using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using NavMeshSurface = UnityEngine.AI.NavMeshSurface;
using KairoEngine.Core;
using KairoEngine.Chunks;
using KairoEngine.NoiseUtilities;
using Utilities = KairoEngine.Utility.Utilities;
using Sirenix.OdinInspector;
using UniRx;


namespace KairoEngine.TerrainEngine
{
    [HideMonoScript]
    public class ChunkTerrainGenerator : MonoBehaviour
    {
        [BoxGroup("Configurations")] public Vector3 voxelSize = new Vector3(1f, 1f, 1f);
        [BoxGroup("Configurations")] public Vector3Int chunkSize = new Vector3Int(16, 16, 16);
        [BoxGroup("Configurations")] public Vector3Int chunkLimit = new Vector3Int(2, 1, 2);
        [BoxGroup("Configurations")] public StartConfig startConfiguration = StartConfig.DoNothing;
        [BoxGroup("Configurations"), ShowIf("@startConfiguration == StartConfig.WaitForEvent")] public string generateWorldEvent = "GenerateWorld";
        [BoxGroup("Configurations")] public int dataProcessLimit = 4;
        [BoxGroup("Configurations")] public int parallelMeshJobs = 4;
        [HorizontalGroup("Configurations/NavMesh")] public bool processNavMesh = false;
        [HorizontalGroup("Configurations/NavMesh"), ShowIf("@processNavMesh"), HideLabel] public NavMeshSurface navMeshSurface;
        [HorizontalGroup("Configurations/OnChunkGeneratedEvent")] public bool triggerOnChunkGeneratedEvent = true;
        [HorizontalGroup("Configurations/OnChunkGeneratedEvent"), ShowIf("@triggerOnChunkGeneratedEvent"), HideLabel] public string onChunkGeneratedEvent;
        [HorizontalGroup("Configurations/OnTerrainGeneratedEvent")] public bool triggerOnTerrainGeneratedEvent = true;
        [HorizontalGroup("Configurations/OnTerrainGeneratedEvent"), ShowIf("@triggerOnTerrainGeneratedEvent"), HideLabel] public string onTerrainGeneratedEvent;
        [BoxGroup("Configurations")] public bool showChunkData = false;
        [BoxGroup("Configurations")] public bool showDebug = false;
        
        [InlineProperty, HideLabel, BoxGroup("Marching Cubes")] public MarchingCubes4 marchingCubes = new();
        [BoxGroup("Map Data Generator")] public bool useRandomSeed = false;
        [BoxGroup("Map Data Generator"), InlineProperty, HideLabel, SerializeReference] public IMapDataGenerator mapDataGenerator;
        
        [ShowIf("@showChunkData"), BoxGroup("Chunk System"), InlineProperty, HideLabel] public ChunkSystem<BlockBase> chunkSystem;
        
        public Dictionary<Vector3, GameObject> terrainMeshes = new Dictionary<Vector3, GameObject>();

        [ShowInInspector] private List<Vector3> chunkDataBuffer = new List<Vector3>(); // Store list of chunks for populating with data
        [ShowInInspector] private List<Vector3> chunkMeshBuffer = new List<Vector3>(); // Store list of chunks for generating the mesh
        [ShowInInspector] private List<Vector3> chunkMeshProcessBuffer = new List<Vector3>(); // Store list of chunks that are waiting for their meshes

        private bool initialized = false;
        private bool buildingNavmesh = false;

        public class VoxelUpdateData
        {
            public Vector3 position;
            public BlockBase block;

            public VoxelUpdateData(Vector3 position, BlockBase block)
            {
                this.position = position;
                this.block = block;
            }
        }
        private Dictionary<Vector3,List<VoxelUpdateData>> chunkUpdates = new Dictionary<Vector3, List<VoxelUpdateData>>();

        private void Start()
        {
            if(startConfiguration == StartConfig.GenerateOnStart) GenerateWorld();
            else if(startConfiguration == StartConfig.WaitForEvent) GenericEvents.StartListening(generateWorldEvent, GenerateWorld);
        }

        private void Update()
        {
            marchingCubes.UpdateFinishedJobs();
        }

        private void OnDisable()
        {
            if(startConfiguration == StartConfig.WaitForEvent) GenericEvents.StopListening(generateWorldEvent, GenerateWorld);
        }

        private void OnDestroy()
        {
            marchingCubes.OnDestroy();
        }

        public void Initialize ()
        {
            chunkSystem = new ChunkSystem<BlockBase>(chunkSize,voxelSize, true);
            initialized = true;
            if(useRandomSeed) mapDataGenerator.SetSeed(Random.Range(0, 100000));
        }

        public bool IsInitialized() => initialized;

