using System.Collections.Generic;
using Unity.Collections;
using Unity.Jobs;
using Unity.Mathematics;
using UnityEngine;

namespace DanieleMarotta.RiversongCodeShowcase
{
    public class TerrainChunkMeshGenerator : ChunkMeshGenerator
    {
        public TerrainChunkMeshGenerator(World world, GameConfig config) : base(world, config)
        {
        }

        protected override int GetLodCount()
        {
            return 1;
        }

        protected override string GetGameObjectName(string chunkName, int2 chunkCoords, int lod)
        {
            return $"{chunkName}_Terrain";
        }

        protected override void InitializeChunk(TerrainChunk chunk, int lod, GameObject gameObject, Mesh mesh, Renderer renderer)
        {
            gameObject.layer = GameObjectLayers.Terrain;

            chunk.Terrain = new TerrainChunk.RenderData(mesh, renderer);
        }

        protected override Mesh GetMesh(TerrainChunk chunk, int lod)
        {
            return chunk.Terrain.Mesh;
        }

        protected override JobHandle ScheduleJob(ChunkGenerationJobState jobState, NativeArray<int2> chunkCoords)
        {
            return new GenerateTerrainChunkJob
            {
                WorldSize = World.Size,
                ChunkCoordsArray = chunkCoords,
                ChunkSize = Config.WorldGen.ChunkSize,
                Heightmap = World.Heightmap.GetNativeArray(),
                MeshDataArray = jobState.MeshDataArray
            }.Schedule(chunkCoords.Length, Config.WorldGen.ChunksPerThread);
        }

        protected override void OnCompleted(int lod, List<TerrainChunk> chunks)
        {
            foreach (var chunk in chunks)
            {
                var mesh = chunk.Terrain.Mesh;
                var renderer = chunk.Terrain.Renderer;

                var subMeshCount = mesh.subMeshCount;

                var materials = new Material[subMeshCount];
                materials[0] = Config.Terrain.GroundMaterial;
                if (subMeshCount > 1) materials[1] = Config.Terrain.CliffMaterial;

                renderer.sharedMaterials = materials;

                renderer.gameObject.AddComponent<MeshCollider>();
            }
        }
    }
}