using System.Collections;
using System.Collections.Generic;
using UnityEngine;

[ExecuteInEditMode]
public class Poly_Clouds : MonoBehaviour {

    public bool Generate;
    [Range(1,500)]
    public int CloudDensity;
    [Range(1,30)]
    public int CloudPartCount;
    [Range(1,10000)]
    public float CloudSize;
    [Range(0,1)]
    public float CloudSizeVariation;
    [Range(1,10000)]
    public float CloudHeight;


    // Here u must Set a PrefabModel ( i use a basic Icosphere out of Blender )

    public GameObject CloudPrefab;
    private MeshFilter MF;
    private MeshRenderer MR;

    void Start () {
        enabled = false;
    }

    void Update () {
        if(Generate ){
            Generate = false;
            CreatePlanetClouds();
        }
    }

    public void CreatePlanetClouds() {
        if( !MR ) {
            MR = GetComponent<MeshRenderer>();
            if( !MR ) {
                MR = gameObject.AddComponent<MeshRenderer>();
            }
        }
        GameObject SenorCloud = CreateSingleCloud( transform.position, 1f );
        for( int i = 0; i < CloudDensity; i++ ) {
            SenorCloud.transform.rotation = Quaternion.Euler( Random.Range( 0, 360 ), Random.Range( 0, 360 ), Random.Range( 0, 360 ) );
            Vector3 Pos = transform.position + ( SenorCloud.transform.up * CloudHeight );
            GameObject Cloud = CreateCloud( Pos, CloudSize, CloudPartCount );
            Cloud.transform.rotation = SenorCloud.transform.rotation;
            Cloud.transform.parent = transform;
        }
        DestroyImmediate( SenorCloud );
        if( MF ) {
            if( MF.sharedMesh ) {
                MF.sharedMesh.Clear();
            }
            DestroyImmediate( MF );
        }
        MeshFilter[] Meshes = GetComponentsInChildren<MeshFilter>();
        CombineInstance[] combine = new CombineInstance[Meshes.Length];
        for( int i = 0; i < Meshes.Length; i++ ) {
            combine[i].mesh = Meshes[i].sharedMesh;
            combine[i].transform = Meshes[i].transform.localToWorldMatrix;
        }
        if( !MF ) {
            MF = GetComponent<MeshFilter>();
            if( !MF ) {
                MF = gameObject.AddComponent<MeshFilter>();
            }
        }

        MF.sharedMesh = new Mesh();
        MF.sharedMesh.name = "Poly_Cloud";
        MF.sharedMesh.CombineMeshes( combine );
        clean();
    }

    void clean() {
        foreach( MeshFilter MFilter in GetComponentsInChildren<MeshFilter>() ) {
            if( MFilter != GetComponent<MeshFilter>() && MFilter ) {
                DestroyImmediate( MFilter.gameObject );
            }
        }
    }

    GameObject CreateCloud( Vector3 Pos, float Size, int Count ) {
        float variSize = Size * Random.Range( 1f - CloudSizeVariation, 1f + CloudSizeVariation );
        GameObject Cloud = CreateSingleCloud( Pos, variSize );
        GameObject LastCloud = Cloud;
        for( int i = 0; i < Random.Range( 1, Count ); i++ ) {
            LastCloud.transform.localRotation = Quaternion.Euler( 0, Random.Range( 0, 360 ), 0 );

            float variSize2 = Size * Random.Range( 1f - CloudSizeVariation, 1f + CloudSizeVariation );
            GameObject SingleCloud = CreateSingleCloud( LastCloud.transform.position + ( LastCloud.transform.forward * ( variSize + 1f) / 7f ), variSize2 );
            SingleCloud.transform.parent = LastCloud.transform;
            LastCloud = SingleCloud;
        }
        return Cloud;
    }

    GameObject CreateSingleCloud( Vector3 Pos, float Size ) {
        GameObject SingleCloud = (GameObject)Instantiate( CloudPrefab , Pos, Quaternion.identity );
        SingleCloud.transform.localScale = Vector3.one * (Size) ;
        return SingleCloud;
    }
}