        [Button("Generate World"), ButtonGroup("Buttons")]
        void GenerateWorld()
        {
            if(mapDataGenerator == null)
            {
                Debug.LogError("Missing planet template", this.gameObject);
                return;
            }
            DestroyTerrain();
            Debug.Log("Starting chunk generation");
            Initialize();
            for (int x = 0; x < chunkLimit.x; x++) {
                for (int z = 0; z < chunkLimit.z; z++) {
                    for (int y = 0; y < chunkLimit.y; y++) {
                        Vector3 chunkGlobalPos = new Vector3(x * chunkSize.x * voxelSize.x, y * chunkSize.y * voxelSize.y, z * chunkSize.z * voxelSize.z);
                        Vector3Int chunkPos = new Vector3Int(x * chunkSize.x, y * chunkSize.y, z * chunkSize.z);
                        chunkSystem.CreateChunk(chunkGlobalPos, chunkPos, (Chunk<BlockBase> c, Vector3Int pos) => new BlockBase(0, 0));
                        PopulateChunkData(chunkGlobalPos);
                    }
                }
            }
            for (int x = 0; x < chunkLimit.x; x++) {
                for (int z = 0; z < chunkLimit.z; z++) {
                    for (int y = 0; y < chunkLimit.y; y++) {
                        //Vector3Int chunkPos = new Vector3Int(x * chunkSize.x, y * chunkSize.y, z * chunkSize.z);
                        Vector3 chunkPos = new Vector3(x * chunkSize.x * voxelSize.x, y * chunkSize.y * voxelSize.y, z * chunkSize.z * voxelSize.z);
                        GenerateTerrainMesh(chunkPos);
                        //else if(marchingCubes2 != null) marchingCubes2.Generate(chunkSystem, chunkPos);
                    }
                }
            }
            #if UNITY_EDITOR
                UpdateEditor ();
            #endif
        }

        public void GenerateChunk(Vector3 position)
        {
            position = chunkSystem.GetChunkGlobalPositionFromGlobalPosition(position);
            bool buffered = false;
            for (int i = 0; i < chunkDataBuffer.Count; i++)
            {
                if(chunkDataBuffer[i] == position) buffered = true;
            }
            for (int i = 0; i < chunkMeshBuffer.Count; i++)
            {
                if(chunkMeshBuffer[i] == position) buffered = true;
            }
            //if(chunkSystem.ChunkExists(position)) buffered = true;
            //bool meshGenerated = terrainMeshes.TryGetValue(position, out GameObject obj);
            //if(meshGenerated) buffered = true;
            if(buffered) return;
            chunkDataBuffer.Add(position);
        }

        void PopulateChunkData(Vector3 initialPos)
        {
            float width = (float)(chunkLimit.x * chunkSize.x * voxelSize.x);
            float height = (float)(chunkLimit.y * chunkSize.y * voxelSize.y);
            float length = (float)(chunkLimit.z * chunkSize.z * voxelSize.z);
            for (int x = 0; x < chunkSize.x; x++) {
                for (int z = 0; z < chunkSize.z; z++) {
                    for (int y = 0; y < chunkSize.y; y++) {
                        // Get a terrain height using regular old Perlin noise.
                        Vector3 pos = initialPos + new Vector3(x * voxelSize.x, y * voxelSize.y, z * voxelSize.z);
                        // Old example noise:
                        //float thisHeight = height * Mathf.PerlinNoise((float)pos.x / width * noiseMultiplier + 0.001f, (float)pos.z / length * noiseMultiplier + 0.001f);
                        float elevation = mapDataGenerator.SamplePoint((float)pos.x / width, (float)pos.z / length);
                        float thisHeight = height * elevation;
                        uint code = mapDataGenerator.SamplePointColor((float)pos.x / width, (float)pos.z / length, elevation);
                        BlockBase block = new BlockBase(code, (uint)Mathf.FloorToInt(thisHeight * 1000));
                        chunkSystem.SetBlock(pos, block);
                    }
                }
            }
            chunkUpdates.TryGetValue(initialPos, out List<VoxelUpdateData> updates);
            if(updates == null) return;
            for (int i = 0; i < updates.Count; i++)
            {
                chunkSystem.SetBlock(updates[i].position, updates[i].block);
            }
        }

