilleTemplate()
        {
            pilleTemplateEntity = entityManager.CreateEntity(
                typeof(PilleComponent),
                typeof(LocalTransform),
                typeof(LocalToWorld));

            var desc = new RenderMeshDescription(ShadowCastingMode.On, receiveShadows: true);
            var renderMeshArray = new RenderMeshArray(new[] { pilleMaterial }, new[] { pilleMesh });

            RenderMeshUtility.AddComponents(
                pilleTemplateEntity,
                entityManager,
                desc,
                renderMeshArray,
                MaterialMeshInfo.FromRenderMeshArrayIndices(0, 0));

            entityManager.SetComponentData(pilleTemplateEntity,
                LocalTransform.FromPosition(new float3(0, spawnHeight, 0)));

            entityManager.SetComponentData(pilleTemplateEntity, new PilleComponent
            {
                Velocity = new float3(1, 0, 0),
                Speed = speed
            });

            // WICHTIG: Prefab-Tag, damit dieses Template NICHT von den Queries/Systemen
            // (Bewegung, Kollision, Zählung) erfasst wird. Instantiate() entfernt den Tag
            // automatisch bei jeder Kopie.
            entityManager.AddComponent<Prefab>(pilleTemplateEntity);
        }

        void Update()
        {
            if (Input.GetKeyDown(KeyCode.K))
            {
                ToggleCollision();
            }

            if (Time.time - lastActionTime < actionDelay)
                return;

            if (Input.GetKey(KeyCode.Space))
            {
                SpawnPille();
                lastActionTime = Time.time;
            }
            else if (Input.GetKey(KeyCode.M))
            {
                DeletePille();
                lastActionTime = Time.time;
            }
            else if (Input.GetKey(KeyCode.C))
            {
                for (int i = 0; i < 100; i++)
                    SpawnPille();
                lastActionTime = Time.time;
            }
        }

        void SpawnPille()
        {
            float3 spawnPos = new float3(0, spawnHeight, 0);

            int existing = pilleQuery.CalculateEntityCount();
            if (existing > 0)
            {
                var transforms = pilleQuery.ToComponentDataArray<LocalTransform>(Allocator.Temp);
                int idx = UnityEngine.Random.Range(0, transforms.Length);
                spawnPos = transforms[idx].Position;
                transforms.Dispose();
            }

            Entity newPille = entityManager.Instantiate(pilleTemplateEntity);

            float angle = UnityEngine.Random.Range(0f, math.PI * 2f);
            var velocity = new float3(math.cos(angle), 0, math.sin(angle));

            entityManager.SetComponentData(newPille, LocalTransform.FromPosition(spawnPos));
            entityManager.SetComponentData(newPille, new PilleComponent
            {
                Velocity = velocity,
                Speed = speed
            });

            pilleCount++;
        }

        void DeletePille()
        {
            if (pilleQuery.CalculateEntityCount() == 0)
                return;

            var entities = pilleQuery.ToEntityArray(Allocator.Temp);
            entityManager.DestroyEntity(entities[0]);
            entities.Dispose();
            pilleCount--;
        }

        void ToggleCollision()
        {
            if (configQuery.CalculateEntityCount() == 0)
                return;

            var configEntity = configQuery.GetSingletonEntity();
            var cfg = entityManager.GetComponentData<PilleSimulationConfig>(configEntity);
            cfg.PilleCollisionEnabled = !cfg.PilleCollisionEnabled;
            entityManager.SetComponentData(configEntity, cfg);
            collisionEnabledCache = cfg.PilleCollisionEnabled;
        }

        Texture2D MakeTex(Color color)
        {
            var tex = new Texture2D(1, 1);
            tex.SetPixel(0, 0, color);
            tex.Apply();
            return tex;
        }

        void OnGUI()
        {
            GUI.DrawTexture(new Rect(5, 5, 430, 90), backgroundTexture);

            GUI.color = Color.white;
            GUI.skin.label.fontSize = 18;
            GUI.Label(new Rect(15, 10, 410, 25), $"Pillen: {pilleCount} | FPS: {(int)(1f / Time.deltaTime)}");
            GUI.Label(new Rect(15, 35, 410, 25), $"Pille-Kollision (K): {(collisionEnabledCache ? "AN" : "AUS")}");
            GUI.Label(new Rect(15, 60, 410, 25), "Space=Spawn  M=Delete  C=Spawn100  K=Kollision Toggle");
        }

        void OnDestroy()
        {
            if (backgroundTexture != null)
                Destroy(backgroundTexture);
        }
    }
}