        public void GenerateChunkData(Vector3 position)
        {
            position = chunkSystem.GetChunkGlobalPositionFromGlobalPosition(position);
            Vector3Int chunkPos = chunkSystem.GetChunkPositionFromGlobalPosition(position);
            if(!chunkSystem.ChunkExists(position))
            {
                //Debug.Log($"Generating Terrain Data ({position} | {chunkPos})");
                chunkSystem.CreateChunk(position, chunkPos, (Chunk<BlockBase> c, Vector3Int pos) => new BlockBase(0, 0));
                PopulateChunkData(position);
            }
        }

        public void GenerateTerrainMesh(Vector3 position, bool overwrite = false)
        {
            bool meshExists = terrainMeshes.TryGetValue(position, out GameObject obj);
            if(meshExists && !overwrite && obj != null) return;
            if(!overwrite) terrainMeshes.Add(position, null);
            if(marchingCubes != null) 
            {
                chunkMeshProcessBuffer.Add(position);
                marchingCubes.Generate(chunkSystem, this, position);
            }
        }

        public void UpdateGenerator()
        {
            if(marchingCubes.GetJobCount() == 0) ProcessChunkDataBuffer();
            ProcessChunkMeshBuffer();
        }

        public void UpdateEditor ()
        {
            Timer.ExecuteRealTime(50, () => {
                if(marchingCubes != null)
                {
                    UpdateGenerator();
                    if(!marchingCubes.IsGeneratorDone()) UpdateEditor();
                }
            });
        }

        private void ProcessChunkDataBuffer()
        {
            int limit = chunkDataBuffer.Count < dataProcessLimit ? chunkDataBuffer.Count : dataProcessLimit;
            for (int i = 0; i < limit; i++)
            {
                Vector3 position = chunkDataBuffer[i];
                List<Vector3> positions = new List<Vector3>{
                    new Vector3( 0,  0,  0),
                    new Vector3( 1,  0,  0),
                    new Vector3( 1,  0, -1),
                    new Vector3( 0,  0, -1),
                    new Vector3(-1,  0, -1),
                    new Vector3(-1,  0,  0),
                    new Vector3(-1,  0,  1),
                    new Vector3( 0,  0,  1),
                    new Vector3( 1,  0,  1),
                    new Vector3( 0,  1,  0),
                    new Vector3( 1,  1,  0),
                    new Vector3( 1,  1, -1),
                    new Vector3( 0,  1, -1),
                    new Vector3(-1,  1, -1),
                    new Vector3(-1,  1,  0),
                    new Vector3(-1,  1,  1),
                    new Vector3( 0,  1,  1),
                    new Vector3( 1,  1,  1),
                    new Vector3( 0, -1,  0),
                    new Vector3( 1, -1,  0),
                    new Vector3( 1, -1, -1),
                    new Vector3( 0, -1, -1),
                    new Vector3(-1, -1, -1),
                    new Vector3(-1, -1,  0),
                    new Vector3(-1, -1,  1),
                    new Vector3( 0, -1,  1),
                    new Vector3( 1, -1,  1),
                };
                for (int a = 0; a < positions.Count; a++)
                {
                    //position = new Vector3(position.x + chunkSize.x * voxelSize.x, position.y, position.z);
                    Vector3 chunkPos = new Vector3(
                        position.x + (positions[a].x * chunkSize.x * voxelSize.x), 
                        position.y + (positions[a].y * chunkSize.y * voxelSize.y), 
                        position.z + (positions[a].z * chunkSize.z * voxelSize.z)
                    );
                    GenerateChunkData(chunkPos);
                }
                chunkMeshBuffer.Add(chunkDataBuffer[i]);
            }
            chunkDataBuffer.RemoveRange(0, limit);
        }

        private void ProcessChunkMeshBuffer()
        {
            marchingCubes.UpdateFinishedJobs();
            int limit = marchingCubes.GetJobCount() < parallelMeshJobs ? parallelMeshJobs - marchingCubes.GetJobCount() : 0;
            limit = limit < chunkMeshBuffer.Count ? limit : chunkMeshBuffer.Count;
            for (int i = 0; i < limit; i++)
            {
                GenerateTerrainMesh(chunkMeshBuffer[i]);
            }
            chunkMeshBuffer.RemoveRange(0, limit);
        }

        public void DestroyChunk(Vector3 position)
        {
            DestroyChunkData(position);
            DestroyChunkMesh(position);
        }

        public void DestroyChunkData(Vector3 position)
        {
            chunkSystem.DestroyChunk(position);
        }

        public void DestroyChunkMesh(Vector3 position)
        {
            terrainMeshes.TryGetValue(position, out GameObject obj);
            if(obj != null) 
            {
                Destroy(obj);
                #if UNITY_EDITOR
                DestroyImmediate(obj);
                #endif
            }
            terrainMeshes.Remove(position);
        }

        public void ClearChunkDataBuffer() => chunkDataBuffer.Clear();

        [Button("Destroy"), ButtonGroup("Buttons")]
        public void DestroyTerrain()
        {
            var childTransforms = this.gameObject.transform.GetComponentsInChildren<Transform>();
            if(childTransforms.Length > 0) Debug.Log($"Destroying {childTransforms.Length} terrain objects");
            for (int i = 0; i < childTransforms.Length; i++)
            {
                if(childTransforms[i] == this.transform) continue;
                #if UNITY_EDITOR
                DestroyImmediate(childTransforms[i].gameObject);
                #else
                Destroy(childTransforms[i].gameObject);
                #endif
            }
            terrainMeshes = new Dictionary<Vector3, GameObject>();
            chunkDataBuffer = new List<Vector3>();
            chunkMeshBuffer = new List<Vector3>();
            chunkSystem.chunks = new Dictionary<Vector3Int, Chunk<BlockBase>>();
            chunkSystem.chunkList = new List<Vector3>();
        }

        public enum VoxelOperation
        {
            Add,
            Remove,
            Level
        }
        public void ChangeVoxels(Vector3 pos, uint code, VoxelOperation operation, int radius = 3)
        {
            int startHeigth = 0, endHeigth = 0, targetHeigth = 0, updatedVoxels = 0;
            switch (operation)
            {
                case VoxelOperation.Add:
                    startHeigth = -1;
                    endHeigth = radius;
                    targetHeigth = (int)(((chunkSystem.GetBlock(pos).value/1000) + (radius * voxelSize.y)) * 1000);
                    break;
                case VoxelOperation.Remove:
                    startHeigth = -1 * (radius + 1);
                    endHeigth = radius + 1;
                    targetHeigth = (int)(Mathf.Clamp((chunkSystem.GetBlock(pos).value/1000) - (radius * voxelSize.y), 0, 10000) * 1000);
                    break;
                case VoxelOperation.Level:
                    startHeigth = -1 * radius;
                    endHeigth = radius;
                    targetHeigth = (int)chunkSystem.GetBlock(pos).value;
                    break;
                default:
                    return;
            }
            Vector3 chunkPosition = chunkSystem.GetChunkGlobalPositionFromGlobalPosition(pos);
            List<Vector2Int> points = Utilities.GetPointsInRadius(radius, true);
            List<Vector3> chunkPositions = new List<Vector3>();
            for (int j = 0; j < points.Count; j++)
            {
                for (int y = startHeigth; y < endHeigth + 1; y++)
                {
                    updatedVoxels += 1;
                    Vector3 voxelPos = new Vector3(pos.x + points[j].x * voxelSize.x, pos.y + y * voxelSize.y, pos.z + points[j].y * voxelSize.z);
                    BlockBase block = chunkSystem.GetBlock(voxelPos);
                    block.code = code;
                    block.value = (uint)targetHeigth;
                    chunkSystem.SetBlock(voxelPos, block);
                    // Get positions
                    Vector3Int localVoxelPos = chunkSystem.GetVoxelFromGlobalPosition(voxelPos);
                    Vector3 chunkPos = chunkSystem.GetChunkGlobalPositionFromGlobalPosition(voxelPos);
                    // Save data update
                    VoxelUpdateData updateData = new VoxelUpdateData(voxelPos, block);
                    chunkUpdates.TryGetValue(chunkPos, out List<VoxelUpdateData> chunkUpdate);
                    if(chunkUpdate != null) 
                    {
                        bool exists = false;
                        for (int h = 0; h < chunkUpdate.Count; h++)
                        {
                            if(chunkUpdate[h].position.Equals(updateData.position))
                            {
                                exists = true;
                                chunkUpdate[h].block = updateData.block;
                            }
                        }
                        if(!exists) chunkUpdate.Add(updateData);
                    }
                    else chunkUpdates.Add(chunkPos, new List<VoxelUpdateData>{updateData});
                    // Check if changed voxels are in the edge of the chunk and if true add the neightboring chunk to the update list
                    List<Vector3> chunks = new List<Vector3>();
                    chunks.Add(chunkPos);
                    if(localVoxelPos.x == 0) chunks.Add(new Vector3(chunkPos.x - chunkSize.x * voxelSize.x, chunkPos.y, chunkPos.z));
                    if(localVoxelPos.x == 16) chunks.Add(new Vector3(chunkPos.x + chunkSize.x * voxelSize.x, chunkPos.y, chunkPos.z));
                    if(localVoxelPos.y == 0) chunks.Add(new Vector3(chunkPos.x, chunkPos.y  - chunkSize.y * voxelSize.y, chunkPos.z));
                    if(localVoxelPos.y == 16) chunks.Add(new Vector3(chunkPos.x, chunkPos.y + chunkSize.y * voxelSize.y, chunkPos.z));
                    if(localVoxelPos.z == 0) chunks.Add(new Vector3(chunkPos.x, chunkPos.y, chunkPos.z - chunkSize.z * voxelSize.z));
                    if(localVoxelPos.z == 16) chunks.Add(new Vector3(chunkPos.x , chunkPos.y, chunkPos.z + chunkSize.z * voxelSize.z));
                    for (int i = 0; i < chunks.Count; i++)
                    {
                        bool duplicate = false;
                        for (int k = 0; k < chunkPositions.Count; k++)
                        {
                            if(chunkPositions[k].Equals(chunks[i]))
                            {
                                duplicate = true;
                                break;
                            }
                        }
                        if(!duplicate) chunkPositions.Add(chunks[i]);
                    }
                }
            }
            for (int c = 0; c < chunkPositions.Count; c++) GenerateTerrainMesh(chunkPositions[c], true);
            Debug.Log($"Changing voxel at {pos}, updated {updatedVoxels} voxels and {chunkPositions.Count} chunks");
        }

        public void AddGeneratedTerrainMesh(Vector3 chunkPosition, GameObject meshObj)
        {
            chunkMeshProcessBuffer.Remove(chunkPosition);
            bool meshExists = terrainMeshes.TryGetValue(chunkPosition, out GameObject currentMesh);
            if(currentMesh != null)
            {
                //Debug.Log($"Updating chunk mesh at {chunkPosition}");
                DestroyChunkMesh(chunkPosition);
                terrainMeshes[chunkPosition] = meshObj;
            }
            else 
            {
                //Debug.Log($"Adding chunk mesh at {chunkPosition}");
                //terrainMeshes.Add(chunkPosition, meshObj);
                terrainMeshes[chunkPosition] = meshObj;
            }
            if(triggerOnChunkGeneratedEvent) GenericEvents.Trigger(onChunkGeneratedEvent, chunkPosition);
            if(!buildingNavmesh && chunkMeshProcessBuffer.Count == 0 && chunkMeshBuffer.Count == 0 && chunkDataBuffer.Count == 0)
            {
                buildingNavmesh = true;
                Timer.ExecuteRealTime(50, () => {
                    if(processNavMesh && navMeshSurface != null) 
                    {
                        var cron = new Cronometer();
                        navMeshSurface.BuildNavMesh();
                        //navMeshSurface.UpdateNavMesh(navMeshSurface.navMeshData);
                        cron.Stop();
                        if(showDebug) Debug.Log($"Generated Navmesh in {cron.Print()}");
                        buildingNavmesh = false;
                    }
                    if(triggerOnTerrainGeneratedEvent) GenericEvents.Trigger(onTerrainGeneratedEvent);
                });
            }
        }

        [Button("Save"), ButtonGroup("Buttons")]
        public void SaveChunkUpdateData()
        {

        }

        public enum StartConfig
        {
            DoNothing,
            GenerateOnStart,
            WaitForEvent
        }
    }
}